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Cellulose nanofiber (CNF) as a bio-based reinforcement has attracted tremendous interests in engineering polymer composites. This study developed a sustainable approach to reinforce polyamide-6 or nylon-6 (PA6) with CNFs through solvent casting in formic acid/water mixtures. The methodology provides an energy-efficient pathway towards well-dispersed high-CNF content PA6 biocomposites. Nanocomposite formulations up to 50 wt.% of CNFs were prepared, and excellent improvements in the tensile properties were observed, with an increase in the elastic modulus from 1.5 to 4.2 GPa, and in the tensile strength from 46.3 to 124 MPa. The experimental tensile values were compared with the analytical values obtained by micromechanical models. Fractured surfaces were observed using scanning electron microscopy to examine the interface morphology. FTIR revealed strong hydrogen bonding at the interface, and the thermal parameters were determined using TGA and DSC, where the nanocomposites’ crystallinity tended to reduce with the increase in the CNF content. In addition, nanocomposites showed good thermomechanical stability for all formulations. Overall, this work provides a facile fabrication pathway for high-CNF content nanocomposites of PA6 for high-performance and advanced material applications This research was funded by the Biocomposites Program within the Knut and Alice Wallenberg Foundation (Sweden), a UdG grant (IFUdG 2017), Spain, and a three-month research grant from KTH (C2019-1106), Sweden. Support from the Spanish Ministry of Science, Innovation and Universities (RTI 2018-102070-B-C22) is also acknowledged

On an industrial scale, it is a challenge to achieve cellulose based nanocomposites due to dispersion issues and high process temperatures sensitivity. The current study describes methods to develop mechanically strong and thermally stable polyamide 6 (PA 6) and cellulose nanofibers (CNF) composites capable of tolerating high processing temperatures. With PA 6 being a very technical polymer matrix to be reinforced with CNF, good dispersion can be achieved with a high speed kinetic mixer and also shield the CNF from excess thermal degradation by implementing extremely short processing time. This paper presents an industrially feasible method to produce PA 6/CNF nanocomposites with high CNF composition processed by a high speed kinetic mixer (GELIMAT®) followed by compression molding to obtain a homogenous and thermally stable nanocomposites aimed at high performance applications. PA 6 was reinforced with three different wt % formulations (5, 15 and 25 wt %) of cellulose nanofibers. The resulting nanocomposites exhibited significant increase in Young’s modulus and ultimate strength with CNF content, owing to the effective melt processing and the surface charge density of the CNF, which necessitated the dispersion. The thermal stability and polymer crystallinity with respect to CNF composition for the PA 6/CNF nanocomposites were examined by TGA and DSC analysis. Rheology studies indicated that viscosity of the composites increased with increase in CNF composition. Overall, this work demonstrates industrially viable manufacturing processes to fabricate high performance PA 6/CNF nanocomposites This research was funded by the Wallenberg Wood Science Institute—KTH (KAW 2018.0451, Sweden) in Sweden, the by UdG grant (IFUdG 2017) in Spain, and by the Spanish Ministry of Science, Innovation and Universities (RTI 2018-102070-B-C22)

Dyes are complex molecules that can sometimes cause damage to the aquatic environment and harm human health. They are often not completely removed from effluent by the usual treatments; therefore, efforts have been made to increase their exhaustion from dyeing through chemical and physical processes. In this context, the use of β-cyclodextrin (β-CD) as dyeing auxiliary agent promotes the reduction of harmful products, also increasing the color intensity of the fabric. In this paper, β-CD was used as a complexing agent to dye polyamide (PA) using the dye C.I. Disperse Yellow 211 (DY211) in order to improve dye exhaustion and color intensity using the β-CD:DY211 complex. The conventional dyeing process and β-CD:DY211 dyeing process by exhaustion were compared, and adsorption kinetics, isotherms, and the coloristic intensity were evaluated. The chemical shifts in the FTIR spectra and the thermal stability evidenced the formation of the β-CD:DY211 complex. Regarding dyeing kinetics and isotherm, the pseudo-first-order model was the most appropriate to describe the process, while Nernst isotherm was the one that best represented the adsorption results. Categorically, the samples dyed with the β-CD:DY211 complex obtained higher coloristic intensity in comparison with the conventional process. With this evidence, it is possible to conclude that cyclodextrin is a suitable replacement for environmentally harmful textile aides without adding further steps into the dyeing process or the need for additional equipment.

