自六十年代初即有不少文献和专利声称用Ziegler-Natta催化剂制备了A—B、A—B—A和型乙烯、丙烯嵌段共聚物。根据络合催化聚合活性中心寿命的有限性和链转移的可能性,有人对络合催化聚合合成嵌段共聚物的可能性提出了质疑,从实验上说明商品聚丙烯-聚乙烯(PP-PE)实际是PP+PE的混合物或含大量PP。 Since the early 1960s, there are a lot of literature and patents claiming that A-B, A-B-A and ethylene-propylene block copolymers are prepared using Ziegler-Natta catalysts. According to the limitation of the life of the complex catalytic polymerization center and the possibility of chain transfer, some people have questioned the possibility of synthesizing the block copolymer by catalytic polymerization, and experimentally demonstrated that the commercial polypropylene-polyethylene (PP-PE ) Is actually a mixture of PP + PE or contains a lot of PP.