Synthesis Of Nano Silica Supported Nickel,Palladium Catalysts And Its Application Research On Cyclic Olefin Catalytic Polymerization

Addition polymer of norbornene (NB) and their copolymer with olefins possess excellent thermal and optical properties and are recently hot topical for using in fields of optoelectronics, engineering and medicine. However, these polymers suffer some weakness in solubility, brittleness and adhesion, which is a drawback in the use of the polymers for the construction and forming process of devices. However, polymer microstructure and morphology changed by different catalysts and monomers to improve solubility and brittleness may be come true by using heterogeneous catalysts, due to which have the complex design property of homogeneous and the benefit of the supported. Moreover, heterogeneous catalysts has many good aspect as well heat and mass transfer, controlling the polymer morphology, ability to use it in commercial slurry and gas-phase processes, producing polymers easy to process with broad molecular weight distributions and higher Mw. While nano-particle supports offer great advantages such as increased surface area, mass transfer, and better heat and decreased internal surface area. In this respect, it is desirable to have easy and versatile laboratory methods to prepare nanocomposites with different flexibility and functionalization.In this paper, covalently immobilized silica supported acetylacetonate dichloride palladium(II) and β-ketoamine ligand nickel(II) dibromide precatalyst were successfully prepared. The silica supported catalysts were used in slurry polymerizations of norbornene and polar derivative to afford a highly productive norbornene addition polymerization system in combination with B(C6F5)3cocatalyst to afford nano-silica hybrid polynorbornene nanocomposite. The affect of polymerization temperature, time and amount of cocatalyst on polymer properties and catalytic activity were studied, as well as polymer growth mechanism, the crystalline structure, thermal, mechanical and optical properties of the in situ nano-composite polynorbornene materials.The silica supported acetylacetonate dichloride palladium(II) catalyst was used in slurry polymerizations of norbornene to afford a highly productive norbornene addition polymerization system in combination with B(C6F5)3cocatalyst. It exhibits productivity of84kg polymer (mol Pd)-1h-1at the initial activity and the catalyst deactivation kinetics in the early stage of polymerization has been fitted well by the first order deactivation kinetics with about40min. The obtained nano-silica hybrid polynorbornene nanocomposite has sound heat stability. UV-vis and mechanical measurements respectively reveal that transparency of nanocomposites is close ca.90%and the brittleness was obviously improved. The tensile strength of these nanocomposites is estimated to be as high as11.8MPa. The film of PNB nanocomposite has good transparency and mechanical properties compared with that PNB catalyzed by homogeneous catalyst as well as film forming ability. The yield is close to20%after48h.The silica supported β-ketoamine ligand Nickel(II) dibromide catalyst was used in slurry polymerizations of NB and copolymerization with NB-COOCH3to afford a highly productive addition polymerization system in combination with B(C6F5)3cocatalyst. It exhibits high productivity of176.8kg polymer (mol Ni)-1h-1at low ration of B/Ni and the catalyst deactivation kinetics in the early stage of polymerization has been fitted well by the first order deactivation kinetics with about60min. The yield is close to70.5%at48h.The obtained nano-silica hybrid copolymer nanocomposites have decent heat resistant. UV-vis and mechanical measurements respectively reveal that transparency of nanocomposites is close ca.60%and the brittleness was obviously improved. The tensile strength of these nanocomposites is estimated to be as high as47.8MPa.