Segmental chain dynamics in polymer blends is a very important topic, not only from a fundamental point of view but also from technological applications. Because of the difficulties in the commercialization of new polymers, industries have turned increasingly towards blending of polymers to optimise their end use (mechanical, rheological) properties. The design of tailor-made materials would be enormously facilitated by the understanding of the blending phenomena at a molecular level. The key question to address is to understand the dynamics of each component of the blend modified by blending? The thesis has systematically studied the effect of multiwalled carbon nanotubes on the chain dynamics, demixing temperature, structural properties and evolution of morphology in a classical miscible polymer blend system (PVDF/PMMA). The thesis comprises of six chapters, Chapter 1 is an introductory chapter that outlines the fundamentals of polymer blends, crystallisation in polymer blends and the basics of dielectric spectroscopy. As one of the rationales of this work is to systematic study whether phase separated in these blends can be used as a tool to develop membrane for water purification. This chapter also gives an overview of the reported studies of ultrafiltration membrane fabrication, factors affecting membrane morphology and flux. In Chapter 2, the materials and methodology used to carry out experiments and the experimental procedures are discussed. Chapter 3 discusses the effect of concentration of PMMA and amine functionalized multiwalled carbon nanotubes (MWNTs) on the crystallisation induced phase separation using FTIR, XRD, POM and shear rheology. Electron microscopy and selective etching confirmed the localisation of MWNTs in the PVDF phase of the blends. Blends with MWNTs facilitated in heterogeneous nucleation manifesting in an increase in crystallisation temperature. The crystallisation induced phase separation in PVDF/PMMA blends was observed to influence the interconnected network of MWNTs in the blends. Chapter 4 discuss the effect of concentration of PMMA and MWNTs on the miscibility and the segmental relaxations was probed in situ by DSC and dielectric relaxation spectroscopy (DRS). The dynamic heterogeneity in the blends as manifested by the presence of an extra relaxation at a higher frequency at or below the crystallisation induced phase separation temperature was also discussed. We found that PVDF/PMMA blend (PVDF ≥ 80 wt%) exhibits three distinct relaxations; αc corresponding to crystalline PVDF, αβ segmental relaxation of PMMA and αm of amorphous miscibility whereas all relaxations overlap and constitute a single broad relaxation in PVDF/PMMA blend (PVDF ≤ 70 wt%). This confirms that there is a certain composition width in this blend wherein three distinct relaxations can be traced. This could due to many reasons like the width of crystal-amorphous interphase in the crystal lamellae, crystal size and morphology is strongly contingent on the concentration of PMMA. Relaxations are not very distinct in presence of MWNTs due to defective spherulites that shift the relaxations towards a higher frequency. Chapter 5 has attempted to tune the microporous morphology of PVDF membranes using crystallisation induced phase separation in PVDF/PMMA blends. As PVDF/PMMA is a melt-miscible blend, the samples were allowed to crystallise and the amorphous PMMA phase, which isolates in the interlamellar or inter-spherulitic regions in the blends, was etched out to generate microporous structures. The pore sizes can be tuned by varying the PMMA concentration in the blends. We observed that 60/40 PVDF/PMMA blends showed larger pores as compared to 90/10 PVDF/PMMA blends. We further modified PVDF membranes by sputtering silver on the surface. The bacterial cell viability was distinctly suppressed (99 %) in silver sputtered membranes. The ICP analysis suggests that slow Ag+ ions release from the sputtered membrane surface assisted in developing antibacterial surface. Our findings open new avenues in designing water filtration membranes and also help in understanding the crystallisation kinetics for tuning pore size in membranes. Chapter 6 summarises the important results of this work. MWNTs act as hetero nucleating agent and specifically interact with PVDF thereby influences the dynamics of PVDF chains. MWNTs can also restrict the amorphous segmental mobility and can influence the intermolecular cooperativity and coupling. The crystallisation induced phase separation in various blends can result in various crystalline morphologies depending on the PVDF concentration. By selectively etching PMMA from the phase-separated blends, microporous morphology can be generated

