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Aliphatic polyamides (nylons) show a remarkable variability in terms of crystallographic structures, polymorphic transitions and crystal morphology despite all polymers of this family have a simple constitution that is based on amide groups and polymethylene segments. Nylons derived from diamines and dicarboxylic acids having different parity (e.g., even or odd) have peculiar characteristics due to the difficulty of establishing an optimal hydrogen-bonding geometry when molecular chains adopt a typical all trans conformation. In this work, two isomeric odd-even (nylon 7,10) and even-odd (nylon 10,7) polyamides with the same methylene/amide ratio have been studied. Specifically, crystallization kinetics have been evaluated from calorimetric data, while thermal degradation mechanisms from thermogravimetric analysis. Classical methods (e.g., Avrami) together with isoconversional analyses have been considered for crystallization studies, being found significant differences between both nylons in terms of nucleation and activation energies. The isoconversional analyses of the non-isothermal crystallization allowed to determine the temperature dependence of both the crystal growth and the overall crystallization rate that points out the slower crystallization process of nylon 10,7. Isoconversional methods (integral and differential) were applied to evaluate thermal degradation. The mechanism was similar for both nylons (e.g., A3/2 and A1.8 for nylons 7,10 and 10,7, respectively), although a remarkable difference was determined for the corresponding activation energies (175 and 210 kJ/mol for nylons 7,10 and 10,7, respectively)., This research was funded by the Spanish Ministry of Science and Innovation through PID2022-140302OB-I00 and by the Generalitat de Catalunya under the project 2021-SGR-01042. Matteo Arioli is grateful for the support received from the Spanish Ministry of Science and Innovation, with the scholarship “Ayudas para contratos predoctorales para la formación de doctors/as 2019”., Peer Reviewed, Postprint (published version)

Linear polyamides, known as nylons, are a class of synthetic polymers with a wide range of applications due to their outstanding properties, such as chemical and thermal resistance or mechanical strength. These polymers have been used in various fields: from common and domestic applications, such as socks and fishing nets, to industrial gears or water purification membranes. By their durability, flexibility and wear resistance, nylons are now being used in addictive manufacturing technology as a good material choice to produce sophisticated devices with precise and complex geometric shapes. Furthermore, the emergence of triboelectric nanogenerators and the development of biomaterials have highlighted the versatility and utility of these materials. Due to their ability to enhance triboelectric performance and the range of applications, nylons show a potential use as tribo-positive materials. Because of the easy control of their shape, they can be subsequently integrated into nanogenerators. The use of nylons has also extended into the field of biomaterials, where their biocompatibility, mechanical strength and versatility have paved the way for groundbreaking advances in medical devices as dental implants, catheters and non-absorbable surgical sutures. By means of 3D bioprinting, nylons have been used to develop scaffolds, joint implants and drug carriers with tailored properties for various biomedical applications. The present paper aims to collect evidence of these recently specific applications of nylons by reviewing the literature produced in recent decades, with a special focus on the newer technologies in the field of energy harvesting and biomedicine., Peer Reviewed, Postprint (published version)

Bacterial contamination is a hazard in many industries, including food, pharmaceuticals, and healthcare. The availability of a rapid and simple method for detecting this type of contamination in sterile areas enables immediate intervention to avoid or reduce detrimental effects. Among these methods, colorimetric indicators are becoming increasingly popular due to their affordability, ease of use, and quick visual interpretation of the signal. In this article, a bacterial contamination indicator system was designed by incorporating MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) into an electrospun PADAS matrix, which is a biodegradable poly(ester amide) synthesized from L-alanine, 1,12-dodecanediol, and sebacic acid. Uniaxial stress testing, thermogravimetric analysis and scanning electron microscopy were used to examine the mechanical properties, thermal stability, and morphology of the mats, respectively. The capacity for bacterial detection was not only analyzed with agar and broth assays but also by replicating important environmental conditions. Among the MTT concentrations tested in this study (0.2%, 2%, and 5%), it was found that only with a 2% MTT content the designed system produced a color response visible to the naked eye with optimal intensity, a sensitivity limit of 104 CFU/mL, and 86% cell viability, which showed the great potential for its use to detect bacterial contamination. In summary, by means of the process described in this work, it was possible to obtain a simple, low-cost and fast-response bacterial contamination indicator that can be used in mask filters, air filters, or protective clothing., This research was funded by the Spanish Ministry of Science, Innovation and Universities through PID2022-140302OB-I00 and by the Generalitat de Catalunya under the project 2021-SGR-01042., Peer Reviewed, Postprint (published version)

Tesi amb menció de Doctorat Industrial (Generalitat de Catalunya), (English) Surfaces with special functionalities owed to their surface topographies or textures are present all around us in nature. Millions of living organisms around us profit from those special functionalities thanks to the features existing on the interfaces that separate them from the surrounding environment. These functionalities, such as special wettability or antibacterial properties, for example, arise from the micro- and nanometre periodically organized features present on those interfaces. These properties that arise from the specific interactions of the micro- and nanotextures present on the surfaces with the surrounding environment (light, liquids, infectious agents, etc.), constitute a powerful inspiration towards the functionalization of the surfaces of plastic parts. The possibility of functionalizing the surface of plastic parts using a replication based technique applied to a high-volume and low-cost-per-part well-known production technology such as injection moulding has acquired a lot of scientific interest during the last years. This technology allows for the production of such parts without the need of using special coatings or treatments. This in turn reduces their complexity and also the resources and times needed for the manufacturing, while also lowering their environmental footprint. The production of such surfaces through injection moulding requires the use of micro- and nanotextured mould inserts that serve as negative template tooling for the obtention of the textured features on the surface of the final plastic produced part. In this regard, the usage of two different types of tooling have been researched in this study: first, metallic micro- and nanotextured inserts and second, flexible polymeric inserts. In the first part of this research, the use of micro- and nanotextured metallic materials as injection mould inserts, a thoroughly studied technology for the production of micro- and nanotextured surfaces on polymeric parts, is studi, (Castellà) Las superficies con funcionalidades especiales debidas a sus topografías o texturas superficiales están muy presentes en la naturaleza que nos rodea. Millones de organismos vivos a nuestro alrededor se benefician de dichas funcionalidades especiales gracias a las características existentes en las interficies que los separan del entorno. Estas funcionalidades, tales como la humectabilidad especial o las propiedades antibacterianas, surgen de las características micro y nanométricas organizadas periódicamente presentes en esas interfaces. Estas propiedades que surgen de las interacciones de las micro y nanotexturas presentes en las superficies con el entorno circundante (luz, líquidos, agentes infecciosos, etc.), representan una poderosa fuente de inspiración hacia la funcionalización de las superficies de las piezas plásticas. La posibilidad de funcionalizar la superficie de piezas de plástico mediante una técnica basada en la replicación aplicada a una tecnología de producción de alto volumen y bajo coste por pieza tal como el moldeo por inyección ha adquirido un gran interés científico en los últimos años. Esta tecnología permite la producción de dichas piezas sin necesidad de utilizar recubrimientos o tratamientos especiales. Esto a su vez reduce la complejidad de dichas piezas y también los recursos y tiempos necesarios para la fabricación, al tiempo que reduce su huella ambiental. La producción de dichas superficies a través del moldeo por inyección requiere el uso de insertos de molde micro y nanotexturizados que sirven como herramientas de plantilla negativa para la obtención de las características texturizadas en la superficie de la pieza plástica final producida. En este sentido, en este estudio se ha investigado el uso de dos herramientas diferentes: insertos metálicos micro y nanotexturizados y en segundo lugar, insertos poliméricos flexibles. En la primera parte de esta investigación se estudia el uso de materiales metálicos micro y nanotexturi, Postprint (published version)

Lately, there has been an increasing demand for materials that could improve tissue regenerative therapies and provide antimicrobial effects. Similarly, there is a growing need to develop or modify biomaterials for the diagnosis and treatment of different pathologies. In this scenario, hydroxyapatite (HAp) appears as a bioceramic with extended functionalities. Nevertheless, there are certain disadvantages related to the mechanical properties and lack of antimicrobial capacity. To circumvent them, the doping of HAp with a variety of cationic ions is emerging as a good alterative due to the different biological roles of each ion. Among many elements, lanthanides are understudied despite their great potential in the biomedical field. For this reason, the present review focuses on the biological benefits of lanthanides and how their incorporation into HAp can alter its morphology and physical properties. A comprehensive section of the applications of lanthanides-substituted HAp nanoparticles (HAp NPs) is presented to unveil the potential biomedical uses of these systems. Finally, the need to study the tolerable and non-toxic percentages of substitution with these elements is highlighted., Peer Reviewed, Postprint (published version)

The industrial interest in the patterning of polymeric surfaces at the micro/nanoscale to include new functionalities has considerably increased during the last years. Hierarchical organization of micro/nanometric surface textures yields enhanced functional properties such as hydrophobicity, hydrophilicity, antibacterial activity, and optical or chromatic effects to cite some. While high accuracy methods to pattern hierarchical surfaces at the nanoscale have been developed, only some of them have been applied for high volume manufacturing with limited success, mainly because they rely on the use of expensive machinery and moulds or complicated inserts. Therefore, a method using low cost recyclable tooling and process conditions applicable to high-volume manufacturing is currently missing. In this work, a scalable and low-cost method to replicate hierarchical micro/nanostructured surfaces on plastic films is presented, which can be latter used as inlays for injection moulded parts with standard processing conditions. This method is used to demonstrate the feasibility of replicating three level hierarchical micro/nano textured surfaces using recyclable bio-based polymers (of high relevancy in the current plastic pollution context) achieving replication ratios above 90%, comparing the replication results with those obtained in polypropylene. The presence of the micro/nanotextures substantially increases the contact angle of all the polymers tested, yielding values higher than 90° in all the cases. Also, various mechanical properties of the replicated parts for all the polymers injected are characterized one and thirty days after the samples were manufactured, showing fairly constant values. This highlights the validity of the replicated surfaces, regardless of the biopolymers special crystallization characteristics., Peer Reviewed, Postprint (published version)

