The kinetics of the functionalization of linear and cross-linked poly(methyl acrylate) (PMA) and its low-molecular-weight analogs by reactions with various amines in a series of binary solvents or in the solid state have been studied in situ by $ sp{13}$C NMR. Fitting the kinetic data of reactions of PMA with ethanolamine and n-hexylamine (HAN) in DMSO-rich solvent by use of the neighboring-group model shows an auto-acceleration effect due to hydrogen-bonding and/or polar interactions, and hydrophobic interactions; however, PMA and cyclohexane-methylamine shows an auto-retardation effect due to strong steric hindrance. At low extent of reaction the steric effect dominates the kinetics of the reaction of PMA with benzylamine, but hydrophobic interactions become predominant at high extent of reaction. Monomer sequence distributions of the partially functionalized PMA for some of these reactions are not in accord with the predictions of the neighboring-group model, probably due to the long-range neighboring-group effects and/or side reactions. / Despite a pseudo-first order behavior with respect to the concentration of ester groups found for the reaction of cross-linked PMA with HAN, a mono-amine, deviations from first order behavior were also observed for reactions with multi-functional amines. This is due to the formation of extra cross-links, which restrict the diffusion of amines within the polymeric beads, and is confirmed by NMR studies of the chain mobility using the dipolar dephasing technique by the measurement of the decay time constants. / Studies of the binding of bile acid anions by metal-containing polymeric resins, obtained from amine-functionalized PMA and poly(glycidyl methacrylate), show that the type of metal ion and the complexes formed between metal ions and functional groups play a more important role in the binding than factors such as the hydrophobicity of polymer backbones, the structures of functional groups, and the introduction of a spacer between the functional group and the backbone. It is proposed, in addition to the conventional ion exchange process, ligand exchange is involved in the binding mechanism. This is confirmed by results of $ sp{15}$N NMR and proton spin-lattice relaxation time experiments.

Layer thickness measurements are used to investigate polymer adsorption and possible conformations of adsorbed polymer. / In a first step, photon correlation spectroscopy (PCS) is used to monitor the layer thickness at different ratios of polyethylene oxide (PEO) per polystyrene (PS) latex spheres. Comparison of the polymer concentration at which the equilibrium layer thickness was attained with the concentration where the adsorption isotherm reached its plateau leads to a proposed three step adsorption process. Kinetic studies of the layer thickness build-up also support this mechanism. Polymer polydispersity and the effect of anchored end groups on layer thickness are found to be in agreement with theoretical predictions. / In a second step, a rheological investigation of PEO coated polystyrene-butadiene (PSB) latex spheres was performed. The influence of coating on the second virial coefficient was determined. Comparison of the layer thickness as measured by viscosity and PCS shows the relative importance of the latex polydispersity for the two methods.

Ammonium-containing polyacrylamide resins, ammonium-containing polystyrene resins, and their metal-ion coordinated analogs have been synthesized for the sorption of bile salts (BS). The effects of altering the backbone, the type of ammonium group, the number of ammonium group, the hydrophobicity of the pendant group, and of varying the metal ions on the adsorption of BS's, were studied to elucidate the structure-activity relationship. / The binding capacity of the resins for BS's generally increased with increasing number of ammonium groups per pendant group of the ammonium-bearing resins, and with higher charge of the metal complex cation of the metal-ion coordinated resin, demonstrating the primary importance of electrostatic interactions. It was also observed that, as the resin backbone was changed from hydrophilic polyacrylamide to hydrophobic polystyrene, the adsorption capacity increased substantially, demonstrating that hydrophobic interactions (H-H's) between the resin backbone and the BS's also play a significant role in the binding. The incorporation of hydrophobic segments -(CH$ sb2) sb{ rm n}$- into the pendant groups on polyacrylamide resins increased binding capacity, but had no effect for the more hydrophobic polystyrene resins. Primary ammonium-bearing resins often showed higher binding capacities than their quarternary analogs, suggesting that H-bonding reinforces the binding. Isotherms with an S-shape observed for most polyacrylamide resins indicate a positive cooperativity in the binding due to H-H's and H-bonding among BS anions bound at adjacent positions within resin beads. Binding models have been proposed to depict the formation of pendant group-BS mixed reversed micelles and ordinary BS micelles. / The studies of the kinetics of the binding of BS anions by the resins showed that a small resin particle size and more intense shaking substantially increase the rate of binding. This indicates that the binding process is mainly controlled by the diffusion of BS anions near and within the beads. (Abstract shortened by UMI.)

