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Polyurethanes are versatile organic materials that have transformed modern-day life.Made from polyols and diisocyanates, their versatility is largely determined by the combination of monomers used. In foams, the polyols can be sourced from renewable feedstocks and are diverse in their structures and properties, however, the dominating process for aromatic diisocyanates from fossil fuels has limited the monomers used in polyurethane materials. As society depletes the petroleum resources on this planet, there is an incentive to expand to renewable sources that can further diversify the aryl diisocyanates used in polyurethane products. Herein, I take inspiration from naturally abundant phenolic compounds to expand the scope of starting materials to access novel aromatic diisocyanates. I explore established synthetic methodologies to prepare the aniline precursor to access novel monomer, 3,5- diisocyanto-1,1’-biphenyl.

In the present research, a single-step electrospinning technique was implemented to develop homogeneous hydrophilic nanostructures with a self-cleaning characteristic based on non-woven polyurethane (PU) altered by quaternary ammonium salts (QAS). By transferring the nanofibrous structures to the polyethylene terephthalate substrate, the filtering membranes were fabricated. The fabricated PU and PU/QAS membranes were compared and characterized for assessing their self-cleaning properties. The synthesized nanofibers were mechanically tested and also characterized by scanning electron microscopy. At low trans-membrane pressure of 7.5 kPa, water permeation flux and biofouling effect of electrospun nanocomposite membrane performance were primarily studied by means of dead-end filtration. Following a 5-day filtration, the modified nanofibrous structure displayed promising results in the recovery of the flux after a day 3 and inhibited the development of biofilm as well. The tensile strength and modulus of PU-QAS were 7.5MP and 31.7% higher compared to PU membrane. The pore size was also observed to be 360n in PU, while for PU-QAS, it was observed as 340 nm. It was concluded that the developed PU/QAS membrane can be restored to its original flow properties by cleaning with tap water.

Polyurethane (PU) is one of the most common and versatile polymers in many applications especially in the construction and automotive industry where the improvement of thermal stability and flame retardancy is crucial. As polyisocyanaurate (PIR) is well known to have a high decomposition temperature and phosphorus motifs are usually used as flame retardants in polymers, the introduction of PIR and phosphorus motifs in polyurethanes can lead to PUs with high thermal stability and flame retardancy. We investigated a synthetic pathway to introduce polyisocyanurate (PIR) and phosphorus motifs in polyurethanes via co-trimerization of 4,4′-methylene diphenyl diisocyanate (4,4′-MDI) and monoisocyanate, which was synthesized from the reaction between diethyl (hydroxymethyl)phosphonate (DEHP) and 4,4′-MDI. The resulting PIR-DEHP prepolymer was used to prepare PIR-DEHP elastomers in both solvent and solvent-free conditions. The elastomer with polyester polyol and 15 wt % 1,4-butanediol in the polyol component showed high char formation (25.5 wt %) and 55% reduction in the total heat release (THR) relative to the reference elastomer without PIR and phosphorus content. It is expected that the use of the PIR-DEHP prepolymer can be extended to other applications, such as rigid PU foams and compact thermosets where the flame retardancy and bulk reaction conditions are required.

Amphiphilic hyperbranched polyurethanes (HPUs) based on PEG and PCL are promising for several biomedical applications. However, the lack of control over the molar mass and composition hinders a deep understanding of the aqueous self-assembly of HPUs. In this paper, the control over the HPU molar mass and composition was provided by dynamic urea bond-mediated polymerization (DUBMP), enabling a careful evaluation of their aqueous self-assembly by 1H NMR, DLS, and Cryo-TEM. HPUs containing a single PCL block per chain self-assemble into nanoaggregates (Rh ≈ 10 nm) in water up to its cloud-point temperature (Tcp) of 34 °C. On the other hand, HPUs with more than one PCL block per chain self-assemble into nanoaggregates and their clusters below Tcp. In this case, the solution behavior can be tuned by the HPU molar mass. Increasing Mw¯¯¯¯¯¯¯¯ from 4 to 19 kDa, HPUs of similar composition can form colloidally stable cluster suspensions (Mw¯¯¯¯¯¯¯¯ = 4 kDa) and phase separate into a denser liquid aggregate–cluster phase (Mw¯¯¯¯¯¯¯¯ = 7 kDa) or into a highly viscous aggregate-network phase (Mw¯¯¯¯¯¯¯¯ = 19 kDa). This type of control over the hierarchical aggregation of HPUs was reported for the first time and is interesting for biomedical applications.

Polyurethanes (PUs) are one of the most widely employed classes of polymers, with a continuously increasing production demand that is expected to reach around 21 million tons in 2022. Due to the simple polymerization process by which they are produced, the versatility in PU chemistry, and the strong inter/intramolecular interactions present between urethane moieties, these robust materials can be used in diverse applications ranging from elastomers to foams. However, this high versatility, combined with the high stability of the urethane bond and the chemically cross-linked nature of most commercial PUs, leads to long-lasting, potentially contaminating, PU waste in landfill sites. While many strategies are under investigation to improve the end-of-life options for polyurethanes, in this review we focus primarily on the latest advances in the chemical and biological routes for PU recycling. These two routes can potentially allow for monomer recovery and reuse for further synthesis of PUs, achieving materials with identical properties to the virgin materials. Aside from reviewing the latest advances in the field, we will highlight the importance of using life cycle assessment (LCA) to find a truly sustainable solution to landfilling and to incentivize the implementation of chemical and biological recycling approaches at the industrial scale.

Polyurethanes (PUs) are widely used in many applications due to their versatile chemical and physical properties. To meet the increasing demands on PU with respect to intrinsic mechanical and thermal properties, they can be modified with thermally stable aromatic imide structures to form poly(urethane imide) (PUI). However, the preparation of PUI materials has been limited by the need for strong polar solvents, which hinder their industrial scale development. In this work, we prepared imide-containing isocyanate-terminated prepolymers via the reaction of polymeric aromatic or aliphatic isocyanates and pyromellitic dianhydride in completely solvent-free conditions. The subsequent PUI elastomers made from these prepolymers exhibited enhanced char formation and stiffness in comparison to the reference elastomers without imide structures, among which the aromatic PUI elastomer shows improved flame retardancy according to the initial cone calorimetry measurement. This work demonstrates the potential use of imide prepolymers in other PU applications where high thermal stability and flame retardancy are required. The solvent-free synthesis also paves a way for the large-scale production of PUI materials.

Polyurethanes (PUs) are an exceedingly heterogeneous group of plastic polymers, widely used in a variety of industries from construction to medical implants. In the past decades, we have witnessed the accumulation of PU waste and its detrimental environmental impacts. PUs have been identified as one of the most toxic polymers leaching hazardous compounds derived both from the polymer itself and the additives used in production. Further environmental impact assessment, identification and characterization of substances derived from PU materials and establishing efficient degradation strategies are crucial. Thus, a selection of eight synthetic model compounds which represent partial PU hydrolysis products were synthesized and characterized both in terms of toxicity and suitability to be used as substrates for the identification of novel biocatalysts for PU biodegradation. Overall, the compounds exhibited low in vitro cytotoxicity against a healthy human fibroblast cell line and virtually no toxic effect on the nematode Caenorhabditis elegans up to 500 µg mL−1, and two of the substrates showed moderate aquatic ecotoxicity with EC50 values 53 µg mL−1 and 45 µg mL−1, respectively, on Aliivibrio fischeri. The compounds were successfully applied to study the mechanism of ester and urethane bond cleaving preference of known plastic-degrading enzymes and were used to single out a novel PU-degrading biocatalyst, Amycolatopsis mediterranei ISP5501, among 220 microbial strains. A. mediterranei ISP5501 can also degrade commercially available polyether and polyester PU materials, reducing the average molecular number of the polymer up to 13.5%. This study uncovered a biocatalyst capable of degrading different types of PUs and identified potential enzymes responsible as a key step in developing biotechnological process for PU waste treatment options.

