Effect of molecular weight on crystallization, melting behavior and morphology of poly(trimethylene terephalate)
Effect of molecular weight on crystallization, melting behavior and morphology of poly(trimethylene terephalate)
复制标题
分子量对聚对苯二甲酸丙二醇酯结晶、熔融行为和形貌的影响
DOI：
10.1016/j.polymertesting.2006.08.011
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发表时间：
2007-04-01
期刊：
影响因子：
5.1
通讯作者：
Zhou, Hui
中科院分区：
文献类型：
--
作者：
Chen, Xudong;Hou, Gong;Zhou, Hui
采用差示扫描量热法（DSC）、温度调制差示扫描量热法（TMDSC）和偏光显微镜（PLOM）研究了聚对苯二甲酸丙二醇酯（PTT）在非等温和等温条件下的结晶行为与相对分子质量的关系。整体结晶的总速率随分子量的增加而降低。PTT的非等温冷结晶焓（Δ H-c）、熔融焓（Δ H-m）、熔点（T-m）和熔融结晶焓（Δ H-m，H-c）随PTT分子量的增加而降低。这表明PTT的冷结晶速率和冷却过程中的结晶速率随着PTT分子量的增加而降低。等温结晶过程的有效能垒以及t（0.5）和t（0.5）（-1）值表明，这些PTT的相对结晶能力随着分子量的增加而降低。PTT的初始结晶度和平衡结晶度随分子量的增加而降低，这也证实了PTT的结晶能力随分子量的增加而降低。三重熔融吸热是明显的：低，中，高温熔融吸热峰分别标记为I，II和III。峰I和峰II的位置随结晶温度、升温速率和PTT分子量的增加而增加。晶体的形貌研究表明，所有的球晶均为黄色和白色相间的环状结构，随着晶化温度的升高，球晶明显变粗。球晶尺寸随分子量的增加而减小。(C)2006年由Elsevier Ltd.出版
The crystallization behavior of poly(trimethylene terephthalate) (PTT) as a function of molecular weight was investigated under non-isothermal and isothermal conditions using differential scanning calorimetry (DSC), temperature-modulated differential scanning analysis (TMDSC) and polarized light optical microscopy (PLOM). The overall rate of bulk crystallization decreased with increasing molecular weight. The enthalpy for non-isothermal cold crystallization (Delta H-c), the melting enthalpy (Delta H-m), the melting point (T-m) and the enthalpy of melting crystallization (Delta H-m,H-c) decreases with increasing molecular weight of PTT. This indicates that the cold-crystallization rate and the crystallization rate of PTT during cooling decrease as the molecular weight of PTT increases. The effective energy barrier for the isothermal crystallization process and both the t(0.5) and t(0.5)(-1) values suggest that the relative crystallization ability for these PTTs decreases with increasing molecular weight. The initialization crystallinity and equilibrium crystallinity of PTT decreases as the molecular weight increases, this also confirmed that the crystallization ability of PTT decreases with increasing molecular weight. Triple-melting endotherms were evident: the peaks were labeled as I, II and III for the low-, middle- and high-temperature melting endotherms, respectively. The positions of both peaks I and II steadily increase with increasing crystallization temperature, heating rate and molecular weight of PTT. The morphology studies indicated that all of the spherulites are in rings of alternating yellow and white bands, the spherulites apparently became coarser with increasing crystallization temperature. The spherulitie size decreases with increasing molecular weight. (C) 2006 Published by Elsevier Ltd.