摘要
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 poly(ethylene terephthalate)(PET)films with different degree ofplannar orientation[Δ(xy)z],crystallinity(X_c)and molecular weight(Mn)are obtained bybiaxial stretching,annealing at 110℃ and a larger dose γ-irradiation respectively.The behaviorof α transition of oriented,crystallized and γ-irradiated PET is studied with the method ofthermally stimulated current(TSC).The α-peak of short-circuit thermally stimulated current isshifted to a higher temperature as Δ(xy)z and X_c are increased,and is shifted to a lower tem-perature as the γ-irradiation dose is increased.The activation energy of dipolar thermo-relaxa-tion(ΔH)for main-chain segmental motion in amorphous region is decreased linearly and thetime constant of dipolar thermal relaxation(τ_0)is enlarged exponentially with enhancingΔ(xy)z and X_c.The γ-irradiation has no remarkable effect on ΔH and τ_0.
关键词
热释电流
绝缘材料
PET
poly(ethylene terephthalate)
thermally stimulated current
glass transition temperature
dipolar thermal relaxation
