Highly resilient PBAT foams fabricated by bamboo powder limiting strategy using supercritical CO2 foaming

Abstract

High-performance Poly (butylene adipate-co-butylene terephthalate) (PBAT) foam holds significant potential for application in packaging, construction and other sectors, but it has the problems of high shrinkage rate and poor resilience. In this study, highly resilient PBAT/bamboo powder (BP) foams were produced using the supercritical carbon dioxide (scCO₂) foaming technique, with BP as the reinforcement material. A systematic investigation was conducted to assess the effects of BP content and foaming conditions on foam properties. In addition, the mechanism of enhancement of foam's resistance to shrinkage using BP limiting strategy were elucidated. When the content of BP was 15 wt%, the foaming temperature was 100 ℃, and the foaming pressure was 12 MPa, the foaming ratio of the foam was 10.11 times, the density was 0.13 g/cm³ , and the shrinkage rate was significantly reduced from 68.57 % of pure PBAT to 5.24 % (a substantial reduction of 92.36 %). BP enhances the melt strength of PBAT and acts as the heterogeneous nucleation site to increase cell density, achieving synergistic resistance for foam shrinkage. The PBAT/BP foams exhibited outstanding resilience (can recover the original state after being folded, twisted, or compressed). Additionally, the prepared PBAT/BP foams showed similar thermal conductivity 28.85 mW/(m·K) to commercial polyurethane (PU) and polystyrene (PS) foams, offering ideal substitutes for fossil-based foams. This study offers a broadly applicable strategy for the production of shrinkage-resistant, heat insulating, and resilient biodegradable polyester foams.