119.ポリ(p-メトキシスチレン)の双極子モーメント : 双極子モーメントに対する排除体積効果の検討

概要

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Dipole moment of PMeOSt was studied on five samples having a vareity of molecular weight from 8×10^4 to 75×10^4. All the polymer samples were prepared by anionic polymerization, of which molecular weight dispersity index, M_w/M_n (M_w, weight average molecular weight; M_n, number average molecular weight), was 1.04〜1.11. The dipole moments were determined from measurements of the dielectric constants and densities in benzene solution at several temperatures in the range between 25 and 55℃. It was found that the value of the dipole moment showed little change depending on molecular weight; the average dipole moment per repeating unit, μ, was obtained as 1.209D at 30℃ for the sample of M_w=7.9×10^4, 1.218D (M_w=33.1×10^4) and 1.212D (M_w=75.5×10^4). The experimental results leads a conclusion that excluded volulme effect dosen't exhibit on the dipole moment of polymer. It was also found that the value of the dipole moment ratio, D_r=<μ^2>/μ^2_0, showed little change with changing temperature and its value was 0.928±0.005, (μ_0, dipole moment of structural unit of the polymer chain). The experimental values of the dipole moment ratio were compared with those calculated from conformational analysis of the polymer chain.
東京女子大学の論文
1996-03-15