The purpose of this research is to prepare and characterize poly(Beta-L-Malic acid) and its benzyl ester derivative from the intermediate optically active malolactone. The polymer prepared from the racemic malolactone will be investigated and its physical properties compared to the optically active poly(malic acid). The starting compounds for the lactone synthesis will be the racemic and optically active malic acid (L-form). They are readily available in both optical forms and the L-malic acid is a naturally occurring product. Polymerization of the benzyl ester of the optically active lactone will be carried out using selected anionic and cationic initiators. The reaction mechanism will be studied, with particular emphasis on the stereochemistry of the polymerization reaction and the physical properties of the isolated polymers. Future work will include the determination of the effect of stereoregularity on biological activity, biocompatibility and biodegradability of the polymers. The synthetic goals of the thesis are to obtain polymers having greater than 90% isotactic configuration (corresponding to greater than 90% optical purity of the lactone) and having a molecular weight in the range 10,000-20,000. The polymerization conditions, specifically the temperature, solvent and monomer/initiator concentrations ratio, will be varied to determine the effects on the polymerization kinetics and ultimately the molecular weights. Modifications of the polymerization conditions affected overall yield of isolated polymer. However, they seem to cause no effect on the molecular weight of the polymer. Varying the initiator, polymerization temperature, and solvent gave polymers with different molecular weight distributions (MWD) and yields but had no effect on the number average molecular weight (Mn). Differential scanning calorimetry and optical rotary dispersion spectroscopy demonstrated that the polymer possesses excellent stereoregularity.

Magnesium Chloride supported catalyst with proper external Lewis-base has high activity and high stereospecificity for olefin polymerization. The supported CW-catalyst MgCl(,2)/Ethylbenzoate/p-cresol/AlEt(,3)/TiCl(,4) with cocatalyst AlEt(,3)(.)Methyl-p-toluate has been thoroughly characterized. Chemical composition of supports and catalyst have been determined by elemental analysis and gas chromatography. Double redox titrations showed the distribution of Ti oxidation states in catalyst were 50% of Ti('+4), 40% of Ti('+3) and 10% of Ti('+2). Only one fifth of the Ti('+3) was observable by EPR. The addition of coactivators reduced Ti to lower oxidation states: 10% of Ti('+4), 70% of Ti('+3) and 20% of Ti('+2). The physical states of the materials obtained during each stages of catalyst preparation were studied by BET, porosimetry and x-ray diffraction techniques. Final catalyst has surface area ca. 110 - 150 m('2) g('-1). The ultimate crystallite size 20 A - 30 A of MgCl(,2) was obtained by ball-milling with ethyl benzoate for 60 h. By comparing the profiles of polymerization of propylene to insoluble PP and of decene-1 to soluble PD with the same catalyst. We concluded that the polymerization rate decay is not caused by monomer diffusion limitations. The kinetic of propylene polymerization was studied using same catalyst. The active sites concentration were determined by radio-tagging with tritiated methanol and ('14)CO. The results are in agreement with those obtained by kinetic methods. There are at least four different kinds of active center exist in catalyst. By varying polymerization conditions such as Cat , C(,3)H(,6) , temperature and Al to Ti ratio, the propagation rate constant K(,p), activating energy of propagation, (DELTA)E(,p), the termination constant, K(,t), were determined. The average molecular weight and molecular weight distribution have been examined by GPC, viscometry, and end group analysis. The rate constant of chain transfer with monomer, K(,tr,M), and rate constant of (beta)-hydride transfer, K(beta), were calculated. The effect of hydrogen on propylene polymerization has been studied. The rate of polymerization was increased with H(,2) that is caused by the increasing of active centers.

Drawing behavior of a high pressure crystallized chain-extended polyethylene in solid-state extrusion was studied. Because of the reduced trapped entanglements at the fold surfaces and interlamellar links in this morphology, there was insufficient continuity to provide stress transfer for effective orientation. Draw efficiency increases to a maximum of 0.71 when the polyethylene was crystallized at higher undercoolings. Tensile moduli were found to be a unique linear function of molecular draw ratio, measured by thermal shrinkage, independent of the initial morphology, draw temperatures and techniques. Electron microscopy of the fracture surface replicas at low draw showed the coexistence of undeformed, tilted, partially drawn lamellae and the generated fibrillar structure. The observations were consistent with Peterlin's model of plastic deformation. The question of melting and recrystallization during deformation was studied by small-angle X-ray scattering of the drawn chain-extended polyethylene. The results showed that melting and recrystallization did not occur for this morphology. A partially dried Nylon 6 gel in benzyl alcohol was solid-state co-extruded at 150(DEGREES)C up to draw ratio 5.7. Double orientation was observed in this uniaxial drawing with the crystal chain axis oriented parallel and perpendicular to the draw direction. A deformation mechanism was proposed from the studies of birefringence, wide- and small-angle X-ray scatterrings. A new drawing technique for Nylon 6 by reversible plasticization with iodine was proposed. A complex was obtained by imbibing a Nylon 6 film in a KI(,3) solution. It was drawn up to 790% elongation at 55(DEGREES)C and iodine was removed by titration with sodium thiosulfate to generate back a drawn Nylon 6 of controlled crystal form. The complex has a stoichiometry of (Nylon 6)(I(,3)('-))(,0.24)(I(,2))(,0.35). X-ray studies showed that interchain hydrogen bonds in both the crystal and amorphous regions were interrupted. The drawn complex has a new monoclinic crystal structure with iodine intercalated between the hydrogen bond sheets.