Elastomers play a significant role across different fields including healthcare. They have similar mechanical properties to some of the soft tissues of the human body, which makes them useful in applications such as implants and prosthetics. However, forming elastomers for tailored-fit medical devices using 3D printing is still not yet widely utilized because of the current problems seen as innate to the elastomer properties, and the principles of 3D printing techniques. With a focus on silicone and polyurethane, this review details the state-of-the-art 3D printing techniques that are being modified over the years to allow its printability for medical applications. The paper also discusses the manufacturing challenges faced by the researchers in printing elastomers, and how these challenges are currently being addressed. This review paper shows further research direction and hopes to initiate further development of these solutions. This will allow the 3D printing of elastomers to gain widespread use in patient-specific medical devices and components with optimized functionality in the near future.

Wind energy is considered a clean energy source and is predicted to be one of the primary sources of electricity. However, leading-edge erosion of wind turbine blades due to impacts from rain drops, solid particles, hailstones, bird fouling, ice, etc., is a major concern for the wind energy sector that reduces annual energy production. Therefore, leading-edge protection of turbine blades has been an important topic of research and development in the last 20 years. Further, there are critical issues related to the amount of waste produced, including glass fiber, carbon fiber, and various harmful volatile organic compounds in turbine fabrication and their end-of-life phases. Hence, it is vital to use eco-friendly, solvent-free materials and to extend blade life to make wind energy a perfect clean energy source. In this study, cellulose microparticles (CMP) and cellulose microfibers (CMF) have been used as fillers to reinforce water-based polyurethane (PU) coatings developed on glass fiber reinforced polymer (GFRP) substrates by a simple spray method for the first time. Field emission scanning electron microscopy images show the agglomerated particles of CMP and fiber-like morphology of CMF. Fourier transform infrared spectra of CMP, CMF, and related coatings exhibit associated C–H, C=O, and N–H absorption bands of cellulose and polyurethane. Thermal gravimetric analysis shows that CMP is stable up to 285 °C, whereas CMF degradation is observed at 243 °C. X-ray photoelectron spectroscopy of C 1s and O 1s core levels of CMP, CMF and related coatings show C–C/C–H, C–O, C–OH, and O–C=O bonds associated with cellulose structure. The solid particle erosion resistance properties of the coatings have been evaluated with different concentrations of CMP and CMF at impact angles of 30° and 90°, and all of the coatings are observed to outperform the PU and bare GFRP substrates. Three-dimensional (3D) profiles of erosion scans confirm the shape of erosion scars, and 2D profiles ha

Structural floor systems made of Timber-Concrete Composites (TCC) slabs are becoming more and more popular in office and residential buildings as well as in systems used for the renovation of old ceilings. Timber elements can be constructed as beams or solid slabs (massive CLT). Regardless of the main structural layout, individual components require using interlayer connections, which provide composite action in cross-sections. The most used connection types for TCC are mechanical fasteners, grooved or notched connections, and bonded shear joints. Bonded connections with rigid thin-layer adhesives provide high load capacity, but they are characterized by brittle failure due to their low ductility and introduced stress concentrations. An innovative flexible adhesive joint that ensures the transfer of high loads and high deformations simultaneously is presented in the paper. This connecting structural element, named PolyUrethane Flexible Joint (PUFJ) was examined experimentally in double shear lap tests of connections formed between two external CLT slabs of dimension 120 × 350 × 400 mm3 and a central concrete slab of dimension 100 × 250 × 400 mm3. Shear connections between the composite elements were made of a two-component polyurethane PS type adhesive layer of thickness 3 mm. The tested specimens were prepared in two variants of the application: wet application in the form of liquid adhesive and dry application in the form of prefabricated polyurethane layer glued to the elements by thin polyurethane adhesive. The effect of the adhesive application method on the stiffness and capacity of the TCC joint was investigated. In the paper, the analysis of the experimental tests’ results is presented.

A new device and procedure for the in situ quantification of the extent of the self-healing and the kinetics of self-healing of polymeric materials were proposed. The device consisted of flowing an inert gas below the sample placed in a hermetically closed chamber. When the sample was perforated/damaged, the gas passed through the hole made in the polymeric material and the gas flow rate declined as the self-healing was produced. Once the gas flow rate stopped, the self-healing was completed. The proposed method was simple, quick, and reproducible, and several in situ self-healing experiments at different temperatures could be performed in the same sample. As a proof of concept, the new device and method have been used for measuring the self-healing ability of different polyurethanes.

Textile industries are hailed as one of the major environmental polluters in the world, owing to their release of undesirable dye effluents. Synthetic dyes do not adhere to fabric firmly and are released into the aquatic ecosystem as effluent. Consequently, the consistent release of wastewater from numerous textile industries without previous treatment has detrimental effects on the ecosystem and human health. Treatment methods currently being used fail to degrade the dye effluents and have their own shortcomings. Immobilized nanoparticles have been extensively studied for dye remediation because of their many advantages over conventional methods. The present study aimed to compare the efficiency of two different carrier matrices [namely Poly(vinylidene fluoride) and Polyurethane] for iron nanoparticle and their decolorization activity on an azo dye (RED ME4BL). Scanning Electron Microscopy was carried out to show the deposition of iron nanoparticles on the membrane. The reaction kinetics of the bare nanoparticles were compared with that of the immobilized nanoparticles, and all were found to follow pseudo-second-order kinetics. Polyurethane immobilized iron nanoparticles showed a significant degradation of RED ME4bl than the Poly(vinylidene fluoride) immobilized iron and bare nanoparticles. This paper also demonstrates a relatively newer method for nanoparticle immobilisation using the synthetic polyurethane form.

Polyurethanes (PUs) are an exceedingly heterogeneous group of plastic polymers, widely used in a variety of industries from construction to medical implants. In the past decades, we have witnessed the accumulation of PU waste and its detrimental environmental impacts. PUs have been identified as one of the most toxic polymers leaching hazardous compounds derived both from the polymer itself and the additives used in production. Further environmental impact assessment, identification and characterization of substances derived from PU materials and establishing efficient degradation strategies are crucial. Thus, a selection of eight synthetic model compounds which represent partial PU hydrolysis products were synthesized and characterized both in terms of toxicity and suitability to be used as substrates for the identification of novel biocatalysts for PU biodegradation. Overall, the compounds exhibited low in vitro cytotoxicity against a healthy human fibroblast cell line and virtually no toxic effect on the nematode Caenorhabditis elegans up to 500 µg mL−1, and two of the substrates showed moderate aquatic ecotoxicity with EC50 values 53 µg mL−1 and 45 µg mL−1, respectively, on Aliivibrio fischeri. The compounds were successfully applied to study the mechanism of ester and urethane bond cleaving preference of known plastic-degrading enzymes and were used to single out a novel PU-degrading biocatalyst, Amycolatopsis mediterranei ISP5501, among 220 microbial strains. A. mediterranei ISP5501 can also degrade commercially available polyether and polyester PU materials, reducing the average molecular number of the polymer up to 13.5%. This study uncovered a biocatalyst capable of degrading different types of PUs and identified potential enzymes responsible as a key step in developing biotechnological process for PU waste treatment options.