Aquest projecte es centra en el principi de l'economia circular d'obtenir productes a partir de residus, en aquest cas, utilitzant microorganismes capaços de produir polímers amb propietats similars als tradicionals. El polímer seleccionat per a aquest projecte és el Poli(3-Hidroxibutirat-co-3-Hidroxivalerat), obtingut a partir de substrats de baix valor i recursos renovables. L'objectiu del projecte és sintetitzar un pegat transdèrmic utilitzant l’electrospinning. Aquest mètode genera nano i microfibres a partir d'una dissolució amb polímer per crear una matriu, on s’hi afegeixen dos fàrmacs, l’escopolamina i la clonidina. El pegat té com a objectiu ser utilitzat com un sistema d’alliberació de fàrmacs pel tractament de la hipertensió i el mareig. Es buscaran les condicions òptimes d'operació de l’electrospinning per aquest cas. Un cop obtingut el pegat, s'avaluarà el seu correcte funcionament, demostrant la distribució uniforme del fàrmac i estudiant la seva alliberació tant en un medi salí com en pell de porc. Els resultats obtinguts són satisfactoris. S'han pogut optimitzar les condicions d'operació de l'electrospinning utilitzant 5 mL/hi 15kV per a les matrius sense fàrmacs i 2.5ml/h a15 kV i 17kV per a l'escopolamina i la clonidina. Els diàmetres de les fibres obtingudes estan tots inclosos al rang dels micròmetres, obtenint diferents morfologies depenent de la composició de la matriu. Es va poder estimar la ràtio real de mfàrmac/mmòstra per a la Clonidina i l'Escopolamina, obtenint valors iguals a 16.12 ±1.69 (%-W/W) i 6.24 ± 0.83 (%-W/W) confirmant la seva distribució uniforme a la matriu. Dels estudis d'alliberament s'ha obtingut un alliberament de la clonidina de 6.77±0.16(%-W/W) a PBS i 6.24±0.83 (%-W/W) a la pell de porc. Per a l'Escopolamina de 10.79±0.94(%-W/W) a PBS i 7.60±01.30 (%-W/W) a la pell de porc., Este proyecto se centra en el principio de la economía circular de obtener productos a partir de residuos, en este caso utilizando microorganismos capaces de producir polímeros con propiedades similares a los tradicionales. El polímero seleccionado para este proyecto es el Poli(3-Hidroxibutirato-co-3-Hidroxivalerato), obtenido a partir de sustratos de bajo valor y recursos renovables. El objetivo del proyecto es sintetizar un parche transdérmico utilizando electrospinning, un método que genera nano y microfibras de una solución con polímero para crear una matriz, cargando dos fármacos por separado, escopolamina y clonidina. El parche tiene como objetivo ser utilizado como un sistema de liberación de fármacos para el tratamiento de la hipertensión y el mareo. Se buscarán las condiciones óptimas de operación del electrospinning para este caso. Una vez obtenido el parche, se evaluará su correcto funcionamiento, demostrando la distribución uniforme del fármaco y estudiando su liberación tanto en un medio salino como en piel de cerdo. Los resultados que se han obtenido mayoritariamente son satisfactorios. Se ha podido optimizar las condiciones de operación del electrospinning utilizando 5 mL/h y 15kV para las matrices sin fármacos 2.5ml/h a 15 kV y 17kV para la Escopolamina y la clonidina. Los diámetros de las fibras obtenidas están todas incluidas en el rango de los micrómetros, obteniendo diferentes morfologías dependiendo de la composición de la matriz. Se pudo estimar el ratio real de mfármaco/mmuestra para la Clonidina y la Escopolamina, obteniendo valores iguales a 16.12 ±1.69 (%-W/W) y 6.24 ± 0.83 (%-W/W) confirmando su distribución uniforme en la matriz. De los estudios de liberación se ha obtenido una liberación de la clonidina de 6.77±0.16(%-W/W) en PBS y 6.24±0.83 (%-W/W) en la piel de cerdo. Para la Escopolamina de 10.79±0.94(%-W/W) en PBS y 7.60±01.30 (%-W/W) en la piel de cerdo., This project focuses on the Circular Economy principle of obtaining products from waste, specifically utilizing microorganisms capable of producing polymers with properties similar to traditional ones. The selected polymer for this project is Poly 3-Hydroxybutyrate-co-3-Hydroxyvalerate, derived from low-value substrates and renewable resources. The objective of the project is to synthesize a transdermal patch using electrospinning, a method that draws nano and microfibres from a polymer solution to create a scaffold, loading two drugs, scopolamine and clonidine. The proposed patch aims to serve as a drug release system for the treatment of hypertension and dizziness. The optimal operating conditions for electrospinning in this case will be sought. Once the patch is obtained, its proper functioning will be evaluated, demonstrating the uniform distribution of the drug and studying its release in both a saline medium and pig skin. The obtained results are satisfactory. The operating conditions of electrospinning were successfully optimized using 5 mL/h and 15 kV for the drug-free matrices, 2.5 mL/h at 15 kV for Scopolamine, and 17 kV for Clonidine. The diameters of the obtained fibres are all within the range of micrometres, with different morphologies depending on the matrix composition. The real drug-to-sample ratio was estimated for Clonidine and Scopolamine, resulting in values of 16.12 ± 1.69 (% w/w) and 6.24 ± 0.83 (% w/w) respectively, confirming their uniform distribution in the matrix. In the release studies, Clonidine exhibited a release of 6.77 ± 0.16 (% w/w) in PBS and 6.24 ± 0.83 (% w/w) in pig skin, while Scopolamine showed a release of 10.79 ± 0.94 (% w/w) in PBS and 7.60 ± 1.30 (% w/w) in pig skin. To conclude, it has been confirmed that the release rate obtained for the Scopolamine-loaded patch is equal to the commercially available patch, amounting to 0.979 mg.

Medical gloves, along with masks and gowns, serve as the initial line of defense against potentially infectious microorganisms and hazardous substances in the health sector. During the COVID-19 pandemic, medical gloves played a significant role, as they were widely utilized throughout society in daily activities as a preventive measure. These products demonstrated their value as important personal protection equipment (PPE) and reaffirmed their relevance as infection prevention tools. This review describes the evolution of medical gloves since the discovery of vulcanization by Charles Goodyear in 1839, which fostered the development of this industry. Regarding the current market, a comparison of the main properties, benefits, and drawbacks of the most widespread types of sanitary gloves is presented. The most common gloves are produced from natural rubber (NR), polyisoprene (IR), acrylonitrile butadiene rubber (NBR), polychloroprene (CR), polyethylene (PE), and poly(vinyl chloride) (PVC). Furthermore, the environmental impacts of the conventional natural rubber glove manufacturing process and mitigation strategies, such as bioremediation and rubber recycling, are addressed. In order to create new medical gloves with improved properties, several biopolymers (e.g., poly(vinyl alcohol) and starch) and additives such as biodegradable fillers (e.g., cellulose and chitin), reinforcing fillers (e.g., silica and cellulose nanocrystals), and antimicrobial agents (e.g., biguanides and quaternary ammonium salts) have been evaluated. This paper covers these performance-enhancing materials and describes different innovative prototypes of gloves and coatings designed with them., Peer Reviewed, Objectius de Desenvolupament Sostenible::3 - Salut i Benestar, Postprint (published version)

Agents reticulants com l’aziridina, la melamina i l’isocianat s'han utilitzat i s'utilitzen avui dia pel seu alt rendiment en aplicacions de revestiment. No obstant això, són composts perillosos que han de substituir-se per opcions més sostenibles que ofereixin el mateix o major nivell de rendiment. Les policarbodiimides són una excel·lent alternativa sense etiquetes per als revestiments sostenibles, en comparació amb els reticulants més perillosos esmentats. No obstant això, la vida útil de la mescla resultant de policarbodiimida i resina ha d'augmentar-se per a aconseguir el rendiment desitjat en les aplicacions de recobriment. Això s'aconsegueix mitjançant la microencapsulació de policarbodiimida. L'objectiu d'aquesta tecnologia és dissenyar un sistema de microencapsulació de policarbodiimida que ofereixi un pot life durador de la mescla amb resina. Mitjançant la caracterització dels dos tipus de microcàpsules obtingudes i la determinació del control de la cinètica de difusió i el rendiment d'encapsulació dels dos tipus diferents de microcàpsules, s'utilitza finalment una d'elles per a la seva possible aplicació, duent a terme una avaluació del rendiment d'una mescla que contingui microcàpsules., Agentes reticulantes como la aziridina, la melamina y el isocianato se han utilizado y se utilizan hoy en día por su alto rendimiento en aplicaciones de revestimiento. Sin embargo, son compuestos peligrosos que deben sustituirse por opciones más sostenibles que ofrezcan el mismo o mayor nivel de rendimiento. Los policarbodiimidas son una excelente alternativa sin etiquetas para los revestimientos sostenibles, en comparación con los reticulantes más peligrosos mencionados. Sin embargo, la vida útil de la mezcla resultante de policarbodiimida y resina debe aumentarse para conseguir el rendimiento deseado en las aplicaciones de recubrimiento. Esto se consigue mediante la microencapsulación de policarbodiimida. El objetivo de esta tecnología es diseñar un sistema de microencapsulación de policarbodiimida que ofrezca una vida útil duradera de la mezcla con resina. Mediante la caracterización de los dos tipos de microcápsulas obtenidas y la determinación del control de la cinética de difusión y el rendimiento de encapsulación de los dos tipos diferentes de microcápsulas, se utiliza finalmente una de ellas para su posible aplicación, llevando a cabo una evaluación del rendimiento de una mezcla que contenga microcápsulas., Crosslinking agents such as aziridine, melamine and isocyanate have been and are used today for their high performance in coating applications. However, they are hazardous compounds that need to be replaced by more sustainable options that offer the same or a higher level of performance. Polycarbodiimide crosslinkers are an excellent label-free alternative for sustainable coatings, compared to the mentioned more hazardous crosslinkers. Nevertheless, the pot life of the resulting carbodiimide and binder blend must be increased to achieve the desired performance for coating applications. This is done by polycarbodiimide microencapsulation. The technology aims to design a microencapsulation system of polycarbodiimide that offers a long-lasting pot life of the blend with resin. By characterizing the two types of microcapsules obtained and determining how controlled the diffusion kinetics and encapsulation performance of the two different types of microcapsules are, one of them is finally used for its possible application by carrying out a performance evaluation of a microcapsule-containing blend.

This review presents a comprehensive update of the biopolymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), emphasizing its production, properties, and applications. The overall biosynthesis pathway of PHBV is explored in detail, highlighting recent advances in production techniques. The inherent physicochemical properties of PHBV, along with its degradation behavior, are discussed in detail. This review also explores various blends and composites of PHBV, demonstrating their potential for a range of applications. Finally, the versatility of PHBV-based materials in multiple sectors is examined, emphasizing their increasing importance in the field of biodegradable polymers., Peer Reviewed, Postprint (published version)

The objective of this project has been the study of a biopolymer produced by microorganisms from waste, with biodegradability and biocompatibility properties, for use as a nanocapsule/nanoparticle in the pharmaceutical industry. The nanoparticles, made from Poly(3-hydroxybutyrate-co-3- hydroxyvalerate) (P(3HB-co-3HV)), a copolymer belonging to the family of polyhydroxyalkanoates (PHAs), have been obtained using the single emulsion/solvent evaporation technique. To produce the nanoparticles by emulsion, two immiscible phases are needed, in this case an organic phase, where chloroform (CHCl3) is used as a solvent for P(3HB-co-3HV), and an aqueous phase where Poly(vinyl alcohol) (PVA) is dissolved, which acts as a stabilizer/surfactant for the emulsion. Once the emulsion is obtained, the solvent is evaporated, and the nanoparticles are washed. Nanoparticles have been produced under conditions of different concentrations of polymer, surfactant, and speed of rotation of the homogenizer. The different groups of nanoparticles have been characterized by dynamic light scattering (DLS) and electrophoretic light scattering (ELS) to evaluate their mean hydrodynamic diameter and their polydispersity index (PDI), and their Z potential, respectively. In addition, a morphological characterization has been carried out using an optical microscope and scanning electron microscopy (SEM). The results of this analysis have been useful for the optimization of the production parameters of the nanoparticles, where it has been shown that the concentration of surfactant, and the speed of rotation have the most prominent role. Once the optimal conditions have been obtained, the functionalization or loading of the nanoparticles has been carried out with Triclosan, which is an antibacterial and antifungal agent, and with Ibuprofen, which is a nonsteroidal anti-inflammatory drug (NSAID) that is used to relieve pain, fever, and inflammation. The loaded nanoparticles have been subjected to tests to