This thesis presents the results of several studies, the overall goal of which was the design and understanding of a block copolymer micelle in which the coronal chains act as a catalyst support for organometallic species. A model system consisting of reverse micelles of polystyrene-block -poly (sodium acrylate), PS-b-PANa, with coronal chain composed of ca. 210 styrene repeat units and a core radius of ca. 3.0 nm was used in the first study. The coronal chains were loaded to varying extents with Cr(CO)3 fragments in an effort to observe the effect of loading on the corona. The hydrodynamic radii, Rh, were measured by dynamic light scattering, DLS, and compared to a similarly treated sample of PS homopolymer. An increase in Rh by a factor of 3.4 was observed in the micelles, compared to only 1.5 in the homopolymer. A new block copolymer aggregate consisting of Poly (4-bromostyrene)-block-poly(4-vinylphenol), PBS- b-P4VPOH, in which the P4VPOH block could be used to crosslink the core, was developed for use as a coronal support for catalytically active organometallic species. bis-dimethylaminodimethylsilane was used to generate a crosslinked network of siloxane linkages within the core, resulting in a stable micelle. KPPh2 was then reacted with the PBS corona of the micelle to convert the bromostyrene units to analogues of triphenylphosphine. These micelles were then successfully loaded with a rhodium based catalyst. Catalytic activity was tested using the hydrogenation of 1-decene as a model reaction, in which turn-over frequencies of ca. 130 were achieved. The expansion seen in the first study also prompted an effort to develop a theoretical model of coronal chain behavior. A combined hypernetted-chain, mean spherical, Monte-Carlo method was used to model the corona of a micelle. The potential governing the interactions between repeat units was modified to include the effect of having several different species present along the chains. Th

The main objective of the present thesis is to prepare bactericidal filter paper by employing hydrophobic biocides of very low water solubility. To achieve this goal, two different strategies were proposed. One involves the use of amphiphilic block copolymer micelles which serve as a carrier for loaded biocides, and are subsequently attached to the pulp fibres; the other utilizes biocide emulsions stabilized with polymeric materials. As a part of first strategy, the mechanisms of loading of biocide into and release from the block copolymer micelles of poly(styrene)-b-poly(acrylic acid) were elucidated. It was found that loading is a two step process; first, the micelle surface is saturated with biocide molecules. In the next step, the biocide penetrates as a front into the hydrophobic polystyrene core, while lowering the glass transition temperature of the polystyrene. The release of the biocide from the micelles was found to be a slower process than loading; the rate determining step of the release is the removal of the biocide molecules from the surface of the micelles, since the biocide molecules have to pass over an energy barrier to go into the aqueous solution. E. coli bacteria deactivation by biocide loaded micelles in solution was studied next. As a main conclusion, it was found that block copolymer micelles loaded with triclosan biocide are efficient in deactivating the bacteria in less than two minutes. Also, the mechanism of biocide uptake by the bacteria was elucidated, which involves transfer of biocide molecules during transient collisions between loaded micelles and bacteria. An antibacterial filter paper was prepared by modifying commercial filter papers or paper towels by changing the natural negative charge of the pulp fibres to positive by adsorption of cationic poly(acryl)amide, followed by attachment of negatively charged biocide loaded micelles to the pulp fibres. After passage through the modified filter paper, the bacteria were found to be / L'objectif principal de la présente thèse est de préparer un papier filtre bactéricide en employant des biocides hydrophobiques ayant une très faible solubilité dans l'eau. Pour atteindre ce but, deux différentes stratégies furent proposées. L'une implique l'utilisation de micelles de copolymère bloc amphiphiles qui servent au transport de biocides dopés, et sont subséquemment attachées aux fibres de pâte; l'autre utilise des émulsions biocides stabilisées avec des matériaux polymères. Comme partie de la première stratégie, les