聚丙烯/共聚酯/蒙脱土复合材料结晶行为的研究

Study on the Crystalline Behavior of PP/COPET/MMT Composites

采用热台偏光显微镜研究了聚丙烯(PP)/共聚酯(COPET)以及PP/COPET/蒙脱土(MMT)复合材料等温结晶时的结晶形态,结果表明:两样品均呈现清晰的球晶所特有的黑十字消光图像,PP/COPET/MMT复合材料的球晶尺寸比PP/COPET样品的球晶尺寸大大减小。采用差示扫描量热法对PP/COPET以及PP/COPET/MMT复合材料的非等温结晶行为进行了研究,结果表明:随着MMT含量的增加,复合材料样品的结晶初始温度和结晶峰温基本呈现逐渐降低趋势,结晶放热焓随MMT含量增加先增加后减小;在不同的降温速率下结晶,两种样品结晶峰温均随降温速率的增大而降低,结晶放热焓也随着结晶速率的增大而降低。采用Jeniorny法处理了PP/COPET和PP/COPET/MMT样品的非等温结晶过程,得出了两体系的结晶速率总体上随着冷却速率的增加而加快,为多维结晶生长体系。

The crystalline morphologies of polypropylene （PP）/copolyester （COPET） and PP/COPET/ montmorillonite （MMT） composite samples at isothermal crystallization were studied by XP-201 thermal plataform polarized light microscope.The results showed that two samples assumed black cross extinct pictures characteristic of spherulites and the dimensions of the spherulites of PP/COPET/MMT composite were much smaller than that of PP/COPET composite.The nonisothermal crystalline behavior of PP/ COPET and PP/COPET/MMT composite specimens was studied by differential scanning calorimetry,the results indicated that the crystallization-initial temperature and crystallization-peak temperature of the composites decreased gradually and the crystallization-exothermic enthalpy of the composite samples increased and then decreased with the increase of MMT content.When the specimens crystallized at different cooling rates,their crystallization-peak temperature all decreased,the crystallization-exothermic enthalpy decreased with the increase of crystallization rate.The nonisothermal crystallization process of the specimens was analyzed by the method of Jeziorny,the results showed that the nonisothermal crystallization rate of the two systems generally increased with the cooling rate increasing.