Tissue engineering is nowadays a powerful tool to restore damaged tissues and recover their normal functionality. Advantages over other current methods are well established, although a continuous evolution is still necessary to improve the final performance and the range of applications. Trends are nowadays focused on the development of multifunctional scaffolds with hierarchical structures and the capability to render a sustained delivery of bioactive molecules under an appropriate stimulus. Nanocomposites incorporating hydroxyapatite nanoparticles (HAp NPs) have a predominant role in bone tissue regeneration due to their high capacity to enhance osteoinduction, osteoconduction, and osteointegration, as well as their encapsulation efficiency and protection capability of bioactive agents. Selection of appropriated polymeric matrices is fundamental and consequently great efforts have been invested to increase the range of properties of available materials through copolymerization, blending, or combining structures constituted by different materials. Scaffolds can be obtained from different processes that differ in characteristics, such as texture or porosity. Probably, electrospinning has the greater relevance, since the obtained nanofiber membranes have a great similarity with the extracellular matrix and, in addition, they can easily incorporate functional and bioactive compounds. Coaxial and emulsion electrospinning processes appear ideal to generate complex systems able to incorporate highly different agents. The present review is mainly focused on the recent works performed with Hap-loaded scaffolds having at least one structural layer composed of core/shell nanofibers., Peer Reviewed, Postprint (published version)

L’objectiu d’aquest treball final de màster va ser la fabricació de fibres poroses uniaxials i amb tricapa que presentésfuncions antibacterianesi potencialment d’altresfuncionalitats (antitumoral, antioxidant, antibaterial...). Les fibres es van fabricar mitjançant la tècnica de l’electrospinning a partir d’una dissolució de polímers i sempre treballant amb un polímer comercial, el PHB. El disseny de les matrius va consistir en una capa de mescla PLA/PEG als extrems i PHBV al mig, amb configuració similar a un tipus sandvitx. La droga antibacterial es va incorporar també a la capa intermitja, mesclada amb el PHBV. A més, van afegir també partícules d’hidroxiapatita per formar complexes Matriu-Hidroxiapatita i així poder estudiar la alliberació de droga. Per tal d’obtenir les matrius amb les condicions òptimes, es van modificar els paràmetres durant l’electrospinning de fibres amb una sola capa i es van provar diferents concentracions i diferents dissolvents. Un cop obtinguts els valors òptims dels paràmetres i el dissolvent adequat, es va procedir a crear diferent matrius amb diferents característiques i components per el seu posterior estudi. En el desenvolupament del projecte es van dur a terme diferents caracteritzacions, tant físiques com químiques de les matrius creades. Primer es va estudiar els angles de contacte, en funció del comportament de l’aigua al estar en contacte amb la superfície de les matrius. Tots els resultats obtinguts van ser superiors a 120º per tant, es va considerar el polímer estudiat era de tipus hidrofòbic, ja que presentava valors superiors al 90º. Posteriorment, es van analitzar els diàmetres de les fibres que s’obtenien a les matrius mitjançant microscòpia electrònica de rastreig (SEM) i també es va obtenir l’espectre de cadascuna dels components que es van utilitzar per muntar les matrius (per espectroscòpia infraroig) per tal d’obtenir les absorcions dels components que formaven part d’elles. Per últim es va realitzar un estudi de l, El objetivo de este trabajo final de máster fue la fabricación de fibras porosas uniaxiales y con tricapa que presentase funciones antibacterianas y potencialmente otras funcionalidades (antitumoral, antioxidante, antibacterianas...). Las fibras se fabricaron mediante la técnica de la electrospinning a partir de una disolución de polímeros y siempre trabajando con un polímero comercial, el PHB. El diseño de las matrices consistió en una capa de mezcla PLA/PEG en los extremos y PHBV en medio, con configuración similar a un tipo sándwich. La droga antibacteriana se incorporó también a la capa intermedia, mezclada con el PHBV. Además, se añadieron también partículas de hidroxiapatita para formar complejos Matriz-Hidroxiapatita y así poder estudiar la liberación de droga. Para obtener las matrices con las condiciones óptimas, se modificaron los parámetros durante el electrospinning de fibras con una sola capa y se probaron diferentes concentraciones y diferentes disolventes. Una vez obtenidos los valores óptimos de los parámetros y el disolvente adecuado, se procedió a crear diferentes matrices con diferentes características y componentes para su posterior estudio. En el desarrollo del proyecto se llevaron a cabo diferentes caracterizaciones, tanto físicas como químicas de las matrices creadas. Primero se estudió los ángulos de contacto, en función del comportamiento del agua al estar en contacto con la superficie de las matrices. Todos los resultados obtenidos fueron superiores a 120° por lo tanto, se consideró que el polímero estudiado era de tipo hidrofóbico, puesto que presentaba valores superiores al 90°. Posteriormente, se analizaron los diámetros de las fibras que se obtenían mediante microscopia electrónica de rastreo (SEM) y también se obtuvo el espectro de cada uno de los componentes que se utilizaron para montar las matrices (por espectroscopia infrarrojo) para obtener las absorciones de los componentes que formaban parte de ellas. Por último, se realizó un e, The objective of this final master thesis was the fabrication of porous uniaxial trilayer fibers that present antibacterial functions and other potential functionalities (antitumoral, antioxidant, antibacterial...). Fibers were made by means of electrospinning technique, from a polymer solution and aways working with a commercial polymer type, PHB. Scaffolds design consists of a mixture PLA/PEG applied in a layer on extremes and PHBV at the middle, with a sandwich seems configuration. Antibacterial drug was added to intermediate layer, mixed with PHBV. Additionally, it was added particles of hydroxyapatite to form Scaffold-Hydroxyapatite complexes and allow to study drug liberation. To obtain scaffolds in optimum conditions, it was modified the parameters during electrospinning process with unilayer scaffolds and there were tested different concentrations and solvents. Once optimal parameters were obtained and the suitable solvent, different scaffolds were created with different characteristics and components for its posterior study. During the development of the project, different physical and chemical characterizations were made on the created polymer scaffolds. Firstly, contact angle of the scaffolds was evaluated in function of water behavior been in contact with surface scaffold. All angles obtained were higher than 120º and, for so, it was considered that the polymer analyzed was hydrophobic, as it has values higher than 90º. Subsequently, it was analyzed the diameters of fibers by means ofscanning electron microscopy (SEM) and spectra were obtained for each of the components that were used to make the scaffolds (by FTIR spectroscopy) and obtain the absorbances of the components that be part of them. Finally, it was made a liberation of the drug study, dissolving a sample of the scaffold that contains the drug per triplicated, with a biological grown media (PBS). The study was done during a total time of 48h, making periodical samplings and, finally, analyzing

Amorphous molecule-macromolecule mixtures are ubiquitous in polymer technology and are one of the most studied routes for the development of amorphous drug formulations. For these applications it is crucial to understand how the preparation method affects the properties of the mixtures. Here, we employ differential scanning calorimetry and broadband dielectric spectroscopy to investigate dispersions of a small-molecule drug (the Nordazepam anxiolytic) in biodegradable polylactide, both in the form of solvent-cast films and electrospun microfibres. We show that the dispersion of the same small-molecule compound can have opposite (plasticizing or antiplasticizing) effects on the segmental mobility of a biopolymer depending on preparation method, temperature, and polymer enantiomerism. We compare two different chiral forms of the polymer, namely, the enantiomeric pure, semicrystalline L-polymer (PLLA), and a random, fully amorphous copolymer containing both L and D monomers (PDLLA), both of which have lower glass transition temperature (Tg) than the drug. While the drug has a weak antiplasticizing effect on the films, consistent with its higher Tg, we find that it actually acts as a plasticizer for the PLLA microfibres, reducing their Tg by as much as 14 K at 30%-weight drug loading, namely, to a value that is lower than the Tg of fully amorphous films. The structural relaxation time of the samples similarly depends on chemical composition and morphology. Most mixtures displayed a single structural relaxation, as expected for homogeneous samples. In the PLLA microfibres, the presence of crystalline domains increases the structural relaxation time of the amorphous fraction, while the presence of the drug lowers the structural relaxation time of the (partially stretched) chains in the microfibres, increasing chain mobility well above that of the fully amorphous polymer matrix. Even fully amorphous homogeneous mixtures exhibit two distinct Johari–Goldstein relaxation proc, Peer Reviewed, Postprint (author's final draft)

We present a fabrication process for the production of 3-dimensional micro-structured polymeric films. The microstructures are fabricated in a single step using thermal nanoimprint lithography as patterning technique. The micro-structured polymer films are then transformed into a 3D shape by means of a plug-assisted thermoforming process, while keeping the functionality of the micro-patterned areas. The preserved functionality is characterized by water contact angle measurements, while the deformation of the micro-structured topographies due to the thermoforming process is analyzed using confocal microscopy and Digital Image Correlation (DIC) techniques. This combined fabrication process represents a promising solution to complement in-mold decoration approaches, enabling the production of new functional surfaces. As the microstructures are fabricated by means of a mechanical modification of the surface, without the need of chemical treatments or coatings, the presented technique represents a promising, simple and green solution, suitable for the industrial fabrication of 3D nonplanar shaped functional surfaces., Peer Reviewed, Postprint (published version)

In the area of coating development, it is extremely difficult to find a substitute for bisphenol A diglycidyl ether (DGEBA), the classical petroleum-based raw material used for the formulation of epoxy thermosets. This epoxy resin offers fast curing reaction with several hardeners and the best thermal and chemical resistance properties for applications in coatings and adhesive technologies. In this work, a new biobased epoxy, derived from poly(limonene carbonate) oxide (PLCO), was combined with polyetheramine and polyamineamide curing agents, offering a spectrum of thermal and mechanical properties, superior to DGEBA-based thermosets. The best formulation was found to be a combination of PLCO and a commercial curing agent (Jeffamine) in a stoichiometric 1:1 ratio. Although PLCO is a solid due to its high molecular weight, it was possible to create a two-component partially biobased epoxy paint without the need of volatile organic compounds (i.e., solvent-free formulation), intended for use in coating technology to partially replace DGEBA-based thermosets., Peer Reviewed, Postprint (author's final draft)

