PVCフィルムの配向消失過程の複屈折による研究

概要

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Birefringence was measured in the creep recovery of preoriented PVC cast films both of the unplasticized sort and of the plasticized sort. The PVC films were stretched under dead load at various temperature ranging below and above glass transition temperature. The measurements of temperature dependence of orientaion birefringence were conducted between room temperature and 160℃ at a constant rate of temperature increase. The experimental findings are as follows : (1) Birefringence increases almost linearly between room temperature and T_g (2) T_g is independent of the temperature at the films are stretched. (3) Another transition above T_g exists at 105℃, which dose not depend on the stretching temperature, and is affected by plasticizer. (4) Transition nearby the stretching temperature can be visualized easily at T_<ori> using birefringence measurement. The initial in birefringence is explained having been caused by thermal expansion. The 105℃-transition is proposed to be a lower limit of melting point, T_m(min), of a microcrystalline structure formed by stretching. T_&lo;ori> corresponds to one of the state of the polymer association being observable under stretching between T_m(min) and T_m(max) which is the conventional primary transition.
社団法人日本材料学会の論文
1971-05-15