Les propriétés des polymères sont intéressantes pour des applications pneumatiques, de verres organiques, de joints, … Leurs propriétés mécaniques sont néanmoins mal comprises. Dans ce manuscrit, le comportement mécanique du PMMA et du CR39 est étudié en fonction du temps.Il en résulte des courbes maîtresses à partir d’expérience de relaxation de contrainte et de fluage d’indentation. D'autre part, le comportement mécanique au contact est analysé sur des expériences de fluage et recouvrance d’indentation et de rayures analysées pour la première fois dans cette thèse. Finalement, des lois de comportements sont construites, leurs précisions sont comparées grâce à des calculs par éléments finis aux expériences en contact. / Polymer's low weight, deformability and easy manufacturing make them attractive materials for tire, organic glasses, sealing applications … Their mechanical properties are nonetheless poorly understood. In particular, two fields are searched over this thesis: time dependency and contact behavior for two transparent polymer: PMMA and CR39. The mechanical behavior time dependency is observed by the construction of stress relaxation and contact master curves. The mechanical contact behavior is analyzed by indentation creep and recovery experiments. Moreover the immediate scratch recovery is measured in the thesis. Finally, the uniaxial data is used to build constitutive laws, which accuracy is compared by Finite Element Modeling to contact tests.

Objectives. Polyamide-12 (PA) is a flexible material suited for denture bases and clasping. This study investigated its potential aging effects with a focus on surface roughness, color stability, and elasticity. Methods. PA specimens (Valplast) of 40 × 10 × 2mm and equally measuring PMMA specimens (Palapress) as control were fabricated. Color changes after storage in air, water, coffee, and red wine (n = 10) were measured using the CIE L*a*b color specification. Elasticity after thermocycling (1000, 3000, and 7000 cycles, n = 15) was measured by three-point bending testing. Mean surface roughness (Ra) was determined after storage in the liquids mentioned above and thermocycling (n = 10). Results. Tukey’s HSD test (P < 0.05) revealed statistically significant color changes of PA in red wine (ΔE = 4.27 after 12 days, EΔE = 6.90 after 12 days) and coffee (ΔE = 3.93 after 36 days) but no color changes in PMMA. Elastic modulus of PA was 845MPa and not affected by thermocycling (Tukey’s HSD test, P > 0.81). Dry specimens showed significantly decreased elasticity (P < 0.001). Mean surface roughness (PA 0.20 μm, PMMA 0.28 μm) did not change significantly after thermocycling or storage (Mann-Whitney U-test, 0.16 < P < 0.65). Significance. PA exhibited a higher susceptibility to discoloration than PMMA. Neither surface roughness nor elasticity of PA was altered by artificial aging.

En estas últimas décadas, la ingeniería tisular ha llegado a ser uno de los campos de aplicación más prometedores de los polímeros macroporosos para soportes o matrices porosas tridimensionales donde las células se pueden cultivar. Una de las formas de obtener un polímero poroso es mediante la polimerización en disolución. De esta forma, los poros se forman debido a la segregación de disolvente de la red polimérica durante el proceso de polimerización. En esta tesis, se han sintetizado redes poliméricas de polimetacrilato de metilo (PMMA) por polimerización en presencia de etanol con diferentes porosidades y contenidos de entrecruzador. También se ha sintetizado PMMA polimerizado en masa (no poroso) como material de referencia. El PMMA macroporoso se coloca en una atmósfera saturada de vapor de monómero de acrilato de hidroxietilo. La ausencia de iniciador térmico o fotosensible hace difícil el inicio del proceso de polimerización del monómero adsorbido. Sin embargo, este problema se puede resolver mediante la polimerización por plasma. Se estudia las propiedades mecánicas de estos nuevos materiales mediante espectroscopía dinámico-mecánica (DMS). El espectro dinámico-mecánico muestra que los materiales sintetizados en esta tesis son un nuevo tipo de hidrogel macroporoso con un alto módulo mecánico a temperatura ambiente y capaz de adsorber agua manteniendo sus propiedades mecánicas. Mediante medidas de porosidad se determina la fracción en volumen de poros en las muestras antes y después del tratamiento de plasma. La estructura y morfología de estos sistemas macroporosos se ha observado mediante microscopía electrónica de barrido (SEM). La estabilidad de este recubrimiento hidrófilo se ha analizado mediante calorimetría diferencial de barrido (DSC), ATR FTIR, TGA e inmersión en agua. Estos resultados demuestran que el plPHEA es muy estable y solo en condiciones muy drásticas como en agua hirviendo puede sufrir degradación hidrolítica. / Serrano Aroca, Á. (2005). Synthesis and characterisation of macroporous poly(methyl methacrylate) with plasma-polymerised hydrophilic coating [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/1857

