| The preparation of polycarbonate via ring-opening copolymerization of epoxides and CO2 has typical green chemical characteristics due to CO2 has the characteristics of abundant, non-toxic and etc.; while the polyester prepared by ring-opening copolymerization of anhydride and epoxy has high molecular weight, narrow molecular weight distribution and rich backbone structure which can chemically modified by some functional groups. What should point out is that the choice of catalyst is the most important factor during the preparation of polyester and polycarbonate and the catalysts used in catalyze epoxides and CO2 ring-opening polymerization can also catalyze the ring-opening copolymerization of anhydride with the epoxides to form polyester. Among the catalytic systems, Salan analogues exhibits excellent catalytic performance. Based on above, the main contents of this paper were summarized as follows:1. Three kinds of [OSSO]-type Salan analogues ligands with sulfur and oxygen as ordination atoms were synthesized and after coordination with chromium, we obtained four kinds of complexes. Complexes are la with a cyclohexene backbone, Ib with with a cyclohexene backbone and a axial anion of N3, Ic with a ethyl backbone and Id with a benzene ring backbone, respectively.2. The two-component catalysts composed by four kind of complexes and Lewis base or a quaternary ammonium salt can catalyze the the copolymerization of 4-vinyl cyclohexene oxide (VCHO) and CO2 to prepare polycarbonate. The TOF can up to 134 h-1 and the carbonate unit content is greater than 95% in polycarbonate. The structure and amount of co-catalyst, reaction temperature, molar ratio, reaction pressure, reaction time and other factors on copolymerization were investigated systematically and the copolymerization mechanism was discussed. The copolymer (PVCHC) of VCHO and CO2 were functional modified by thiol-ene reaction, radical polymerization reaction, oxidation of the double bond and further forming cyclic carbonate.3. The influence of different epoxides, different acid anhydride, reaction time and reaction temperature on the copolymerization were investigated systematically, the copolymerization mechanism was discussed too. Among the four kinds of complexes, Ia with a cyclohexene backbone has the highest activity to form polyester and DMAP possess the best catalytic performance among the five kinds of Lewis base cocatalyst. The VCHO/PA copolymer can be modified by thiol-ene reaction.4. The two-component catalyst systems composed by la and Ic, respectively, with bis (triphenylphosphoranylidene) ammonium chloride (PPNC1) has equivalent catalytic activity and the catalytic activity of them were greater than two-component catalyst of Id/PPNCl. The effects of the kinds of solvent and monomers, the molar ratio of monomer/catalyst, reaction time and reaction temperature on the copolymerization were discussed. Triazole ring was obtained after the reaction of 3-butyn-l-ol with ECH/PA and NaN3 reacted product. The glass transition temperature of ECH/PA copolymer decreased and increased 23.3℃ and 25.1 ℃ after the reaction with NaN3 and further reaction with 3-butyn-l-ol... |