mécanismes de dopage du biocide ainsi que de la libération des micelles de copolymère bloc de poly(styrène)-b-poly(acide acrylique) furent élucidés. Il fut découvert que le dopage est un processus à deux étapes; premièrement, la surface de la micelle est saturée avec des molécules biocides. Dans l'étape qui suit, le biocide pénètre de front dans le cœur hydrophobique de polystyrène, diminuant la température de transition vitreuse du polystyrène. La libération du biocide des micelles fut déterminée comme étant un processus plus lent que celui du dopage; l'étape déterminante de la vitesse de libération est l'enlèvement des molécules biocides de la surface des micelles, étant donné que les molécules de biocide doivent passer au-dessus d'une barrière énergétique pour aller dans la solution aqueuse. La désactivation de bactéries E. coli par les micelles dopées de biocide en solution fut ensuite étudiée. Comme conclusion générale, il fut découvert que les micelles de copolymère bloc dopées avec le biocide triclosan sont efficaces pour désactiver les bactéries en moins de deux minutes. Aussi, le mécanisme de consommation du biocide par les bactéries fut élucidé, impliquant le transfert des molécules de biocide durant les collisions transitoires entre les micelles dopées et les bactéries. Un papier filtre antibactérien fut préparé en modifiant des papiers filtres commercia

The goal of this thesis was to synthesize two poly(lactic acid)-co-poly(ethylene glycol) biodegradable amphiphilic block copolymers that can self-assemble in an aqueous environment into a micellar morphology. Also, the physicochemical characteristics of both the copolymers and resultant micelles were studied using a variety of chemical characterization techniques to gain insight into the factors that are important in the formation and function of the micelles. Two copolymers were synthesized which had different sizes and relative block lengths. These copolymers were characterized using NMR spectroscopy, gel permeation chromatography and thermogravimetric analysis. With these two polymers the self-assembly conditions which lead to the most narrow size distribution as determined by dynamic light scattering, were found and micelles were characterized by scanning electron microscopy, and through the partitioning of pyrene between the core of the micelles and water. Finally, an investigation of the time scales of micelle degradation was performed by monitoring a solution of micelles over an extended period of time.

A cantilever based sensor system was adapted to characterize the photo-mechanical effect in thin films of azobenzene based polymers coated on silicon and mica cantilevers. The photomechanical effect is defined as a reversible molecular shape change upon absorption of light, resulting in a significant mechanical macroscopic deformation of the host material. The sensor was used to calculate cantilever bending, changes in surface stress, photo-mechanical energy, efficiency, and energy per unit volume for the polymers PDR1A, PDR13A and PMMA-co-PDR1A based on DR1 and DR12 dyes. The study demonstrated fast and significant cantilever bending as well as a robust, repeatable, and measurable photo-mechanical effect for the polymers studied. PDR1A exerted the largest forces and PMMA-co-PDR1A the greatest efficiency. This exhibits the ability of these thin polymer layers to act as strong light-driven 'artificial muscles' for larger mechanical systems, and the utility of the cantilever sensor platform for quantitative characterization of the photomechanical effect of azobenzene based polymers.While micron-scale surface mass transport and formation of surface relief gratings in azobenzene polymers is a well-known phenomenon, a complete understanding of the underlying mechanism has yet to be achieved. Nanoindentation experiments were conducted to elucidate the changes in mechanical properties of PDR1A, a well-known covalent side-chain azo polymer and P4VP(DY7)0.5, a hydrogen-bonded polymer-azobenzene complex, under irradiation. Material creep was characterized by calculation of the strain rate sensitivity m, of the two polymers for the dark and illuminated states. The experiments show a significant change in material creep between the dark and illuminated states of both materials. The measured strain rate sensitivity m increases from 0.021 to 0.038 (81%) for PDR1A and 0.086 to 0.192 (123%) for P4VP(DY7)0.5 between the dark and illuminated states respectively. The