Novel amorphous thermoplastic poly(phenylquinoxaline)s (PPQ), poly(aryl ether ketone)s (PAEKs) and poly(aryl ether phthalazine)s have been synthesized. / The reaction of an aromatic Schiff's base and a tertiary amine incorporating an activated methylene moiety in the presence of strong base to produce an enamine has been investigated. Hydrolysis of the resulting enamines resulted in deoxybenzoins which were converted to benzils by a mild oxidation reaction. This chemistry was investigated as a possible method for the synthesis of the tetraketone compounds (sometimes called bisbenzils) which serve as monomers for poly(phenylquinoxaline) polymers. Two novel monomers have been prepared, the corresponding polymers with 1,1$ sp prime$,2,2$ sp prime$-tetraminobiphenyl were synthesized and their physical properties evaluated. The novel polymers exhibited increased solvent resistance as compared to other PPQ polymers reported previously in the literature. / Two novel fluorine containing monomers were synthesized and polymerized with commercial biphenols to produce amorphous, fluorinated poly(aryl ether ketone)s. The physical properties of these polymers were evaluated and compared to those of analogous nonfluorinated polymers in order to determine what benefits can be obtained by introducing fluorine into the polymer architecture. The fluorinated polymers were found to show enhanced solubility. They were readily soluble in solvents which contain a ketone moiety, such as acetone, or cyclohexanone. / A novel dihalide monomer incorporating bulky 2-naphthalenyl moieties was synthesized and polymerized with commercial biphenols in an attempt to obtain poly(aryl ether ketone)s with extremely high glass transition temperatures (Tg's). / Several poly(aryl ether ketone) polymers were reacted with hydrazine monohydrate in the presence of a catalytic quantity of acid to produce poly(aryl ether phthalazine)s via ring closure of the o-diketone moiety in the backbone of the PAEKs. The resulting polymers are amorphous thermoplastics which displayed increased glass transition temperatures (Tg) and Young's moduli. It was found that the poly(aryl ether phthalazine)s undergo a thermal reaction above the Tg of the polymer resulting in a rearrangement of the phthalazine moiety to a quinazoline moiety. Some crosslinking of the polymers also occurs, resulting in insoluble polymers which showed an increase in the Tg.

The chiral nematic texture of a number of anisotropic cellulosic systems is revealed with the help of transmission electron microscopy (TEM) and atomic force microscopy (AFM). TEM and AFM examination of sections of cellulose films, ethyl cellulose (EC) films, ethyl methyl cellulose (EMC) films, cellulose acetate (CA) films and (6-O-trityl 2,3-O-hexyl) cellulose (C(Tr)(He))1 films showed periodicities which are characteristic of chiral nematic arrangements. Those periodicities are related to the helicoidal pitch of such organisations. Furthermore, specific structural defects were observed in sections of the chiral nematic films. These defects are associated with a parabolic focal conic texture. / Chiral nematic gels were produced by $ gamma$-ray irradiation of (hydroxypropyl)cellulose (HPC) mesophases in water or methanol. Solid/liquid extraction performed on irradiated HPC films and mesophases allow us to evaluate their respective degrees of crosslinking. Optical microscopy, TEM and AFM results showed that a chiral nematic order is preserved in the crosslinked mesophases. / Helicoidal suspensions of cellulosic microfibrils were prepared by acidic hydrolysis of wood pulp. Solid films, dried from these microfibril suspensions, show that the chiral nematic arrangement of the cellulosic microfibrils can be maintained in a solid material. Basic morphological data on chiral nematic films made from cellulosic microfibrils are given in this thesis. / The origin of the strong contrast observed in TEM images of sections of chiral nematic cellulosic materials is discussed. We also introduce novel sample preparation techniques for microscopic observation.

The objective of the thesis is the preparation and study of properties of polymer optical fibres. / The first part of the thesis describes the complete process of making polymer optical fibres from a monomer using styrene as a reagent. A solid preform is obtained from the polymerization before being drawn into a fibre. Once obtained, the fibre is characterized in terms of its chemical (composition), optical (acceptance angle, attenuation, refractive index profile), physical (elongation-to-break) and spectroscopic (Infrared, Raman, NMR) properties. Polarized Raman spectroscopy is employed to analyse the conformation of the polymer molecules in the fibre. The results of the spectroscopic studies show an axial symmetry around the main axis of the fibre. Symmetry is created when the fibre is drawn. / In the second part of the project, styrene is copolymerized with glycidyl methacrylate. The latter has an epoxy group on its side chain that can be polymerized independently from the vinyl group. (Abstract shortened by UMI.)

