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京都大学 / 新制・課程博士 / 博士(工学) / 甲第23930号 / 工博第5017号 / 新制||工||1783(附属図書館) / 京都大学大学院工学研究科化学工学専攻 / (主査)教授 大嶋 正裕, 教授 山子 茂, 教授 佐野 紀彰 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

A series of modified poly(arylene ether sulfone)s (PAES) incorporating hexafluoroisopropylidene units and co-monomers, bisphenol A (BA), 4,4′-dihydroxyterphenyl (DHTP) and triptycene-1,4-hydroquinone (TPDH), were synthesized using a polyetherification synthetic method. These thermoplastic PAES were copolymerized with the elastomer, polydimethylsiloxane (PDMS) to form segmented block copolymers. The segmented block copolymers with diverse PAES structures were studied and investigated for their thermal, tensile, and morphological properties. These multiphase segmented block copolymer materials have the potential to impart useful combinations of optical transparency, thermal stability, and enhanced tensile properties, and enhanced environmentally resistant properties for various high impact, high performance applications. In Chapter 2, hexafluoroisopropylidene bisphenol PAES (BAF PAES) segmented block copolymers containing various volume fraction of PDMS were synthesized. Analysis of the segmented block copolymer films by atomic force microscopy (AFM) and small angle x-ray scattering (SAXS) show the materials are microphase separated. Further analysis of the BAF PAES segmented block copolymers by transmission electron microscopy (TEM) show an increased morphological order with decreasing PDMS content, with lamellar morphologies formed at higher or near equal PAES and PDMS volume fractions. Comparatively, the morphological properties of the BAF PAES segmented block copolymers are considerably different from the isopropylidene bisphenol PAES (BA PAES) segmented block copolymer of similar PDMS volume percents. In this document, segmented block copolymers prepared from BA PAES incorporating 4,4′-dihydroxyterphenyl (DHTP) and triptycene-1,4-hydroquinone (TPDH) co-monomers were characterized by proton nuclear magnetic resonance spectroscopy (¹H NMR). Films of these materials, prepared from THF solution, were tested for thermal and tensile properties. These materials provide higher thermal stabilities over the BA PAES segmented block copolymers with thermal degradation ranging 380–435 °C under nitrogen at 5%-wt. loss. Similarly, the PAES incorporating co-monomers gave higher Tg (200 °C) than the BA PAES (183 °C) synthesized in our labs. Previously synthesized BA PAES segmented block copolymers showed plastic to elastomeric tensile properties upon increasing addition of PDMS content. These new segmented block copolymers, incorporating co-monomers, provided comparable results with the reported BA PAES segmented block copolymers analogues. The last research topic discussed in this dissertation covers the preparation of blends from 5% of segmented block copolymer and 95% of Udel®, donated by Solvay Advanced Polymers. The preparation of blends from the segmented block copolymers containing random copolymers led to materials with higher moduli than Udel® as observed by dynamic mechanical analysis (DMA). Tensile measurements performed by Instron also show the blends have high moduli, though no changes in the tensile elongation comparable to Udel®. / Ph. D.

