Asymmetric polymeric materials can be formed by either top-down or bottom-up methods. Bottom-up methods involve assembling the atoms and molecules to form small nanostructures by carefully controlled synthesis, which results in a reduction of some of the top-down limitations. In this dissertation, thermal, tribological and antireflective properties of polymeric materials have been enhanced by introducing structural asymmetry. The overall performance of commercial polymeric coatings, e.g. epoxy and polyvinyl chloride, has been improved by conducting the blending methods, specifically, chemical modification (α,ω-dihydroxydimethyl(methyl-vinyl)oligoorganosiloxane), cross-linking (triallyl isocyanurate), and antioxidant (tris(nonylphenyl) phosphite) incorporation. The nonequilibrium polymeric structures (moth-eye and square array) have been developed for the ultrahigh molecular weight block copolymers via the short-term solvent vapor annealing self-assembly. The large domain size of the moth eye structure allows for improvement of the light transmittance particularly in the visible and near infrared ranges, while the square arrangement of the block copolymer opens the possibility of magnetic data storage application by the large magnetic nanoparticles' embedment or masking of the superconductors.

In this study, traditional Japanese washi paper was sandwiched with poly(butylene succinate)(PBS) in order to produce a paper-based composite material that can be biologically degraded. Specimens were prepared using a hot press, and the mechanical properties of the washi paperand the new composite material were investigated by tensile tests. The cross-sections of specimens were then observed with a digital microscope as well as by scanning electron microscope (SEM) analysis. The microscope images indicated that therelatively hollow washi provides a structure for the polymer to settle into, which could contribute to the improved strength of the composite material. Specimens made from three layers of washipaper and combined with two layers of PBS film had remarkable mechanical propertiesincluding a UTS of 95 MPa.The composite material was incubated in compost and a MODA C-S (Microbial Oxidative Degradation Analyzer) was used to evaluate its biodegradability. The material showed good biodegradability with significant losses of mass (-32 %) as well as major loss of mechanical strength after four weeks of incubation. The biodegradability of the material will be further investigated.

Polyamides are commonly used in additive manufacturing for final part production, but the material performance can be affected by environmental conditions. The purpose of this project was to evaluate the effects of moisture and temperature on 3D printed polyamides and how structural optimization can benefit from condition-specific data. Conditioned and unconditioned specimens were tensile tested in regions of -20 °C, 23 °C and 60 °C. Two techniques were evaluated; multi jet fusion and selective laser sintering, and mainly two polyamides; polyamide 11 and polyamide 12. Simulations with the obtained data were performed as well as conceptual structural optimization with the intent of optimizing for the intended end-use environment. Infrared thermography provided specimen temperatures as well as temperature and strain relations present during testing. The stress-strain curves obtained showed generally decreasing stiffness and strength with increasing moisture and temperature, albeit moisture in certain cases increased the tensile modulus at freezing temperatures. Temperature affected stiffness and strength more so than moisture. Polyamide 11 absorbed moisture at a higher rate than polyamide 12. The mechanical performance of laser-sintered polyamide 12 was superior, while laser-sintered polyamide 11 showed great elongation before breakage. Further investigation of polymer crystallinity could explain the behaviour of the 3D printed polyamides.