Segmented (AB) $\sb{n}$ polyurethanes. A series of polyether-polyurethane (PEPU) were synthesized and characterized. Soft segments were poly(propylene oxide) (PPO; M$\sb{\rm n}$ = 2,000) or poly(tetrahydrofuran) (PTHF; M$\sb{\rm n}$ = 1,650). Hard segments were formed from 4,4$\sp\prime$-diphenylmethanediisocyanate (MDI) and different short chain diols as chain extenders. In the PPO series 1,5-pentandiol (P), diethylene glycol (D), triethylene glycol (T) and 1,3-bis(N,N $\sp\prime$-methyl- N,N $\sp\prime$-2-hydroxyethyl)isophthalamide (Bi(M)) were used as chain extenders. In the PTHF series 1,6-bis(N,N $\sp\prime$-2-hydroxyethyl)adipamide (A), Bi(M), D, T, bis(N,N $\sp\prime$-hydroxyethyl)isophthalamide (Bi) and 1,6-bis(N,N $\sp\prime$-methyl- N,N $\sp\prime$-2-hydroxyethyl)adipamide (A(M)) were used as chain extenders. Degree of phase separation was investigated by IR and low temperature DSC. In the PPO-based series, P- and D-extended PEPU polymers have higher degrees of phase separation than T-extended PEPU polymers. In the PTHF-based series, the relative degree of phase separation decreases in following order, A- $>$ D- $>$ T-extended polymers. In either PPO- and PTHF-based series, Bi(M)-extended PEPU copolymers are phase-separated but with disordered or amorphous hard domain. Styrene-THF-Styrene Triblock copolymer. A-B-A triblock copolymer with A block as polystyrene and B block as PTHF was synthesized and characterized. IR, GPC and simple visual observation demonstrated the effectiveness of this coupling processes. $\sp{1}$H NMR analysis revealed a styrene content of 50% by weight. Also, this triblock copolymer did not flow below 125$\sp\circ$C. Acid-catalyzed decomposition of polyether, polyacetal and urethane copolymers. PTHF and poly(1,3-dioxepane) (PDXP) in addition to their acetate- and phenyl isocyanate-capped derivatives as well as PTHF-based PEPU's were the subjects of TGA studies. Ethyl 2-naphthalenesulfonate (ET-NS) was used as acid-generator to catalyze polymer decomposition. Homopolymers PTHF, PDXP, acetate-capped PTHF and PDXP showed enhanced decomposition in the presence of ET-NS as compared with thermal decomposition. End-capping improved stability towards thermal and acid-catalyzed decomposition. PEPUs synthesized from amide type chain-extenders such as A and Bi(M) exhibited no acid-catalyzed decomposition. This contrasts with PEPU copolymers synthesized from D and T chain-extenders, in which acid-catalyzed decomposition was observed. The possible role of amide linkages in PEPU as base is proposed.

This thesis studies the development of crystal texture and deformation mechanisms of isotactic polypropylene (i-PP) in the solid state. The strain field is hydrostatic, equibiaxial as produced by uniaxial compression. The central issue addressed is the deformation-induced order-disorder phenomenon. The disordered phase, referred to as the smectic modification of i-PP is stable below 70$\sp\circ$C and its formation is used to probe the deformation mechanism and its kinetics. The biaxial field induces a particular orientation of the smectic phase with respect to the crystal to reveal unique information on the deformation mechanism of i-PP, and the structure (and formation) of the smectic phase. The deformation mechanism of i-PP is explained by a decrystallization-recrystallization process. For deformation at high strain rates and low temperature, the recrystallized phase is the smectic phase which further participates in the deformation process inducing ductility. Thus the deformation undergoes two activated processes: crystal-to-smectic and smectic-to-crystal. Ductility can be enhanced by diminishing the second process. This principle of enhanced ductility induced by a crystal-to-crystal transition, can be generalized to other semicrystalline polymers to maximize crystal orientation for a given draw ratio. The crystal orientation (as measured by WAXS) on compression drawn i-PP revealed a double texture: (i) Fiber texture and (ii) Planar texture. The Planar texture converts to Fiber texture as the deformation proceeds. The reason for the two textures is explained in terms of major slip system: (0k0), $\langle001\rangle$. From this texture analysis a classification of semicrystalline polymers is proposed, based on their slip systems. The proposal states a criteria (and testing method) for selection of polymers for applications requiring biaxial orientation. A theoretical model is developed to simulate the stress-strain behavior of i-PP on uniaxial compression. The model assumes a rigid plastic behaviour of i-PP with Bauschinger effect. This one parameter theory fits the experimental curve (within 5%) up to compression ratios $>$ 7x and temperature range from 30 to 130$\sp\circ$C. Yield stress in compression and tension is obtained in a single experiment from such a fit. The dependence of yield stress and the ratio of the two yield stress on draw temperature is consistent with the order-disorder phenomenon and the deformation mechanism.

