Study On Preparation Of Poly(4-Methyl-1-Pentene) Using A Solution Polymerization

Poly（4-methyl-1-pentene）（PMP）is the polymer of 4-methyl-1-pentene（4MP1）or the copolymer of 4MP1 and α-olefin synthesized by coordination catalyst.The monomer for PMP,4MP1,is produced by the dimerization of propylene.PMP presents high temperature resistance and has good electrical,optical,and mechanical properties.So,it is applied to LED modules,food packaging materials and medical devices.Based on the solution polymerization technology,this topic carries out the research about dimerization of propylene to prepare 4MP1 and polymerization of 4MP1 to synthesis PMP.Investigate the influence of process conditions and.characterize the chain structure and thermal performance of PMP.Reveal the structure-activity relationship between the composition,the chain structure and property that will provide guidance for the industrialization of PMP.The main innovations and achievements of this thesis are as follows:（1）Evaluated β-[N-（C₅H₇O）PhCH₃]₂Ni and Cp^*₂HfCl₂ which catalyzes propylene dimerization.Cp^*₂HfCl₂ had a higher cost-effectiveness and was more suitable for industrial.In the Cp^*₂HfCl₂ catalytic system,PMAO had the best activation ability for the catalyst,which could significantly improve the activity of propylene dimerization reaction,and the high selectivity of 4MP1 without the formation of C6,which was beneficial to the separation of 4MP1.Adding a small amount of TIB A to the system could improve the activity and selectivity of the dimerization,but too much would have negative effects.Ph₃CB（C₆F₅）₄ helped to improve the activity and selectivity,but the amount of PMAO needed to be reduced accordingly.（2）rac-Et（Ind）₂ZrCl₂,rac-Me₂Si（Ind）₂ZrCl₂,Ph₂C（Cp）（Flu）ZrCl₂ and pyridylamido hafnium complexes that could catalyze the preparation of PMP were studied.Under the same conditions,the catalyst pyridylamido hafnium complexes had the highest activity,and its product had a high melting point and molecular weight.In the reaction system catalyzed by pyridylamido hafnium complexes,the type of methylaluminoxane had a significant effect on the polymerization of 4MP1.By controlling the reaction temperature,catalyst and co-catalyst concentration,the activity of the reaction,the molecular weight,and the thermal performance of the PMP could be changed.（3）4MP1 and 1-hexene were polymerized using pyridylamido hafnium complexes catalyst system.With the use of 1-hexene,activity of the system containing MMAO was higher to that of PMAO,and PMP of the system containing MMAO had higher melting point and molecular weight.Increasing the polymerization temperature and catalyst concentration was beneficial for the copolymerization of 1-hexene,but the molecular weight and melting point of the copolymer decreased.Reducing the feed ratio of 1-hexene to 4MP1 increased the molecular weight,crystallinity,and melting point of the copolymer.