The thesis contains a background and reflections section, an introduction, and three appended articles. The first section is reserved for some of the background and basics on polymers and polymer composites and a discussion on their effect on our everyday lives. The introduction gives a brief recap of the project. The articles contain the research that was performed on the thermal oxidation of thermosetting polyimides and their composites during the project. The first article covered the thermal oxidative degradation of satin weave and thin-ply composites made by resin transfer molding with carbon fibers and thermosetting polyimide. The degradation was studied by weight loss measurements and X-ray computed microtomography. The weight loss measurements showed that the initial desorption stage during ageing followed Fickian behavior and the proposed model. It was also observed that the satin weave composites formed crack clusters that grew into a network of cracks, voids and delaminations throughout the specimens as the ageing time progressed, while the thin-ply composites only formed delaminations at the free edges. The second manuscript studied the behavior of the neat polyimide resin when aged for up to 1500 hours in ambient air, and compared it with a newly developed polyimide formulation, with slightly altered chemical composition. The reduced amount of internal crosslinkers in the newer formulation was expected to enhance the fracture toughness of the material. Three-point bending, differential scanning calorimetry, dilatometry, weight loss, light optical microscopy and nanoindentation experiments were performed and highlighted the differences in the thermal and mechanical properties of the two formulations. A slight increase in the fracture toughness was observed, while the glass transition of the new formulation had decreased. The third manuscript was aimed at continuing the discussion from the second article on the differences between the two thermosetting polyimides. Thermogravimetric scans showed that the polyimide formulations behaved very similarly under thermal oxidative tests. The initial analysis gave indications that the model could capture well the degradation at high temperatures, but is not adequate in predicting long-term degradation at temperatures around 288–400 °C.

Functionalizable spherical colloidal lignin particles (CLPs) represent a valuable asset for the valorization of lignin side-streams from the pulp industry. The spherical structure allows for the circumvention of the heterogeneous and poorly dispersible structure of the biopolymer. However, organic solvents and alkaline media degrade the particle structure and dissolve the polymers due to their chemical nature and solubility. The solvents will alter the aggregated polymers into irregular shapes that would correspond to inconsistent physicochemical properties. Then, the material will become unusable for advanced material applications, namely wood adhesives. In this study, a replicable process to yield pH ca. 12 stable CLPs for wood adhesives or further functionalization for other advanced material applications was developed and optimized. Lignin was functionalized with cross-linkers, glyoxal or formaldehyde, and selfassembled into spherical structures in the micro emulsification of the organic solution. The formed colloids were partially rotary evaporated to retain organic solvents within the colloidal structures, and then be cured at 73-76 °C until pH stable and further functionalized for advanced material applications. The functionalization with glyoxal was pursued further for its possibly increased reactivity and the health concerns associated with formaldehyde. The process requires the addition of glyoxal to lignin in an acidic organi cmedia at ambient temperature, and the solution to react at 64 °C. Glyoxal is likely added to the polymer structure in its hydrated and dimerized form, and its attachment to lignin should be analyzed through the behavior of glyoxal in different media. The formed colloids were rotary evaporated to an organic solvent content of 60 wt. % of the spheres to allow the occurrence of the curing reaction. These materials were finally cured by thermosetting them at 73-76 °C until pH stable. The particles can be cured with base-catalysis through the controlled addition of the base NaOH(aq). However, the mode and rate of addition of the catalyst are critically important for a nondegradative infusion of a base into solvent present ot removed particles without morphological changes. Further procedural improvement and larger batches are necessary to conduct CLP adhesive experiments. / Funktionaliserbara sfäriska kolloidala ligninpartiklar (CLP) är en värdefull tillgång för valorisering av ligninsidoströmmar från massaindustrin. Den sfäriska strukturen reducerar effekten av den heterogena och dåligt dispergerbara biopolymeren. Organiska lösningsmedel och alkaliska medier försämrar emellertid partikelstrukturen och löser upp polymererna på grund av deras kemiska natur och löslighet. Lösningsmedel kommer att resultera i att de aggregerade polymererna antar oregelbundna former vilket skulle resultera i inkonsistenta fysikalisk-kemiska egenskaper. Därigenom blir materialet oanvändbart för avancerade materialapplikationer, såsom t ex trälim. I denna studie, utvecklades och optimerades en reproducerbar process för att ge pH ca. 12 stabila CLP för trälim eller ytterligare funktionalisering för andra avancerade materialapplikationer. Lignin funktionaliserades med tvärbindare, glyoxal eller formaldehyd och självorganiserades till sfäriskas trukturer genom mikroemulgering av organfasen. De bildade kolloiderna indunstades delvis roterande för att bibehålla det organiska lösningsmedlet i de kolloidala strukturerna och härdades sedan vid 73-76 ° C tills pH-stabilitet och funktionaliserades ytterligare för avancerade materialapplikationer. Funktionaliseringen med glyoxal utfördes också för att reaktiviteteten och begränsa de hälsoproblem som är förknippade med formaldehyd. Förfarandet kräver tillsats av glyoxal till lignin i ett surt organiskt medium vid rumstemperatur för att sedan reageras vid 64 ° C. Glyoxal i dess hydratiserade och dimeriserade form adderas sannolikt till polymeren, och dess kemiska inbindning till lignin kan analyseras genom att undersöka glyoxal uppförande i olika medier. De bildade kolloiderna indunstades till ett organiskt lösningsmedelsinnehåll av 60 viktprocent för att möjliggöra härdning. Dessa material härdades slutligen genom värmehärdning vid 73-76 ° C tills pH var stabilt. Partiklarna kan härdas med baskatalys genom kontrollerad tillsats av basen NaOH (aq). Emellerti där sättet och tillsatshastigheten för katalysatorn kritiskt viktigt. Ytterligare processförbättringar och större satser är nödvändiga för att genomföra CLP-limexperiment.