L'objectiu principal d'aquest Treball Final de Grau és l'estudi de la cristal·lització d'una nova poliamida, tipus AABB, diferent a les poliamides convencionals del tipus parell, parell (per exemple, el niló 6, 6). En concret s'ha enfocat en l'estudi de la poliamida 7,10, amb un nombre imparell de metilens en la diamina i un nombre parell de metilens en el diàcid. Per a dur a terme el projecte s'ha cristal·litzat el polímer a partir de mostres foses i s'ha estudiat la seva cinètica de cristal·lització en diferents condicions, variant tant la temperatura com la velocitat de cristal·lització. Per a veure la influència del pes molecular, els experiments s'han dut a terme amb tres fraccions de diferent pes molecular. La cristal·linitat i morfologia cristal·lina dels polímers és clau en les propietats finals d'aquests. Mitjançant Calorimetria Diferencial d'Escombratge, DSC, s'ha caracteritzat tèrmicament el polímer per a determinar els paràmetres necessaris per a poder programar els experiments de cristal·lització, com són la temperatura de fusió, la temperatura de transició vítria i el rang de temperatures òptim de cristal·lització. La morfologia cristal·lina s'ha estudiat mitjançant microscòpia òptica de llum polaritzada, seguint el creixement de les esferulites i mesurant l'evolució del radi de les mateixes amb el temps. El règim de cristal·lització s'ha determinat mitjançant el model de Lauritzen-Hoffman. El objetivo principal de este Trabajo Final de Grado es el estudio de la cristalización de una nueva poliamida del tipo m,n, diferente a las poliamidas convencionales del tipo par, par (por ejemplo, nylon 6, 6). En concreto se ha enfocado en el estudio de la poliamida 7,10, con un número impar de metilenos en la diamina y un número par de metilenos en el diácido. Para llevar a cabo el proyecto se ha cristalizado el polímero a partir de muestras fundidas y se ha estudiado su cinética de cristalización en diferentes condiciones, variando tanto la temperatura como la velocidad de cristalización. Para ver la influencia del peso molecular, los experimentos se han llevado a cabo con tres fracciones de distinto peso molecular. La cristalinidad y morfología cristalina de los polímeros es clave en las propiedades finales de los mismos. Mediante Calorimetría Diferencial de Barrido, DSC, se ha caracterizado térmicamente el polímero para determinar los parámetros necesarios para poder programar los experimentos de cristalización, como son la temperatura de fusión, la temperatura de transición vítrea y el rango de temperaturas óptimo de cristalización. La morfología cristalina se ha estudiado mediante microscopía óptica de luz polarizada, siguiendo el crecimiento de las esferulitas y midiendo la evolución del radio de las mismas con el tiempo. El régimen de cristalización se ha determinado mediante el modelo de Lauritzen-Hoffman. The main objective of this Final Degree Project is the study of the crystallization of a new m,n polyamide, different from conventional even, even polyamides (for example, nylon 6, 6). Specifically, it has focused on the study of polyamide 7,10, with an odd number of methylenes in the diamine and an even number of methylenes in the diacid. To carry out the project, the polymer has been crystallized from molten samples and its crystallization kinetics have been studied under different conditions, changing the temperature and the crystallization rate. To see the influence of molecular weight, the experiments have been carried out with three fractions of different molecular weight. The crystallinity and crystalline morphology of polymers are so important for their final properties. Using Differential Scanning Calorimetry, DSC, the polymer has been thermally characterized to determine the parameters necessary to be able to program the crystallization experiments, such as the melting temperature, the glass transition temperature and the optimum crystallization temperature range. The crystalline morphology has been studied by the polarized light optical microscopy, following the growth of the spherulites and measuring the evolution of their radius over time. The crystallization rate has been determined using the Lauritzen-Hoffman model.

Cellulose is being considered as a suitable renewable reinforcement for materials production. In particular, cellulose based composites are attracting global interest for their unique and intrinsic properties such as strength to weight ratio, dimensional stability and low thermal expansion and contraction. This article investigates the preparation of cellulose pulp fibers with polyamide-6 (PA6) polymer and the effect of fiber orientation within the matrix on the final properties of the biocomposite. Cellulose pulp fibers were melt compounded with PA6 using a thermo-kinetic mixer. Different formulations were prepared and the compounds were manufactured into test samples by injection molding. Mechanical characterization revealed that elastic modulus and the flexural properties increased linearly with the fiber composition. The effect of fiber orientation was examined from square samples out of which individual specimens were cut at different directions with respect to the flow direction. The contributions related to fiber content and effect of fiber orientation on the tensile properties assessed lent positively towards parallel oriented samples (0&deg, ) with respect to flow direction. Furthermore, the cellulose network within the biocomposite revealed the superior interfacial properties between the cellulose and PA6 matrix when observed under a scanning electron microscope.