Pla de Doctorat Industrial, Generalitat de Catalunya, The plastics industry is in constant evolution looking to improve the properties of new materials and performance in different applications. Currently, the environmental impact associated with the use of plastics is one of the main concerns for the society. It was reflected in regulations at European level such as SUP Directive, Green Deal or studies such as Patents for tomorrow's plastics by European Patent Office on the trends reflected in research on alternative materials to conventional plastic. In order to transfer these new and more sustainable alternatives to an industrial and realistic environment, first applied research has to be carried out on both the development and processes of the materials to optimize their performance. In this thesis study, applied research was carried out using ultrasound technology on different nanocomposites and their transformation processes. Advances in the application of ultrasound for different transformation processes have been studied previously to ensure the approach of the practical study. This study focuses on the application of ultrasound in the process of obtaining new formulations by compounding extrusion and in injection molding, specifically in microinjection. The application of nanotechnology in the development of new materials will allow an improvement in performance and will open a range of new possibilities and applications. To explore the potential of ultrasonic molding (USM) technology, a preliminary process stability study was performed with polypropylene. The evaluation was carried out from a mechanical point of view, in which it was shown that, with an optimization of the process parameters and a correct design approach of the components with the nodal point allow a stability close to production was allowed. To deepen into the potential of USM technology in synergy with new nanocomposite formulations, a comparative study with the conventional microinjection process was performed. Two different nanocomposites, El sector del plástico está en continuo cambio en busca de mejorar sus propiedades y rendimiento en diferentes aplicaciones. Actualmente. el impacto ambiental asociado al uso de los plásticos es una de las principales preocupaciones en el ámbito social. Se puede ver reflejado en regulaciones a nivel europeo como SUP Directive. Green Deal o estudios como el que efectúa la Oficina de Patentes Europeas Patents for tomorrow's plastics sobre las tendencias que reflejan las investigaciones en materiales alternativos al plástico convencional. Para poder llevar a un ambiente industrial y realista estas nuevas alternativas más sostenibles. primero se ha de llevar a cabo una investigación aplicada tanto del desarrollo de los materiales como de los procesos que pueden optimizar su rendimiento. En este estudio de tesis se lleva a cabo una investigación aplicada sobre diferentes nanocompuestos y sus procesos de transformación que pueden ser mejorados con la tecnología de ultrasonidos. Se ha estudiado los avances en la aplicación de ultrasonidos para diferentes procesos de transformación con el objetivo de enfocar correctamente el estudio práctico. Este estudio centra la aplicación de los ultrasonidos en el proceso de obtención de nuevas formulaciones por extrusión compounding y en el moldeo por inyección, concretamente en microinyeccion. La aplicación de nanotecnología en el desarrollo de nuevos materiales permitirá una mejora del rendimiento y abrirá un abanico de nuevas posibilidades y aplicaciones. Para explorar el potencial de la tecnología de microinyección por ultrasonidos (USM}, se realizó un estudio preliminar de estabilidad del proceso con un polipropileno. La evaluación fue llevada a cabo desde un punto de vista mecánico, en el que se demostró que con una optimización de los parámetros de proceso y un enfoque de diseño correcto de los componentes que hacen intervenir el punto nodal, se puede alcanzar un nivel de estabilidad cercano a producción. Para profundizar en el, Postprint (published version)

Biocompatible hydrogels with antibacterial properties derived from ¿-polyglutamic acid (¿-PGA) were prepared from bulk and electrospun nanofibers. The antibacterial drugs loaded in these hydrogels were triclosan (TCS), chlorhexidine (CHX) and polyhexamethylene biguanide (PHMB); furthermore, bacteriophages were loaded as an alternative antibacterial agent. Continuous and regular ¿-PGA nanofibers were successfully obtained by the electrospinning of trifluoroacetic acid solutions in a narrow polymer concentration range and restricted parameter values of flow rate, voltage and needle-collector distance. Hydrogels were successfully obtained by using cystamine as a crosslinking agent following previous published procedures. A closed pore structure was characteristic of bulk hydrogels, whereas an open but structurally consistent structure was found in the electrospun hydrogels. In this case, the morphology of the electrospun nanofibers was drastically modified after the crosslinking reaction, increasing their diameter and surface roughness according to the amount of the added crosslinker. The release of TCS, CHX, PHMB and bacteriophages was evaluated for the different samples, being results dependent on the hydrophobicity of the selected medium and the percentage of the added cystamine. A high efficiency of hydrogels to load bacteriophages and preserve their bactericide activity was demonstrated too., Peer Reviewed, Postprint (published version)

The purpose of this paper is to demonstrate the easy manufacturing and quick characterization of several microtextured functional surfaces on two transparent thermoplastics of general interest for several industrial sectors. Microtextured polymeric surfaces with special optical, tribological and easy-cleaning properties were manufactured via isothermal injection-molding using laser-microtextured steel mold inserts. For that purpose, conventional injection molding of two chosen amorphous transparent polymers (polycarbonate, PC, and polymethyl methacrylate, PMMA) utilizing laser-microtextured steel inserts was carried out, and a detailed morphological and functional characterization of the injected specimens was conducted later on. We also report on the suitable process conditions for the injection molding of these specimens using design of experiment (DOE) techniques. The analysis of the degree of replication (DR%) on the injected samples shows that mold temperature and injection speed are the most relevant parameters to obtain a successful replication and confirm the viability of conventional injection molding as a processing technique to obtain microtextured functional surfaces in amorphous transparent thermoplastics. The success of the procedure is further checked by the confirmation of the obtained surface functionalities by various standard and self-developed methods., Peer Reviewed, Postprint (published version)

Great advances in cancer treatment have been undertaken in the last years as a consequence of the development of new antitumoral drugs able to target cancer cells with decreasing side effects and a better understanding of the behavior of neoplastic cells during invasion and metastasis. Specifically, drug delivery systems (DDS) based on the use of hydroxyapatite nanoparticles (HAp NPs) are gaining attention and merit a comprehensive review focused on their potential applications. These are derived from the intrinsic properties of HAp (e.g., biocompatibility and biodegradability), together with the easy functionalization and easy control of porosity, crystallinity and morphology of HAp NPs. The capacity to tailor the properties of DLS based on HAp NPs has well-recognized advantages for the control of both drug loading and release. Furthermore, the functionalization of NPs allows a targeted uptake in tumoral cells while their rapid elimination by the reticuloendothelial system (RES) can be avoided. Advances in HAp NPs involve not only their use as drug nanocarriers but also their employment as nanosystems for magnetic hyperthermia therapy, gene delivery systems, adjuvants for cancer immunotherapy and nanoparticles for cell imaging., Peer Reviewed, Postprint (published version)

Electrospun scaffolds of the biodegradable and biocompatible poly-4-hydroxybutyrate (P4HB) polyester have been prepared using horizontal and vertical set-up configurations of electrospinning. Specifically, it has been evaluated the influence of solvent, polymer concentration, and processing parameters, such as applied voltage, flow rate, and needle tip-collector distance. Scaffolds obtained under the most favorable conditions were characterized in terms of crystallinity, lamellar supramolecular order, thermal (including calorimetric and thermogravimetric data), mechanical, and surface properties. Results pointed out significant differences with respect to commercial sutures (based in P4HB, e.g., MonoMax®) and demonstrated that electrospun scaffolds were constituted by crystalline microfibers with a tangled distribution that leads to high modulus Young modulus (4¿MPa), maximum strength (28¿MPa), and elongation (360%). Furthermore, new scaffolds had thermal stability and a rough surface that led to a hydrophobic character (105°). Scaffolds could also be successfully loaded during the electrospinning process with a peptide analog to the fibroblast growth factor (e.g., CYRSRKYSSWYVALKRC), giving rise to fully biocompatible samples with a clear acceleration in wound healing., Peer Reviewed, Postprint (author's final draft)

Aplicat embargament des de la data de defensa fins el 31 de juliol de 2022, TIPS process followed by freeze-dtying was used to prepare blodegradable and biocompatible matrices from poly(3- hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) containing 5 and 12 wt% of 3-hydroxyvalerate (HV) and poly(butylene succinate) (PBS). 1,4 dioxane (DXN) and tetrahydofuran (THF) were used as solvents. The cloud points of the polymer solutions were determíned by turbidimetry method, to predict the locus of binodal curve in the binary phase diagrams. A multidirectional cooling from ~70ºC to 25ºC, and then to -5 ºC or -25 ºC was applied to PHBV solutions in the TIPS process. The effect of the applied thermal gradients and HV molar ratio of PHBV copolymer on phase separation mechanism, morphology and mechanical properties of the scaffolds was studied. Upon high HV contents and fast cooling, the solid-liquid phase separation through crystallization of DXN was the controlling mechanism and generated large pores with well-distinguished walls and great structural continuity. The morphologies ascribed to polymer crystallizatíon, mostly with low structural consistency were further discernible upon slow cooling. An improvement in scaffolds rigidity were observed in low HV and fast cooling conditions, due to the increased polymer crystallinity and the greater structural consistency, respectively. PHBV scaffolds showed a complete biocompatibility towards MDCK and NRK cell adhesion and proliferation. A multidirectional cooling from ~70 ºC to -20 or -74 ºC were applied to PBS-DXN and PBS-THF solutions and a uniaxial cooling from ~70ºC to -74 or -196 ºC to PBS-DXN. 5 and 100 wt% ofcurcumin (CUR) and piperine (PIP) natural drugs were loaded into PBS matrices via a one-step TIPS fabrication/drug loadlng protocot. Utílizing DXN and THF solvents, solid-liquid and liquid-liquid phase separation were respectívely detected as the main mechanisms responsible for creating the porous structures, while the subregions composed of crysta llized PBS were also obse rved . The applied uniax, El proceso TIPS seguido de liofilización fue usado para preparar matrices porosas ("scaffolds") biodegradables y biocompatibles a partir del poliéster poli (3-hidroxibutirato-co-3-hidroxivalerato) (PHBV) que contiene 5 y 12 wto/o de 3- hidroxivalerato (HV) y del poliéster poli(butilensuccinato) (PBS). El 1.4 dioxano (DXN) yel tetrahidofurano (THF) fueron los disolventes. En el TIPS para las disoluciones de PHBV se aplicó un enfriamiento multidireccional de 70 a 25ºC y luego a -5 ó -25ºC. Se estudiaron los efectos del gradiente térmico y contenido de HV del copolímero sobre el mecanismo de separación de fases, la morfología y propiedades mecánicas de los scaffolds. La separación de fase sólido-líquido en la cristalización del DXN durante el enfriamiento rápido fue el mecanismo que controla la formación de los scaffolds del copolímero con alto contenido de HV. Los scaffolds mostraron grandes poros con paredes bien formadas y gran integridad estructural. Las morfologías atribuidas a la cristalización del polímero. en su mayoría con poca integridad estructural. fueron obtenidas con el enfriamiento lento. Se observó una mejora en la rigidez y mayor integridad estructural de los scaffolds con bajo HV y enfriamiento rápido. debido al aumento de la cristalinidad del polímero. Los scaffolds de PHBV mostraron gran biocompatibilidad determinada por la adhesión y proliferación de células MDCK y NRK. Las disoluciones de PBS-DXN y PBS-THF fueron enfriadas multidireccionalmente de 70ºC a -20 ó -74ºC. y de manera uniaxial para PBS-DXN de 70ºC a -74 ó -196ºC. Los scaffolds de PBS durante su preparación por TIPS fueron cargados con 5 y 100 wt% de curcumina (CUR) o piperina (PIP). La separación de fases sólido-líquido y líquido-líquido (con los disolventes DXN y THF respectivamente) fueron los principales mecanismos responsables para formar las estructuras porosas y subregiones compuestas por PBS cristalizada. El gradiente térmico uniaxial permitió la cristalización del DXN a lo largo, Postprint (published version)