No / This review summarises the recent developments in the synthesis and applications of polymers derived from malic acid. There has been an increased interest in the design of sustainable and biodegradable polymers as a result of the drive to use renewable feedstocks as an alternative to petrochemicals in addition to their significant potential in biomedical applications. Synthetic strategies to access polymers from malic acid based on both condensation and ring-opening polymerization, across a broad range of conditions, are reviewed along with their advantages and limits. The role that such materials are studied for in biomedical applications is discussed, and their environmental impact based on the biodegradability of the malic polymer backbone is outlined. / The Royal Society, EPSRC, BBSRC

A cold extrusion process has been developed to tailor a porous structure from polymeric waste. The use of an extruder to manufacture acoustic materials from recycled waste is a novel idea and the author is not aware of any similar attempts. The extruder conveys and mixes the particulates with a reacting binder. The end result is the continuous production of bound particulates through which a controlled amount of carbon dioxide gas that is evolved during the reaction is used to give the desired acoustic properties. The cold extrusion process is a low energy consuming process that reprocesses the post manufacturing waste into new vibro-acoustic products that can be used to meet the growing public expectations for a quieter environment. The acoustical properties of the developed products are modelled using Pade approximation and Johnson-Champoux-Allard models. Applications for the developed products are widespread and include acoustic underlay, insulation and panels in buildings, noise barriers for motorways and railway tracks, acoustic insulation in commercial appliances and transport vehicles.

Conjugated polymers are novel organic electronic materials highly important for organic photovoltaic applications. Charge transport is one of the key properties which defines the performance of conjugated polymers in electronic devices. This work aims to explore the charge transport anisotropy in thin films of P3HT, one of the most common conjugated polymers. Using X-ray diffraction techniques and charge transport measurements, the relation between vertical charge transport through thin P3HT films and structure of the films was established. It was shown that particular orientations of crystalline domains of P3HT, namely face-on and chain-on, are beneficial for vertical charge transport. These orientations provide the efficient pathways for the charges to be transported vertically, either via π-π stacking interaction between the adjacent conjugated chains, or via the conjugated chain backbones. It was also demonstrated that particular orientations of crystallites are favourable for the formation of interconnected percolated pathways providing enhanced vertical charge transport across the film. Deposition of P3HT on most commonly used silicon substrates typically results in the formation of mostly edge-on orientation of crystallites which is unfavourable for vertical charge transport. Nanoimprint lithography was demonstrated as a powerful processing method for reorienting the edge-on crystalline domains of P3HT into chain-on (vertical) orientation. It is also shown that thin P3HT films with preferentially face-on orientations of crystallites can be deposited on graphene surface by spin coating. Using patterning of thin P3HT films by nanoimprint lithography, unprecedentedly high average vertical mobilities in the range of 3.1-10.6 cm2 V-1 s-1 were achieved in undoped P3HT. These results demonstrate that charge transport in thin films of a relatively simple and well-known conjugated polymer P3HT can be significantly improved using optimization of crystallinity,orientation of crystallites, polymer chain orientation and alignment in the films.