Metal-polymer interfaces were investigated by the synthesis and characterization of two model systems. The first system consisted of a coordinating ligand attached to a clean platinum black surface, which when activated initiated polymerization of monomer. A series of coordinating ligands were investigated and 4-picoline was chosen because it adsorbed irreversibly and perpendicularly, and its pseudo-benzylic hydrogens were acidic and could be removed to form an anionic polymerization initiator. The amount of 4-picoline adsorbed to platinum black was determined by three independent methods: UV-vis spectroscopy, gravimetric and elemental analyses. The platinum-picoline-polystyrene interface was characterized by FTIR spectroscopy and elemental analyses. A control experiment was run in which polystyrene was polymerized anionically in the presence of clean platinum. FTIR identified the polystyrene in the polymer-grafted-platinum sample, while none was observed in the control. The second system investigated consisted of polymer monolayers prepared by the spontaneous adsorption of thiol-terminated polystyrene and polystyrene/poly(propylene sulfide) block copolymers from solution onto glass-supported evaporated gold films. Experiments were performed to determine what control of polymer film thickness could be exercised by changes in molecular weight, concentration, solvent composition and extent of sulfur-functionalization. The monolayers were characterized by various techniques: External reflectance FTIR spectroscopy was used to identify the polymer adsorbed to the gold surface. X-ray photoelectron spectroscopy provided information about the elemental composition of the outer surface. Liquid scintillation counting was used to determine the mass of the polymer adsorbed to the gold surface. Sulfur-containing polymers were prepared by living anionic polymerization techniques. Radiolabelled polymers were prepared using $\sp3$H-styrene. Polystyrene containing a terminal thiol group (M$\sb{\rm n}$ = 1,000-200,000) adsorbed to gold under conditions that polystyrene did not. At higher molecular weight (M$\sb{\rm n}$ = 500,000) adsorption did not occur. Polystyrene/poly(propylene sulfide) block copolymers adsorbed to gold and the thickness of the adsorbed layer could be controlled by the length of the poly(propylene sulfide) block. This work demonstrates the importance of using organic chemistry to make specifically designed functional polymers that can be used to investigate interfacial phenomena.

This dissertation details the study of the properties of some unique radial, or 'star', liquid-crystalline polymers: block copolymers with poly(dimethyl siloxane) (at the arm centers) (PDMS) and poly(p-benzamide) (at the ends) (PBA). They were studied in the solid state and in solutions with dimethylacetamide/lithium chloride. The critical variable was the molecular weight of the siloxane, which was varied from 650/arm to 4250/arm. The molecular weight of the PBA was held constant, at an Mn = 7000/arm, for all the star-block copolymers. In total, there were four such radial copolymers for study, as well as one linear block copolymer, used as a standard for comparison. Characterization of the solid copolymers was performed using Thermogravimetric Analysis (TGA) and X-Ray Scattering. The copolymers are soluble with difficulty. The solutions obtained were characterized in the quiescent state by polarized-light microscopy (PLM), and by Wide- and Small-Angle X-Ray Scattering (WAXS, SAXS). It was found by PLM that the PDMS spacer length greatly influenced the ability of the polymers to form a liquid-crystalline solution. The block copolymers of highest PDMS molecular weight (largest flexible spacer), above 1500/arm, formed anisotropic solutions. Below this molecular weight, the solutions were isotropic at concentrations up to saturation. Rheological characterization was performed by steady-shear solution rheology in both the cone-plate and parallel-disk modes. The viscosity and normal-stress behavior of the solutions were evaluated with respect to concentration and liquid-crystallinity. It was found that both the isotropic and mesophasic solutions were sharply shear-thinning, with no low-shear Newtonian plateau. The liquid-crystalline polymers were found to exhibit a "rheological phase diagram", a peak in viscosity vs. concentration, confirming the phase behavior observed by polarized-light microscopy. The solutions showed a positive primary normal-stress coefficient which decreased with increasing shear rate, and which also was dependent on the presence or absence of liquid-crystallinity in the solutions. To understand further the deformation behavior of the solutions, fibers were spun from the solutions and the results characterized by X-Ray Scattering. It was found that the fibers spun from anisotropic solutions showed a greater degree of crystalline orientation.

