丙二酸处理硫酸钡填充等规聚丙烯复合材料的结晶性能

Crystallization Properties of Isotactic Polypropylene Composites Filled with Malonic Acid Treated BaSO_4

采用差示扫描量热仪、广角X射线衍射仪、偏光显微镜研究了等规聚丙烯/沉淀法硫酸钡复合材料在120℃等温结晶后的熔融和结晶行为。结果表明,与未处理填料体系相比,丙二酸处理硫酸钡有利于聚丙烯中β晶的形成,β晶晶粒明显细化。在7.5%填料含量时,丙二酸处理硫酸钡复合材料的β晶型相对含量(K_(WAXD))达到最大值0.853,而未处理硫酸钡复合材料的K_(WAXD)为0.222。丙二酸处理硫酸钡时,发生化学反应生成的丙二酸钡起到了聚丙烯β晶型成核剂的作用。

The melting and crystallization behavior of isotactic polypropylene/barium sulfate composites after isothermal crystallization at 120 ℃ were investigated by means of differential scanning calorimetry （DSC）, wide angle X-ray diffraction （WAXD） and polarizing microscope （PLM）. Compared with the untreated filler, the filler treated by malonic＇acid facilitates the formation of （3 spherulites in iPP, and the size of the spherulites decreases obviously. At the filler content of 7.5%, the relative β form content （KWAXD） for composite filled with the treated filler reaches the maximum 0.853, while the value is 0.222 for the untreated system. Barium malonate is formed by the chemical reaction between malonic acid and barium sulfate, which serves as the β nucleating agent for iPP.