L’objectiu d’aquest article és investigar el millor disseny de motlle per produir plaques corbades de compòsit de ciment reforçat amb aramida. Després d’estudiar el comportament i els límits del material, s’estudien i es comparen conceptes de motlle preexistents. El comportament del material estudiat va revelar que no era necessari aplicar una compressió addicional a la proveta un cop situada sobre el motlle corbat. També es va fer evident que durant la primera etapa de curat, el compost es pot quedar fora de la cambra de curat, al motlle. Després de 24 hores, el compòsit es pot alliberar del motlle per posar-lo a la cambra d’humitat. Arran d’aquestes observacions, es consideren dos dissenys diferents: un motlle estàtic per a una forma corba específica i un motlle variable on es poden configurar múltiples formes corbes. El motlle estàtic és més rendible per produir, tot i que, per supòsits de recerca, un motlle variable resulta de major interès. El objetivo de este trabajo es investigar el mejor diseño de molde para producir placas curvas compuestas de cemento reforzadas con aramida. Después de estudiar el comportamiento y los límites del material, se estudian y comparan conceptos de molde preexistentes. El comportamiento del material en estudio reveló que no era necesario aplicar compresión adicional a la muestra una vez en el molde curvo. También se hizo evidente que, durante la primera etapa de curado, el material compuesto puede permanecer fuera de la cámara de humedad, en el molde. Después de 24 horas, el compuesto se puede liberar del molde y colocar en la cámara climática. A raíz de estas observaciones, se consideran dos diseños diferentes: un molde estático para una forma curva específica y un molde variable donde se pueden configurar múltiples formas curvas. El molde estático es más rentable de producir, aunque para fines de investigación un molde variable resulta más interesante. The aim of this paper is to research the best mould design to produce curved aramid reinforced cement composite plates. After studying the behaviour and the limits of the material, pre-existing mould concepts are studied and compared. The behaviour of the material under study revealed that it was not needed to apply extra compression to the specimen once in the curved mould. It also became apparent that during the first curing stage, the composite can remain outside of the curing chamber in the mould. After 24 hours the composite can be released from the mould and placed into the moisture chamber. Guided by these findings, two different designs are considered: a static mould for one specific curved shape, and a variable mould where multiple curved shapes can be configured. The static mould is more cost-effective to produce although for research purposes a variable mould is more interesting. Incoming

This paper aims at elucidating the degradation mechanism of linear polyamidoamines (PAAs) in water. PAAs are synthesized by the aza-Michael polyaddition of prim-monoamines or bis-sec-amines with bisacrylamides. Many PAAs are water-soluble and have potential for biotechnological applications and as flame-retardants. PAAs have long been known to degrade in water at pH &ge, 7, but their degradation mechanism has never been explored in detail. Filling this gap was necessary to assess the suitability of PAAs for the above applications. To this aim, a small library of nine PAAs was expressly synthesized and their degradation mechanism in aqueous solution studied by 1H-NMR in different conditions of pH and temperature. The main degradation mechanism was in all cases the retro-aza-Michael reaction triggered by dilution but, in some cases, hints were detected of concurrent hydrolytic degradation. Most PAAs were stable at pH 4.0, all degraded at pH 7.0 and 9.0. Initially, the degradation rate was faster at pH 9.0 than at pH 7.0, but the percent degradation after 97 days was mostly lower. In most cases, at pH 7.0 the degradation followed first order kinetics. The degradation rates mainly depended on the basicity of the amine monomers. More basic amines acted as better leaving groups.

Composite materials have attracted the attention of some industrial fields due to their lightness and relatively good mechanical properties. One of these properties is impact strength, essential to ensure the processability and application of these materials under impact conditions. In addition, it is known that water absorption has a plasticizing effect in polymers and polymer composites which can change the properties of such materials and limit their use. Moreover, this effect worsens when hydrophilic reinforcement is used. In this work, the impact and water uptake behavior of totally bio-based composites from polyamide 11 (PA11) and lignocellulosic pine fibers mechanically processed as stone groundwood (SGW) were studied. The impact resistance of PA11 and its composites was higher than expected, obtaining better results than those of polyolefin-based materials. The evaluated mechanical properties and the micrographs showed an adequate interface. The water uptake test showed that PA11 and its composites had non-Fickian and Fickian case I behaviours, respectively. It was found that the maximum water absorbance was similar to that of SGW reinforced polypropylene.

