A new strategy to achieve high-performance thermally insulating biodegradable foams enabled by polylactide and...

As the thermal energy dissipation and environmental pollution intensify, light-weight and biodegradable thermal insulation materials have gained significant attention. Poly(butylene adipate-co-terephthalate) (PBAT) foams, renowned for their exceptional biodegradability and thermal insulation properties, could serve as a promising material for thermal insulation. Regrettably, the insufficient foamability and inherent shrinkage behavior of PBAT foams continue to be major obstacle in developing high-performance flexible PBAT foams. In this study, epoxidized soybean oil (ESO) was grafted onto the PBAT/PLA by the ring-opening reaction to achieve micro-crosslinked structures and induce the formation of PBAT fibers within the PBAT/PLA blend. Then, further CO₂ treatment significantly enhanced the crystallinity of PBAT/PLA/ESO composite, which contributed to the improvement of mechanical properties. The design of the reactive cross-linked network, coupled with enhanced crystallization, synergistically improve the foamability and mitigate the shrinkage of PBAT foams. Therefore, the PBAT/PLA/ESO foam exhibited a highly stable cellular structure with higher expansion ratio of 19.5 and low thermal conductivity of 36.7 mW/m·K. Meanwhile, the reinforced cellular structure achieved by this innovative strategy effectively provides an enhanced biodegradability, degraded by 16.1 % after only nine weeks. This approach is expected to inspire further research into the development of functional foams in thermal insulation and cushioning.