Conversion of CO2 into valuable chemicals is not only a very challenging topic but also a socially demanding issue. In this work, permanently polarized hydroxyapatite obtained using a thermal stimulated polarization process is proposed as a highly selective catalyst for green production of ethanol starting from CO2 and CH4., Peer Reviewed, Postprint (author's final draft)

A new methodology for the pH-triggered degradation of polymers or for therelease of drugs under visible light irradiation based on the cyclization ofortho-hydroxy-cinnamates (oHC) to coumarins is described. The keyoHCstructural motif can be readily incorporated into the rational design of novelphotocleavable polymers via click chemistry. This main-chain moietyundergoes a fast photocleavage when irradiated with 455 nm light providedthat a suitable base is added. A series of polyethylene glycol-alt-ortho-hydroxycinnamate (polyethylene glycol (PEG)n-alt-oHC)-based polymers aresynthesized and the time-dependent visible-light initiated cleavage of thephotoactive monomer and polymer is investigated in solution by a variety ofspectroscopic and chromatographic techniques. The photo-degradationbehavior of the water-soluble poly(PEG2000-alt-oHC) is investigated within abroad pH range (pH=2.1–11.8), demonstrating fast degradation at pH 11.8,while the stability of the polymer is greatly enhanced at pH 2.1. Moreover, theneat polymer shows long-term stability under daylight conditions, thusallowing its storage without special precautions. In addition, twowater-soluble PEG-based drug-carrier molecules(mPEG2000-oHC-benzhydrol/phenol) are synthesized and used for drugdelivery studies, monitoring the process by UV–vis spectroscopy in anON/OFF intermittent manner., Peer Reviewed, Postprint (published version)

Hybrid free-standing biomimetic materials are developed by integrating the VDAC36 ß-barrel protein into robust and flexible three-layered polymer nanomembranes. The first and third layers are prepared by spin-coating a mixture of poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVA). PVA nanofeatures are transformed into controlled nanoperforations by solvent-etching. The two nanoperforated PLA layers are separated by an electroactive layer, which is successfully electropolymerized by introducing a conducting sacrificial substrate under the first PLA nanosheet. Finally, the nanomaterial is consolidated by immobilizing the VDAC36 protein, active as an ion channel, into the nanoperforations of the upper layer. The integration of the protein causes a significant reduction of the material resistance, which decreases from 21.9 to 3.9 kO cm2. Electrochemical impedance spectroscopy studies using inorganic ions and molecular metabolites (i.e.L-lysine and ATP) not only reveal that the hybrid films behave as electrochemical supercapacitors but also indicate the most appropriate conditions to obtain selective responses against molecular ions as a function of their charge. The combination of polymers and proteins is promising for the development of new devices for engineering, biotechnological and biomedical applications.Hybrid free-standing biomimetic materials are developed by integrating the VDAC36 ß-barrel protein into robust and flexible three-layered polymer nanomembranes. The first and third layers are prepared by spin-coating a mixture of poly(lactic acid) (PLA) and poly(vinyl alcohol) (PVA). PVA nanofeatures are transformed into controlled nanoperforations by solvent-etching. The two nanoperforated PLA layers are separated by an electroactive layer, which is successfully electropolymerized by introducing a conducting sacrificial substrate under the first PLA nanosheet. Finally, the nanomaterial is consolidated by immobilizing the VDAC36 protein, active as an ion channe, Peer Reviewed, Postprint (author's final draft)

This work aims to synthesize biocompatible composite materials loaded with recycled porcine bone powder (BP) to fabricate scaffolds for in-situ reconstruction of bone structures. Polylactic acid (PLA) and poly(e-caprolactone) (PCL) were tested as matrices in percentages from 40 wt% to 80 wt%. Chitosan (CS) was selected for its antibacterial properties, in the amount from 5 wt% to 15 wt%, and BP from 20 wt% to 50 wt% as active filler to promote osseointegration. In this preliminary investigation, samples have been produced by solvent casting to introduce the highest possible percentage of fillers. PCL has been chosen as a matrix due to its greater ability to incorporate fillers, ensuring their adequate dispersion and lower working temperatures compared to PLA. Tensile tests demonstrated strength properties (6–10 MPa) suitable for hard tissue engineering applications. Based on the different findings (integration of PLA in the composite system, improvements in CS adhesiThis work aims to synthesize biocompatible composite materials loaded with recycled porcine bone powder (BP) to fabricate scaffolds for in-situ reconstruction of bone structures. Polylactic acid (PLA) and poly(e-caprolactone) (PCL) were tested as matrices in percentages from 40 wt% to 80 wt%. Chitosan (CS) was selected for its antibacterial properties, in the amount from 5 wt% to 15 wt%, and BP from 20 wt% to 50 wt% as active filler to promote osseointegration. In this preliminary investigation, samples have been produced by solvent casting to introduce the highest possible percentage of fillers. PCL has been chosen as a matrix due to its greater ability to incorporate fillers, ensuring their adequate dispersion and lower working temperatures compared to PLA. Tensile tests demonstrated strength properties (6–10 MPa) suitable for hard tissue engineering applications. Based on the different findings (integration of PLA in the composite system, improvements in CS adhesion and mechanical properties), the aut, Peer Reviewed, Postprint (published version)

This work reports a simple and scalable strategy to prepare a series of thermoresponsive polyurethanes synthesized via copolymerization of dicyclohexyl diisocyanate with glycerol ethoxylate in a single one-pot system. These polyurethanes exhibit lower critical solution temperatures (LCST) at 57¿°C. The LCST of synthesized polyurethane was determined from Dynamic Scanning Calorimetry and UV-vis measurements. Both the LCST and Tg of synthesized polyurethane was tuned by varying the ratio between hard segment (dicyclohexyl diisocyanate) and soft segment (glycerol ethoxylate). Thus, Tg values could be tuned from -54.6¿°C to -19.9¿°C for samples with different flexibility. The swelling and deswelling studies were done at room temperature and above the LCST respectively. The results showed that the swelling ratio increases with the increase of soft segment (glycerol ethoxylate) in synthesized polyurethanes. Furthermore, the mechanical properties of the membrane were studied by universal tensile testing measurements. Specifically, stress at break values varied from 0.35±0.07 MPa to 0.91±0.15 MPa for the tested membranes, whereas elongation at break data ranged from 101.9±20.9¿% to 192.4±24.4¿%, and Young's modulus varied from 0.35±0.03 MPa to 1.85±0.19 MPa. Tensile strength of the films increased with the increase of the hard segment and elongation at break decreased., Peer Reviewed, Postprint (published version)

Melt electrospinning of polylactide (PLA) loaded with chloramphenicol (CAM) has been performed and characteristics of fibers, physical properties of scaffolds, CAM release behavior, antibacterial properties and biocompatibility have been evaluated. The interest of CAM loaded samples is nowadays enhanced for biomedical applications since this antibiotic has been demonstrated to be efficient for the treatment of cancer. Melt electrospinning has been selected as an ideal preparation process because it avoids the use of toxic solvents which are harmful to the environment and could be problematic for biomedical applications. The electrospinning process rendered fibers with a relatively large diameter (between 20 µm and 40 µm depending on the load) and minimum polymer degradation. Characteristics of melt electrospun scaffolds were also compared with those prepared by solution electrospinning. Differences consisted in a more sustained release and a higher biocompatibility for the melt processed samples. Bactericide effect was evaluated as an evidence of the maintenance of the CAM bioactivity after melt processing at high temperature and the slower release caused by the relatively high diameter of the constitutive fibers. Since pure CAM showed thermal degradation at temperatures relatively close to the PLA melting temperature, a complete analysis of the degradation process of pure CAM as well as of PLA samples loaded with CAM was performed. The Invariant Kinetic Parameters method allowed determining an initial decomposition step that followed an autoaccelatory Avrami model, and then an autocatalytic decomposition reaction took place for conversions higher than 50%. Dispersion in the PLA matrix enhances the thermal stability of the antibiotic, with an onset temperature of degradation that was higher by 16 ¿C in the meltelectrospun fibers than in the liquid state of pure CAM., Peer Reviewed, Postprint (author's final draft)

Current market trend is moving to miniaturized specimens, especially in the biomedical field seeking high effective and less invasive treatrnent. Ultrasound (US) micromolding is a new technique developed to the aim of producing microsized pieces based on the use of ultrasound waves as a heating source. This heating method is highly precise and can lead to produce microsized pieces with high energy and material efficiencies by using short cycling times compared to other conventional techniques. This PhD work explores further possibilities of ultrasound micromolding to the production of polymers with added value. The work is divided in two main blocks: the production of micropieces based on biodegradable polymers focused on biomedical applications and the application of this technique as a new method to obtain nanocomposites with a homogenous dispersion ofthe reinforcing material. Polylactide (PLA) was selected as polymer matrix in the first block to produce drug loaded pieces and scaffolds with antibacterial activity or increased osteoconductivity by the incorporation of hydroxyapatite (HAp). Chlorhexidine (CHX) and triclosan (TCS), selected as representative bactericide agents, were successfully loaded with a homogenous distribution into the polymer matrix Drugs were slowly released from micropieces and presented clear bactericide and bacteriostatic effect against both Gram-positive and Gram-negative bacteria. Microporous scaffolds have been produced from the subsequent leaching of incorporated salts. By using NaCI cavitation problems could be avoided but pores interconnections were insufficient anda small amount of water soluble polymer (i.e. polyethylene glycol) was required in order to improve the leaching process. Final scaffolds showed enhanced cell proliferation compared to non-porous PLA PLNHAp scaffolds with a porosity degree close to 35% could be achieved with relatively good mechanical properties. lncorporation of HAp increased the thermal stability, hydro, El uso de piezas de tamaño reducido se ha extendido en los últimos años como sinónimo de evolución tecnológica, especialmente en biomedicina, donde se están realizando grandes avances con el fin de mejorar la eficiencia de los tratamientos terapéuticos y aumentar el uso de procedimientos menos invasivos. El micromoldeo por ultrasonidos (USM) es una novedosa técnica para la obtención de micropiezas caracterizada por el uso de ultrasonidos como fuente de calor; gracias a este sistema calefacción el USM presenta tiempos de ciclo extremadamente cortos y un alto rendimiento energético. El trabajo expuesto en esta tesis doctoral se divide en dos partes, un primer bloque enfocado en explorar posibles aplicaciones biomédicas de micropiezas basadas en polímeros biodegradables y un segundo bloque en el que se estudia la posibilidad del uso de dicha técnica para la preparación de nanocompuestos. La polilactida (PLA) fue seleccionada como polímero biodegradable en el primer bloque para la producción de micropiezas cargadas con fármacos y scaffolds con actividad antibacteriana o reforzada con hidroxiapatita (HAp) para incrementar su osteoconductividad. Como agentes bactericidas se escogieron clorhexidina (CHX) y triclosan (TCS), los cuales se cargaron con éxito en la matriz de PLA presentando una distribución uniforme y una clara actividad antibacteriana. Los scaffolds porosos se prepararon por un proceso indirecto al remover la sal soluble en agua tras ser moldeada junto al polímero. Aunque era factible obtener piezas de PLA cargadas con NaCI sin problemas de cavitación o degradación del polímero la conexión entre los poros era insuficiente y una gran cantidad de sal quedaba retenida en la pieza final. Con tal de incrementar dicha interconexión y conseguir un scaffolds poroso libre de NaCI fue necesario agregar polietilenglicol (PEG). Los scaffolds finales cargados con TCS presentan una mejora en la proliferación celular, un efecto bactericida y bacteriostático y una liberación, Postprint (published version)

