SEBS-g-MA对PS／PA6的相形态及非等温结晶行为的影响

Effect of styrene-ethylene/butylene-styrene elastomer grafted with maleic anhydride on morphology and non-isothermal crystallization behavior of polystyrene/polyamide 6 blends

采用熔融共混的方法制备共混物PS/PA6(质量比为50/50)和PS/PA6/SEBS-g-MA(质量比50/50/5)。SEM观察发现PS/PA6呈现双连续的相态,加入质量分数为5%的SEBS-g-MA到PS/PA6中,PS和PA6的相畴尺寸均减小,但仍然保持双连续的相态。采用差示扫描量热法分析了PS/PA6和PS/PA6/SEBS-g-MA的非等温结晶行为,加入SEBS-g-MA提高了PS/PA6中PA6的结晶起始温度T0、结晶峰温度Tp,减小了结晶过程总时间?t和半结晶时间t1/2。Jeziorny法和Mo法都适用于PS/PA6和PS/PA6/SEBS-g-MA的非等温结晶动力学过程,通过Jeziorny法分析第一阶段非等温结晶过程得到PS/PA6的Avrami常数n为4.40～4.91,PS/PA6/SEBS-g-MA的Avrami常数n为2.47～3.25,PS/PA6/SEBS-g-MA的Zc也大于PS/PA6的Zc。通过Mo法得到在相同的相对结晶度Xt下,PS/PA6/SEBS-g-MA的lgF(T)小于PS/PA6的lgF(T)值。这些都说明SEBS-g-MA对PS/PA6中的PA6有诱导结晶作用。而Ozawa法不适合于PS/PA6和PS/PA6/SEBS-g-MA的非等温结晶动力学过程。

Polystyrene/polyamide6 （PS/PA6） （weight ratio 50/50 ） and polystyrene/polyamide 6/styrene-ethylenefoutylene-styrene elastomer grafted with maleic anhydride （PS/PA6/SEBS-g-MA） （weight ratio 50/50/5 ） blends were prepared through melt blending. The phase morphologies investigated by using scanning electron microscope （SEM） revealed that co-continuous morphologies were formed in both of the blends of PS/PA6 （weight ratio 50/50） and PS/PA6/SEBS-g-MA （weight ratio 50/50/5 ）. But the PS phase and PA6 phase in PS/PA6/SEBS-g-MA （weight ratio 50/50/5 ） blends became finer than that in PS/PA6 （weight ratio 50/50） blends. The non-isothermal crystallization behavior of PA6 in both of the blends was studied with differential scanning calorimetry （DSC）. It was found that the onset temperature （To） and the peak temperature （Tp） of crystallization shifted to higher temperatures, and the whole-time （At）and half-time （t1/2）of crystallization decreased after adding 5% SEBS-g-MA in the PS/PA6 blends. Both the Jeziorny＇s method and Mo＇s method can describe the non-isothermal crystallization kinetics of both of the blends very well. The Avrami exponent of PS/PA6 blends was from 4.40 to 4.91 and the Avrami exponent of PS/PA6/SEBS-g-MA was from 2.47 to 3.25, and Zc of PS/PA6 blends was smaller than that of PS/PA6/SEBS-g-MA by the Jeziorny＇s method. When Xt of PA6 in both of the blends reached the same, lgF （T） of PS/PA6/SEBS-g-MA blends was smaller than that of PS/PA6 blends. These demonstrated that SEBS-g-MA could play a role of heterogeneous nuclei. The Ozawa＇s method was not suitable for the non-isothermal crystallization kinetics of PS/PA6 blends and PS/PA6/SEBS-g-MA blends.