Sacopa és una empresa que pertany al grup multinacional Fluidra, dedicat al sector de la Piscina i el Wellness i amb seu a Barcelona. L’activitat comercial és la injecció de termoplàstics, fonamentalment accessoris per piscines, des de filtres, skimmers i embornals fins a làmpades LED. A banda també disposa d’una secció de Sala Blanca dedicada a la fabricació de productes pel sector mèdic i farmacèutic. L’any 2011 es va publicar la norma europea EN 13451:2011, les parts 1 i 3 especifiquen els requisits de seguretat i els mètodes d’assaig per a dispositius d’entrada i sortida d’aire/aigua i pels accessoris destinats a l’oci que utilitzen aire/aigua. En valorar els requisits de la norma, des de Sacopa es va observar que les tapes dels embornals fabricades amb material ABS (Acrilonitril butadiè estirè), podien no complir Sacopa is a company that belongs to the multinational group Fluidra, dedicated to Pool and Wellness sector and based in Barcelona. The commercial activity is the injection of thermoplastics, mainly accessories for swimming pools, from filters, skimmers and drains to LED lamps. It also has one on the side Sala Blanca section dedicated to the manufacture of products for the medical sector and pharmacist In 2011, the European standard EN 13451:2011, parts 1 and 3, was published specify safety requirements and test methods for devices air/water inlet and outlet and for the leisure accessories they use air/water When assessing the requirements of the rule, from Sacopa it was observed that the covers of the manholes manufactured with ABS material (Acrylonitrile butadiene styrene), they could not comply

Se presenta en el trabajo una línea de investigación dividida en dos bloques fundamentalmente. En una primera parte se da una imagen global de la situación actual acerca de la demanda, consumo, reciclaje y desechos plásticos a nivel mundial y europeo. Además, se presenta la problemática que supone la pérdida o extravío de las redes de pesca en los mares y océanos, así cómo las distintas organizaciones e instituciones que se encargan de la recogida y reciclado de estos desechos. Una vez comprendida la magnitud del problema, se propone una solución basada en la adición del residuo a morteros de yeso y cemento para su utilización en el campo de la construcción, más concretamente para la producción de sistema de fachadas SATE (Sistemas de Aislamiento Térmico por el Exterior). The document presents a line of investigation divided into two main parts. In the first one, a global image of the current situation regarding the demandt, consumption, recycling and plastic waste at aglobal and European level is given. Furthermore, the problem of the loss of fishing gears in the seas and oceans is presented, as well as the different organizations and institutions that are responsible for the collection and recycling of these wastes. Once the magnitude of the problem is understood, a solution is proposed based on the addition of the residue to plaster and cement mortars for use in the construction field, more specifically for the production of a ETICS (External Thermal Insulation Composite Systems) façade system. Universidad de Sevilla. Grado en Fundamentos de la Arquitectura

Se presenta en el trabajo una línea de investigación dividida en dos bloques fundamentalmente. En una primera parte se da una imagen global de la situación actual acerca de la demanda, consumo y reciclaje de plásticos a nivel tanto mundial como europeo. Además, se presenta la problemática que supone la pérdida o extravío de las redes de pesca en los mares y océanos, así cómo las distintas organizaciones e instituciones que se encargan de la recogida y reciclado de estos desechos. Una vez comprendida la magnitud del problema, se propone una solución basada en la adición del residuo a morteros de yeso y cemento para su utilización en el campo dela construcción, más concretamente para la producción de placas de yeso laminadas y reforzadas mediante la adición de las fibras de las redes de pesca. Por último, se pondrá de manifiesto las ventajas de este producto a través de la aplicación a un caso práctico, donde se constará el impacto medioambiental que supondría la utilización del mismo. The document presents a line of investigation divided into two mainparts. In the first one, a global image of the current situation regarding the demandt, consumption, recycling and plastic waste at a global and European level is given. Furthermore, the problem of the loss of fishing gears in the seas and oceans is presented, as well as the different organizations and institutions that are responsible for the collection and recycling of thesewastes. Once the magnitude of the problem is understood, a solution is proposed based on the addition of the residue to plaster and cement mortars for use in the construction field, more specifically for the production of gypsum laminated and reinforced boards, by addition of fishing gear fibers. Finally, the advantages of this product will be revealed through the application to a study case, where the environmental impact will be stated. Universidad de Sevilla. Grado en Fundamentos de la Arquitectura