The uncontrollable disposal of plastic waste has raised the concern of the scientific community, which tries to face this environmental burden by discovering and applying new techniques. Regarding the biotechnology field, several important microorganisms possessing the necessary enzymatic arsenal to utilize recalcitrant synthetic polymers as an energy source have been discovered. In the present study, we screened various fungi for their ability to degrade intact polymers, such as ether-based polyurethane (PU) and low-density polyethylene (LDPE). For this, ImpranIil® DLN-SD and a mixture of long-chain alkanes were used as sole carbon sources, indicating not only the most promising strains in agar plate screening but also inducing the secretion of depolymerizing enzymatic activities, useful for polymer degradation. The agar plate screening revealed three fungal strains belonging to Fusarium and Aspergillus genera, whose secretome was further studied for its ability to degrade the aforementioned non-treated polymers. Specifically for ether-based PU, the secretome of a Fusarium species reduced the sample mass and the average molecular weight of the polymer by 24.5 and 20.4%, respectively, while the secretome of an Aspergillus species caused changes in the molecular structure of LDPE, as evidenced by FTIR. The proteomics analysis revealed that the enzymatic activities induced in presence of Impranil® DLN-SD can be associated with urethane bond cleavage, a fact which was also supported by the observed degradation of the ether-based PU. Although, the mechanism of LDPE degradation was not completely elucidated, the presence of oxidative enzymes could be the main factor contributing to polymer modification.

Polyurethanes (PUs) are an exceedingly heterogeneous group of plastic polymers, widely used in a variety of industries from construction to medical implants. In the past decades, we have witnessed the accumulation of PU waste and its detrimental environmental impacts. PUs have been identified as one of the most toxic polymers leaching hazardous compounds derived both from the polymer itself and the additives used in production. Further environmental impact assessment, identification and characterization of substances derived from PU materials and establishing efficient degradation strategies are crucial. Thus, a selection of eight synthetic model compounds which represent partial PU hydrolysis products were synthesized and characterized both in terms of toxicity and suitability to be used as substrates for the identification of novel biocatalysts for PU biodegradation. Overall, the compounds exhibited low in vitro cytotoxicity against a healthy human fibroblast cell line and virtually no toxic effect on the nematode Caenorhabditis elegans up to 500 µg mL−1, and two of the substrates showed moderate aquatic ecotoxicity with EC50 values 53 µg mL−1 and 45 µg mL−1, respectively, on Aliivibrio fischeri. The compounds were successfully applied to study the mechanism of ester and urethane bond cleaving preference of known plastic-degrading enzymes and were used to single out a novel PU-degrading biocatalyst, Amycolatopsis mediterranei ISP5501, among 220 microbial strains. A. mediterranei ISP5501 can also degrade commercially available polyether and polyester PU materials, reducing the average molecular number of the polymer up to 13.5%. This study uncovered a biocatalyst capable of degrading different types of PUs and identified potential enzymes responsible as a key step in developing biotechnological process for PU waste treatment options.

The uncontrollable disposal of plastic waste has raised the concern of the scientific community, which tries to face this environmental burden by discovering and applying new techniques. Regarding the biotechnology field, several important microorganisms possessing the necessary enzymatic arsenal to utilize recalcitrant synthetic polymers as an energy source have been discovered. In the present study, we screened various fungi for their ability to degrade intact polymers, such as ether-based polyurethane (PU) and low-density polyethylene (LDPE). For this, ImpranIil® DLN-SD and a mixture of long-chain alkanes were used as sole carbon sources, indicating not only the most promising strains in agar plate screening but also inducing the secretion of depolymerizing enzymatic activities, useful for polymer degradation. The agar plate screening revealed three fungal strains belonging to Fusarium and Aspergillus genera, whose secretome was further studied for its ability to degrade the aforementioned non-treated polymers. Specifically for ether-based PU, the secretome of a Fusarium species reduced the sample mass and the average molecular weight of the polymer by 24.5 and 20.4%, respectively, while the secretome of an Aspergillus species caused changes in the molecular structure of LDPE, as evidenced by FTIR. The proteomics analysis revealed that the enzymatic activities induced in presence of Impranil® DLN-SD can be associated with urethane bond cleavage, a fact which was also supported by the observed degradation of the ether-based PU. Although, the mechanism of LDPE degradation was not completely elucidated, the presence of oxidative enzymes could be the main factor contributing to polymer modification.

The formulation of nanoemulsions by low-energy strategies, particularly by the phase inversion composition method, and the use of these nanoemulsions as templates for the preparation of polymer nanoparticles for biomedical applications are reviewed. The methods of preparation, nature of the components in the formulation, and their impact on the physicochemical properties, drug loading, and drug release are discussed. We highlight the utilization of ethyl cellulose, poly(lactic-co-glycolic acid), and polyurethane/polyurea in the field of nanomedicine as potential drug delivery systems. Advances are still needed to achieve better control over size distribution, nanoparticle concentration, surface functionalization, and the type of polymers that can be processed

In view of the global objective of carbon neutrality, using natural biomaterials to prepare bio-based polyurethane (BPU) is a significant means of reducing our heavy dependence on fossil fuels. If the utilization of these biomaterials is to increase, appropriate treatment methods after they reach the end of their life cycle are a challenge that must be addressed in advance. In the present study, thermogravimetric (TG) experiments were conducted for bio-based polyurethane (BPU) as a reference case compared to neat polyurethane (NPU) from fossil resources. The resultant generation of pyrolysis products was analyzed using coupled thermogravimetric analysis, Fourier-transformed infrared spectroscopy and gas chromatography mass spectrometry (TG-FTIR-GC/MS). The reaction kinetics were investigated using three model-free methods by Flynn–Wall–Ozawa (FWO), Kissinger–Akahira–Sunose (KAS), and Starink, in addition to the model-fitting Coats–Redfern (CR) method. The TG analysis indicated that the decomposition of BPU and NPU can be divided into three similar stages with temperature ranges of <200 °C, 220–450/500 °C and above 500 °C. Activation energies (Ea) of BPU and NPU conversion fell in the range of 149.4–221.0 kJ mol−1 and 95.6–162.6 kJ mol−1 respectively when using the model-free methods. The apparent reaction mechanism study revealed that both samples were in accordance with the reaction order models, with orders of 3 for BPU and 2.5 for NPU.

To investigate the impact of chain scission on the tensile properties of elastomers, a polyester-based polyurethane was aged in seawater at several temperatures ranging from 40 °C to 90 °C. Before the hydrolysis process, water diffusion was first characterized and described by Fickian behaviour. In terms of temperature dependence, both mass at saturation and water diffusivity followed Arrhenius behaviour. For ageing durations that exceed saturation time, ester bond hydrolysis occurs and leads to chain scission within the polymer network. This chain scission rate could be described using a first-order reaction and followed Arrhenius behaviour with an activation energy of 71 kJ/mol. From a mechanical point of view, hydrolysis leads to large changes in both stress and strain at break. A gradual decrease in stress at break was observed for all ageing temperatures. Nevertheless, strain at break first increases during ageing and then drops off when the crosslink density is below a critical value of 1.25 kg/mol. After considering more than 30 ageing conditions, relationships between the average crosslink density and these ultimate properties were proposed and discussed here.