Syfte Syftet med föreliggande studie var att undersöka böjhållfastheten på 3D-printat material avsett för stabiliseringsskenor som är tillverkade i olika vinklar och både före och efter polering. Material och Metod Totalt framställdes 50 rektangulära provkroppar i vinklarna 0°, 25°, 45°, 75° och 90° med måtten 64 x 10 x 4,5 mm av Keysplint Hard och hälften polerades med Otec poleringsmaskin. Alla provkroppar utsattes för ett trepunktsböjhållfasthetstest med Instron 4465 med en lasthastighet på 5 mm/min till fraktur och värdena dokumenterades i Bluehill-mjukvara. Resultatet analyserades med One-Way ANOVA, Tukey s’ test och signifikansnivån sattes till α = 0,05. Resultat Enligt resultat från programmet SPSS (IBM® SPSS® Statistics powerful statistical software platform) observerades högst böjhållfasthet i den 3D-printade gruppen vid 25° som var polerad, vilket innebar en signifikant skillnad mellan denna grupp (25°) och de övriga grupperna (p&lt;0,05). Statistisk påvisades inga signifikanta skillnader mellan de andra grupper oavsett om det var opolerade och polerade provkroppar printade i vinklarna 0॰, 45॰, 75॰,90॰ (p&gt;0,05). Slutsats Inom ramen för studiens begränsningar kan följande slutsats dras: Printningsvinkel och polering påverkar böjhållfastheten hos 3D-printad polymer. En printningsvinkel på 25॰ i kombination med polering ger högst böjhållfasthet. En printningsvinkel på 0॰ger numeriskt lägst böjhållfasthet. Mer omfattande studier beträffande olika printningvinklar, olika printningsmaterial (resin) och 3D-printrar och dess inverkan på böjhållfastheten krävs för att säkerställa resultaten. / Aim The purpose of this in vitro study was to investigate the flexural strength of 3D-printed material intended for stabilization splints that are manufactured at different angles, both before and after polishing. Material and Method A total of 50 rectangular specimens at angles of 0°, 25°, 45°, 75° and 90° with dimensions of 64 x 10 x 4.5 mm were produced by Keysplint Hard and half were polished with the Otec polishing machine. All specimens were subjected to three-point flexural strength test using the Instron 4465 at a loading rate of 5 mm/min to fracture and the values were documented in Bluehill software. The result was analyzed with One-Way ANOVA, Tukey's test and the significance level was set at α = 0.05. Results According to results from the software SPSS (IBM® SPSS® Statistics powerful statistical software platform), the highest flexural strength was observed in the 3D-printed group at 25° that was polished, which means a significant difference between this group (25°) and the other groups (p&lt;0.05). Statistically, no significant differences were detected between the other groups regardless of whether they were unpolished and polished specimens printed at angles 0°, 45°, 75°, 90° (p&gt;0.05). Conclusion Within the limitations of the study, the following conclusion can be drawn: Printing angle and polishing affect the flexural strength of 3D-printed polymer. A printing angle of 25° in combination with polishing gives the highest flexural strength. A printing angle of 0° gives the numerically lowest flexural strength. More extensive studies regarding different printing angles, different printing materials (resin) and 3D-printers and the effect on the flexural strength are required to ensure the results.

