PC/PET/EPDM共混体系的结晶与熔融行为

本文用解偏振光法与DSC法分别测定并研究了PC/PET/EPDM共混体系的结晶速度、结晶度、Avrami指数(n)和熔融温度及其影响因素,共混物中PET的结晶速度、结晶度均随PC含量增加而下降;EPDM用量不超过10%时,可提高PET的结晶速度,但不影响结晶度和成核与增长方式,n值不变。当EPDM为5%时,结晶速度呈现极大值。经退火处理的共混物呈现熔融双峰,PC量增加,高温熔融峰略移向高温方向;热处理温度升高或时间延长,则低温熔融峰移向高温方向。

Crystallization and Melting Behavior of PC/PET/EPDM Blend System

The crystallization rate, crystallinity, Avrami exponent and melting temperature of the blend system of PC with PET and EPDM were investigated by means of depolarized light and differential scanning calorimetry respectively. Both of the crystallization rate and crystallinity of the blends of PET with PC, and with or without EPDM showed a marked drop with the increase of the content of PC. In contrast, the crystallization rate of blends of PET with EPDM was increased to a maximum when the weight fraction of EPDM was about 5% , but the crystallinity showed little change when the amount of addition of EPDM was up to 10%. The Avrami exponent, calculated on the basis of Avrami equation, did not seems to be influenced by the composition of blends. The DSC thermograms of annealed samples showed double melting peaks. The melting peak at higher temperature, i. e. melting point, shifted to the side of higher temperature with increasing PC content slightly and the melting peak at lower temperature shifted to the side of higher temperature when the annealing temperature was raised or the annealing time was prolonged.