Se presenta en el trabajo una línea de investigación dividida en dos bloques fundamentalmente. En una primera parte se da una imagen global de la situación actual acerca de la demanda, consumo, reciclaje y desechos plásticos a nivel mundial y europeo. Además, se presenta la problemática que supone la pérdida o extravío de las redes de pesca en los mares y océanos, así cómo las distintas organizaciones e instituciones que se encargan de la recogida y reciclado de estos desechos. Una vez comprendida la magnitud del problema, se propone una solución basada en la adición del residuo a morteros de yeso y cemento para su utilización en el campo de la construcción, más concretamente para su aplicación en capas de compresión de pavimentaciones continuas. The document presents a line of investigation divided into two main parts. In the first one, a global image of the current situation regarding the demandt, consumption, recycling and plastic waste at a global and European level is given. Furthermore, the problem of the loss of fishing gears in the seas and oceans is presented, as well as the different organizations and institutions that are responsible for the collection and recycling of these wastes. Once the magnitude of the problem is understood, a solution is proposed based on the addition of the residue to plaster and cement mortars for use in the construction field, more specifically for application incompression layers of continuous paving. Universidad de Sevilla. Grado en Fundamentos de la Arquitectura

In this paper, a novel polyamide containing pyrimidine and methine thiophene linkages (poly(pyrimidine-thiophene-amide) (P(P-T-A))) was synthesized. Then, the magnetic calcium alginate nanocomposite containing P(P-T-A) (CA-P(P-T-A)-Ni0.2Zn0.2Fe2.6O4 (NZFO)) was synthesized for studying neodymium (Nd+3), terbium (Tb+3), and dysprosium (Dy+3) ions adsorption in the single ion solutions. The obtained results of X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray (EDX), nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), vibrating sample magnetometer (VSM), and Fourier transform infrared (FT-IR) indicated the successful synthesis of the materials. The value of saturation magnetization of the nanocomposite was reported to be 15.28 emu/g, indicating an appropriate magnetic response. Under the optimum conditions, adsorption efficiency for Nd+3, Tb+3, and Dy+3 was 96.73, 94.82, and 97.58 %, respectively. According to the experimental results, it can be stated that the data of REEs adsorption were efficiently fitted by nonlinear pseudo-second-order kinetic model. Adsorption isotherms were also evaluated by fitting with Freundlich and Langmuir isotherm models. A better fit was achieved by Freundlich model in the case of Tb+3 and Dy+3 ions, while Langmuir isotherm fitting reported a better result for Nd+3 adsorption data. Moreover, the changes in Gibbs free energy (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) values presented a feasible and endothermic ions adsorption process onto the nanocomposite that occurred spontaneously under the investigated conditions. The obtained results indicated that the nanocomposite can be considered as a potential adsorbent for the efficient adsorption of the investigated ions. This work has been supported by the Spanish Ministry of Economy and Competitiveness (Ref. CTM2017-83581-R). Hamedreza Javadian acknowledges the financial support received (Ref. BES-2015-072506).

The plastics industry is increasingly oriented towards the use of bio-based polymers replacing the fossil-based ones. Bio-based polyamides (PAs) in the film packaging application are not still used and need enhancement to overcome some drawbacks. In this scenario, fully (PA10.10) and partially (PA6.10) bio-based PAs were extruded in a laboratory sheet-casting machine. The materials used to obtain films were previously melt blended with modified clay in a twin-screw extruder. The resulting films were morphologically investigated through the scanning electron microscope. The magnifications show agglomerated particles and the packed layers are preferentially aligned in the extrusion machine direction. X-rays confirm that 5 wt% of clay content is difficult to exfoliate in such matrices. The crystallinity was studied by using X-ray diffraction (XRD) and differential scanning calorimetry. The XRD results show coexisting a and ¿ phases in the PA6.10 while the presence of only ¿ in the PA10.10. The presence of clay platelets constrains the crystallites formation, especially in the more polar PA6.10, resulting in changes in the type and the amount of crystals. The mechanical analysis data showed that 5 wt% of clay induced significant improvement in Young's modulus (+68 and + 14%), a slight increase in the tensile yield stress (+21 and + 5%) and only a surprisingly small decrease in the deformation at break (-15 and -24%) for PA10.10 and PA6.10, respectively. Furthermore, the addition of clay gave the best oxygen barrier properties reaching a value of 1.8 ± 0.2 cm3 × mm/m2 × day × atm comparable to a commercial PA6 film used in the packaging field.

