Research progress of diimide catalysts for olefin polymerization
The research progress of α-diimide catalysts for olefin polymerization is reviewed,which focuses on the modification of ligand structures,including the control strategies of spatial and electronic effects,as well as the influence of ligand structure changes on the activity and thermal stability of catalysts.The regulation of axial steric hindrance of α-diimide ligands can improve the activity and thermal stability of catalysts,relative molecular mass of polymers and regulate branching degree.Substituents with different electronic effects are introduced to modify the structure of ligands under appropriate steric hindrance,which can improve the performance of α-diimide catalyst as well.