• Applied Chemistry for Engineering
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• v.10 no.1
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• pp.148-153
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• 1999

In situ composites containing a thermotropic liquid crystalline polymer were prepared by polycondensation of 1,4-bis(p-hydroxy-benzoyloxy)butane with 2-bromoterephthaloyl chloride in a poly(methyl methacrylate) solution. Morphology and mechanical, thermal properties of the composites were examined by differential scanning calorimeter(DSC), dynamic mechanical thermal analyser(DMTA), optical microscope and scanning electron microscope(SEM). The TLCP domains showed nematic phase. The glass transition temperature($T_g$) and mechanical properties of the PMMA in the composites increased with increasing the content of TLCP. The TLCP domains were finely dispersed in the PMMA matrix. The 20 wt % TLCP/PMMA composite prepared by in situ polymerization showed more improved mechanical property with finely well dispersed morphology compared with that prepared by solution blending of the same composition.

• Journal of the Korean Electrochemical Society
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• v.3 no.3
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• pp.169-172
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• 2000

A new gel polymer electrolyte based on the modified polyacrylonitrile (PAN), polyacrylonitrile-co-bis[2-(2-methoxyethoxy)ethyl]itaconate (abbreviated as PANI) copolymer was synthesized in expectation of enhanced trapping ability of liquid electrolytes. PAN and PANI blend was complexed with organic solvents, ethylene carbonate (EC) and dimethyl carbonate (DMC), and $LiClO_4$ salt. The highest room temperature conductivity of $2\times10^{-3}\;Scm^{-1}$ was found for a film of 25PAN+10PANl+50EC/DMC+$15LiClO_4$. The solvent-rich crystalline part decreases due to the blending of PANI and therefore number of charge carriers increases giving higher ionic conductivity. The addition of PAM as a host polymer in the PAN-based gels has beneficial effects such as higher ionic conductivity, better thermal characteristics, better miscibility with solvent, wider electrochemical stability, and better interfacial stability with lithium electrode, though it exhibits slightly less mechanical rigidity.

• Macromolecular Research
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• v.12 no.2
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• pp.156-171
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• 2004

We describe the precision synthesis schemes of siloxane-containing polymers, i.e., the control of their molecular weight, stereoregularity, and higher-order structures. First, we found a new catalytic dehydrocoupling reaction of water with bis(dimethylsilyl)benzene to give poly(phenylene-disiloxane). Together with this reaction, we applied hetero-condensations to the synthesis of thermally stable poly(arylene-siloxane)s. The dehydrocoupling reaction was applied to the synthesis of syndiotactic poly(methylphenylsiloxane) and poly(silsesquioxane)s, which we also prepared by hydrolysis and deaminative condensation reactions. We discuss the tendency for loop formation to occur in the synthesis of poly(silsesquioxane) by hydrolysis, and provide comments on the design of functionality of the polymers produced. By taking advantage of the low energy barrier to rotation in the silicon-oxygen bond, we designed selective oxygen-permeable membrane materials and liquid crystalline materials. The low surface free energy of siloxane-containing systems allows surface modification of a blend film and the design of holographic grating materials.