Modification Of Aliphatic Polycarbonates Derived From Carbon Dioxide

Carbon dioxide?CO₂? is a kind of greenhouse gas and also an inexpensive C1-feedstock. Thus, the utilization of CO₂ has attracted increasing attention. The alternating copolymerization of CO₂ and epoxides to produce a variety of aliphatic polycarbonates which is a effective method to fixate CO₂, Although polycarbonates has a promising prospect, but the practical application of polycarbonates has been limited by its poor degradability, thermal stability and mechanical performance.Therefore, the modification of CO₂-based aliphatic polycarbonates have important research significance.Tercopolymerization reaction, graft copolymerization and block copolymerization were used to modificate the aliphatic polycarbonates, and study structure and properties,principal results are as follows:First, by introducing the third monomer?EA? into the copolymerization of CO₂ and propylene oxide has been considered as an efficient method to prepare poly?carbonate-ester?s?PPCEA? which catalyzed by ZnGA successfully, And confirm the reaction conditions, the terpolymers were characterized by ¹H NMR and GPC. It turned out that the terpolymerization of CO₂,PO and EA was catalyzed by ZnGA effectively, and the yield of the PPCEA3 came to 56.4 g/g?Zn?, high yield,superior thermal and mechanical performance, compared with PPC, in the phosphate buffer solution of p H 7.4, PPCEAs have high degradability.GPCond, copolymerization of CO₂ and ECH catalyzed by ZnGA to prepare aliphatic polycarbonates and confirm the perfect the reaction conditions: temperature40 Co, reaction time 96 h, catalyst ZnGA 0.1 g and pressure 5.0 Mpa. Copolymers were characterized by ¹H NMR and GPC. And the results show that alternative copolymerization of CO₂ and ECH catalyzed by ZnGA.Putting the aliphatic polycarbonate as a raw material to prepare polycarbonatebased?CET? and confirme the perfect the reaction conditions. Copolymers were characterized by ¹H NMR and the ¹H NMR can prove the result. And putting the CET as a raw material to prepare graft copolymer with styrene, and confirme the perfect reaction conditions. Graft copolymers were characterized by ¹H NMR and GPC. And the results show that graft copolymer was prepared successfully.Third, the ZnGA/PO system to catalyst the copolymerization of CL was studied firstly. And the perfect reaction conditions of the catalyst was confirmed, the controlled weight PCL was prepared successfully. Copolymers were characterized by ¹H NMR, the results show that the ZnGA/PO system can catalyze the controlled weight PCL effectively.Bi-block copolymerization?PPC-PCL? was prepared by series process, and the perfect reaction condition was confirmed. ¹H NMR and GPC can prove the bi-block copolymer. And the results show that we can prepare the controlled bi-block polymers?PPC-PCL?.