| Exploring new catalysts is of the primary importance in the field of polymer synthesis. In this thesis, new Schiff base complexes of rare earth were synthesized, combined with Al(i-Bu)3 (MAO) as cocatalyst, these complexes were applied in the homo and copolymerization of Styrene and Isoprene.Polystyrene with high molecular and high tacticity was obtained by a ternary system composed of rare earth-Schiff base complex Nd(H2Sale)2Cl3·2C2H5OH, Al(i-Bu)3 and CCl4. The copolymerization of Styrene (St) and Ethyl methacrylate (EMA) were carried out using this catalytic system successfully.Polystyrene having Mη of 17×104, Mn of 8.37×104, MWD of 3.92 with 48% isotacticity and 52% syndiotacticity was obtained by a ternary rare earth catalytic system Nd(H2Sale)2Cl3·2C2H5OH/Al(i-Bu)3/CCl4 under the following conditions: [St]/[Nd]=1000, [CCl4]/[Nd]=9, [Al]/[Nd]=30, 50℃ polymerized for 20h. The polymer yield was about 54%.Copolymer of styrene and ethyl methacrylate was also obtained by above catalytic system using following conditions: [Al]/[Nd]=30 , [CCl4]/[Nd]=8, [Monomer]/[Nd]= 300, [St]/[EMA]=1, aging for 1 hour, 50℃ copolymerized in toluene for 20h. The copolymer has yield of 57% and 89mol% of St content, and [η] of 0.52dL/g.Using MAO as a cocatalyst, a novel catalytic system Nd(H2Sale)2Cl3·2C2H5OH /MAO/CCl4 was found, and showing activity for the polymerization of Styrene. Polystyrene was obtained under following conditions: [MAO]/[Nd]=175 , [CCl4]/[Nd]=8, [St]/[Nd]=500, aging for one hour, polymerized for 24h at 70℃ in toluene. Polystyrene with high syndiotacticity (about 86%) was obtained with 52% conversion, Mη of 11×104.High cis-1,4 content Polyisoprene was also obtained successfully by a novel binary rare earth catalytic system Nd(H2Sale)2Cl3/Al(i-Bu )3. The catalytic alsoshows high catalytic activity following polymerization conditions: [Al]/[Nd]=30, [IP]/[Nd]=1000, aging for one hour, polymerized in toluene at 50 °C for 4 hours. The polymer yield was about 97%. PIP obtained has a high molecular weight (Mn=2.3x 105, MWD=4.87) and high cis-1 A content(about 96%).
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