Ultrasound micromolding (USM) preparation of hybrid scaffolds based on polylactide (PLA) and hydroxyapatite (HAp) particles has been evaluated. PLA was stable under the applied ultrasound source since a minimum degradation was detected. Porous materials were achieved using polyethylene glycol (PEG) and NaCl salts to the initial PLA and the subsequent leaching of the micromolded specimens. To avoid cavitation and decomposition problems during micromolding, it was necessary to use HAp free of typical synthesis impurities like carbonate and nitrate compounds. Compact PLA/HAp pieces allowed a maximum HAp load of 60 wt%, while porous specimens could be obtained with a maximum load of 38 wt%. Physical characterization of new scaffolds was performed by X-ray diffraction, spectroscopic and calorimetric techniques, stress-strain tests and contact angle measurements. Results indicated that a degree of porosity of 35% and relatively good mechanical properties could be achieved (i.e., 580 MPa, 4%, and 15.6 MPa for the Young modulus, elongation at break, and tensile strength, respectively). Scaffolds showed the positive effect of HAp and porosity on cell proliferation; this latter was 40% higher than that detected for non-porous PLA specimens., Peer Reviewed, Postprint (published version)

Porous biodegradable scaffolds provide a physical substrate for cells allowing them to attach, proliferate and guide the formation of new tissues. A variety of techniques have been developed to fabricate tissue engineering (TE) scaffolds, among them the most relevant is the thermally-induced phase separation (TIPS). This technique has been widely used in recent years to fabricate three-dimensional (3D) TE scaffolds. Low production cost, simple experimental procedure and easy processability together with the capability to produce highly porous scaffolds with controllable architecture justify the popularity of TIPS. This paper provides a general overview of the TIPS methodology applied for the preparation of 3D porous TE scaffolds. The recent advances in the fabrication of porous scaffolds through this technique, in terms of technology and material selection, have been reviewed. In addition, how properties can be effectively modified to serve as ideal substrates for specific target cells has been specifically addressed. Additionally, examples are offered with respect to changes of TIPS procedure parameters, the combination of TIPS with other techniques and innovations in polymer or filler selection., Peer Reviewed, Postprint (published version)

The fight against nosocomial infections in hospitals, has promoted the use of microencapsulated essential oils on medical wearing uniforms. These types of microcapsules can be improved with the use of antimicrobial polymers in the shell structure. Chitosan is one of the most used biopolymers and the effectiveness of the treatment can be increased with the combination of different molecular weight chains of chitosan. This modification in the composition of shell structure allows controlling the rate of hydrolysis and, therefore the amount of its cationic form. The main objective of this work is to define a methodology to get microcapsules with different shell compositions, using surfactants as stabilizers in their first step. Once they have been obtained, these microcapsules will be fixed into textile substrates with the objective to use these tissues as surgical and medical clothes to spread the antibacterial effect, in sanitary staff, as well as in the own patient. In the process of microencapsulation the molecular weight distribution of polymers, influences strongly the delivery mechanisms of the active principle, as well as the chemical characteristics of the textile substrate used in every case. In this work, several chitosan biopolymers have been checked. Structural changes in the stabilization first step and the influence of the cross-linking extension have been related with the final antibacterial effect when fixed on cotton substrates, Authors want to show their acknowledgements to the institutions and companies that helped to the development of this work. Spanish Ministry of Science and Technology. TEXBICO (RTI2018-094014-B-100) that granted the necessary funds to do the experimental work and Biomedical Chitosan (Australia) and CHIBIO (China), for kindly supply the samples used in the Shell structure of microcapsules, Postprint (published version)

The synthesis of hydroxyapatite (HAp) with different shapes and sizes has attracted increasing attention because the applicability of this ceramic material depends on structure-properties relationships (i.e., the dimensions and morphology of HAp crystals determine properties such as the bioactivity and mechanical strength). Although different synthetic routes based on the addition of surfactants, organic modifiers, or dispersants have been proposed to control the growth of HAp crystals, many efforts are being devoted to simplify the whole process using simple parameters such as pH. However, the control of the morphology is still poor and shows low reproducibility. In this work, a new additive-free synthetic route, which is based on the hydrothermal method and the utilization of nonaqueous solvents, is proposed. The influence of the synthesis parameters such as pH, concentration of starting solutions, and the solvent on relevant features such as phase purity, crystallinity, crystallite size, and morphology has been examined using spectroscopic techniques, X-ray diffraction, and scanning electron microscopy. As a consequence, this work presents an easy and robust method based only on the use of organic solvent and the control of the pH that produces pure and crystalline HAp with a controlled shape and size. This method has been used to elucidate some of the key aspects of the crystal growth mechanism and to synthesize HAp crystals with different and well-defined shapes (e.g., belts, rods, flakes needle-like, or polymorph) and sizes, in a reproducible way., Peer Reviewed, Postprint (author's final draft)

In the present study, a composite made of conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), and a biodegradable hydrogel of poly(aspartic acid) (PASP) were electrochemically interpenetrated with poly(hydroxymethyl-3,4-ethylenedioxythiophene) (PHMeDOT) to prepare a new interpenetrated polymer network (IPN). Different cross-linker and PEDOT MPs contents, as well as different electropolymerization times, were studied to optimize the structural and electrochemical properties. The properties of the new material, being electrically conductive, biocompatible, bioactive, and biodegradable, make it suitable for possible uses in biomedical applications., Postprint (author's final draft)

Intracellular calcium (Ca2+) is a key signaling element that is involved in a great variety of fundamental biological processes. Thus, Ca2+ deregulation would be involved in the cancer cell progression and damage of mitochondrial membrane and DNA, which lead to apoptosis and necrosis. In this study, we have prepared amorphous calcium phosphate nanoparticles (ACP NPs) for studied their incorporation by endocytosis or electroporation to epithelial, endothelial and fibroblast cells (MCF-7, HUVEC and COS-1 cells, respectively). Our results showed that internalized ACP NPs have cytotoxic effects as a consequence of the increase of the intracellular calcium content. The endocytosis pathways showed a greater cytotoxic effect since calcium ions could easily be released from the nanoparticles and be accumulated in the lysosomes and mitochondria. In addition, the cytotoxic effect could be reversed when calcium ion was chelated with ethylene glycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA). Modification of ACP NPs by coating with different compounds based on phosphates was also evaluated. The results indicated a reduction of the cytotoxic effect, in the order polyphosphate¿<¿phosphonic acid¿<¿orthophosphate. A differential cytotoxic effect of ACP-NPs was observed in function of the cell type; the cytotoxic effect can be ordered as i.e., HUVEC¿>¿COS-1¿>¿MCF-7. The greater cytotoxic effect caused by the increase of intracellular calcium that is observed in normal cells and the greater resistance of cancer cells suggests new perspectives for cancer research., Peer Reviewed, Postprint (published version)

Aliphatic polyamides (nylons) constitute a family of polymers with outstanding properties and multiple applications. Despite the intensive research studies carried out with nylons, there are still multiple unsolved questions concerning crystallization processes, crystalline structures, polymorphic transitions, and crystalline morphologies. Constrains imposed by the strong intermolecular interactions affect the amorphous state, the rigid amorphous phase, the molecular folding, the morphology and obviously the crystalline structure. Some of these relevant points are discussed in the present work., Peer Reviewed, Postprint (published version)

Hydrolytic degradation of poly(4-hydroxybutyrate) (P4HB) films has been studied considering media of different pH values (i.e., 3, 7 and 10) and temperatures (i.e., 37 and 55 °C). Enzymatic degradation has also been evaluated at physiological conditions using two different lipases: Pseudomonas cepacia and Rhizopus oryzae. Different bulk and surface erosion mechanisms with random chain scissions and successive removal of monomer units have been supported through weight loss measurements, molecular weight determinations by GPC and NMR spectroscopy and changes on thermal properties by DSC. Thermal annealing during exposure to different media and even degradation influenced on the melting temperature and crystallinity of samples, as well as on the lamellar geometrical parameters as evaluated by SAXS. Enzymatic degradation was ideal to selectively eliminate the amorphous regions and highlight the spherulitic morphology. Presence of ringed textures were therefore evident in bright field optical micrographs in addition to SEM images, namely observations under polarized light was not necessary to distinguish the presence of banded spherulites. Rhizopus oryzae was revealed to be the most suitable enzyme to crop out the P4HB spherulites that form part of the initial smooth surfaces of solvent casting films. After determining the appropriate activity and exposure time, the presence of rings constituted by cooperative C-shaped edge-on lamellae and flat-on lamellae was highlighted., Peer Reviewed, Postprint (author's final draft)

The self-assembly behavior of chemoenzymatic high molecular weight (ca. 30 000 Da) poly-L-phenylalanine (ePLP) and the nano-morphologies thereof are investigated. Interestingly, this supramolecular ePLP changes from a non-ordered secondary structure when solubilized in water to an a-helix with the addition of only 1 vol% HFIP co-solvent, and at a relatively low concentration (0.5 mg mL-1). The results also indicate a temperature-dependent structural stabilization, wherein the self-assembly process is mainly governed by hydrogen bonding. The analyses evidence self-assembly under controlled conditions to obtain nanotubes with an average diameter of 0.21 ± 0.04 µm, and above 100 µm length. Microbeam synchrotron radiation infrared (SRIR) spectroscopy demonstrates parallel orientations of the amide moieties in the a-helical structure, which is extraordinary for this long chain ePLP. The achievement of these highly homogeneous nanotubes is relevant since previous reports only demonstrated this arrangement for end-capped F-moc-containing short oligophenylalanines. In the same way, the conductivity behaviors of the nanotubular structure remained unchanged in the range of 273–313 K demonstrating its stability from hydrogen bonds, and also, direct dielectric measurements reveal a high orientation and stabilization by intra- and intermolecular hydrogen bonds in the nanotubes. These characteristics allow drug delivery assays with tetracycline-loaded nanotubes and further applications are envisaged., Peer Reviewed, Postprint (author's final draft)

Chronic wounds represent a major health burden and drain on medical system. Efficient wound repair is only possible if the dressing materials target simultaneously multiple factors involved in wound chronicity, such as deleterious proteolytic and oxidative enzymes and high bacterial load. Here we develop multifunctional hydrogels for chronic wound management through self-assembling of thiolated hyaluronic acid (HA-SH) and bioactive silver-lignin nanoparticles (Ag@Lig NPs). Dynamic and reversible interactions between the polymer and Ag@Lig NPs yield hybrid nanocomposite hydrogels with shear thinning and self-healing properties, coupled to zero-order kinetics release of antimicrobial silver in response to infection-related hyaluronidase (HNase). The hydrogels inhibit the major enzymes myeloperoxidase (MPO) and matrix metalloproteinases (MMPs) responsible for wound chronicity in a patient’s wound exudate. Furthermore, the lignin-capped AgNPs provide the hydrogel with antioxidant properties and strong antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa. The nanocomposite hydrogels are not toxic to human keratinocytes after 7 days of direct contact. Complete tissue remodeling and restoration of skin integrity is demonstrated in vivo in a diabetic mouse model. Hematological analysis reveals lack of wound inflammation due to bacterial infection or toxicity, confirming the potential of HA-SH/Ag@Lig NPs hydrogels for chronic wound management., Peer Reviewed, Postprint (author's final draft)

