固相缩聚与PET的熔融性能

应用差示扫描量热法（ＤＳＣ）和广角Ｘ射结衍射（ＷＡＸＤ）研究了低温干燥高温固相缩聚ＰＥＴ的熔融行为和结晶结构。根据ＤＳＣ结果分析了固相缩聚反应温度和时间对熔融双峰的影响，得到熔点与固相缩聚反应温度有红性关系，熔点和结晶度与固相缩聚反应时间的对数呈线性关系。利用ＷＡＸＤ研究了固相缩聚反应温度和时间对表观晶粒尺寸的影响。结果说明低温结晶时形成的不完善晶体在固相缩聚过程中发生部分熔融、重结晶，结晶结构趋

MELTING BEHAVIOUR OF POLY(ETHYLENE TEREPHTHALATE)PREPARED BY SOLID STATE POLYCONDENSATION

The melting behaviour of poly(ethylene terephthalate) prepared by solid state polycondensation(SSP) has been investigated using differential scanning calorimetry and wide angel X ray diffraction(WAXD). The effect of SSP reaction temperature and time on dual melting endotherms in the DSC thermograms of PET has been examined. It is showed that a linear relation of lower temperature endotherm peak of PET, T ml , with SSP reaction temperature holds, and that T ml and crystallinity increase almost linearly with the logarithm of reaction time. In addition the influence of SSP reaction temperature and time on apparent crystalline size has been studied by means of WAXD. The result indicates that the imperfect crystallites formed at lower crystallization temperature undergo a continuous perfection process as a result of partial melting and recrystallization during SSP, in consequence, the perfection of crystalline structure and the formation of new stable crystallites during SSP increase the melting point and crystallinity of PET.