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采用溶胶-凝胶法,将聚(苯乙烯-co-丙烯酸)(PSA)膜材料和氯化镁的复合物包覆在以硅胶为载体的TiCl3催化剂上,负载TiCl4后制得Ziegler-Natta复合催化剂.采用红外光谱、激光粒度仪和扫描电镜对催化剂进行了表征,结果表明该复合催化剂呈核壳结构.同时,考察了复合催化剂中膜的厚度和反应中的氢气含量对催化剂的聚合活性和聚乙烯性能的影响,实验发现,膜厚约为3μm的核壳结构复合催化剂活性良好,其具有带诱导期的平稳型动力学曲线;膜厚1.5μm的复合催化剂的活性接近于实验所用的以硅胶为载体的TiCl3催化剂,且其具有相似的衰减型动力学曲线.研究同时表明,不同的膜厚能够调节复合催化剂的氢调性能及所得聚乙烯的分子量分布.
The composite of poly (styrene-co-acrylic acid) (PSA) membrane material and magnesium chloride was coated on a TiCl3 catalyst supported on silica gel by sol-gel method to obtain a Ziegler-Natta composite catalyst after TiCl4 was loaded. The catalysts were characterized by FTIR, laser particle size analyzer and scanning electron microscopy, and the results showed that the composite catalyst was core-shell structure. At the same time, the thickness of the composite catalyst and hydrogen content in the reaction on the catalyst polymerization activity and polyethylene The experimental results show that the composite catalyst with core-shell structure with membrane thickness of about 3μm has good activity and has a stationary kinetic curve with induction period. The activity of composite catalyst with 1.5μm membrane thickness is close to that of silica gel with Carrier TiCl3 catalyst with similar decay kinetic curves.The study also shows that the different film thickness can regulate the hydrogen performance of the composite catalyst and the molecular weight distribution of the resulting polyethylene.