Cross-linked resins of poly(divinylbenzene-co-ethylvinylbenzene) were characterized and modified by a variety of reactions with the pendant vinylbenzene groups. Laboratory-prepared resins of a known composition were compared and contrasted to a commercial version with regard to surface area, porosity, and vinylbenzene content. The commercial resin, Amberlite XAD-4 (Rohm and Haas Company), had a higher surface area (831 m2 /g), porosity (1.18 mL/g), and accessible vinylbenzene groups (2.5 mmol/g, degree of functionalization 33%). Modifications of both resins by radical addition of a variety of thiols led to higher conversions (of vinylbenzene groups to modified groups) with use of the commercial resin (as high as 76%). Further modifications were done strictly with XAD-4. Some thiol additions to XAD-4 were done with water as the solvent, with conversions as high as 43%. Disulfides were added across the vinylbenzene groups of XAD-4 with iodine catalysis, with conversions as high as 55%. This simple one-step reaction has never been done with a polymer system before. XAD-4 was completely epoxidized using a solution of dimethyldioxirane in acetone, and completely brominated to form a resin with (1,2-dibromoethyl)benzene groups (3.76 mmol Br/g). Resins with (1-hydroxy-2-bromoethyl)benzene groups (1.5 mmol/g) were prepared by reaction of XAD-4 with N-bromosuccinimide and water, with 73% conversion. Resins with thiol groups (2.5 mmol S/g) were prepared by a one-pot reaction of brominated XAD-4 with N,N-dimethylthioformamide followed by methanolysis. From one commercially-available resin, several polymers with a variety of functional groups have thus been prepared by simple one- to three-step modifications.

Multiple morphologies of self-assembled aggregates of polystyrene- b-poly(ethylene oxide) (PS-b-PEO) diblock copolymers in dilute solution have been studied. The PS blocks are relatively long compared to the PEO blocks. The aggregates are prepared by the addition of water or methanol to the copolymer solutions in N,N-dimethylformamide (DMF), dioxane, or tetrahydrofuran (THF) to induce the aggregation of the PS blocks. Aqueous solutions of the aggregates are obtained by dialysis with water. Morphologies are directly studied by transmission electron microscopy (TEM). / The morphogenic effect of the copolymer composition indicates that as the EO content in the diblock decreases, the morphology of the self-assembled aggregates changes progressively through spheres, rods, bilayers, and ultimately to inverted aggregates. The observed bilayers include lamellae, vesicles, tubules and large compound vesicles (LCVs), and the inverted aggregates include inverted (hollow) hoops with a hexagonal array and large compound micelles (LCMs). / The morphological transition from vesicles to inverted hoops is investigated, and a three-step mechanism is proposed. This mechanism involves a thickening of the vesicle walls accompanied by the formation of the hollow rods in the walls, and a decrease in the size of the original water core. Possible mechanisms of the formation of large vesicles from lamellae, as well as tubules and LCVs from vesicles are discussed. / The formation of the self-assembled aggregates with various morphologies is believed to be mainly controlled by the balance of three interactions arising from the core, the corona, and the core-solvent interface. Any factors, such as the addition of salt, which affect the balance will cause morphological changes. Accordingly, the morphogenic effects of added electrolytes, temperature, the common solvent, and the precipitant are studied. The study shows that various morphologies can be prepared from one diblock copolymer.