L’objectiu principal del projecte és elaborar mapes de procés que relacionin la quantitat reforç de fibra que és necessari en funció dels requeriments mecànics al que estan sol·licitats els components que s’imprimeixen amb la tecnologia de FDM amb fibra contínua. Prèviament, cal estudiar el principi de funcionament d’aquesta tecnologia, fent una caracterització dimensional de diferents components, i una caracterització mecànica del material base sobre el qual s’imprimeix el reforç. Per tal de realitzar el treball, es duran a terme les següents tasques: - Experiments preliminars amb material base, Nylon (PA), per tal de conèixer la tecnologia i l’efecte dels paràmetres de procés en el resultat final de la peça. En aquesta fase inicial també es caracteritzarà aquest material base que s’utilitzarà. - Impressió de provetes estandarditzades amb diferents estratègies i graus de reforçament amb fibra contínua i caracterització de les propietats mecàniques. - Anàlisi dels resultats obtinguts en l’experimentació preliminar i durant els assajos de les propietats mecàniques de les provetes. - Extreure les conclusions dels resultats analitzats The main goal of the project is to develop process maps that relate to the amount of fiber reinforcement that is needed depending on the mechanical requirements to which components that are printed with FDM technology with fiber are required keep on. Beforehand, it is necessary to study the principle of operation of this technology, making one dimensional characterization of different components, and a mechanical characterization of the base material on which the reinforcement is printed. In order to carry out the work, the following tasks will be carried out: - Preliminary experiments with base material, Nylon (PA), in order to know the technology and the effect of process parameters on the final result of the part. In this initial phase will also characterize the base material to be used. - Printing of standardized test tubes with different strategies and degrees of continuous fiber reinforcement and characterization of mechanical properties. - Analysis of the results obtained in the preliminary experiment and during the tests of the mechanical properties of the test tubes. - Draw conclusions from the results analyzed

Most of the decisions taken during the early design and development steps of a new product compromise a large part of its cost, including its environmental footprint and energy consumption. This is of special interest for the automotive industry that has made an effort to increase its sustainability. Adjectives like bio-based, recyclable or biodegradable are commonly used as synonyms of greener; nonetheless, such materials must achieve the requirements of the industry. This paper researches the use of alternative materials instead of glass fiber reinforced polypropylene, a commodity material. The authors propose using a wood fiber reinforced polyamide 11 composite as replacement. The research discussed the mechanical properties of such composites, obtaining values similar to the currently used materials. Moreover, a case study was performed to assess the behavior of the composites when used to manufacture a door car handle. The materials with reinforcement contents ranging from 40 to 60% showed its ability to replace the commodity materials. Furthermore, a preliminary LCA analysis was performed to evaluate the environmental footprint of the researched materials. In was found, that, in terms of energy and carbon footprint, the PA11 composites were penalized by the energy cost of the PA11 monomer production.

Automotive and industrial design companies have profusely used commodity materials like glass fiber-reinforced polypropylene. These materials show advantageous ratios between cost and mechanical properties, but poor environmental yields. Natural fibers have been tested as replacements of glass fibers, obtaining noticeable tensile strengths, but being unable to reach the strength of glass fiber-reinforced composites. In this paper, polyamide 6 is proposed as a matrix for cellulosic fiber-based composites. A variety of fibers were tensile tested, in order to evaluate the creation of a strong interphase. The results show that, with a bleached hardwood fiber-reinforced polyamide 6 composite, it is possible to obtain tensile strengths higher than glass-fiber-reinforced polyolefin. The obtained composites show the existence of a strong interphase, allowing us to take advantage of the strengthening capabilities of such cellulosic reinforcements. These materials show advantageous mechanical properties, while being recyclable and partially renewable Authors wish to acknowledge the economic support of CONACYT for the mobility grant of Francisco J. Alonso-Montemayor (grant no. 627977)