The surface-specific technique of vibrational sum frequency spectroscopy (VSFS) can provide vibrational information about chemical bonds at surfaces and interfaces. Two photons, of visible and infrared frequency, are spatially and temporally overlapped at a surface/interface to produce a photon at the sum frequency (SF) of the two input photons. As well as this process only being allowed in non-centrosymmetric media (i.e. VSFS is surface/interface specific), the SF process is enhanced when the IR beam is resonant with vibrational resonances. Broadband VSFS has been used in this project to study surfaces of two distinct classes of materials, namely graphene and polymers. Firstly, broadband VSFS was used to investigate the heating polymeric thin films using a home-built heated sample cell. The cell was tested using self-assembled monolayers (SAMs) of 1-octadecanethiol (ODT) grown on gold substrates. It was subsequently used to investigate thin films of poly(methyl methacrylate) (PMMA) of four different thicknesses and two different molecular weights that were spin-coated onto gold substrates. It was shown that the monolayers of ODT become disordered upon heating and solidified to incorporate the disorder introduced by the heating process. The PMMA films were also shown to become more disordered as a function of temperature. Secondly, broadband VSFS was used to investigate modified graphene, motivated by the fact that modifications to pristine graphene, be it intentional (i.e. functionalisation) or unintentional (i.e. contamination), cause the properties of graphene to change. This project focused on studying hydrogenated graphene, N-methylbenzamide functionalised graphene and contamination on commercial graphene. A method for calculating the number of hydrogen atoms in a hydrogen island was developed. VSF spectra of CH stretches in N-methylbenzamide functionalised graphene were obtained. Residues on commercially bought graphene were detected using VSFS and RAIRS. These residues were assigned to PMMA that remained on the CVD graphene by the process of transferring the CVD graphene from the copper foil on which it was grown onto the gold substrates.

Hip resurfacing arthroplasty has changed the treatment of end stage arthritis without severe deformity for young, active adults. Presently, there are varying clinical approaches to implant design selection and cementation techniques. The purpose of this project is to determine what amount of reamer-femoral component offset allows for the best cement penetration into the femoral head. Rapid prototyped femoral component models were produced with reamer femoral component offsets of 0.0 mm, 0.5 mm, and 1.0 mm. After implantation onto models of reamed femoral heads made from high-density open-cell reticulated carbon foam, cement penetration was assessed from cross-sections of the foam-implant unit. Increased offset was found to decrease the extent of cement over penetration from the dome and chamfer. Increased offset also yielded optimal cement penetration as measured from the walls. Finally, increased offset was found to increase the height of cement mantle formation while maintaining complete seating of all implants.

Ce manuscrit rassemble les recherches effectuées dans le cadre du développement d’une résine thermoplastique photopolymérisable pour une application composite. Ce travail a été effectué dans le cadre du projet COMPOFAST, lancé par ARKEMA à la fin de l’année 2012. Ce projet, accompagné par l’ADEME, a pour but, la mise au point d’une nouvelle génération de composites thermoplastiques à haute cadence de production pour la conception de pièces pour l’automobile. L’intérêt de ces matériaux, et donc du projet, est l’allégement des véhicules par réduction de la masse des pièces utilisées et la recyclabilité des matrices choisies. A travers ce projet, plusieurs techniques ont été envisagées. Dans le cadre de cette thèse c’est le procédé QCM, pour Quick Composite Molding, qui a été étudié au sein du LPIM. L’utilisation de la lumière pour assurer la polymérisation de la matrice rend novateur ce procédé. Cette étape dite de photopolymérisation est connue pour être l’un des moyens les plus rapides pour former une résine solide à partir d’une formulation liquide. Le procédé repose également sur la dépose automatisée de bandes de préimprégnés sur un moule ouvert afin d’augmenter la vitesse de production des pièces de composites. Techniquement, deux étapes ont été prévues : la première consiste en la réalisation des bandes de préimprégnés de manière automatique. La deuxième étape est la conception du composite par dépose automatique sur un moule des bandes de renforts préirradiés à laquelle succède une étape finale d’irradiation pour obtenir le composite requis. / This manuscript brings together research in the development of a light-curing thermoplastic resin for a composite application. This work was performed under the COMPOFAST project launched by Arkema at the end of 2012. This project, along with the ADEME, aims at the development of a new generation of thermoplastic composites with high production rates for designing automobile parts. The advantages of these materials, and therefore of the project, is making vehicles lighter by reducing the mass of the parts used and the recyclability of the selected matrices. Through this project, several techniques were considered. As part of this thesis, it's the QCM method for Quick Composite Molding, which has been studied within the LPIM. The use of light to ensure the polymerization of the matrix makes this method innovative. This step called photopolymerization is known to be one of the fastest ways to form a solid resin from a liquid formulation. The method also relies on the automated removal prepreg bands on an open mold in order to increase the rate of production of composite parts. Technically, two stages were planned: the first involves the automatically construction of prepreg tapes. The second step is the design of the composite by automatically depositing prepregs on the mold which is followed by a final step of irradiation to give the desired photocomposite.