correlation of experimental data describing photo-induced softening to the structure-property relationships of the two materials and their implications to understanding surface mass transport in azobenzene based materials is discussed. / Un système de détection utilisant un micro-lévier fut adapté pour caractériser l'effet photomécanique dans des couches mince de polymères contenant de l'azobenzène sur des micro-lévier fabriqués de silicium et mica. L'effet photomécanique est défini comme un changement réversible de la forme moléculaire lors de l'absorption de la lumière, ce qui entraîne une déformation importante mécanique macroscopique du matériel. Ce capteur a été utilisé pour calculer la flexion du micro-lévier, les changements dans la tension de surface, l'énergie photomécanique, l'efficacité du système et l'énergie capté par unité de volume pour les polymères PDR1A, PDR13A et PMMA-co-PDR1A basé sur les chromophores DR1 et DR12. L'étude a démontré une flexion rapide ainsi que robuste du micro-lévier, basé sur des mesure reproductible photomécanique pour les polymères étudiés. Nous avons trouvé que les polymères PDR1A exercent la plus grande force et PMMA-co-PDR1A la plus grande efficacité. Ceci démontre la capacité de ces couches minces de polymères à agir en tant que «muscles artificiels» pour des systèmes mécaniques macroscopique, et l'utilité de la plate-forme du capteur micro-lévier pour la caractérisation de l'effet photomécanique des polymères à base d'azobenzène.Bien que le transport de masse micrométrique et la formation des reliefs de surface dans les polymères d'azobenzène est un phénomène bien connu, une compréhension complète du mécanisme que mène a ceux-ci n'a pas encore été atteint. Des expériences de nanoindentation sous irradiation ont été menées pour élucider les changements dans les propriétés mécaniques de PDR1A, un polymère bien connu avec des chaînes latérales azoïques et P4VP(DY7)0,5, un polymère complexé à l'aide de liens d'hydrogène. Du fluage de ces matériaux a été caractérisé par le calcul du rapport de la sensibilité de déformation (m) de ces deux polymères pour les états sombres et lumineux. Les expériences montrent un changement significatif du fluage des polymères entre les états sombres et lumineux de ces deux matériaux. Le taux de la sensibilité de déformation (m) mesuré augmente de 0,021 à 0,038 (81%) pour PDR1A et de 0,086 à 0,192 (123%) pour P4VP(DY7)0,5 entre les états sombres et lumineux, respectivement. La corrélation des données expérimentales décrit l'adoucissement photo-induit basé sur les relations structure-propriété des deux matériaux, leurs implications pour la compréhension du transport de masse pour les matériaux à base d'azobenzène sont discutées.

Owing to its unique structure, along with the inexhaustible renewability, cellulose has been a subject of scientific and commercial interest for over 150 years. However, given attractive structural properties, such as stiffness, hydrophilicity, stereoregularity, potential for chemical modifications and ability to form superstructures, utilization of this biopolymer is far below its potential. Over the past few years the number of research projects to modify cellulose fibers to make them more suitable for numerous applications has increased. Transforming hydrophilic cellulose fibers into hydrophobic, non-hygroscopic fibers could potentially lead to a variety of new products, such as flexible packaging, self-cleaning films and strength-enhancing agents in polymer composites. To achieve this, we choose two different routes to chemically modify the cellulose fibers. In first method, cellulose fibers were oxidized with peridoate oxidation to different extent to prepare reactive dialdehyde cellulose (DAC) derivatives. Because introducing too many charge groups leads to fiber disintegration, we decided to cross-link the fibers to prevent this. These DAC fibers were in turn successfully cross-linked with 1,12-diaminododecane using methanol as solvent. Next, the cross-linked fibers were amidated in another Schiff-base reaction with n-butylamine to introduce the hydrophobic non-polar aliphatic chains. The cross-linked fibers exhibited stronger structural stability and the fibers did not disintegrate upon further alkylation with butylamine. The fibers were characterized with FTIR, 13 C-NMR, SEM, TGA, X-ray, contact angle and water sorption measurements. This procedure yielded very hydrophobic fibers with contact angles as high as 