PROGRESS IN FUNCTIONAL CARBON DIOXIDE BASED ALIPHATIC POLYCARBONATES

Transformation of CO2 into biodegradable polycarbonates by the alternating copolymerization with epoxides has attracted much attention not only in academic research but also in industry. The review first summarized the industry progress of CO2 based plastics, and the advantages and disadvantages of this CO2 based plastics have been discussed based on poly(propylene carbonate) (PPC), a typical CO2 based plastics from alternating copolymerization of CO2 and propylene oxide. One disadvantage lies in that the CO2 based copolymer is seldom functionalized, leading to its poor hydrophilicity. This review tries to emphasize that introducing functional groups to CO2 based copolymer, such as pendant ally groups, carbonate groups, mesogenic groups, can produce functionalized CO2 based copolymers, moreover, introducing urethane-amine group, ether group in the mainchain or side chain may be a practical way to adjust the balance of hydrophobicity and hydrophilicity of the copolymers, leading to novel thermal/pH dual responsive CO2 based copolymers. Of course, due to the strong polarity or hydrophylicity of the functional monomer, the functional CO2 based copolymers generally show relatively lower molecular weight, and unlike the common copolymerization between CO2 and propylene oxide, the catalytic activity for producing functional copolymers needs further improvement.