摘要
Polymerizations of linear α-olefins(CnH2n, CH2=CH―R, R = Cn-2) catalyzed by early transition metals typically afford amorphous polymers with alkyl chains(Cn-2), while chain-straightening polymerizations of α-olefins with nickel-based catalysts produce semicrystalline polyolefins. Polymerizations of various α-olefins were carried out using an α-diamine nickel catalyst with a significantly distorted chelating ring. The influences of temperature, monomer concentration, and chain length of α-olefins on polyolefin microstructure were examined in detail. The α-diamine nickel catalyst realized highly regioselective 2,1-insertion of α-olefins regardless of reaction temperature and monomer concentration. Increased chain length of α-olefins led to the formation of more linear polyolefin.Semicrystalline polyolefins with high melting temperatures(Tm) were made from α-olefins through highly regioselective 2,1-insertion and precise chain-straightening.
Polymerizations of linear α-olefins(CnH2n, CH2=CH―R, R = Cn-2) catalyzed by early transition metals typically afford amorphous polymers with alkyl chains（Cn-2）, while chain-straightening polymerizations of α-olefins with nickel-based catalysts produce semicrystalline polyolefins. Polymerizations of various α-olefins were carried out using an α-diamine nickel catalyst with a significantly distorted chelating ring. The influences of temperature, monomer concentration, and chain length of α-olefins on polyolefin microstructure were examined in detail. The α-diamine nickel catalyst realized highly regioselective 2,1-insertion of α-olefins regardless of reaction temperature and monomer concentration. Increased chain length of α-olefins led to the formation of more linear polyolefin.Semicrystalline polyolefins with high melting temperatures（Tm） were made from α-olefins through highly regioselective 2,1-insertion and precise chain-straightening.
基金
financially supported by the National Natural Science Foundation of China (Nos. 21674130, 51873234)
Natural Science Foundation of Guangdong Province (No. 2017A030310 349)
Fundamental Research Funds for the Central Universities (No. 17lgjc02)
PetroChina Innovation Foundation (No. 2017D-5007-0505)
