Studies On Synthesis,Characterization And Catalytic Properties Of POPs-Supported Metal Titanium Zirconium Catalysis

Polyolefin material is widely used in all aspects of our life because of its rich raw materials,low price,easy processing and forming,and excellent comprehensive performance.In the 21st century,as a very important pillar industry in the petrochemical industry,its development polyolefin industry trend has an important impact not only on the development of the entire petrochemical industry,but also on China’s national economic development.Olefin polymerization catalyst is the core of research and development of polyolefin materials and industrial production,which determines the structure,performance and morphology of polyolefin materials.For small molecule non-metallocene catalysts,they are usually loaded on some inorganic carriers or polymer carriers in industrial production and then used for catalytic polymerization.The industrial loading can control the size and size distribution of polymer particles in a certain extent scale.However,the activity of some catalysts decreases obviously after loading,and the polyolefins generated by catalysis will introduce ash impurities,the molecular weight distribution becomes wider and the composition becomes more complex,which makes the microstructure and properties of polyolefin materials difficult to control.In recent years,our research group has designed a series of amine-bridged bisphenol[N,N,O,O]tetradentate titanium-zirconium complexes as olefin polymerization catalysts.Under the activation of MAO,these non-metallocene catalysts showed high activity towards ethylene polymerization leading to polymers with high molecular weight,compared with inorganic carriers or polymer carriers,the structure and electronic environment of porous organic polymers with high specific surface area can be modefied easily.As a kind of excellent catalyst carrier,porous organic polymers have a bright future in the field of heterogeneous catalysis.In order to obtain polyolefin catalysts with high activity and meet the needs of industrial production,we have synthesized two kinds of porous organic polymer carriers with triphenylamine triacetylene structure.Four kinds of heterogeneous catalysts with different substituents and different metal content prepared by reacting the two kinds of porous organic polymer carriers with TiCl₄ and ZrCl₄ under different conditions,were characterized by IR,elemental analysis,thermogravimetric analysis,specific surface area and pore size distribution analysis,and solid magnetic resonance（NMR）analysis of metal ion content.The ethylene polymerization catalyzed by these four kinds of catalysts was also studied.The results showed that,the four kinds of catalysts all showed long catalytic life activated by MAO.After 24 hours of polymerization,the yield of polyethylene was high.The product of polyethylene was linear polyethylene.The molecular weight of polyethylene obtained was determined by viscous average molecular weight.The morphology of porous organic polymer supports,catalysts and polyethylene was found to be granular by scanning electron microscopy（SEM）.This indicated that the morphology of the catalyst was well duplicated by the polymer products during the polymerization process.