时域微分介电谱与 PET 结构相变及软模

Domain Differential Spectrum of Dielectric and PET Structual Phase Transition and Soft Mode

在－１８７～６０℃范围内用微分时域介电谱方法测量了聚对苯二甲酸乙二醇酯的极化效应．实验证明空间电荷扩散理论给出的慢极化弛豫规律在极性聚合物中也成立．在样品的低温β转变过程中静态介电常数被分解为一个快项和三个慢项之和．在聚合物的结构转变中，快介电常数不出现奇异；但三个慢介电常数各自的倒数均出现抛物型软化．

With differential dielectric spectroscopy method in time domain, the slow polarization effects of polyethylent terephthalato (PET) were measured in temperatrure range of -187℃ to 60℃. The experimental results show that the diffusion theory of space charges for slow polarization effects is also avaible in polar polymers. In the process of β transition of PET in low temperature, the static dielectric constant has one fast component and three slow components. In the structural transition of PET, the anomaly of fast dielectric constant is absent; but the reciprocal of every slow one softens with parabolic type.