145o. Moreover, they had very low moisture uptake and high thermal strength, which makes them suitable for many potential products specially to be used in composites. The second method was based on intermediate carboxymethylation of cellulose with monochloroacetic acid, followed by subsequent substitution with an amine. The carboxylmethylated cellulose fibers (CCF) were cross-linked in an EDC assisted bioconjugation reaction with adipic acid anhydride (ADH). In order to alkylate the fibers and introduce aliphatic amine chains to the cross-linked fibers, a second carboxymethylation reaction was performed to introduce more charge groups to the cross-linked fibers to act as reactive sites for further alkylation reaction with butylamine. The resulting carboxymethylated cross-linked fibers were then reacted with n-butylamine to introduce non-polar aliphatic amine chains. The modified fibers were characterized by a variety of techniques, such as conductometric titration, infrared spectroscopy (FTIR), scanning electron microscopy (SEM), mechanical properties such as tensile strength and Young's modulus, water contact angle and water vapor transition rate (WVTR) measurements. / Grace à sa structure unique et son renouvellement quasi-inépuisable, la cellulose a été un sujet d'intérêt scientifique et commercial depuis plus de 150 ans. Toutefois, avec ses propriétés structurelles fascinantes, telles la rigidité, l'hydrophilie, la stéréorégularité, le potentiel de modifications chimiques et la capacité à former des superstructures, l'utilisation de ce biopolymère est bien en deçà de son potentiel. Au cours des dernières années, la recherche visant à modifier les fibres de cellulose pour les adapter à de nombreuses applications a augmenté. La transformation de fibres cellulosiques hydrophiles en fibres hydrophobes et non-hygroscopiques pourrait potentiellement mener à une variété de nouveaux produits, tels que des emballages flexibles, des films autonettoyants et des agents qui augmentent la résistance des composites polymériques. Pour atteindre ce but, nous avons choisi deux voies différentes pour modifier chimiquement les fibres de cellulose.Dans la première méthode, les fibres de cellulose sont oxydées à divers degrés par du periodate pour obtenir un dérivé réactif, le dialdéhyde de cellulose (DAC). Parce que l'introduction de beaucoup de groupements chargés mène à la désintégration des fibres, nous avons décidé, pour éviter cela, de réticuler les fibres. Les fibres de DAC ont donc été réticulées avec succès avec du 1,12-diaminododécane en utilisant du méthanol comme solvant. Ensuite, ces fibres réticulées ont été transformées en amides par une autre réaction de base de Schiff avec du n-butylamine qui a pour effet de greffer des chaînes hydrophobes aliphatiques non polaires. Les fibres réticulées se sont avérées avoir une stabilité structurel accrue et ne se sont pas désintégrées lors d'une alkylation plus poussée avec du butylamine. Les fibres ont été caractérisées par FTIR, 13 C-RMN, MEB, TGA, diffractométrie par rayons X, mesures de l'angle de contact et de sorption d'eau. Cette procédure a donné des fibres très hydrophobes avec des angles de contact plus élevés que 145o. De plus, elles ont une absorption d'humidité très faible et une résistance thermique élevée, ce qui les rend potentiellement adaptables à des usages dans de nombreux produits et tout spécialement dans les produits composites.La seconde méthode est basée sur la carboxyméthylation intermédiaire de la cellulose avec de l'acide chloroacétique, suivie d'une substitution ultérieure avec une amine. Les fibres de cellulose carboxyméthylées (CCF) ont été réticulées par une réaction de bioconjugaison classique utilisant l'EDC et l'anhydride d'acide adipique (ADH). Une seconde réaction de carboxyméthylation est alors effectuée sur les fibres réticulées pour y introduire plus de groupements chargés qui pourrons ensuite servir de sites réactifs pour une réaction d'alkylation. Cette réaction est accomplie avec du n-butylamine et a pour résultat la greffe de chaînes non polaires aliphatiques. Les fibres modifiées ont été caractérisées par une variété de techniques, telles le titrage conductimétrique, la spectroscopie infrarouge (FTIR), la microscopie électronique à balayage (MEB), les mesures de propriétés mécaniques telles la résistance à la traction et le module de Young, la mesure de l'angle de contact avec l'eau et la mesure du taux de transmission de la vapeur d'eau.