The enhanced catalytic activity of permanently polarized hydroxyapatite, which is achieved using a thermally stimulated polarization process, largely depends on both the experimental conditions used to prepare crystalline hydroxyapatite from its calcium and phosphate precursors and the polarization process parameters. A mineral similar to brushite, which is an apatitic phase that can evolve to hydroxyapatite, is found at the surface of highly crystalline hydroxyapatite. It appears after chemical precipitation and hydrothermal treatment performed at 150 °C for 24 h followed by a sinterization at 1000 °C and a polarization treatment by applying a voltage of 500 V at high temperature. Both the high crystallinity and the presence of brushite-like phase on the electrophotocatalyst affect the nitrogen and carbon fixation under mild reaction conditions (95 °C and 6 bar) and the synthesis of glycine and alanine from a simple gas mixture containing N2, CO2, CH4 and H2O. Thus, the Gly/Ala ratio can be customized by controlling the presence of brushite on the surface of the catalyst, enabling to develop new strategies to regulate the production of amino acids by nitrogen and carbon fixation., Peer Reviewed, Postprint (author's final draft)

Aplicat embargament des de la data de defensa fins al 12/6/2021, In the last decades, polymeric biomaterials, due to their advanced physical and mechanical properties, have been used in a vast variety of surgical and pharmaceutical applications. In this thesis, a study on crystallinity, properties, and degradability of poly-4-hydroxybutyrate (P4HB), commercially marketed as MonoMax® by B. Braun Surgical S.A.U. as an absorbable monofilament suture, and related polyesters is presented. Part of this work has been executed under the collaborative research project established between PSEP (Polímeros Sintéticos. Estructura y Propiedades) research group of Universitat Politècnica de Catalunya and B.Braun Surgical S.A.U. (Center of Excellence for Closure Technologies) with the principal purpose of evolving and investigating polymeric systems with specific biomedical applications. This study covers different topics related to P4HB such as (a) the physical, chemical, thermal and mechanical characterization; (b) the study of the crystallization kinetics; (c) the study of the degradation behavior of P4HB; and (d) the production of nanofibers by the electrospinning technique. Moreover, the work includes a study on blends of two different polyesters: PGA/PCL blends also produced employing the electrospinning technique and biphasic PLA/PA blends. Crystallization was studied under both isothermal and non-isothermal conditions using optical microscopy and differential scanning calorimetry. Furthermore, supplementary experiments performed in a synchrotron radiation facility provided us with further information about the lamellae morphology, crystal structure, and molecular orientation. Hydrolytic and enzymatic degradation of different matrices of P4HB was carried out in different buffered media. The hydrolytic degradation has been studied considering media of different pH values and temperatures. Enzymatic degradation has also been evaluated at physiological conditions using two different lipases. The hydrolytic degradation mechanism differs from, En los últimos años se ha extendido el uso de los biomateriales poliméricos en una amplia variedad de aplicaciones quirúrgicas y farmacéuticas debido a sus óptimas propiedades físicas y mecánicas. En esta tesis doctoral se presenta un estudio sobre la cristalinidad, propiedades y degradabilidad del poli-4-hidroxibutirato (P4HB) y poliésteres relacionados. El P4HB se comercializa por la empresa B. Braun Surgical S.A.U. bajo la marca comercial MonoMax® como sutura monofilamento absorbible. Parte de este trabajo se ha realizado bajo un convenio de colaboración entre la Universidad Politécnica de Cataluña, concretamente entre el grupo de investigación PSEP (Polímeros Sintéticos. Estructura y Propiedades) y la empresa B. Braun Surgical S.A.U. (Centro de Excelencia para Cierre de Heridas) con el principal objetivo de investigar acerca de sistemas poliméricos con determinadas aplicaciones biomédicas. El estudio abarca diferentes temas relacionados con el P4HB como son: (a) la caracterización física, química, térmica y mecánica, (b} el estudio de la cinética de cristalización, (c) el estudio del comportamiento de degradación y d) la producción de nanofibras mediante la técnica de electrohilado. Además, el trabajo incluye un estudio de mezclas de dos sistemas poliméricos diferentes, por una parte, mezclas de dos poliésteres: poliglicolato (PGA) y poliéaprolactona (PCL) y por otra mezcla de ácido pollláctico (PLA) y poliamida. Los procesos de cristalización se estudiaron en condiciones isotérmicas y no-isotérmicas utilizando microscopía óptica y calorimetría diferencial de barrido. También, se llevaron a cabo experimentos con fuentes de luz sincrotrón que proporcionaron información adicional sobre las morfologías de las lamelas, la estructura cristalina y la orientación molecular. La degradación hidrolítica y enzimática de las diferentes matrices de P4HB se realizó en medios tamponados. La degradación hidrolítica se estudió en medios con diferente pH y temperatura y la degrad, Postprint (published version)

Fibers of poly(4-hydroxybutyrate) (P4HB) have been submitted to both hydrolytic and enzymatic degradation media in order to generate samples with different types and degrees of chain breakage. Random chain hydrolysis is clearly enhanced by varying temperatures from 37 to 55 ¿C and is slightly dependent on the pH of the medium. Enzymatic attack is a surface erosion process with significant solubilization as a consequence of a preferent stepwise degradation. Small angle X-ray diffraction studies revealed a peculiar supramolecular structure with two different types of lamellar stacks. These were caused by the distinct shear stresses that the core and the shell of the fiber suffered during the severe annealing process. External lamellae were characterized by surfaces tilted 45¿ with respect to the stretching direction and a higher thickness, while the inner lamellae were more imperfect and had their surfaces perpendicularly oriented to the fiber axis. In all cases, WAXD data indicated that the chain molecular axis was aligned with the fiber axis and molecules were arranged according to a single orthorhombic structure. A gradual change of the microstructure was observed as a function of the progress of hydrolysis while changes were not evident under an enzymatic attack. Hydrolysis mainly affected the inner lamellar stacks as revealed by the direct SAXS patterns and the analysis of correlation functions. Both lamellar crystalline and amorphous thicknesses slightly increased as well as the electronic contrast between amorphous and crystalline regions. Thermal treatments of samples exposed to the hydrolytic media revealed microstructural changes caused by degradation, with the inner lamellae being those that melted faster, Peer Reviewed, Postprint (published version)

Nanotechnology is regarded as a promising tool to advance science for a wide range of applications, ranging from nanomedicine, nanoelectronics, imaging and diagnosis. Whilst the unique surface properties of nanostructured materials improve their performance in comparison to conventional materials, little has been done to inspect the correlation between such nanofeatures and the thermomechanical response of nanomaterials. Herein, we report the influence of structural nanofeatures in the glass transition and cold crystallization temperatures (Tg and Tcc) of poly(lactic acid) (PLA) thin films using a technology that detects the microcantilever deflection as a function of temperature. Measurements were conducted on arrays of 8-cantilevers spin-coated with PLA films (thickness of ~120–200 nm and weight of 6–9 ng) displaying several patterns (compact, nanopored and/or nanoperforated). The Tg increases by 8–13 °C when nanopores and nanoperforations are present, while only the latter affect the Tcc, which increases by ~6 °C. These phenomena have been attributed (i) the stress of the PLA molecules located at the interface of the pores and perforations, and (ii) to the film-air interface effect, which is associated with the quasi-2D nature of thin films (i.e. those with an aspect ratio of size and thickness greater than 105). On the other hand, the thermomechanical response of PLA thin films loaded with curcumin (CUR) or stiripentol (STP), which formed segregated nanodomains, also differs from that displayed by unloaded PLA films. The size and abundance of CUR and STP nanodomains are directly related to the stress of the PLA chains at the interface and the free volume, which affects the interactions strength and the mobility of polymer molecules (i.e. Tg and Tcc) with respect to neat PLA. Overall, the thermal properties of thin films, which cannot be studied using conventional calorimetric methods, is modified by the presence of nanofeatures. As a consequence, their design ne, Peer Reviewed, Postprint (published version)

En l’última dècada, s’ha desenvolupat el melt electrospinning com a un procés ecològic i lliure de dissolvent per disminuir la bretxa entre els avantatges que presenta l’electrospinning en solució i la necessitat d’una tècnica rendible per l’àmbit industrial. Malgrat els beneficis que suposa utilitzar el melt (o fos) comparat amb l’electrospinning en solució són sorprenents, encara hi ha certs reptes i/o desavantatges a superar, com ara la capacitat dels polímers fosos a ser processats, l’elevat diàmetre de fibra i la seva limitació en controlar la mida, la degradació dels polímers durant el processat i l’estabilitat del filat de la fibra. Apart del desenvolupament de noves tècniques, també s’ha fet recerca en la incorporació de mescles de polímers, d’additius que, per exemple, millorin la conductivitat, modificadors de la viscositat del polímer fos i fàrmacs i d’altres agents per aplicacions específiques. Aquest treball de fi de màster resumeix diferents articles de recerca científica sobre noves tècniques i mètodes, paràmetres de procés, diferents additius, mescles de polímers i nanocompotos (o nanocomposites) i, també, l’aplicació de fibres preparades per melt electrospinning carregades amb fàrmacs, les quals se centren en proporcionar fibres ultrafines amb diferents propietats. En l’últim apartat, es tracten diferents aplicacions potencials del melt electrospinning per aportar noves idees en la producció de fibres ultrafines a gran escala. Finalment, s’ha inclòs un annex amb una part experimental que descriu la preparació de matrius de fibres d’àcid polilàctic (PLA) carregades amb un fàrmac amb la intenció d’obtenir scaffolds (o bastides) temporals per aplicacions en enginyeria de teixits, com ara la prevenció d’infeccions en ferides obertes amb l’agent antibacterià polihexametilenbiguanida (PHMB)., Durante la última década, se ha desarrollado el melt electrospinning como un proceso ecológico y libre de disolvente para disminuir la brecha entre las ventajas que presenta el electrospinning en solución y la necesidad de una técnica rentable para el ámbito industrial. Aunque los beneficios que supone utilizar el melt (o fundido) comparado con el electrospinning en solución son sorprendentes, todavía hay ciertos retos y/o desventajas a superar, como, por ejemplo, la capacidad de los polímeros fundidos a ser procesados, el elevado diámetro de la fibra y su limitación en controlar el tamaño, la degradación de los polímeros durante el procesado y la estabilidad del hilado de la fibra. Aparte del desarrollo de nuevas técnicas, también se ha estudiado la incorporación de mezclas de polímeros, de aditivos que, por ejemplo, mejoren la conductividad, modificadores de la viscosidad del polímero fundido y fármacos y otros agentes para aplicaciones específicas. Este trabajo de fin de máster resume diferentes artículos de investigación científica sobre nuevos métodos y técnicas, parámetros de proceso, diferentes aditivos, mezclas de polímeros y nanocompuestos (o nanocomposites) y, también, la aplicación de fibras preparadas por melt electrospinning cargadas con fármacos, las cuales ser centran en proporcionar fibras ultrafinas con distintas propiedades. En el último apartado se tratan diferentes aplicaciones potenciales del melt electrospinning para aportar nuevas ideas en la producción de fibras ultrafinas a gran escala. Finalmente, se ha incluido un anexo con una parte experimental que describe la preparación de matrices de ácido poliláctico (PLA) cargadas con un fármaco con la intención de obtener scaffolds (o andamios) temporales para aplicaciones en ingeniería de tejidos, como la prevención de infecciones en heridas abiertas con el agente antimicrobiano polihexilmetilenbiguanida (PHMB)., Melt electrospinning has been developed in the last decade as an eco-friendly and solvent-free process to fill the gap between the advantages of solution electrospinning and the need of a cost-effective technique for industrial aspects. Although the benefits of using the melt compared to solution electrospinning are impressive, there are still challenges like processability of polymer melts, large fibre diameter and limitation on the size control, degradation of polymers during their processing, and stability of fibre spinning. Besides developing new techniques in which researchers have focused, incorporation of polymer blends, of additives that improve the conductivity as well as melt-viscosity modifiers, and drugs and other agents for specific applications has also been investigated. This dissertation summarises research papers that discuss new methods and techniques, process parameters, different additives, polymer blends and nanocomposites, and also, the application of drug-loaded melt-electrospun fibres, which focus on providing the ultrafine fibres with different properties. In the last section, some potential applications of melt electrospinning are discussed to bring new ideas for large-scale ultrafine-fibre production. Finally, an appendix with an experimental section in which drug-loaded polylactic acid (PLA) fibrous matrices were prepared by both solution and melt electrospinning has been included. These matrices were intended to be temporary scaffolds for tissue engineering applications to prevent infections in wounds with the antibacterial agent polyhexamethylene biguanide (PHMB).