During the last few years, cellular materials research has pointed to aerogels as one of the most promising materials. This is due to the combination of properties, such as their low density, large specific surface area, excellent thermal and acoustic insulation, and high porosity. These properties are the consequence of their interesting structures characterized by pores and particles in the nanometric scale. This thesis focuses on the synthesis and characterization of aerogels and aerogel-based composites. The main objective has been the development of polyurethane-based organic aerogels obtained by sol-gel technology followed by supercritical drying. These materials present interesting optical properties (transparency to visible light), a thermal conductivity below that of the aerogels previously described for this matrix (included in the superinsulating range), achieving values of 12 mW/mK, and superior mechanical properties than the widely investigated silica aerogels. Additionally, the effect of the addition of infrared blockers on its thermal conductivity has been studied. On the other hand, the incorporation of polyurethane foams with reticulated structures during the synthesis of silica aerogels has allowed the notable improvement of their mechanical properties, providing them with great stiffness and flexibility. In addition, these materials have excellent thermal insulation. As a result of this research, the relationship between formulation-process-structure-properties has been understood, so that, through the analysis of different parameters, their influence on the final properties has been identified. Thus, certain synthesis strategies are established allowing to obtain promising aerogels with potential application in the construction, automotive, and aeronautics sectors, among others. This thesis, supervised by Prof. Dr. Miguel Ángel Rodríguez-Pérez and Prof. Dr. Fernando Villafañe González, constitutes the opening of a new research line at CellMat Lab, Durante los últimos años, la investigación en campo de los materiales celulares ha señalado a los aerogeles como uno de los materiales más prometedores. Esto es debido a la combinación de propiedades entre las cuales se encuentran su baja densidad, gran superficie específica, excelente aislamiento térmico y acústico, y alta porosidad. Estas propiedades son la consecuencia directa de sus interesantes estructuras caracterizadas por tamaños de poro y partículas que se encuentran en la escala nanométrica. Esta tesis se centra en la síntesis y caracterización de aerogeles y materiales compuestos basados en aerogel. El principal objetivo ha sido el desarrollo de aerogeles orgánicos en base poliuretano obtenidos mediante la tecnología sol-gel seguida de secado supercrítico. Estos materiales presentan propiedades ópticas de interés (transparencia a la luz visible), una conductividad térmica por debajo de los aerogeles previamente descritos para esta matriz, que están comprendidos en el rango del superaislamiento consiguiendo valores de tan solo 12 mW/mK, y unas propiedades mecánicas superiores a los aerogeles de sílice ampliamente investigados. Adicionalmente, se ha estudiado el efecto de la adición de partículas bloqueadoras de la radiación infrarroja en su conductividad térmica. Por otro lado, la incorporación de espumas de poliuretano con estructuras reticuladas durante la síntesis de aerogeles de sílice ha permitido la notable mejora de sus propiedades mecánicas, proporcionándoles una gran resistencia a la compresión y flexibilidad. Además, estos materiales presentan un aislamiento térmico excelente. Como resultado de esta investigación, se ha comprendido la relación entre formulación- proceso-estructura propiedades, de forma que, mediante el análisis de diferentes parámetros, se ha identificado su influencia en las propiedades finales. Así, se establecen ciertas estrategias de síntesis que permiten la obtención de aerogeles prometedores con potencial aplicación en el s, Escuela de Doctorado, Doctorado en Física

One of the most important methods of controlling the properties of concrete and cement-based materials is to control the rate and kinetics of cement hydration. In the present study, novel flexible polyurethane-decorated MgO nanohybrids were synthesized using a simple chemical method, added to cement paste in different amounts, and utilized as an effective mechanical performance-enhancing factor for cement paste. It was observed that by adding 3 wt% synthesized PU-MgO nanohybrids to cement paste, its mechanical properties were improved and its compressive strength and flexural strength were increased by up to 13% and 15%, respectively, compared to the plain cement, after 45 days. The effect mechanism of adding PU–MgO nanoparticles on the properties of the cement paste was investigated. The addition of PU–MgO nanohybrids increased the pozzolanic reactions and formed more C-S-H phases., QC 20230613

Fibrous shape memory polymers (SMPs) have received growing interest in various applications, especially in biomedical applications, which offer new structures at the microscopic level and the potential of enhanced shape deformation of SMPs. In this paper, we report on the development and investigation of the properties of acrylate-based shape memory polymer fibers, fabricated by electrospinning technology with the addition of polystyrene (PS). Fibers with different diameters are manufactured using four different PS solution concentrations (25, 30, 35, and 40 wt%) and three flow rates (1.0, 2.5, and 5.0 mu L min(-1)) with a 25 kV applied voltage and 17 cm electrospinning distance. Scanning electron microscope (SEM) images reveal that the average fiber diameter varies with polymer concentration and flow rates, ranging from 0.655 +/- 0.376 to 4.975 +/- 1.634 mu m. Dynamic mechanical analysis (DMA) and stress-strain testing present that the glass transition temperature and tensile values are affected by fiber diameter distribution. The cyclic bending test directly proves that the electrospun SMP fiber webs are able to fully recover; additionally, the recovery speed is also affected by fiber diameter. With the combination of the SMP material and electrospinning technology, this work paves the way in designing and optimizing future SMP fibers properties by adjusting the fiber diameter.

Potentially high-performance lithium metal cells in extreme high-temperature electrochemical environments is a challenging but attractive battery concept that requires stable and robust electrolytes to avoid severely limiting lifetimes of the cells. Here, the properties of tailored polyester and polycarbonate diols as the soft segments in polyurethanes are investigated and electrochemically evaluated for use as solid polymer electrolytes in lithium metal batteries. The polyurethanes demonstrate high mechanical stability against deformation at low flow rates and moreover at temperatures up above 100 degrees C, enabled by the hard urethane segments. The results further indicate transferrable ion transport properties of the pure polymers when incorporated as the soft segments in the polyurethanes, offering designing opportunities of the polyurethane by tuning the soft segment ratio and composition. Long-term electrochemical cycling of polyurethane-containing cells in lithium metal batteries at 80 degrees C proves the stability at elevated temperatures as well as the compatibility with lithium metal with stable cycling maintained after 2000 cycles.

in this study, in situ polymerization procedure in solvent mixture was used for the preparation of thermosetting PU nanocomposites (PUNCs) with different content of soft segment (from 30 to 60 wt%), and with the addition of organomodified montmorillonite clay (Cloisite 30B®) as the nanofiller, in an amount of 0.5 wt.%. The PUNCs were based on poly(dimethylsiloxane) macrodiol (PDMS) that represents soft segment and 4,4′-diphenylmethane diisocyanate (MDI) and hyperbranched polyester (BH-30) which were selected as the hard segment. The PUNCs are marked. so that the last two numbers in title indicate wt.% of soft segment in materials. Namely, the main objective of this study is to analyze the effect of the soft segment content on the morphology of the prepared PU nanocomposite films using atomic force microscopy (AFM), scanning electron microscopy (SEM), and small- and near wide-angle X-Ray scattering (SWAXS) analyses. SEM images of the fractured surfaces were obtained on JEOL JSM-6610LV. AFM analysis was carried out by atomic force microscope (Dimension Icon, Bruker, USA). SWAXS measurements of the PUNCs were performed using SAXS instrument (originally Molecular Metrology, USA, recently considerably upgraded by SAXSLAB, now Xenocs).

Nanocelluloses, the crystalline domains isolated from native cellulose, have gained increasing attention due to their uniquely ultra-high elastic modulus, low axial thermal expansion coefficient, and biocompatibility. All nanocelluloses in the market are hydrophilic and incompatible with most organic liquids and most synthesized polymers, limiting their applications which stated in the 1st chapter. In the 2nd chapter one-pot synthesis of 2-bromopropionyl esterified cellulose nanofibrils (Br-CNFs) coupled with in-situ disintegration by ultrasonication was developed and streamlined in processing and/or matrix media. This coupled functionalization and ultrasonication approach has been optimized to prepare Br-CNFs with tunable levels of esterification in high yields and imaged by atomic force microscopy (AFM) and transmission electron microscopy (TEM). The structures of Br-CNFs were further characterized by Fourier-transform infrared (FTIR) and liquid phase proton nuclear magnetic resonance (1H NMR) spectroscopy. Thermal properties and crystallinity of Br-CNFs were characterized by thermogravimetric analysis (TGA) and X-ray diffraction (XRD), respectively. In the 3rd chapter, the organic compatibility and reactivity of these Br-CNFs have been demonstrated in their polyol role in replacing soft segment or as chain extender in synthesizing polyurethanes with significantly improved modulus (3x), strength (4x), and strain (1.5x) at merely 0.3 w% as polyol or 1.8 w% as extender. The Br bearing esters of these high specific surface Br-CNFs make them excellent macroinitiators for atom transfer radical polymerization (ATRP) of defined lengths of surface polymer grafts on crystalline cellulose, all described in 4th chapter. Br-CNF-g-PLMA from ATRP surface grafting of polylauryl methacrylate (PLMA) have shown to exhibit combined shear thinning behavior of Br-CNF proved by flow behavior index n< 1 and drag reducing effects of PLMA with up to 21071x increased viscosity. Moreover

To investigate the impact of chain scission on the tensile properties of elastomers, a polyester-based polyurethane was aged in seawater at several temperatures ranging from 40 °C to 90 °C. Before the hydrolysis process, water diffusion was first characterized and described by Fickian behaviour. In terms of temperature dependence, both mass at saturation and water diffusivity followed Arrhenius behaviour. For ageing durations that exceed saturation time, ester bond hydrolysis occurs and leads to chain scission within the polymer network. This chain scission rate could be described using a first-order reaction and followed Arrhenius behaviour with an activation energy of 71 kJ/mol. From a mechanical point of view, hydrolysis leads to large changes in both stress and strain at break. A gradual decrease in stress at break was observed for all ageing temperatures. Nevertheless, strain at break first increases during ageing and then drops off when the crosslink density is below a critical value of 1.25 kg/mol. After considering more than 30 ageing conditions, relationships between the average crosslink density and these ultimate properties were proposed and discussed here.

