用介电方法研究COPU/PMMA交联共聚物的转变与松弛

STUDY ON THE TRANSITION AND RELAXATION BEHAVIOUS OF COPU/PMMA CROSSLINKED POLYMER BY DIELECTRIC METHOD

用TRS-10C型介电损耗仪,在不同频率,-180℃～170℃范围内测得COPU/PMMA交联共聚物的介电损耗谱。计算了各松弛过程的活化能,考察了组成和交联密度对分子运动、相容性及形态结构的影响。结果表明,COPU/PMMA交联共聚物是个半相容体系,其相容性随PMMA含量的增加和交联密度的减小而变坏。介电损耗谱上的次级松弛是COPU链段运动的贡献。界面极化区松弛谱的各点温度和频率的关系符合Arrhenius方程,各点温度和其高温侧松弛曲线线性部分斜率的大小可以反映相容性的好坏。

The dielectric relaxation spectra of COPU/PMMA crosslinked polymer were obtained at different frequences from -180℃ to 170℃.The activation energy of all relaxation processes were calculated, the influnces of components and crosslinking density on molecule moton, compatibility and morphology were investigated. The results show that COPU/PMMA crosslinked polymer is a semicompatible system and the compatibility reduces with the increasing PMMA content and the decreasing crosslinking density. The secondary relaxation is attributed to the local motion of the chain segments of polyurethane component. The relationship between valley temperature and frequencies in relaxation spectra of the interfacial polarization region follows the Arrhenius equation. The valley temperature and the slope of curve in high temperature area can reflect the compatibility.