熔融聚合耐高温聚酰胺的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树脂的等温结晶行为。通过Avrami方程分析了PA10T和PA10T/11的等温结晶动力学,其Avrami指数n值介于1.79~2.31之间,表明了PA10T和PA10T/11晶体以一维针状生长和二维片状生长并存,然后计算了相关的结晶动力学参数。通过Arrhenius方程计算了PA10T和PA10T/11的等温结晶活化能,同时通过Hoffman-Weeks外推法得到了PA10T和PA10T/11的平衡熔点。并且,利用Turnbull-Fisher方程和Lauritzen-Hoffman方程研究了PA10T和PA10T/11的结晶生长方式。偏光显微镜和X射线衍射分析表明,在实验条件下PA10T和PA10T/11以一维针状生长和二维片状生长并存,并且加入11-氨基十一酸后PA10T/11的晶粒尺寸显著细化。

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 isothermal crystallization behaviors of PA10T and PA10T/11 were studied by means of differential scanning calorimetry (DSC). The crystallization kinetics under isothermal conditions was analyzed by Avrami equation. It showed that the Avrami equation was applicable for isothermal crystallization very well, and the calculated Avrami index n was from 1.79 to 2.31, which demonstrated that the crystallization of PA10T and PA10T/11 were growing with one or two-dimensional growth crystals in this situation. And then the related kinetics parameters of isothermal crystallization were calculated by Avrami equation. The activation energies for isothermal crystallization of PA10T and PA10T/11 were calculated by Arrhenius equation. The equilibrium melting temperatures of PA10T and PA10T/11 were obtained from Hoffman-Weeks extrapolation. Moreover, the crystal growth mode for PA10T and PA10T/11 was studied by means of Turnbull-Fisher equation and Lauritzen-Hoffman equation. The results of polarized optical microscopy (POM) and X-ray diffraction (XRD) showed that the isothermal crystallization for PA10T and PA10T/11 were one or two-dimensional growth under the experimental conditions. And the spherulite size of PA10T/11 was reduced significantly by the addition of 11-aminoundecanoic acid compared with PA10T.