Transmission electron microscopy, temperature-modulated differential scanning calorimetry, and broadband dielectric spectroscopy were employed to characterize ternary nanocomposites consisting of carboxylated carbon nanotubes (CNT) dispersed in a blend of two immiscible polymers, poly(L,lactide) (PLLA) and thermoplastic polyurethane (TPU). The nanocomposite blends were obtained by melt-compounding of PLLA and TPU in the presence of 0.2 wt-% CNT, either in the presence or absence of a Joncryl® ADR chain extender for PLLA, leading to reactive and non-reactive melt mixed samples. In both cases, the binary PLLA/TPU blend is characterized by phase separation into submicron TPU droplets dispersed in the PLLA matrix, and displays two separate glass transition temperatures. The carbon nanotubes are present either inside the TPU phase (samples obtained without chain extender), or at their boundaries (reactive-melt mixed samples). The effect of the sub-micron confinement of the TPU component is to decrease the cooperativity length of the primary segmental relaxation of this polymer, which is accentuated by the presence of the CNT fillers. Depending on the type of sample, five or six distinct relaxations are observed by means of dielectric spectroscopy, which we are able to assign to different dielectric phenomena. Our dielectric data show that the CNT fillers do not contribute directly to the long-range charge transport in the nanocomposite blends, consistent with the nanocomposites morphology, but rather result in a shift of the Maxwell-Wagner-Sillars space-charge frequency associated with charge accumulation at the PLLA/TPU boundary. Such shift testifies to a selective conductivity enhancement of the TPU phase due to the filler., Peer Reviewed, Postprint (published version)

The influence of curcumin on the thermal stability and degradation kinetics of poly(glycolic acid) (PGA), poly-e-caprolactone (PCL) and their blend has been investigated in detail using thermogravimetric analysis. A 50/50 ratio was chosen for the blend and the effect caused by the addition of different percentages of curcumin (CUR) was evaluated. The thermogravimetric analysis was carried out under an atmosphere of inert nitrogen, operating in a dynamic regime at six different heating rates between 3 and 30¿°C/min. The results obtained from the degradation on a blend of PCL and PGA concluded that CUR hardly affects to the decomposition of PCL but instead, it significantly influences the stability of PGA. To observe this effect in detail, a more complete degradation study was carried out for the system formed by PGA incorporating 5% of the drug. The activation energy could be determined accurately using Kissinger and isoconversional methods like KAS and Friedman, without previously assuming a reaction model. Coats-Redfern method and generalized master curves were adopted to determine the optimal mechanism of degradation. Results showed a F1 model as suitable mechanism able to describe the degradation process of PGA with curcumin in a range of conversions between 20 and 60 %. Incorporation of CUR did not change the degradation mechanism of PGA but had a dramatic effect on the activation energy that was significantly lowered., Peer Reviewed, Postprint (author's final draft)

The influence of stereochemistry on the self-assembly of phenylalanine (Phe) dipeptides bearing aromatic fluorenyl groups at both the N- and C-termini (Fmoc, OFm) has been investigated. For this purpose, Fmoc–d-Phe–l-Phe–OFm and Fmoc–l-Phe–l-Phe–OFm have been examined considering a wide variety of solvents, which differ in dielectric constant and volatility. Results reveal that replacement of l-Phe by d-Phe has a major impact on the self-assembly propensities, restricting drastically the structural diversity and polymorphism shown by the homochiral dipeptide. Thus, the analogous heterochiral dipeptide shows a great propensity to form micro/nanofibers, independently of the environmental conditions. Theoretical calculations revealed that the stability of antiparallel disposition is much higher (a factor of ca. 15) for Fmoc–d-Phe–l-Phe–OFm than that for Fmoc–l-Phe–l-Phe–OFm, which has been attributed to the hydrophobic core formed in the former. Overall, results suggest that control of the backbone chirality is a potent and versatile strategy to drive and finely tune the self-assembly propensities of highly aromatic peptides., Peer Reviewed, Postprint (author's final draft)

The electrophotocatalytic synthesis of Glycine and Alanine from a simple gas mixture containing N2, CO2, CH4 and H2O under mild reaction conditions (95 °C and 6 bar) was recently developed using a catalyst formed by permanently polarized hydroxyapatite, which is achieved using a thermally stimulated polarization process, coated with two layers of aminotris(methylenephosphonic acid) (ATMP) separated by an intermediate layer of zirconyl chloride (ZC). This work reports the optimization of the ATMP- and ZC-coating content by examining the influence of their concentration of each component in each layer on the structural and electrochemical properties of the catalyst. After exhaustive analyses, such properties have been related with the efficiency of the catalysts prepared using different ATMP- and ZC-concentrations to yield Gly and Ala amino acids by fixing nitrogen from N2 and carbon from CO2 and CH4. Results show that, although the concentrations of ATMP and ZC in the first and the intermediate layers are important, the third layer plays a predominant role as is responsible of the apparition of supramolecular structures on the surface and the capacitive behavior of the coating., Peer Reviewed, Postprint (author's final draft)

A nanocomposite based on an antibiotic-loaded hydrogel into a nano-electrospun fibre with antimicrobial and antioxidant capacities is investigated. The material is composed of nanofibres of enzymatic PCL grafted with poly(gallic acid) (PGAL), a recently developed enzyme-mediated hydrophilic polymer that features a multiradical and polyanionic nature in a helicoidal secondary structure. An extensive experimental–theoretical study on the molecular structure and morphological characterizations for this nanocomposite are discussed. The hydrogel network is formed by sodium carboxymethylcellulose (CMC) loaded with the broad-spectrum antibiotic clindamycin. This nano electrospun biomaterial inhibits a strain of Staphylococcus aureus, which is the main cause of nosocomial infections. The SPTT assay demonstrates that PGAL side chains also improve the release rates for this bactericide owing to the crosslinking to the CMC hydrogel matrix. The absence of hemolytic activity and the viability of epithelial cells demonstrates that this nanocomposite has no cytotoxicity., Postprint (published version)

El present Treball de Fi de Màster s’ha dut a terme al site de DSM Coating Resins Spain de Parets del Vallès. El projecte tracta el disseny d’un uretà acrílic i la producció d’aquest uretà acrílic. Inicialment s’introdueix la tecnologia que hi ha darrere dels uretans acrílics. Degut a això, es comenta per una part els poliuretans en base aquosa i per un altre costat les emulsions acríliques. Tant en els poliuretans en base aquosa como en les emulsions acríliques es detalla la química i es fa menció a les primeres matèries necessàries per a la seva producció. Seguidament es dissenya un nou uretà acrílic per a una aplicació concreta esollint les primeres materies i els paràmetres de disseny juntament amb les equacions de disseny. Finalitzat aquest punt es determina les quantitats finals de cada primera materia necessària per a la producció del nou uretà acrílic. També es fa menció al procés final que es durà a terme amb dos nous reactors així com els controls necessaris per assegurar tant la seguretat com la qualitat del procès. Donat que són necessaris dos nous reactors, també es dissenyen mecànicament ambdós equips. Finalment es detallen els aspectes més rellevants de seguretat, higiene i medio ambient així com s’ha evaluat la viabilitat del projecte en l’àmbit econòmic., El presente Trabajo de Fin de Máster se ha llevado a cabo en el site de DSM Coating Resins Spain de Parets del Vallès. El proyecto trata el diseño de un uretano acrílico y la producción de dicho uretano acrílico. Inicialmente se introduce la tecnología que hay detrás de los uretanos acrílicos. Debido a ello, se comentan por un lado los poliuretanos en base acuosa y por otro lado las emulsiones acrílicas. Tanto en los poliuretanos en base acuosa como en las emulsiones acrílicas se detalla la química y se hace mención en las primeras materias necesarias para su producción. Seguidamente se diseña un nuevo uretano acrílico para una aplicación concreta escogiendo las primeras materias y los parámetros de diseño junto con las ecuaciones de diseño. Finalizado este punto se determina la cantidad final de cada primera materia necesaria para la producción del nuevo uretano acrílico. También se hace mención al proceso final que se llevará a cabo con dos nuevos reactores así como los controles necesarios para asegurar tanto la seguridad como la calidad del proceso . Puesto que son necesarios dos nuevos reactores, también se entra en el diseño mecánico de ambos equipos. Finalmente se detallan los aspectos más relevantes de seguridad, higiene y medio ambiente así como se ha evaluado la viabilidad del proyecto en el ámbito económico., The present Master’s thesis has been carried out at DSM Coating Resins Spain in Parets del Vallès Site. In general terms, the project consistes of the design and the production of an urethane acrylic. Initially, the tecnollogy behind the urethane acrylics is introduced and, as consequence, water born polyurethanes on the one hand and acrylic emulsions on the other are discussed. Next, a new urethane acrylic is designed for a specific application by choosing the raw materials, the design parameters together with the design equations. After this point, the final amount of each raw material necessary for the production of the new urethane acrylic is determined. Along the thesis, it is also mentioned the final process to be carried out with two new reactors, as well as the controls required to ensure both safety and the quality of the process. Since two new reactors are required, the mechanical design of both equipment is also included. Finally, the most relevant aspets of safety, health and environment are detailed and the viability of the project in the economic field has been evaluated.