Preparation Of Novel Vanadium Catalyst For Olefin Copolymerization

This thesis is focused on the synthesis of EPDM and the research including:1) Anovel vanadium-based catalyst has been prepared through introducing sulfonateligand to VOCl₃catalyst. Polymerization behaviors and mechanism of the novelcatalyst have been investigated for ethylene polymerization;2) The effect of3rdmonomer on the polymerization behaviors and mechanism of ethylene-propylenecopolymerization was studied.1. Three kinds of catalysts [VOCl₂SO₃CF₃·（IOOH）₃, VOCl（SO₃CF₃）₂·（IOOH）₃,VO（SO₃CF₃）₃·（IOOH）₃] were prepared through modification of VOCl₃·（IOOH）₃withCF₃SO₃H. The ethylene polymerization was carried out by using homogeneousVOCl₂SO₃CF₃·（IOOH）₃and VOCl（SO₃CF₃）₂·（IOOH）₃catalyst （in n-hexane） inconjunction with alkylaluminium cocatalyst. It was found that the novel catalyst showa higher catalyst activity than the original catalyst. However, the catalyst activitydecreased with the increasing ligand numbers. The highest catalyst activity is152g·mmolV-1·h-1·bar-1,（VOCl₂SO₃CF₃·（IOOH）₃） about3times higher than the originalcatalyst. The PDI and Tm of obtained polyethylene （HDPE） were less changed, andthe GPC curves were unimodal. With regard to the ethylene-propylene copolymeri-zation, the catalyst activity of VOCl₂SO₃CF₃·（IOOH）₃and VOCl（SO₃CF₃）₂·（IOOH）₃was higher than VOCl₃·（IOOH）₃and VOCl₃. The catalyst activity of VOCl₂SO₃CF₃·（IOOH）₃for ethylene-propylene copolymerization was in the range from43.6to89.7g·mmolV-1·h-1·bar-1. In contrast to VOCl₃, the polymer obtained from modifiedcatalyst show a broaden PDI and higher Mw. The obtained ethylene-propylenecopolymers were random polymers and the C₃contents was in the range from35to48.9mol%.2. With regard to VOCl₃·（IOOH）₃–Al₂（C₂H₅）₃Cl₃and VOCl₃–Al₂（C₂H₅）₃Cl₃catalyst system, the effect of3rd monomer （LPB） on the polymerization behaviorswere studied. The effect of catalyst composition and polymerization temperature oncatalyst activity and polymer microstructure were investigated. According to the results of¹³CNMR、FTIR、DSC analysis, the LPB was incorporated into the ethylene-propylene copolymer chains. The3rd monomer shows strong effect on the catalystactivity, Mw and PDI. In the same condition, the catalyst activity of VOCl₃·（IOOH）₃catalyst was higher than VOCl3. After addition of LPB3rd monomer, the polymeryield and its Mw decreased, while the PDI broadened. With the increase of [Al]/[V]molar ratio, the catalyst activity and double bond contents of polymers decreasedfirstly, then increased, while the Mw decreased and PDI broadened. With thepolymerization temperature increased, the double bond contents of polymersdecreased firstly, then increased. The vulcanizate and mechanical properties of thecopolymers were investigated.