Although the effects produced by the surface treatment of rubber with organic solvent solutions of trichloroisocyanuric acid (TCI) leading to improved adhesion to polyurethane (PU) adhesive have been established, the mechanism of adhesion involved is still unclear. In this study, the reaction of TCI species on the rubber surface with the PU adhesive leading to the formation of chemical bonds was proposed as the relevant mechanism of adhesion. As a model, TCI was added to polyurethane adhesive (PU + TCI), and a polyurethane film was immersed in TCI solution (PU − TCI), their surface, structural, and viscoelastic properties were monitored for different times. The formation of chemical bonds between the polyurethane chains and TCI species derived from the solid TCI crystals on the rubber surface during bonding formation, and the crosslinking/hardening of the PU surface were evidenced. The reaction with TCI species increased the surface energy on the PU, mainly the polar component, similar surface energies were obtained in both PU + TCI and PU − TCI after 7 days. The enhanced surface energies on the PU that reacted with TCI were ascribed to the creation of new C–Cl and C=O species, their percentages were higher on PU + TCI than on PU − TCI surface. On the other hand, new N–H stretching and carbonyl species were produced; this indicated that TCI species interacted with the hard segments. Furthermore, the crystallization peaks in PU + TCI and PU − TCI at higher temperatures and lower enthalpies than in PU indicated the disruption of the interactions between the soft segments. Therefore, the structural changes in the PU caused by reaction with TCI species affected their degree of phase separation and viscoelastic properties. The addition of solid TCI to the PU caused a noticeable degradation and hardening, the extent of degradation was more marked by increasing the time, this led to lower mechanical properties.

In this research, both experimental test methods and computer models were used to characterise the thermal decomposition processes of selected upholstered furniture component materials, namely; flexible polyurethane foam and a range of different fabric coverings. This was first done at some of the smallest, simplest levels available, and how these materials were tested and the methods chosen to investigate them, was examined. Results here already showed the importance of thorough material characterisation and how sensitivity analysis on the chosen research tools can give the researcher a much better knowledge base to begin further studies. A direct result of this was the production of one of few full factorial analyses within fire research used to characterise the influence of test input on the experimental outcomes.From there, the obtained material characterisation parameters were used to move up the scale in both size and material complexity and investigate how this acquired knowledge from a previous lower scale can be used to predict the fire behaviour as the complexity was increased. Modelling was used to simulate material fire behaviour at a larger scale based on the model input parameters obtained at a previous simpler scale. Additionally, extended experiments, at the larger scales, were performed to act as validation for the models, but were also used to investigate the effects of increasing complexity. One of the outcomes from this work was the development of new or modified testing methods that were designed to provide new knowledge on smoke development, and improve the ability to use fire test outcomes as a means of model validation for the scaling process. Furthermore, investigations at the middle scale highlighted complex interactions when different materials (e.g. foam core and fabric cover) were combined to form a composite product. The form of interaction was also dependent on the type of fabric used, and these interactions were found to be unpredicta

Potentially high-performance lithium metal cells in extreme high-temperature electrochemical environments is a challenging but attractive battery concept that requires stable and robust electrolytes to avoid severely limiting lifetimes of the cells. Here, the properties of tailored polyester and polycarbonate diols as the soft segments in polyurethanes are investigated and electrochemically evaluated for use as solid polymer electrolytes in lithium metal batteries. The polyurethanes demonstrate high mechanical stability against deformation at low flow rates and moreover at temperatures up above 100 degrees C, enabled by the hard urethane segments. The results further indicate transferrable ion transport properties of the pure polymers when incorporated as the soft segments in the polyurethanes, offering designing opportunities of the polyurethane by tuning the soft segment ratio and composition. Long-term electrochemical cycling of polyurethane-containing cells in lithium metal batteries at 80 degrees C proves the stability at elevated temperatures as well as the compatibility with lithium metal with stable cycling maintained after 2000 cycles.

Big quantities of residues and side-streams are generated annually from forest-based and agricultural industries all around the world and present a relatively unexplored renewable resource. Due to the absence of a regularly updated and systematic database of supply, industrial residues and side-streams usually end up in landfill disposal, are used for energy generation, or remain at the production sites. These renewable side-streams are mainly lignocellulosic materials that can be used for fuels, chemicals, and other value-added materials. However, the difficulty in recovering useful components from industrial wastes from a techno-economic point of view is hindering the use of these materials. There are different methods for converting biomass into fuels, chemicals, and materials, including thermochemical, biochemical, and physical conversion. Negative environmental impacts from direct incineration of waste materials and increasing interest in reducing the dependency on fossil-based sources have increased the need for the valorization of the industrial side-streams for material and chemical applications. Among the different thermochemical conversion methods, liquefaction of lignocellulosic materials is an efficient way to convert solid biomass into liquids. Liquefaction including hydrothermal liquefaction (HTL) and moderate acid-catalyzed liquefaction (MACL), is often carried out in an aqueous environment by employing organic solvents with or without catalyst under pressure or ambient conditions. A liquefaction process is influenced by many factors such as material type, solvent, catalyst, time, and temperature. All the parameters of the liquefaction are related to each other, and they affect the yields and the properties of the final products. Studies on the utilization of industrial waste and side-streams as feedstock for liquefaction have increased in recent years, generating significant interest from both academia and industry. This PhD study included a liter, Formas project 942-2016-2 (2017-21) - Utilization of renewable biomass and waste materials for production of environmental-friendly, bio-based composites

Potentially high-performance lithium metal cells in extreme high-temperature electrochemical environments is a challenging but attractive battery concept that requires stable and robust electrolytes to avoid severely limiting lifetimes of the cells. Here, the properties of tailored polyester and polycarbonate diols as the soft segments in polyurethanes are investigated and electrochemically evaluated for use as solid polymer electrolytes in lithium metal batteries. The polyurethanes demonstrate high mechanical stability against deformation at low flow rates and moreover at temperatures up above 100 degrees C, enabled by the hard urethane segments. The results further indicate transferrable ion transport properties of the pure polymers when incorporated as the soft segments in the polyurethanes, offering designing opportunities of the polyurethane by tuning the soft segment ratio and composition. Long-term electrochemical cycling of polyurethane-containing cells in lithium metal batteries at 80 degrees C proves the stability at elevated temperatures as well as the compatibility with lithium metal with stable cycling maintained after 2000 cycles.