A úlcera de pressão é um ferimento que acomete grande número de pessoas hospitalizadas, incapacitadas de movimentação e os idosos. As alterações fisiológicas do envelhecimento seja no sistema cardiocirculatório, respiratório, renal ou no próprio sistema nervoso central, são as responsáveis pela maior predisposição dos idosos a complicações durante a hospitalização. A idade avançada é um dos fatores importantes no desenvolvimento da úlcera de pressão, pois ocorrem muitas mudanças, como o achatamento da junção entre a derme e a epiderme, menor troca de nutrientes, menor resistência à força de cisalhamento, diminuição da capacidade de redistribuir a carga mecânica da pressão. A úlcera de pressão pode ser definida como uma área localizada de necrose celular que tende a se desenvolver quando o tecido mole é comprimido entre uma proeminência óssea e uma superfície dura por um período prolongado de tempo. O tratamento para esse problema é difícil devido ao custo, ao tempo necessário para a cicatrização, aos constantes cuidados e deve proteger a ferida, ser biocompatível e fornecer uma hidratação ideal. Os biomaterias, entre eles, a quitosana apresenta características próprias para um curativo numa lesão grave. O objetivo desse trabalho foi preparar um curativo à base de quitosana que apresente propriedades adequadas ao tratamento de ferimentos relacionados à lesão de pele. O curativo foi obtido a partir da solução de quitosana, um polímero proveniente da quitina, que é encontrada principalmente em cascas de camarões, lagostas e insetos, sendo seco em estufa ou liofilizado, com ou sem suporte mecânico, em diferentes concentrações (1,2,3 e 6%), e em associação com outras substâncias. As membranas com melhores características mecânicas foram aquelas secas por liofilização, com suporte mecânico. Dessas, a que teve uma maior absorção de solução fisiológica 0,9% foi a membrana de quitosana a 1%, liofilizada com poliéster, que apresentou também, a melhor característica física sensorial e melhor preço. A fotomicrografia mostrou que as membranas com maior retenção de líquido apresentaram os maiores poros. Foi obtido, assim, curativos com as qualidades propostas no presente trabalho. / The pressure ulcer is a wound that commits a great number of hospitalized people, people disabled of movement and the elders. The main important factorsthat contribute to the elder\'s predisposition to clinical complications are physiological alterations in the aging process involving the cardiovascular system, respiratory, renal ou even in the central nervous system. The advanced age is one of the important factors in the development of the pressure ulcer therefore many changes may occur such as dermis and epidermis junction f1attening, nutrients decrease exchange, shear force decrease resistance and reduction of the capacity to redistribute the pressure mechanical load. The pressure ulcer may be defined as a cellular necrosis area that tends to develop when the soft skin tissue is compressed over a bony proeminence over a long period of time. The main reasons the treatment is so difficult are as follows: time necessary for scarifying process, constant care and wound protection, must be biocompatible and must provide ideal moisturizing. Biomaterials such as chitosan, presents optimal characteristics for a curative in acute lesions. In this present work the objective was the development of a chitosan made of curative that had adequate properties for treatmente of skin lesion related wounds. The curative was obtained from a chitosan solution which is a polymer obtained from chitin (which is commonly found in shrimp, lobsters and insect shells) and can be both heat-dried or lyophilized, with ou without mechanical support structure, in different solutions concentrations (1, 2, 3 and 6%) and also in association with other substances. The membranes with the best mechanical characteristics where those dried by lyophilization and with mechanical support structure. In this group the one that had the best physiological solution 0,9% absorption was the chitosan 1% lyophilized with polyester that also presented the best physical-sensorial characteristics and best price. The photomicrography showed that membranes with greater liquid retention presented the best pore size. This way, curatives where then obtained with the qualities proposed by this presente work.

