Synthesis Of Norbornene Alkenyl Olefin Polymer

The norbornene-based cyclic olefin copolymer has broad application prospects because of its low dielectric constant,excellent transparency,and extremely low moisture.The late transition metal catalysts have the advantages of easy preparation,low sensitivity to water and oxygen,and the late transition metal catalyst can synthesize a structure-controllable polymer,and the molecular weight distribution of the polymer is narrow.In this paper,a series of high-temperature-resistant late transition metal catalysts(α-diimine nickel catalysts)were used to study the homopolymerization of norbornene and ethylene and norbornene copolymerization in the presence of Methyl aluminoxane(MAO).In addition,this paper also studied:the metallocene catalyst and the novelα-diimine nickel catalysts were used as a composite catalyst to catalyze the copolymerization of ethylene and norbornene.The main results were as follows:1.Four homogeneousα-diimine nickel catalysts C1,C2,C3,C4 and silica supportedα-diimine nickel catalyst S-C4 were designed and synthesized.The structure of the complexes were characterized by FT-IR,elemental analysis and ICP,and the complexes were further determined.2.The homopolymerizations of the norbornene were carried out byα-diimine nickel complexes C1-C4 to obtain an addition polymer.Each catalyst still has a high catalytic activity at 70°C,up to 7.28×10~5 g/(mol·h).With the increase of n(Al)/n(Ni),the activity of the catalysts increased.With the increase of norbornene content,the polymerization activity increased.Thehigh molecular weight of the PNBs was 1.49×10~6 g/mol with comparatively narrow molecular weight distribution was 2.3 by C2.The supported catalyst S-C4 catalyzes the homopolymerization of norbornene.The supported catalyst S-C4 exhibits the highest activity up to 1.89×10~5 g/(mol·h)at a polymerization temperature of 70°C.3.Complexes C1-C4 were used as main catalysts to catalyze the copolymerization of norbornene with ethylene.Theα-diimine Ni catalysts C1,C2 and C3 can efficiently catalyze the copolymerization of ethylene and norbornene,the catalytic performance of C3is slightly higher than the catalytic performance of C1 and C2,and the polymerization activity is as high as 1.35×10~5 g/(mol·h).As the ethylene pressure increased from 0.1 MPa to 0.5 MPa,the catalytic activity of C3 increased from 0.98×10~5 g/(mol·h)to 1.35×10~5g/(mol·h).With the norbornene content increased from 1.5 g to 2.0 g,the polymerization activity also increased.With the polymerization temperature increased from 30~oC to 80~oC,the polymerization activity increased and then decreased.As the n(Al)/n(Ni)increased from1000 to 1800,the copolymerization activity increased and then decreased.4.The composite catalyst of metallocene catalyst rac-Et[Ind]2Zr Cl2 and catalyst C4was used to catalyze the copolymerization of norbornene with ethylene,and the metallocene catalyst rac-Et[Ind]2Zr Cl2 was used as the single catalyst.The case where norbornene is copolymerized with ethylene.The polymerization activity of toluene as a reaction solvent is slightly higher than that of xylene as a solvent.With the increase of norbornene content,the polymerization activity increased and then decreased.The catalytic activity of norbornene added in one time was higher than that in three times.