[EN] Polyurethane foams are presented as very interesting materials as substrates for the horticultural sector. However, there is currently no systematic study available to optimize the physical and chemical properties of this type of substrates. In this work, four series of foams have been prepared to evaluate their performance according to the role of each of their components. In this type of synthetic soils, the density of the foams, their water holding capacity and cell size have been analyzed. As a differentiating element, in the proposed formulations, components with a high content of oxyethylene units have been used to improve water retention. In addition, to avoid chemical contamination of the plant, components capable of immobilizing within the foam matrix were used. Finally, the systematic study was completed with a morphological characterization and its correlation with the water holding capacity., [ES] Las espumas de poliuretano se presentan como materiales muy interesantes como sustrato para el sector horticultural. Sin embargo, actualmente no se dispone de un estudio sistemático de optimización de las propiedades físicas y químicas de este tipo de sustratos. En este trabajo se han preparado cuatro series de espumas, para evaluar sus prestaciones en función del papel de cada uno de sus componentes. En este tipo de suelos sintéticos, se ha estudiado la densidad de las espumas, su capacidad de retención de agua y el tamaño de las celdas. Como elemento diferencial, en las formulaciones propuestas, se han utilizado componentes con un alto contenido en unidades oxietilénicas, para mejorar la retención de agua. Además, para evitar una contaminación química de la planta, se han usado componentes capaces de inmovilizarse dentro de la matriz de la espuma. Finalmente, el estudio sistemático se completó con una caracterización morfológica y su correlación con la capacidad de retención de agua.

Polyurethanes are gaining increasing interest for their use as structural components subjected to cyclic loads, such as leaf springs. Thermoset polyurethane (PUR) based technology offers some advantages, such as fatigue resistance, low viscosity, and fast curing. However, current PUR formulations present two major drawbacks: their petrochemical origin and high reactivity. The aim of this work was to develop a novel biobased PUR (BIO-PUR) with the required mechanical properties and processability for manufacturing structural composites by resin transfer moulding (RTM). For this purpose, a high functionality and high hydroxyl index castor-oil-based polyol was used combined with a biobased glycerol (BIO-Gly) to increase the crosslinking density and improve the final properties of the BIO-PUR. The viscosity and reactivity of the different systems were studied by means of rheology tests and differential scanning calorimetry (DSC). Thermal and mechanical properties were studied by dynamic mechanical analysis (DMA) and flexural tests. Furthermore, the RTM process of a representative part was simulated and validated through the manufacturing and testing of plates. The properties of the BIO-PUR resin systems were strongly influenced by the addition of biobased glycerol and its effect on the crosslinking density. The combination of a high functionality and hydroxyl index biobased polyol with the biobased glycerol resulted in a high-performance BIO-PUR with the required reactivity and final properties for structural applications.

The Government of India has launched the Azadi Ka Amrit Mahotsav to honour and celebrate 75 years of progressive India and the glorious history of its people, culture, and achievements. This conference provides a platform for deliberations on sustainability as a form of celebration of the progress of the country. In the contemporary world, sustainability has emerged as an important area of focus in research, education, and practice. The principles of sustainability recommend an integrated approach that takes environmental and social concerns along with economic development. Sustainability is a paradigm concerned about the future in which environmental, societal, and economic considerations are balanced in the pursuit of improved quality of life. A two-day International conference on ‘Sustainability: Research, Education and Practice (SREP-2022)’ on 30-31 May, 2022 was organized by the Department of Management, BIT Mesra , Jaipur , Lalpur, Noida and Patna Campuses under the aegis of Azadi Ka Amrit Mahotsav.&nbsp

Sammanfattning på svenska: Billacker är exponerade för solljus och nederbörd under hela lackens livslängd. Lacker behöver motstå faktorer i omgivningen som påverkar nedbrytningen för att leva upp till högt ställda visuella krav. Metoder för att bromsa nedbrytningsprocesser kan utvecklas med hjälp av analys av nedbrytningen av lackerna. Målet med detta arbete är att utvärdera möjliga analysmetoder och experimentella tillvägagångssätt för att analysera kemiska nedbrytningsprocesser i akrylat-melamin- och akrylat-isocyanatsystem. Akrylat-melamin- och akrylat-isocyanatsystem har i denna uppsats studerats med olika analysmetoder. Resultaten visar att FTIR (Fourier Transform Infrared) spektroskopi med dämpad totalreflektion (FTIR-ATR) detekterar kemiska förändringar tidigare än andra metoder, såsom glansmätningar, kulörmätningar och ljusoptiskt mikroskop. Tecken på hydrolys och fotooxidation observerades med FTIR-ATR i ett tidigt skede av accelererad provning. Två beräkningssätt, fotooxidationsindex (POI) och melaminförlust, visade på kemiska förändringar i lackerna. Billacker med röd kulör uppvisade de allvarligaste tecknen på nedbrytning., Automotive coatings are exposed to sunlight and rain during the entire service life. Coatings need to withstand degradation factors in the environment in order to maintain high visual demands. Methods to delay the degradation processes can be developed through the analysis of the degradation of the coatings. The purpose of this thesis is to evaluate possible analytical methods and experimental procedures to analyze chemical degradation processes in acrylate-melamine and acrylate-isocyanate systems. Acrylate-melamine and acrylate-isocyanate systems have been studied with different analytical methods in this work. The results show that Fourier Transform Infrared Spectroscopy with attenuated total reflection (FTIR-ATR) detects chemical changes in the coatings earlier than other methods, such as gloss measurements, colour measurements and Light-Optical Microscope. Signs of hydrolysis and photooxidation were observed with FTIR-ATR in an early stage of accelerated testing. Two calculations, photo-oxidation index (POI) and melamine loss indicated chemical changes in the coatings. Automotive coatings of red colours showed the most severe signs of degradation.

Big quantities of residues and side-streams are generated annually from forest-based and agricultural industries all around the world and present a relatively unexplored renewable resource. Due to the absence of a regularly updated and systematic database of supply, industrial residues and side-streams usually end up in landfill disposal, are used for energy generation, or remain at the production sites. These renewable side-streams are mainly lignocellulosic materials that can be used for fuels, chemicals, and other value-added materials. However, the difficulty in recovering useful components from industrial wastes from a techno-economic point of view is hindering the use of these materials. There are different methods for converting biomass into fuels, chemicals, and materials, including thermochemical, biochemical, and physical conversion. Negative environmental impacts from direct incineration of waste materials and increasing interest in reducing the dependency on fossil-based sources have increased the need for the valorization of the industrial side-streams for material and chemical applications. Among the different thermochemical conversion methods, liquefaction of lignocellulosic materials is an efficient way to convert solid biomass into liquids. Liquefaction including hydrothermal liquefaction (HTL) and moderate acid-catalyzed liquefaction (MACL), is often carried out in an aqueous environment by employing organic solvents with or without catalyst under pressure or ambient conditions. A liquefaction process is influenced by many factors such as material type, solvent, catalyst, time, and temperature. All the parameters of the liquefaction are related to each other, and they affect the yields and the properties of the final products. Studies on the utilization of industrial waste and side-streams as feedstock for liquefaction have increased in recent years, generating significant interest from both academia and industry. This PhD study included a liter, Formas project 942-2016-2 (2017-21) - Utilization of renewable biomass and waste materials for production of environmental-friendly, bio-based composites

Big quantities of residues and side-streams are generated annually from forest-based and agricultural industries all around the world and present a relatively unexplored renewable resource. Due to the absence of a regularly updated and systematic database of supply, industrial residues and side-streams usually end up in landfill disposal, are used for energy generation, or remain at the production sites. These renewable side-streams are mainly lignocellulosic materials that can be used for fuels, chemicals, and other value-added materials. However, the difficulty in recovering useful components from industrial wastes from a techno-economic point of view is hindering the use of these materials. There are different methods for converting biomass into fuels, chemicals, and materials, including thermochemical, biochemical, and physical conversion. Negative environmental impacts from direct incineration of waste materials and increasing interest in reducing the dependency on fossil-based sources have increased the need for the valorization of the industrial side-streams for material and chemical applications. Among the different thermochemical conversion methods, liquefaction of lignocellulosic materials is an efficient way to convert solid biomass into liquids. Liquefaction including hydrothermal liquefaction (HTL) and moderate acid-catalyzed liquefaction (MACL), is often carried out in an aqueous environment by employing organic solvents with or without catalyst under pressure or ambient conditions. A liquefaction process is influenced by many factors such as material type, solvent, catalyst, time, and temperature. All the parameters of the liquefaction are related to each other, and they affect the yields and the properties of the final products. Studies on the utilization of industrial waste and side-streams as feedstock for liquefaction have increased in recent years, generating significant interest from both academia and industry. This PhD study included a liter, Formas project 942-2016-2 (2017-21) - Utilization of renewable biomass and waste materials for production of environmental-friendly, bio-based composites