A simplified approach to polycondensation kinetics has been used to develop engineering models for the design of film-forming polycondensation reactor-separators. This approach has been applied to a nylon 6,6 prepolymer in an idealized flowing film device. The model is characterized by two dimensionless groups; the Damkohler number and the Thiele modulus. A realistic kinetic and equilibrium description was incorporated with an activity-based kinetic model with composition-dependent apparent rate and equilibrium constants. The model is suitable for evaluating the effect(s) of changes in throughput, flow, film thickness, temperature and catalyst reactivity on the device performance. Since nylon 6,6 is typically used for fibers, molecular weight is not the only important product property. It must also have the proper balance of end-groups for good dyeability and very small amounts of gelled material for fiber spinning. A simplified thermal degradation model that is consistent with available data has been formulated to predict the amount of degraded material in the final product. The importance of the residence time distribution on the amount of degradation in the flowing film device has demonstrated. Finally, a realistic wiped film model for the design and performance analysis of continuously mixed thin-film nylon 6,6 "finishing" reactors has been constructed. The model incorporates composition dependent rate and equilibrium constants, a realistic degradation scheme and a finite gas-phase concentration. Even small amounts of mixing have been shown to yield very large improvements in both the mass transfer and molecular weight generation in such film reactors.

Capillary Column Inverse Gas Chromatography (CCIGC) has been developed for accurate measurement of diffusion coefficients in polymer-solvent systems at conditions approaching infinite dilution of the volatile component. Measurements of diffusion coefficients have been made for a wide range of solvents in poly(methyl methacrylate) (PMMA), poly(vinyl acetate) (PVAc), and poly(p-methyl styrene) (PPMS). These data are analyzed using a free-volume theory of diffusion to investigate the effects of the solvent and the glass transition on the diffusion process. Experimental data for PPMA-solvent and PVAc-solvent systems clearly demonstrate that certain solvent molecules are able to move segmentally in these polymers. Some of the parameters that influence the size of the solvent jumping unit have been identified experimentally. These are: the size of the entire solvent molecule, the flexibility and geometry of the solvent molecule, and the amount of free-volume present in the polymer. The results suggest that the current free-volume theory of diffusion does not provide a complete description of the diffusion process of solvent molecules that move segmentally. Finally, diffusivity data measured above and below the glass transition temperature of PMMA and PPMS are used to test a free-volume theory of diffusion in glassy polymers. The data appear to be well correlated by the theory, but some of the theoretical predictions were not confirmed experimentally.

The major theme of this dissertation is the study of blends of polyimides with a series of chemically similar polymers, namely poly(ether ether ketone) (PEEK) and three derivatives of PEEK. The synthesis of two new polymers is discussed, as well as the phase behavior of three new completely miscible blends and one partially miscible blend. Sulfonated and sulfamidated PEEKs have been prepared, based on previously determined methods. The first controlled nitration of PEEK is reported. Spectroscopic characterization was performed to determine the substitution pattern. Thermal analysis was performed to determine the dependence of the glass transition temperature and the degradation behavior on the level of substitution. Room temperature solubility has been examined for the nitrated PEEKs in fourteen common solvents. Three methods of reduction of the nitrated polymer to the corresponding aminated polymer have been attempted. Infrared spectroscopy was used to determine the effectiveness of these methods. Thermal properties and solubility of the reduced polymer are compared to those of the parent nitrated PEEK. Six different binary blends and one ternary blend have been studied to determine miscibility, defined by the existence of a single glass transition temperature. The phase behavior of binary blends of a commercial poly(amide imide) with poly(ether ether ketone), sulfonated PEEK (three degrees of sulfonation), sulfamidated PEEK, nitrated PEEK (three degrees of nitration) and a commercially available poly(ether imide) have been determined, as well as the behavior of the binary poly(ether imide)-sulfonated PEEK blend (three degrees of sulfonation). Chemical modification of PEEK was found to have a critical effect on the miscibility of these blends: unmodified PEEK was found to be completely immiscible with the poly(amide imide), yet each PEEK derivative showed partial or complete miscibility. Spectroscopic investigation of the intermolecular interactions responsible for the phase behavior found strong deviations from Beer's law in the ultraviolet region; this was postulated to result from the formation of electron donor-acceptor complexes between the substituted phenylene rings of the PEEKs and the N-phenylene units of the polyimides. The ternary poly(amide imide)--sulfonated PEEK--poly(ether imide) system has also been examined (two degrees of sulfonation). Sulfonated PEEK was found to act as a compatibilizing agent for the two polyimides.