Thesis (Ph. D.) - Carleton University, 2000. / Also available in electronic format on the Internet.

Dissertation (Ph.D.)--University of Akron, Dept. of Polymer Engineering, 2005. / "August, 2005." Title from electronic dissertation title page (viewed 09/24/2005) Includes bibliographical references.

This research aimed to develop the fabrication of mixed matrix membranes (MMMs) utilizing a polymer of intrinsic microporosity (PIM-1) with porous polyimide networks, and to explore their effect on gas transport properties. PIM-1 has been chosen as polymer matrix for its high surface area and high sorption of gases. It is also considered as interesting candidate for membrane gas separation. PIM-1 has been synthesized successfully using high temperature methods (40 min, 160 oC) and low temperature methods (72 h, 65 oC). Porous polyimide networks have been chosen as organic fillers as they have good chemical affinity to polymer matrix and can adhere much better than inorganic fillers. MPN-1 and MPN-2 were synthesized by condensation polymerization of A2 (dianhydride) and B4 (tetraamino). The polymer matrix (PIM-1) and network polyimide fillers were characterized using various characterization techniques, including FTIR, NMR spectroscopy, TGA and N2 sorption analysis. MMMs were fabricated successfully utilizing PIM-1 with 10, 20, and 30wt. % loadings of fillers. The MMMs prepared were homogenous on a macroscale. They characterized using different techniques, such as FTIR spectroscopy, powder x-ray diffraction, and scanning electron microscopy. The gas transport properties of MMMs were obtained using a time lag method. The treatment of MMMs with alcohol showed an increase in the permeability and diffusivity of gases. We aimed in this research to increase solubility of microporous polyimide network (MPN-1) by decreasing the extent of network structure. Different strategies have been utilized. First, using different molar ratios and second, using end-capping modification. The polymers were characterized using various techniques, including FTIR, NMR spectroscopy and TGA. Following this, their CO2 uptake and solubility are also examined.

Phosphorus containing monomers, bis(3-aminophenyl)methyl phosphine oxide (m-DAMPO) and bis(3-aminophenyl)phenyl phosphine oxide (m-DAPPO), were synthesized and incorporated into a thermoplastic poly(arylene ether imide) based upon 2,2'-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride and 1,3-phenylene diamine, in order to study their influence on flame resistance and other properties. DAMPO or DAPPO were quantitatively incorporated in concentrations of 25, 50, 75 and 100 mole percent, using the "one pot" ester-acid method. The number average molecular weights of the prepared materials were controlled to 20,000g/mol by off-setting the stoichiomety and endcapping with phthalic anhydride. This strategy enabled one to distinguish the effects of the phosphine oxide incoporation from the influence of molecular weight. The resulting copolymers demonstrated a significant increase in char yield as a function of the phosphine oxide content, thus suggesting improved fire resistance. Glass transition temperatures similar to the control were determined by DSC analysis. Analysis of the mechanical behavior of the DAMPO system at room temperature showed that tensile strength and elongation at failure values were comparable to the control system, while the DAPPO containing copolymers were surprisingly brittle. The influence of the reactive endgroup on the synthesis, cure behavior and network properties of thermosetting polyetherimides was investigated. Reactive phenylacetylene, acetylene and maleimide terminated poly(ether imide) oligomers were prepared and characterized. Optimal reaction conditions were established to produce fully endcapped oligomers with imidized structures and controlled molecular weight. The phenylacetylene endcapped system was synthesized by a conventional ester-acid method. The acetylene endcapped system was prepared via modified ester-acid method and the maleimide endcapped system was fabricated utilizing an amic-acid route. It was determined that phenylethynyl endcapped polymers could be thermally cured at high temperatures (350-380°C) providing good processibility. The networks exhibited thermal stability, chemical resistance and good adhesion strength, ideal as "primary" bonding adhesives. Acetylene and maleimide endcapped systems were prepared for application as "secondary" bonding materials, meaning that they are cured at a lower temperature than that of the Tg of the primary structure. Lap shear test results indicated good adhesion to titanium when cured at 250°C -280°C. The cured materials showed high glass transition temperatures and good thermal and thermo-oxidative stability as determined by DSC, TGA and DMA. Good chemical resistance was demonstrated via solvent extraction measurements. The influence of molecular weight between crosslinks (Mc) on thermal and mechanical behavior was also investigated. Lower molecular weight oligomers exhibited lower Tg and cure temperatures, whereas the cured networks resulting from lower molecular weight oligomers afforded higher Tg and higher gel fractions, but reduced toughness. / Ph. D.