Low molecular weight liquid polybutadienes (1000 – 2000 g/mol) consisting of 60 mol% 1,2-polybutadiene repeating units were synthesized via anionic telomerization and conventional anionic polymerization. Maintaining the initiation and reaction temperature less than 70 °C minimized chain transfer and enabled the telomerization to occur in a living fashion, which resulted in well-controlled molecular weights and narrow polydispersity indices. MALDI-TOF mass spectrometry confirmed that the liquid polybutadienes synthesized via anionic telomerization contained one benzyl end and one protonated end. Subsequently, 2-ureido-4[1H]-pyrimidone (UPy) quadruple hydrogen-bonding was introduced to telechelic poly(ethylene-co-propylene), and mechanical characterization of the composites with UPy-functionalized carbon nanotubes was performed. The composites enhanced the mechanical properties and the UPy-UPy association between the matrix polymer and carbon nanotubes prevented the decrease of an elongation at break. The matrix polymer was also reinforced without sacrificing the processability. Additionally, UPy groups were introduced to styrene-butadiene rubbers (SBRs). Introducing UPy groups to SBRs drastically changed the physical properties of these materials. Specifically, the SCMHB networks served as mechanically effective crosslinks, which raised Tg and enhanced the mechanical performance of the SBRs. Novel site-specific sulfonated graft copolymers, poly(methyl methacrylate)-g-(poly(sulfonic acid styrene)-b-poly(tert-butyl styrene)), poly(methyl methacrylate)-g-(poly(tert-butyl styrene)-b-poly(sulfonic acid styrene)), and the corresponding sodium sulfonate salts were successfully synthesized via living anionic polymerization, free radical graft copolymerization, and post-sulfonation strategies. The graft copolymers contained approximately 9 – 10 branches on average and 4 wt% of sulfonic acid or sodium sulfonate blocks adjacent to the backbone or at the branch terminus. The mobility of the sulfonated blocks located at the branch termini enabled the sulfonated blocks to more readily interact and form ionic aggregates. The glass transition temperatures (Tg) of the sulfonated graft copolymers with sulfonated blocks at the branch termini were higher than that of copolymers with sulfonated blocks adjacent to the backbone. More facile aggregation of sulfonated blocks at the branch termini resulted in the appearance of ionomer peaks in SAXS whereas ionomer peaks were not observed in sulfonated graft copolymers with sulfonated blocks adjacent to the backbone. In addition, similar analogues, novel site-specific sulfonated graft copolymers, poly(methyl methacrylate)-g-(poly(sulfonic acid styrene)-b-poly(ethylene-co-propylene)) (PMMA-g-SPS-b-PEP), poly(methyl methacrylate)-g-(poly(ethylene-co-propylene)-b-poly(sulfonic acid styrene)) (PMMA-g-PEP-b-SPS), and the corresponding sodium sulfonate salts were successfully synthesized. Estimated ï £N values predicted the phase separation of each block and differential scanning calorimetry (DSC) and dynamic mechanical analysis confirmed the phase separation of each block component of the graft copolymers. The aggregation of sulfonic acid or sodium sulfonate groups at the branch termini restricted the glass transition of the PEP block. This lack of the glass transition of the PEP block resulted in higher storage modulus than a sulfonated graft copolymer with sulfonated blocks adjacent to the backbone. The location of sulfonated blocks in both sulfonic acid and sodium sulfonate graft copolymers significantly affected the thermal, mechanical and morphological properties. Lastly, symmetric (16000 g/mol for each block) and asymmetric (14000 g/mol and 10000 g/mol for each block) poly(ethylene-co-propylene)-b-poly(dimehtylsiloxane) (PEP-b-PDMS) were synthesized using living anionic polymerization and subsequent hydrogenation. The onset of thermal degradation for the PEP-b-PDMS diblock copolymer was higher than 300 ºC and PEP-b-PDMS was more thermally stable than the precursor diblock copolymer, polyisoprene-b-PDMS. DSC analysis of PEP-b-PDMS provided Tg of PDMS -125 ºC, Tg of PEP -60 ºC, Tc of PDMS -90 ºC, and Tm of PDMS -46 and -38 ºC, respectively. Appearance of thermal transitions of each PEP and PDMS block revealed the formation of phase separation. Estimated Ï N also supported the phase separation. / Ph. D.

The overall objective of the project, on which this thesis is based, is to develop a novel hydrocarbon-based proton exchange membrane (PEM) material that can produce a proton conductivity of 0.1 S/cm at the operating conditions of 50 % relative humidity and 120 oC, which is the performance target set by the U.S. DOE for automotive application. As a part of this project, our efforts have been focused on the investigation of the effects of solution-casting conditions on the final morphology and properties of disulfonated poly(arylene ether sulfone) multiblock copolymer films from the viewpoint of phase separation of block copolymers. Of equal importance to this work, is a possibility of utilizing a rheological technique for monitoring the transformation and kinetics of block copolymers during solvent removal process, which was initially examined in order to provide fundamental quantitative understanding and practical information on the solvent removal process. Our results demonstrated that solvent selectivity and drying temperature as well as the block length had considerable effects on the final morphology and properties. The proton conductivity could be significantly increased by simply utilizing a selective solvent, dimethylacetamide (DMAC), which is good and marginal for the sulfonated and unsulfonated blocks, respectively, rather than N-methyl-2-pyrrolidone (NMP), a neutral solvent for both blocks. The drying temperature was also observed to have considerable effects on the final properties, being coupled with the effects of solvent selectivity. Also, it was shown that the multiblock copolymer consisting of longer blocks was more sensitive to the processing conditions. From the morphological study using transmission electron microscopy and small-angle X-ray scattering, evidences for the above observations were obtained. In the second part of this dissertation, the evolution of GÎ and GË of the solutions of a styrene-butadiene-styrene (SBS) triblock copolymer in toluene was obtained as a function of concentration using a modified parallel-plate device and a rheology test scheme developed in this study in an effort to quantify the phase separation kinetics. Then, the information on the phase transformation and kinetics of the SBS block copolymer in the solution was obtained by analyzing the GÎ and GË data with the Avrami equation. The Avrami exponent was found to be approximately 1, which indicates that the phase transformation occurred by a one-dimensional growth mechanism. The rate constant showed a strong concentration-dependence. After the initial increase up to 45 vol %, the rate constant drastically decreased and, finally, converged to 0 at 70 vol %. It is believed that, at the concentration range below 45 vol %, the phase separation became more intense as the polymer molecules had more chances to interact owing to the concentration increase. However, above 45 vol %, the phase transformation became weaker due to the limited mobility of the polymer molecules, which finally led to a “kinetically frozen-in” structure, in which the polymer molecules could not move any longer. Thus, it can be concluded that the solvent removal rate is one of the dominant factors that decide the final microstructures of solution-cast block copolymer films. / Ph. D.