The replacement of commodity polyolefin, reinforced with glass fiber (GF), by greener alternatives has been a topic of research in recent years. Cellulose fibers have shown, under certain conditions, enough tensile capacities to replace GF, achieving competitive mechanical properties. However, if the objective is the production of environmentally friendlier composites, it is necessary to replace oil-derived polymer matrices by bio-based or biodegradable ones, depending on the application. Polyamide 11 (PA11) is a totally bio-based polyamide that can be reinforced with cellulosic fibers. Composites based on this polymer have demonstrated enough tensile strength, as well as stiffness, to replace GF-reinforced polypropylene (PP). However, flexural properties are of high interest for engineering applications. Due to the specific character of short-fiber-reinforced composites, significant differences are expected between the tensile and flexural properties. These differences encourage the study of the flexural properties of a material prior to the design or development of a new product. Despite the importance of the flexural strength, there are few works devoted to its study in the case of PA11-based composites. In this work, an in-depth study of the flexural strength of PA11 composites, reinforced with Stoneground wood (SGW) from softwood, is presented. Additionally, the results are compared with those of PP-based composites. The results showed that the SGW fibers had lower strengthening capacity reinforcing PA11 than PP. Moreover, the flexural strength of PA11-SGW composites was similar to that of PP-GF composites.

Crystalline morphology and structure of nylon 4 9 have been studied by means of optical and transmission electron microscopies, and X-ray diffraction. Rhombic crystals were characteristic of crystallization from glycerin dilute solutions, although the final morphology was dependent on the crystallization temperature. In any case, a single electron diffraction pattern was always obtained, being characteristic a 2 mm symmetry and reflections at spacings that were indicative of a projected rectangular unit cell with hydrogen bonds established along two planar directions (i.e., the diagonals of the unit cell), as it was determined from related polyamides. Crystallization from the melt gave rise to negative birefringent spherulites with a morphology (axialitic, speckled or ringed) that was dependent on the crystallization temperature. Kinetic analysis indicated that melt crystallization took place according to two growth mechanisms (Regimes II and III), which reflect distinct secondary nucleation rates. A complex polymorphic behavior on heating and cooling processes was evidenced by real time synchrotron experiments, being determined an intermediate crystalline structure as well as the typical pseudohexagonal arrangement associated to the Brill transition. Polymorphic transitions were highly dependent on the initial crystalline structure, being enhanced the structural transition from the low temperature structure to the intermediate one when traces of the latter were initially present. Calorimetric and infrared studies supported also the detected thermal transitions of nylon 4 9.

Low density composites of sodium montmorillonite and poly(amide-imide) polymers have been created using an ice templating method, which serves as an alternative to the often-difficult foaming of high temperature/high performance polymers. The starting polymer was received in the poly(amic acid) form which can be cured using heat, into a water insoluble amide-imide copolymer. The resulting materials have densities in the 0.05 g/cm3 range and have excellent mechanical properties. Using a tertiary amine as a processing aid provides for lower viscosity and allows more concentrated polymer solutions to be used. The concentration of the amine relative to the acid groups on the polymer backbone has been found to cause significant difference in the mechanical properties of the dried materials. The synthesis and characterization of low density versions of two poly(amide-imide) polymers and their composites with sodium montmorillonite clay are discussed in the present work.

Este proyecto muestra un estudio empírico del comportamiento de piezas inyectadas con poliamida una vez se condicionan con humedad. Este condicionamiento tiene el objetivo de aumentar o disminuir la ductilidad con el fin de ajustar los esfuerzos necesarios para que las piezas cumplan una función determinada, por ejemplo, reducir ciertos esfuerzos de introducción para luego, perdiendo un porcentaje de esa humedad, los esfuerzos de extracción sean más altos. Se trata de, a partir de unas nociones básicas, determinar la realidad del comportamiento mediante ensayos realizados en piezas reales con unas condiciones de comportamiento reales. Además, se proponen mejoras para paliar errores actuales del sistema de producción, desde que las piezas se inyectan hasta que llegan a su destino final. Todo este estudio ha sido realizado con piezas y en las instalaciones de ITW España. Esta sección de la empresa se dedica a desarrollar y producir componentes plásticos para la industria automovilística.

In this work, polyamide 11 (PA11) and stone ground wood fibres (SGW) were used, as an alternative to non-bio-based polymer matrices and reinforcements, to obtain short fibre reinforced composites. The impact of the reinforcement on the thermal degradation, thermal transitions and microstructure of PA11-based composites were studied. Natural fibres have lower degradation temperatures than PA11, thus, composites showed lower onset degradation temperatures than PA11, as well. The thermal transition and the semi-crystalline structure of the composites were similar to PA11. On the other hand, when SGW was submitted to an annealing treatment, the composites prepared with these fibres increased its crystallinity, with increasing fibre contents, compared to PA11. The differences between the glass transition temperatures of annealed and untreated composites decreased with the fibre contents. Thus, the fibres had a higher impact in the composites mechanical behaviour than on the mobility of the amorphous phase. The crystalline structure of PA11 and PA11-SGW composites, after annealing, was transformed to α’ more stable phase, without any negative impact on the properties of the fibres.