Dans cette étude, nous avons réalisé des matériaux nanostructurés à partir de copolymères méthacryliques greffés par du polyamide 6. Le greffage s'effectue par mélangeage réactif en faisant réagir la terminaison amine du polyamide sur des fonctions réactives du squelette méthacrylique. En étudiant différentes architectures de squelette, nous avons remarqué que la distribution des sites réactifs jouait un rôle important. Dans le but de comprendre cet effet sur la structuration et les propriétés mécaniques de ces matériaux, nous avons synthétisé des copolymères modèles de méthacrylate de butyle par polymérisation radicalaire contrôlée (méthode ATRP). Pour bien contrôler l'architecture de ces copolymères, nous avons développé un système de suivi de la polymérisation, par spectroscopie en proche infrarouge, nous permettant de connaître en temps réel la longueur des chaînes formées. Nous avons ainsi obtenu une variété de copolymères bien contrôlés (masses molaires voisines, polymolécularités faibles) dont les sites réactifs (acide méthacrylique) sont répartis statistiquement sur toute la chaîne (architecture monobloc), sur une partie de la chaîne (dibloc) ou sur les deux extrémités de la chaîne (tribloc). Le greffage du polyamide sur ces squelettes a ensuite été réalisé à l'état fondu en extrudeuse, et nous avons étudié la structuration par microscopie électronique (TEM), les propriétés mécaniques par analyse dynamique (DMA), la cristallisation par analyse enthalpique différentielle (DSC) ainsi que la résistance aux solvants de ces matériaux. Tout d'abord, l'efficacité de greffage du polyamide sur les squelettes méthacryliques est très élevée (jusqu'à 90%) et augmente avec la densité de sites réactifs. Ensuite, la distribution des sites réactifs, donc des greffons polyamide, influence fortement la structuration des mélanges et leurs propriétés. Nous avons pu définir le type de squelette à utiliser pour obtenir une morphologie donnée. Finalement, les résultats de cette étude ont été utilisés pour réaliser des matériaux nanostructurés à partir de squelettes triblocs élastomériques PMMA-b-PABu-b-PMMA et PS-b-PABu-b-PS. Nous avons ainsi obtenu des élastomères thermoplastiques hautes performances transparents, résistants aux solvants et avec une tenue mécanique dépassant les 200°C.

La prise de conscience des problèmes écologiques liés à l'émission de solvants dans l'atmosphère a<br />provoqué la mise en place d'un cadre législatif auquel les fabricants de peintures ont dû s'adapter.<br />L'évolution vers l'utilisation des peintures en phase aqueuse n'a pu être réalisée sans des aménagements tant au niveau des procédés que des produits. Ainsi, les pigments aluminium mis en oeuvre dans les peintures métallisées, principalement destinées à l'industrie automobile, doivent subir des traitements préalables leur permettant d'éviter des phénomènes de corrosion préjudiciables tant du point de vue esthétique que de la sécurité (dégagement d'hydrogène). Les traitements proposés jusqu'ici (composés phospho-organiques, dérivés du chrome hexavalent) ne sont pas exempts de défauts (toxicité). Cette étude a permis de montrer que l'encapsulation des pigments aluminium dans une coque de PMMA par un procédé dérivé de la polymérisation en émulsion permet d'obtenir des pigments stables en phase aqueuse. De plus, la mise au point d'un nouveau procédé de production , mettant en oeuvre des agents silaniques au cours de l'étape de broyage, permet désormais d'envisager l'élaboration d'un grade universel, i.e. adapté pour les<br />peintures en phase aqueuse et solvant.