The isothermal crystallization kinetics, spherulite morphology, and thermal behavior of the melt-crystallized optically active R and S polyenantiomers, their blends, and the stereoblock form of poly(epichlorohydrin) (PECH) and poly(propylene oxide) (PPrO) have been investigated using polarized light microscopy (PLOM), atomic force microscopy (AFM), and differential scanning calorimetry (DSC). The novel optically pure polyenantiomers of PECH were synthesized from the optically active monomers using a triethylaluminum$ cdot$water (1:0.6) catalyst, which was also used in the polymerization of the racemic monomer to an isotactic crystalline stereoblock fraction. The optically pure polyenantiomers and the stereoblock form of PPrO were obtained by the quantitative dechlorination reaction of the corresponding PECH polymers, using LiAlH$ sb4$, with retention of configuration of the main chain chiral centers. / The spherulite radial growth rates of the melt-crystallized PECH equimolar polyenantiomer blend are depressed relative to those of either optically pure components over the range of crystallization temperatures from the glass transition temperature ($T sb{ rm g} = -26 sp circ$C) to the equilibrium melting temperature ($T sb{ rm m} sp circ = 138 sp circ$C), which were determined to be the same for all of the PECH polymers. A further marked reduction in growth rates is recorded for the stereoblock polymer. Conversion of the PECH polyenantiomers to PPrO results in an overall order of magnitude increase in the spherulite radial growth rates. The growth rates of the PPrO stereoblock are only slightly depressed relative to those of either optically pure polyenantiomer over the range of crystallization temperatures from $T sb{ rm g}({-}65 sp circ$C) to $T sb{ rm m} sp circ(82 sp circ$C), which were determined to be the same for all of the PPrO polymers. An analysis of the linear spherulite radial growth rates of the PECH polymers in terms of the Hoffman-Lauritzen treatment gives evidence of a rougher lamellar fold surface in the stereoblock polymer than in the polyenantiomers, but suggests similar surface free energies among the polyenantiomers and stereoblock form of PPrO. / The multiple melting behavior exhibited by the different forms of PECH is greatly dependent on DSC heating rate and isothermal crystallization time, for samples crystallized at low temperatures and high temperatures, respectively. The behavior is demonstrated to be due to reorganization during the DSC heating scan in the former case, and linked to the process of secondary crystallization in the latter. / The optically pure polyenantiomers, their equimolar blend, and the stereoblock form of PPrO exhibit regularly banded spherulites, observed using PLOM. In contrast, only the optically active polyenantiomers of PECH form banded spherulites, whereas the equimolar polyenantiomer blend and the stereoblock display nonbanded, coarser spherulites. The birefringent extinction banding pattern of the PECH optically pure polyenantiomer spherulites corresponds directly to the surface topography mapped by AFM: Regularly alternating concentric ridges and valleys indicate the edges and the fold surfaces, respectively, of the radiating helicoidal lamellae. The direction or "sense" of an apparent surface spiral pattern of a banded spherulite is directly dependent on the chiral sense of the constituent polyenantiomer. It is suggested that the effects of the backbone chirality are being transmitted to the level of the gross spherulite morphology. / On the basis of the observed differences in crystallization kinetics and spherulite morphology among the well characterized PECH polymers, a mechanism of stereospecific segregation at the growth front is proposed.

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.

No description available.

This thesis presents a new approach to generating nonlinear optical side-chain polymers. By functionalizing olefins with nonlinear optical (NLO) chromophores and using late transition metal insertion catalysts of the form (bipy)Pd(CH 3)+ X- (X = OTf or BArF- ), a series of NLO materials were synthesized. These novel NLO polyketones were produced in modest yields with excellent polydispersities and good thermal stabilities via the alternating insertion of CO and NLO-tethered olefin into the palladium-carbon bond of the catalyst. A variety of NLO insertion monomers were examined during this study, beginning with a series of allylic-based monomers and progressing to a number of styrene derivatives. A detailed investigation of the copolymerizations and attempted copolymerizations is presented.

The surface properties of novel 2-D nanoemulsions, composed of mixtures of the perquaternized diblock poly(styrene$ sb{260}$-block-4-vinylpyridinium$ sb{240}$) and homopolystyrene spread at the air-water interface, were thoroughly studied using the Langmuir film balance and microscopy techniques (transmission electron microscopy and atomic force microscopy). The effects of both the molecular weight of homopolystyrene and the amount added were explored. It was found that the surface morphology could be manipulated in a predictable way by the addition of homopolystyrene. The surface films of the diblock families poly(styrene-block-sodium acrylate) and poly(styrene-block-sodium methacrylate) spread at the air-water interface were also investigated. The morphologies of their surface aggregates, i.e., jellyfish micelle, ribbon, and plane, were studied as parameters such as temperature and sub-phase electrolyte concentration were varied. A novel morphology, the 2-D nanofoam, was also investigated. The cellular walls of the 2-D nanofoams are found to consist of the polystyrene blocks of thickness on the order of the radius of gyration of the polystyrene blocks. Quantitative analysis of these cellular networks provides results similar to macroscopic 2-D surfactant foams indicating that the same forces are operative in both systems.