Preparation Of Polythiocarbonate By Copolymerization Of Carbon Dioxide With Cyclohexene / Propylene

In obtaining poly[thio]carbonate, owning excellent solvent resistance, electrical conductivity and magnetic potential, good optical properties and heavy-metal recognition ability, the development of new low toxicity and high catalytic activity catalysts and optimization of polymerization conditions are worth concerning.This thesis aims to develop a series of low toxicity asymmetrical bi-Schiff-base zinc(Ⅱ) complexes, and causes them to catalyze the copolymerization of carbon disulfide (CS2) and cyclohexene oxide (CHO)/propylene sulfide (PS). Specific studies are as follows:Firstly, according to the rational design routes, six new asymmetrical bi-Schiff-base zinc(Ⅱ) complexes (Ln-Zn, n= 1-6) were synthesized and well characterized by EA, FT-IR, 1H NMR,XRD and PXRD.Secondly, in order to verify catalytic performances of these six asymmetrical bi-Schiff-base zinc(Ⅱ) complexes (Ln-Zn, n=1-6), they were applied to catalyze the copolymerization of CS2 and CHO. Among the catalytic performances, L6-Zn was showed the best. Furthermore, using the selected L6-Zn as the suitable catalyst, the Mn of the obtained copolymer was 19.716 kg/mol and the PDI was 1.09 under the optimum polymerization condition with [PPN] Cl as the co-catalyst and the ratio of monomer, catalyst and co-catalyst ratio of 1000:1000:1:1, the reaction temperature of 80℃ and reaction time of 8 h. In addition, oxygen/sulfur atom exchange was found during CS2 and CHO copolymerization.Thirdly, the asymmetrical bi-Schiff-base zinc(Ⅱ) complexes (Ln-Zn, n= 1-6) were applied to catalyze the copolymerization of CS2 and PS. Among catalytic performances of these complexes, L6-Zn was showed the more suitable one. Furthermore, under the optimum polymerization condition of [PPN]Cl as the co-catalyst, the ratio of monomer, catalyst and co-catalyst ratio of 1000:500:1:1, the reaction temperature of 60℃ and the reaction time of 10 h, the Mn of the obtained copolymer was up to 8.672 kg/mol and the PDI was 1.54. Moreover, the selectivity of the polymer/cyclic product was 71/29. the 1H NMR result of the copolymer shows that the segment of the copolymer is completely alternating.