乙烯/1-辛烯嵌段共聚物的合成

Synthesis of ethylene/1-octene block copolymer

以合成的“软段”吡啶胺基铪配合物和“硬段”水杨醛亚胺锆配合物,在二乙基锌链转移剂作用下制备了窄分子量分布的乙烯/1-辛烯嵌段烯烃共聚物。结果表明,链穿梭聚合的活性(以铪催化剂计)能够达到34.8×10^(6) g/(mol·h),辛烯插入摩尔分数达到了23.5%,烯烃嵌段共聚物的重均分子量可达到225 kg/mol,分子量分布较窄(分子量分布指数2.0~2.3),嵌段共聚物熔点能够达到115℃以上。通过调节吡啶胺基铪催化剂与水杨醛亚胺锆催化剂的比例可以调控共聚物的嵌段长度及分子量。

Ethylene/1-octene block olefin copolymers with narrow molecular weight distribution were prepared by using the synthesized pyridylamido haf-nium catalyst for“soft segment”and salicylaldehyde imine zirconium catalyst for“hard segment”in the presence of chain transfer agent,diethylzinc,The results showed that the activity of chain shuttle polyme-rization(calculated by hafnium catalyst)could reach 34.8×10^(6) g/(mol·h),insertion mole fraction of 1-octene reached 23.5%,weight-average molecular weight of olefin block copolymer with narrow molecular weight distribution(polydispersity index 2.0-2.3)could reach 225 kg/mol,while its melting point was above 115℃.The block length and molecular weight of the copolymer could be controlled by adjusting the ratio of pyridylamido hafnium catalyst to salicylaldehyde imine zirconium catalyst.