The Government of India has launched the Azadi Ka Amrit Mahotsav to honour and celebrate 75 years of progressive India and the glorious history of its people, culture, and achievements. This conference provides a platform for deliberations on sustainability as a form of celebration of the progress of the country. In the contemporary world, sustainability has emerged as an important area of focus in research, education, and practice. The principles of sustainability recommend an integrated approach that takes environmental and social concerns along with economic development. Sustainability is a paradigm concerned about the future in which environmental, societal, and economic considerations are balanced in the pursuit of improved quality of life. A two-day International conference on ‘Sustainability: Research, Education and Practice (SREP-2022)’ on 30-31 May, 2022 was organized by the Department of Management, BIT Mesra , Jaipur , Lalpur, Noida and Patna Campuses under the aegis of Azadi Ka Amrit Mahotsav.&nbsp

Potentially high-performance lithium metal cells in extreme high-temperature electrochemical environments is a challenging but attractive battery concept that requires stable and robust electrolytes to avoid severely limiting lifetimes of the cells. Here, the properties of tailored polyester and polycarbonate diols as the soft segments in polyurethanes are investigated and electrochemically evaluated for use as solid polymer electrolytes in lithium metal batteries. The polyurethanes demonstrate high mechanical stability against deformation at low flow rates and moreover at temperatures up above 100 degrees C, enabled by the hard urethane segments. The results further indicate transferrable ion transport properties of the pure polymers when incorporated as the soft segments in the polyurethanes, offering designing opportunities of the polyurethane by tuning the soft segment ratio and composition. Long-term electrochemical cycling of polyurethane-containing cells in lithium metal batteries at 80 degrees C proves the stability at elevated temperatures as well as the compatibility with lithium metal with stable cycling maintained after 2000 cycles.

Potentially high-performance lithium metal cells in extreme high-temperature electrochemical environments is a challenging but attractive battery concept that requires stable and robust electrolytes to avoid severely limiting lifetimes of the cells. Here, the properties of tailored polyester and polycarbonate diols as the soft segments in polyurethanes are investigated and electrochemically evaluated for use as solid polymer electrolytes in lithium metal batteries. The polyurethanes demonstrate high mechanical stability against deformation at low flow rates and moreover at temperatures up above 100 degrees C, enabled by the hard urethane segments. The results further indicate transferrable ion transport properties of the pure polymers when incorporated as the soft segments in the polyurethanes, offering designing opportunities of the polyurethane by tuning the soft segment ratio and composition. Long-term electrochemical cycling of polyurethane-containing cells in lithium metal batteries at 80 degrees C proves the stability at elevated temperatures as well as the compatibility with lithium metal with stable cycling maintained after 2000 cycles.

The development of two novel elastomeric erosion resistant coatings for the protection of wind turbine blades is presented. The coatings are prepared by modifying polyurethane (PU) with (i) hydroxyl functionalised graphene nanoparticles (f-GNP) and (ii) f-GNP and a hydrophobic silica-based sol–gel (SG). Tensile, monotonic and cyclic compression and tearing tests have been conducted on the neat PU and the two newly developed elastomeric PU nanocomposites (PU + GNP and PU + GNP + SG) to allow their properties to be compared. The test results showed that the mechanical properties of PU and the modified PUs have strong dependency on temperature, strain rate and nanoparticles loading and addition of GNP and SG to PU improved the mechanical properties. Compared to PU, Young’s modulus and modulus of toughness of PU + GNP + SG increased 95% and 124%, respectively. The PU + GNP nanocomposite displayed the highest tearing strength and the PU + GNP + SG nanocomposite showed the highest elongation at break. An investigation of the microstructures of the modified PUs by FTIR, field emission scanning electron microscope (FESEM) and energy-dispersive X-ray spectroscopy (EDX) are discussed. Hydrophobicity of the PU and developed PU nanocomposites are reported by measuring their water droplet contact angles and their free surface energies.

Big quantities of residues and side-streams are generated annually from forest-based and agricultural industries all around the world and present a relatively unexplored renewable resource. Due to the absence of a regularly updated and systematic database of supply, industrial residues and side-streams usually end up in landfill disposal, are used for energy generation, or remain at the production sites. These renewable side-streams are mainly lignocellulosic materials that can be used for fuels, chemicals, and other value-added materials. However, the difficulty in recovering useful components from industrial wastes from a techno-economic point of view is hindering the use of these materials. There are different methods for converting biomass into fuels, chemicals, and materials, including thermochemical, biochemical, and physical conversion. Negative environmental impacts from direct incineration of waste materials and increasing interest in reducing the dependency on fossil-based sources have increased the need for the valorization of the industrial side-streams for material and chemical applications. Among the different thermochemical conversion methods, liquefaction of lignocellulosic materials is an efficient way to convert solid biomass into liquids. Liquefaction including hydrothermal liquefaction (HTL) and moderate acid-catalyzed liquefaction (MACL), is often carried out in an aqueous environment by employing organic solvents with or without catalyst under pressure or ambient conditions. A liquefaction process is influenced by many factors such as material type, solvent, catalyst, time, and temperature. All the parameters of the liquefaction are related to each other, and they affect the yields and the properties of the final products. Studies on the utilization of industrial waste and side-streams as feedstock for liquefaction have increased in recent years, generating significant interest from both academia and industry. This PhD study included a liter, Formas project 942-2016-2 (2017-21) - Utilization of renewable biomass and waste materials for production of environmental-friendly, bio-based composites

Big quantities of residues and side-streams are generated annually from forest-based and agricultural industries all around the world and present a relatively unexplored renewable resource. Due to the absence of a regularly updated and systematic database of supply, industrial residues and side-streams usually end up in landfill disposal, are used for energy generation, or remain at the production sites. These renewable side-streams are mainly lignocellulosic materials that can be used for fuels, chemicals, and other value-added materials. However, the difficulty in recovering useful components from industrial wastes from a techno-economic point of view is hindering the use of these materials. There are different methods for converting biomass into fuels, chemicals, and materials, including thermochemical, biochemical, and physical conversion. Negative environmental impacts from direct incineration of waste materials and increasing interest in reducing the dependency on fossil-based sources have increased the need for the valorization of the industrial side-streams for material and chemical applications. Among the different thermochemical conversion methods, liquefaction of lignocellulosic materials is an efficient way to convert solid biomass into liquids. Liquefaction including hydrothermal liquefaction (HTL) and moderate acid-catalyzed liquefaction (MACL), is often carried out in an aqueous environment by employing organic solvents with or without catalyst under pressure or ambient conditions. A liquefaction process is influenced by many factors such as material type, solvent, catalyst, time, and temperature. All the parameters of the liquefaction are related to each other, and they affect the yields and the properties of the final products. Studies on the utilization of industrial waste and side-streams as feedstock for liquefaction have increased in recent years, generating significant interest from both academia and industry. This PhD study included a liter, Formas project 942-2016-2 (2017-21) - Utilization of renewable biomass and waste materials for production of environmental-friendly, bio-based composites