In this thesis, I describe experiments that provide a new and deeper understanding of factors that affect polymer diffusion in acrylic latex films. This is the step that leads to the growth of mechanical properties of these films. Polymer diffusion was studied by fluorescence resonance energy transfer (FRET) in films prepared from dye-labeled latex particles. Poly(n-butyl acrylate-co-methyl methacrylate) [P(BA-MMA)] was chosen for the study of copolymer composition on the polymer diffusion rate. Four sets of P(BA-MMA) copolymers were prepared from various weight ratios of BA/MMA. Polymer diffusion was monitored as a function of annealing temperature, and apparent diffusion coefficients (Dapp) were calculated from the FRET data, using a simple diffusion model. The temperature dependence of polymer dynamics (G’, G”) obtained by linear rheology measurements is in good agreement with the temperature dependence of Dapp. Increasing the BA content of the copolymer led to an apparent increase in long-chain branching, which is reflected in both the time dependence of Dapp and in the dynamic moduli measurements. To study the effect of branching on polymer diffusion rates, latex particles comprised of branched poly(n-butyl methacrylate) (PBMA) were prepared. The degree of branching was controlled by adding various amounts of bisphenol A dimethacrylate as a branching agent, plus 1-dodecanethiol as a chain transfer agent to prevent gel formation and to control the polymer molecular weight. The results of rheology (G’, G”) measurements are consistent with the absence of entanglement in these polymers. After correcting for the effects of Tg, by comparing results at a constant T- Tg, ET data show that the PBMA with the highest degree of branching had the highest diffusivity. In a separate set of experiments I tested the effect of incorporating the highly branched PBMA (HB-PBMA) into P(BA-MMA) dispersions to examine its influence on polymer diffusion in the latex films. Three different approaches were taken to combine these different polymers: latex blends, using HB-PBMA seeds in the synthesis of P(BA-MMA) by semicontinuous emulsion polymerization, and dissolving HB-PBMA in the mixture of BA and MMA for latex particles prepared by miniemulsion polymerization. ET studies indicate that HB-PBMA significantly enhances polymer diffusion rate, comparable with TexanolTM, a volatile organic coalescing agent. Tensile tests show that the films containing HB-PBMA have significant higher mechanical properties than the films containing TexanolTM.

With their potentially extraordinary mechanical, thermal, and electrical properties, Single-Walled Carbon Nanotubes (SWNT)/polymer composites and composite fibers may be the ultimate building blocks for next generation ultra-light-weight, ultra-high performance structural applications. However, the dispersity and processibility of SWNT in polymer matrices have been a challenge because of the strong van der Waal attraction between individual nanotubes and their chemical inertness. Predicated on oleum's (100% H2SO 4 with excess SO3) ability to intercalate between individual SWNT inside SWNT ropes, two types of reinforcing SWNT with much improved solubility and dispersity in common solvents were developed: supra-roped SWNT (SWNT-R) and soluble, ultra-short (length<60 nm), carboxylated SWNT(US-SWNT). SWNT-R hold much improved dispersity in super acid and other solvents, and can facilitate the processing of SWNT/polylmer composites and composites fibers. US-SWNT exhibit up to 2 wt% solubility in common solvents. The availability of SWNT-R and US-SWNT open the opportunities for forming high performance composites, blends, and copolymers without inhibiting their processibility. Studies on the synthesis, processing, properties, and morphology of SWNT-R or US-SWNT/polymer composites and composite fibers have demonstrated the reinforcement efficacy of these SWNT in typical thermoset, thermoplastic and liquid crystalline polymer matrices. The epoxy composite system reinforced with 0.5--1 wt% of US-SWNT has shown an average 15% increase in tensile modulus and 50% increase in tensile toughness over those of the neat epoxy. A linear rule-of-mixture calculation indicates the high reinforcement efficiency of US-SWNT in epoxy matrix. The calculated SWNT's elastic modulus approaches the theoretical value. This processible and high performance US-SWNT/Epoxy resin may serve as a matrix material for advanced fiber composites. A novel solution-processing method was introduced to achieve good dispersion of SWNT-R or US-SWNT in Nylon (6, 6) matrix. In comparison to neat resin, increase in tensile modulus and glass transition temperature were observed with 5 wt% nanotubes incorporation. However, the tensile toughness was significant decreased. An advanced SWNT-R/US-SWNT poly(p-phenylene terephthalamide(PPTA) composite fiber system was developed to realize the ultimate SWNT properties and make them processible by conventional fiber spinning processes.