Carbon dioxide-based copolymers: Environmental benefits of PPC, an industrially viable catalyst

Carbon dioxide-based copolymers utilize the green house gas CO2 and can be applied in research and industry. Here we focus on industrially viable CO2-based catalysts in China and beyond. Poly(propylene carbonate) (PPC), an alternating copolymer of CO2 and propylene oxide, is one of the emerging low-cost biodegradable plastics. We describe the thermal and mechanical performances of as-polymerized PPC, where amorphous state, low glass transition temperature, and biodegradability are the three main properties. We also describe modification of the PPC, the so-called toughening and strengthening at high temperature, and plasticizing at low temperature, including incorporation of a third monomer unit by chemical terpolymerization, and introduction of special intermolecular interactions or crystallizable components by physical blending. The fast development in catalyst design and performance improvement for PPC has created new chances for industry. In particular, high molecular weight PPC from rare earth ternary catalyst is becoming an economically viable biodegradable plastic with tens of thousands of tons produced per year, providing a new solution to overcome the problem of high cost in biodegradable plastics.