Sammanfattning på svenska: Billacker är exponerade för solljus och nederbörd under hela lackens livslängd. Lacker behöver motstå faktorer i omgivningen som påverkar nedbrytningen för att leva upp till högt ställda visuella krav. Metoder för att bromsa nedbrytningsprocesser kan utvecklas med hjälp av analys av nedbrytningen av lackerna. Målet med detta arbete är att utvärdera möjliga analysmetoder och experimentella tillvägagångssätt för att analysera kemiska nedbrytningsprocesser i akrylat-melamin- och akrylat-isocyanatsystem. Akrylat-melamin- och akrylat-isocyanatsystem har i denna uppsats studerats med olika analysmetoder. Resultaten visar att FTIR (Fourier Transform Infrared) spektroskopi med dämpad totalreflektion (FTIR-ATR) detekterar kemiska förändringar tidigare än andra metoder, såsom glansmätningar, kulörmätningar och ljusoptiskt mikroskop. Tecken på hydrolys och fotooxidation observerades med FTIR-ATR i ett tidigt skede av accelererad provning. Två beräkningssätt, fotooxidationsindex (POI) och melaminförlust, visade på kemiska förändringar i lackerna. Billacker med röd kulör uppvisade de allvarligaste tecknen på nedbrytning., Automotive coatings are exposed to sunlight and rain during the entire service life. Coatings need to withstand degradation factors in the environment in order to maintain high visual demands. Methods to delay the degradation processes can be developed through the analysis of the degradation of the coatings. The purpose of this thesis is to evaluate possible analytical methods and experimental procedures to analyze chemical degradation processes in acrylate-melamine and acrylate-isocyanate systems. Acrylate-melamine and acrylate-isocyanate systems have been studied with different analytical methods in this work. The results show that Fourier Transform Infrared Spectroscopy with attenuated total reflection (FTIR-ATR) detects chemical changes in the coatings earlier than other methods, such as gloss measurements, colour measurements and Light-Optical Microscope. Signs of hydrolysis and photooxidation were observed with FTIR-ATR in an early stage of accelerated testing. Two calculations, photo-oxidation index (POI) and melamine loss indicated chemical changes in the coatings. Automotive coatings of red colours showed the most severe signs of degradation.

A framework for optimizing the design of elastomer packaging machine tools, so­ called plunge tools, has been developed and has reached a proof­of­concept state in this thesis. The framework indicates the capability of decreasing prototype expenses and total development time of new plunge tools by roughly three times compared to the existing iterative design methodology. A finite element analysis (FEA) model serves as the core of the framework. Physical experiments based on Design of Experiments (DoE) theory have been conducted to validate the model and, with regression analysis, screen system factors influential on plunge tool performance. The experiments were also useful in detecting large differ­ences in plunge tool performance between the regular plunge tools and the additively manufactured plunge tools currently used as prototypes. Response surface methodology (RSM) has been used together with the FEA model to optimize the design. An optimal space­filling design point scheme used together with a Kriging interpolation response surface was found to be more capable of predict­ ing the FEA model responses than three other configurations. An optimized plunge design was generated with the framework after roughly 24 hours of computation time on an average desktop computer from 2013. The design had large similarities to a production design developed with manual iterative design development but performed even better in the simulation.

The enormous production and consumption of fossil-based plastics has caused severe environmental challenges such as pollution of the ocean, increased CO2-emissions, and various health problems. Many ofthese concerns are intimately connected to the use of fossil fuels in the production of polymers. For this reason, there is a considerable interest to develop bio-based monomers to mitigate some of the issues connected tofossil-based plastics. However, new bio-based monomers are often expensive and need some material advantages to facilitate their market entry. In this context, we have designed several new monomers byconverting bio-based molecules such as 5-chloromethylfurfural (CMF), 5-hydroxymethylfurfural (HMF) and vanillin into rigid diols for polyester and polyurethane synthesis. This thesis has been divided into 5 chaptersdescribing the most important findings from each underlying project.In Chapter 1 and 2, HMF was reacted with pentaerythritol and di(trimethylolpropane) to make two rigid diols with cyclic acetal structures. The monomer made from HMF and pentaerythritol was predicted to have anexceptionally low carbon footprint according to our LCA calculations. These diols were further used to synthesize a series of polyesters and polyurethanes with increased glass transition temperatures. Polyurethanesynthesis was deemed more suitable for this type of monomers, since degradation occurred at the high temperatures required for polyester synthesis. The obtained polyurethanes were used to prepare coatings andtextile fibers. Furthermore, the cyclic acetal structure of the monomers enabled chemical recycling under acidic conditions. In Chapter 3, HMF was produced in a continuous process from fructose, using water anddimethylcarbonate (DMC) in a biphasic system. Both yield and conversion were excellent, demonstrating the utility of DMC for HMF synthesis. The HMF synthesized by this method was sufficiently pure for preparation ofthe monomers in Chapters 1 and 2 in comp

The diverse benefits of synthetic polymers is overshadowed by the amount of plastic waste and its whereabouts. The problem can only be tackled by reducing and recycling of plastics. In this respect, investigating the (microbial) degradation of each type of polymer currently used may provide further understanding that fosters the development of new feasible recycling technologies. Here, we present a strategy to isolate bacteria from environmental samples that are able to degrade hydrolysis products and building blocks of polyurethane (PUR). Protocols are presented to enrich bacteria on the primary diamines 2,4-diaminotoluene (TDA) and 4,4′-diaminodiphenylmethane (MDA) as well as an oligomeric PUR (Sigma Aldrich, proprietary composition). For TDA and the oligomeric PUR, methods are suggested to monitor their concentration in bacterial enrichment cultures.

Producción Científica, The effect of the catalyst concentration on the synthesis and textural properties of polyisocyanurate-polyurethane aerogels is analyzed. The use of different catalyst amounts allows obtaining low-density aerogels (0.10–0.16 g/cm3) with high porosities (85–91%). Their porous structures were analyzed by scanning electron microscopy and nitrogen adsorption–desorption isotherm. A noticeable decrease in the size of the scattering centers, particles and pores, was achieved when reducing the catalyst amount. In some samples, the small size of these features, much smaller than the wavelength of visible light, causes a bare light dispersion, leading to the first transparent polyisocyanurate-polyurethane aerogels. Light transmittance measurements at 532 nm have been made showing high values (ca. 76% for 1 mm thick samples) for the formulations with the smallest particle and pore sizes. These aerogels presenting optical transparency have many potential applications such as solar collectors, glazing systems for insulating windows, and sensors, among others., Ministerio de Ciencia, Innovación y Universidades (grant RTI2018-098749-B-I00), Junta de Castilla y León (grant VA202P20)

Facile monomer synthesis provided routes towards novel step-growth polymers for emerging applications. Adjustment of reaction conditions enabled green synthetic strategies, and promising scalability studies offered impetus for industrial funding. Engineering thermoplastics, such as linear polyetherimides (PEIs), had carefully targeted molecular weights for analysis of the effect of molecular weight and regiochemistry on the thermomechanical and rheological properties of PEIs. The design of linear, high performance PEIs comprising 3,3'- and 4,4'-bisphenol-A dianhydride (bis-DA) and m-phenylene diamine (mPD) provided an opportunity to elucidate the influence of dianhydride regiochemistry on thermomechanical and rheological properties. This unique pair of regioisomers allowed the tuning of the thermal and rheological properties for high glass transition temperature polyimides for engineering applications. The selection of the dianhydride regioisomer influenced the weight loss profile, entanglement molecular weight, glass transition temperature (Tg), tensile strain-at-break, zero-shear melt viscosity, average hole-size free volume, and the plateau modulus prior to viscous flow during dynamic mechanical analysis (DMA). The 3,3'-PEI composition interestingly exhibited a ~20 °C higher Tg than the corresponding 4,4'-PEI analog. Moreover, melt rheological analysis revealed a two-fold increase in Me for 3,3'-PEI, which pointed to the origin of the differences in mechanical and rheological properties as a function of PEI backbone geometry. The frequently studied 4,4'-PEI exhibited exceptional thermal, mechanical, and rheological properties, yet the 3,3'-PEI regioisomer lacked significant study in the industrial and academic sectors due to its 'inferior' properties, namely poor mechanical properties. Introduction of long-chain branching (LCB) into PEIs provided a unique comparison between a commercially relevant PEI (Ultem® 1000) and a regioisomer infrequently found in the lite