In order to study charge trapping and transport in polyimide, we have submitted samples of Kapton HN to corona charging and measured its surface potential decay with an electrostatic voltmeter. We propose a two terms mobility to explain the experimental data: a non dispersive contribution based on Toomer and Lewis model added to a dispersive process, which is associated with the disordered structure of the material. The non-dispersive model alone did not fit well to the data for short times, but our assumption makes the theoretical expresion fit succesfully to the experimental data. Some important parameters related to the charge transport properties of the material are determined and discussed.

Water is a factor which limits the planting of trees in urban soils. This study follows on from other work carried out by the Escola Superior d'Agricultura de Barcelona (ESAB) (the Advanced Agricultural School of Barcelona) whose aim is to improve the planting of trees in urban soils by establishing a series of key factors for the process. They specifically study how Platanus x acerifolia (London Plane) responds to the application of a surfactant product when incorporated into the water in determined doses and the contribution of a hydrogel to the land to be planted. Determined qualitative and quantitative parameters have been determined (initial an final height, initial and final perimeter, number and length of main branches, number and length of secondary and tertiary branches and number of leaves) to evaluate the response of the trees. The work presents the results for 6 months after planting and, therefore, indicates the short-term effects. The results indicate that the effects of the surfactant are observable in the very short-term (2-3 months) and in conditions when water is lacking, but the effects of the polyacrylamide gel are not observable. In conditions when the trees are well-watered there are no significant differences observed between the two types of treatment, or in the absolute values. L'aigua és un factor limitant en el procés d'implantació d'arbrat en sòls urbans. El present estudi és la continuació d'altres treballs realitzats a l'Escola Superior d'Agricultura de Barcelona (ESAB) amb l'objectiu de millorar la implantació d'arbrat en sòl urbà delimitant una sèrie de factors clau en aquest procés. Concretament s'estudia la resposta de Platanus x acerifolia davant l'aplicació d'un producte tensioactiu incorporat amb l'aigua de reg en dosis determinades i l'aportació en les terres de plantació d'un gel de poliacrilamida . S'han determinat paràmetres qualitatius i quantitatius (alçada inicial i final, perímetre inicial i final, nº i longitud de branques primàries, nº i longitud de branques secundaries i terciàries i nº de fulles) per valorar la resposta dels arbres. El treball presenta els resultats obtinguts després de 6 mesos de plantació, per tant, són a curt termini. Els resultats indiquen que a molt curt termini (2-3 mesos) i en condicions de manca d'aigua, l'efecte del tensioactiu és observable però no el del gel de poliacrilamida. En bones condicions de reg no s'observen diferències significatives, ni en valor absolut, entre els diferents tractaments. El agua es un factor limitante en el proceso de implantación de arbolado en suelos urbanos. El presente estudio es la continuación de otros trabajos realizados en la Escola Superior d'Agricultura de Barcelona (ESAB) cuyo objetivo es mejorar la implantación de arbolado en suelo urbano estableciendo una serie de factores clave en este proceso. Concretamente se estudia la respuesta de Platanus x acerifolia a la aplicación de un producto tensoactivo incorporado en el agua de riego en dosis determinadas y el aporte en las tierras de plantación de un hidrogel Se han determinado parámetros cualitativos y cuantitativos (altura inicial y final, perímetro inicial y final, nº y longitud de ramas primarias, nº y longitud de ramas secundarias y terciarias y nº de hojas) para la valoración de la respuesta de los árboles. El trabajo presenta los resultados a los 6 meses de plantación, por lo tanto, indican el efecto a corto plazo. Los resultados indican que a muy corto plazo (2-3 meses) i en condiciones de falta de agua, el efecto del tensoactivo es observable pero no el del gel de poliacrilamida. En buenas condiciones de riego no se observan diferencias significativas, ni en valor absoluto, entre los distintos tratamientos.

The anomalous behaviour of polyamide 6.6 fibres textured by false twist to different physico-chemical techniques (as the critical dissolution time, CDT), compared with those obtained in polyester fibres, was attributed to a cracking of the. surface and/or to an increase in fibre porosity. This cracking appears when original fibre is treated at high temperature and it is due to the breakage of the skin/core structure of polyamide 6.6. This cracking has been demonstrated by the determination of drying kinetics in a thermogravimetric test that has been developed for this fibre