A úlcera de pressão é um ferimento que acomete grande número de pessoas hospitalizadas, incapacitadas de movimentação e os idosos. As alterações fisiológicas do envelhecimento seja no sistema cardiocirculatório, respiratório, renal ou no próprio sistema nervoso central, são as responsáveis pela maior predisposição dos idosos a complicações durante a hospitalização. A idade avançada é um dos fatores importantes no desenvolvimento da úlcera de pressão, pois ocorrem muitas mudanças, como o achatamento da junção entre a derme e a epiderme, menor troca de nutrientes, menor resistência à força de cisalhamento, diminuição da capacidade de redistribuir a carga mecânica da pressão. A úlcera de pressão pode ser definida como uma área localizada de necrose celular que tende a se desenvolver quando o tecido mole é comprimido entre uma proeminência óssea e uma superfície dura por um período prolongado de tempo. O tratamento para esse problema é difícil devido ao custo, ao tempo necessário para a cicatrização, aos constantes cuidados e deve proteger a ferida, ser biocompatível e fornecer uma hidratação ideal. Os biomaterias, entre eles, a quitosana apresenta características próprias para um curativo numa lesão grave. O objetivo desse trabalho foi preparar um curativo à base de quitosana que apresente propriedades adequadas ao tratamento de ferimentos relacionados à lesão de pele. O curativo foi obtido a partir da solução de quitosana, um polímero proveniente da quitina, que é encontrada principalmente em cascas de camarões, lagostas e insetos, sendo seco em estufa ou liofilizado, com ou sem suporte mecânico, em diferentes concentrações (1,2,3 e 6%), e em associação com outras substâncias. As membranas com melhores características mecânicas foram aquelas secas por liofilização, com suporte mecânico. Dessas, a que teve uma maior absorção de solução fisiológica 0,9% foi a membrana de quitosana a 1%, liofilizada com poliéster, que apresentou também, a melhor característica física sensorial e melhor preço. A fotomicrografia mostrou que as membranas com maior retenção de líquido apresentaram os maiores poros. Foi obtido, assim, curativos com as qualidades propostas no presente trabalho. / The pressure ulcer is a wound that commits a great number of hospitalized people, people disabled of movement and the elders. The main important factorsthat contribute to the elder\'s predisposition to clinical complications are physiological alterations in the aging process involving the cardiovascular system, respiratory, renal ou even in the central nervous system. The advanced age is one of the important factors in the development of the pressure ulcer therefore many changes may occur such as dermis and epidermis junction f1attening, nutrients decrease exchange, shear force decrease resistance and reduction of the capacity to redistribute the pressure mechanical load. The pressure ulcer may be defined as a cellular necrosis area that tends to develop when the soft skin tissue is compressed over a bony proeminence over a long period of time. The main reasons the treatment is so difficult are as follows: time necessary for scarifying process, constant care and wound protection, must be biocompatible and must provide ideal moisturizing. Biomaterials such as chitosan, presents optimal characteristics for a curative in acute lesions. In this present work the objective was the development of a chitosan made of curative that had adequate properties for treatmente of skin lesion related wounds. The curative was obtained from a chitosan solution which is a polymer obtained from chitin (which is commonly found in shrimp, lobsters and insect shells) and can be both heat-dried or lyophilized, with ou without mechanical support structure, in different solutions concentrations (1, 2, 3 and 6%) and also in association with other substances. The membranes with the best mechanical characteristics where those dried by lyophilization and with mechanical support structure. In this group the one that had the best physiological solution 0,9% absorption was the chitosan 1% lyophilized with polyester that also presented the best physical-sensorial characteristics and best price. The photomicrography showed that membranes with greater liquid retention presented the best pore size. This way, curatives where then obtained with the qualities proposed by this presente work.