Supercritical CO2-Assisted Fabrication of Environmentally Friendly Poly(Propylene Carbonate)/Poly(Butylene Adipate-co-Terephthalate)/Epoxidized Soybean Oil (PPC/PBAT/ESO) Lightweight Open-Cell Foams With Excellent Degradability and Thermal Insulation Properties.

Driven by the increasing severity of plastic pollution, biodegradable polymers such as poly(propylene carbonate) (PPC), owing to their biodegradability, gas barrier properties, and CO2-fixing capability, have attracted considerable attention as alternatives to conventional plastics. In this work, PPC/poly(butylene adipate-co-terephthalate) (PBAT)/epoxidized soybean oil (ESO) composite foams were successfully fabricated via an environmentally friendly supercritical CO2 foaming process. The results demonstrate that ESO, acting as a reactive compatibilizer, forms chemical linkages between PPC and PBAT through epoxy ring-opening reactions, significantly improving interfacial compatibility. The foaming performance of the composite system is enhanced, and the expansion ratio is markedly increased, reaching approximately 40.46 under the optimized formulation. In addition, the open-cell structure and increased ester bond content substantially accelerate the degradation rate, with a mass loss of 57.96% within 26 days. The thermal conductivity of the foam is reduced to 32.46 mW m-1 K-1, indicating excellent thermal insulation performance. This study provides a feasible strategy for developing lightweight degradable polymer foams with a desirable combination of foaming performance, degradation behavior, and thermal insulation properties.