摘要
以邻苯二甲酸二异丁酯(DIBP),2,4-二戊醇二苯甲酸酯(PDDB)为内给电子体和无内给电子体三种催化剂作参考,研究了复配DIBP/PDDB催化剂的活性以及所得聚丙烯等规度、相对分子质量及其分布,并用核磁共振(13C-NMR)和结晶分级分析(CRYSTAF)对聚丙烯等规级分的序列结构和结晶性能进行了表征。相比参考催化剂,复配催化剂显著提高了催化剂活性,改善了聚丙烯等规度,所得聚丙烯相对分子质量分布明显变宽,暗示存在更多类型的活性中心,所得聚丙烯中高等规序列含量最高,得到CRYSTAF结果的证实,并用模型进行了解释。
Three kinds of catalysts （donor-free, diisobutylphthalate （DIBP）, 2, 4-pentadiol dibenzoate（PDDB） as internal donor） used as reference systems, another catalyst with DIBP/ PDDB as internal donor was studied systematically. The influence of mixed catalyst on polymer yield, isotacticity, relative molecular weight and its distribution was investigated. Isotactic fraction of polypropylene （PP） was characterized by crystallization analysis fractionation （CRYSTAF） and nuclear magnetic resonance spectrum（13C-NMR）. From the experimental results, mixed internal donors remarkably increase mixed catalyst activity and improve polypropylene （PP） isotacticity. Molecular weight distribution of PP obtained is much wider, which suggests that a more multiplicity of active catalytic sites is present. Mixed catalyst will give more stereoregular polymers in which highly isotactic sequences. The results are interpreted on the basis of a model and further confirmed by CRYSTAF.
出处
《高分子材料科学与工程》
EI
CAS
CSCD
北大核心
2010年第7期1-4,共4页
Polymer Materials Science & Engineering
