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用拉伸、热处理和大剂量γ射线辐照的方法制备了一系列具有不同平面取向度、不同结晶度和不同分子链长度的 PET 试样。短路热释电流温度谱显示对应于玻璃化转变的α峰随平面取向度、结晶度的增大向高温区移动;随γ辐照剂量的增大向低温区移动。随平面取向度和结晶度的提高,被冻结的大分子主链链段偶极热弛豫活化能减小,偶极热弛豫时间常数指数增长。γ辐照对偶极热弛豫运动的影响较小。
A series of PET samples with different degree of plane orientation, different crystallinity and different molecular chain lengths were prepared by stretching, heat treatment and high dose γ-ray irradiation. Short-circuit pyroelectric current temperature spectrum showed that the α-peak corresponding to the glass transition shifted with the increase of the degree of crystallinity to the high temperature as the degree of plane orientation was increased, and moved toward the low temperature with the increase of γ-irradiation dose. With the increase of the degree of planar orientation and crystallinity, the activation energy of dipole thermal relaxation of the frozen macromolecule main chain segment decreases and the dipolar thermal relaxation time constant increases exponentially. The effect of γ irradiation on dipolar thermal relaxation is small.