Polyimides derived from 2,2-bis[4-(4-aminophenoxy)phenyl]-hexafluoropropane (BDAF) and pyromellitic dianhydride (PMDA) displayed a glass transition temperature (Tg) at 306°C and a melting point (Tm) near 470°C as measured by differential scanning calorimetry (DSC) with a heating rate of 10°C/min. The degree of crystallinity increased with decreasing molecular weight. The incorporation of 20 mole percent of the comonomer, hexafluoroisopropylidene-2,2-bisphthalic acid anhydride (6FDA), gave a Tm of 440°C that appeared to be stable 20°C above the melt. A fluorinated diamine, 1,1-bis[4-(4-aminophenoxy) phenyl]-1-phenyl-2,2,2-trifluoroethane (SFEDAM), was synthesized in 80% yield from trifluoroacetophenone with a melting point of 169-170°C. The 3FEDAM-PMDA polyimide controlled to 30,000 g/mol with phthalic anhydride exhibited by DSC a Tg of 308°C and a Tm of 476°C. Similar to the BDAF based copolymer, the 3FEDAM-20%6FDA/80%PMDA-PA polyimide had a Tg of 286°C and a Tm of 440°C which appeared to show short term thermal stability above the Tm. Three 1,4-bis(4-aminophenoxy)benzene (TPEQ) homopolyimides were synthesized with 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 3,3',4,4'-biphenylcarboxylic dianhydride (BPDA), and 4,4'-oxydiphthalic anhydride (ODPA). The Tg values were 255°C, 251°C, and 239°C for the TPEQ-BPDA-PA, TPEQ-BTDA-PA, and TPEQ-ODPA-PA polyimides, respectively. The TPEQ-ODPA-PA polyimide displayed the lowest Tm of 411°C. A series of TPEQ-ODPA polyimides of different molecular weights were synthesized using the Carother's equation and the monofunctional reagent, phthalic anhydride. The Tg values ranged from 214°C to 239°C for the 7.5K to the 30K polyimides. All the TPEQ-ODPA polyimides displayed an endotherm on the first heat of the DSC analysis. However, the 7.5K, 10K, and 15K polyimide also recrystallized upon heating. Polyimide powders were directly synthesized via preparation of the poly(amic acid) followed by cyclodehydration by solution imidization. One requirement is the polyimide must be crystalline so that as the polyimide is formed it will crystallize and precipitate from solution as small particles in the range of 2-16 pm. The particle size may be controlled by the concentration of the solution, temperature, and drying process. / Ph. D.

Nano-reinforced polymeric systems have demonstrated a great deal of interest within academia and industry, due to the intrinsic properties of the graphene nanofillers, having excellent mechanical, thermal and electrical properties. The reinforcement of multiwall carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) were introduced into a low cost, non-carcinogenic, high temperature PMR type polyimide resin. The effects of the interfacial interaction and dispersion quality resulted in improvement in the glass transition temperature (Tg), elastic modulus and thermal stability by, 31°C, 63% and 16°C, respectively. In fine, this study presents a simple but effective high temperature polyimide (HTPI) nanocomposites manufacturing procedure and established that nanoparticle reinforcement can be used to improve both thermal and mechanical properties. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

Homogeneous catalysts demonstrate the ability to perform extremely selective organic syntheses with high yields. These catalysts are usually quite expensive and the commercial viability of processes that use homogeneous catalysts depends on the efficiency of catalyst recovery, which is normally quite complex. This obstacle often excludes the use of homogene-ous catalysts from commercial processes. This work investigates the implementation of mem-branes as the unit operation for catalyst recovery as a means to expand the use of homogeneous catalysis. The commercial polyimide, Matrimid, has been examined for its suitability as a membrane material for the homogeneous catalyst recovery of a 1-dodecene hydroformylation reaction, catalyzed by a rhodium-triphenylphosphine transition metal catalyst. This reaction occurs in the liquid phase in solution with toluene. Because of the aggressive environment of the reaction, blends of Matrimid with a crosslinkable, diacetylene-functionalized oligomer have been formed to promote polymer stability through network formation. The diacetylene groups on the oligomer and acetylene end groups can be thermally activated at 250 ??o form distributed polymer networks. Compatible blends of Matrimid and the crosslinking agent can be formed with up to 10% (w/w) crosslinking agent content. Matrimid and the blends have been investigated in the form of dense, nonporous films to evaluate their membrane performance. In terms of material stabilization, it has been found that heat treatment of the neat Matrimid at 250 ??esults in a significant suppression of the material plasticization when exposed to toluene. Addition of the crosslinking oligomer to Matrimid promotes further reduction in swelling and toluene sorption. Transport studies of the reaction components in the materials show that addition of the crosslinking oligomer results in reduced diffusion of the permeating components in the mem-brane materials. However, some increases in solute sorption occur and this is attributed to the oligomer chemistry. A 10% blend of crosslinking agent and Matrimid gave a superior catalyst rejection of 91.5%. The catalyst rejection system has been modeled using Maxwell-Stefan transport equa-tions. Through the model it was found the flux coupling significantly influences the separation characteristics, with sorption of both the solvent and solute as key factors.

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Thesis (M.S.)--Rochester Institute of Technology, 2008. / Typescript. Includes bibliographical references (leaves 101-103).

Thesis (Ph. D.)--University of Texas at Austin, 2004. / Supervisor: Ray T. Chen. Vita. Includes bibliographical references.