A series of cobalt complexes contai-ning benzotriazole-substituted pyridine ligands were synthesized.The effects of the type of cocatalyst,substituent structure,and polymerization tempera-ture and time on 1,3-butadiene polymerization were investigated.The results showed that after activation by methylaluminoxane,these complexes exhibited medium to high activities for 1,3-butadiene polyme-rization.The activity of the complex depended on the substituent at 2-position of pyridine on the ligand.An increment of the bulkiness of substituent resulted in a decrease in activity,but it was not significantly related to the cis-1,4-selectivity of the polymer.Among them,cobalt complex with hydrogen sub-stituent group showed the highest activity and cis-1,4-selectivity,affording polybutadiene with pre-dominant cis-1,4-unit mole fraction of 94.0％,a number average molecular weight of 124.8xl03 g/mol,and a narrow molecualr weight distribution(polydis-persity index 2.0).Raising the reaction temperature could significantly increase the polymerization rate,even at a high temperature of 80 ℃,the polymer yield remained up to 93.6％,implying the high ther-mal stability of the catalyst system.
关键词
苯并三氮唑/聚丁二烯/钴系催化剂/取代基/聚合温度
Key words
benzotriazole/polybutadiene/cobalt catalyst/substituent/polymerization temperature
维普
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