熔融聚合耐高温聚酰胺的非等温结晶动力学研究

通过差示扫描量热仪(DSC)研究了熔融聚合耐高温聚酰胺10T以及10T/11树脂在不同降温速率下的非等温结晶行为。通过Jeziorny法、Ozawa法以及Mo法分析了PA10T和PA10T/11的非等温结晶动力学,并采用Kissinger法、Takhor法以及Vyazovkin法计算了体系的结晶活化能。结果表明,在初期结晶阶段,PA10T和PA10T/11晶体的生长方式是一维针状生长和二维片状生长并存,同时存在异相成核现象;Jeziorny法、Mo法适合研究PA10T和PA10T/11树脂的非等温结晶过程,而Ozawa法不适合研究其非等温结晶过程;随着11-氨基十一酸含量增加,非等温结晶活化能的绝对值呈现先减小后增大再减小的变化趋势,说明结晶速率呈现先增加后减少再增加的变化趋势。

Study on Non-isothermal Crystallization Kinetics of High-temperature Resistant Polyamides Prepared by Melt Polymerization

Poly(decamethylene terephthalamide) (PA10T) and decamethylene terephthalamide-aminoundecanoic copolyamide (PA10T/11) were prepared by melt polymerization. The non-isothermal crystallization behaviors of PA10T and PA10T/11 at di-fferent cooling rates were studied by means of differential scanning calorimetry (DSC). Avrami and Ozawa equations, along with the Mo equation were applied to obtain the non-isothermal crystallization kinetics of PA10T and PA10T/11. Moreover, the activation energy of non-isothermal crystallization of PA10T and PA10T/11 was explored by Kissinger, Takhor and Vyazovkin equations, respectively. The results showed that the mode of the nucleation and crystal growth may be the mixture with one-dimensional, needle-like and two-dimensional, circular. Meanwhile, there was heterogeneous nucleation phenomenon during the non-isothermal crystallization process. Jeziorny and Mo equations well described the non-isothermal crystallization kinetics of PA10T and PA10T/11, while Ozawa equation failed. With the increasing contents of 11-aminoundecanoic acid, the absolute values of activation energy of non-isothermal crystallization first decreased, then increased and finally decreased, which revealed that crystallization rates first increased, then decreased and finally increased.