Heat-counteracted strategy for tailoring the cell structure and properties of sustainable poly(butylene succinate) foams

Abstract

Sustainable poly(butylene succinate) (PBS) with low melt strength suffered serious heat-release from azodicarbonamide (AC) during foaming process, resulting in cell collapse and low properties. Herein, a heat-counteracted strategy was developed to counteract the exothermic effect from AC decomposition by utilizing the endothermic effect of endothermic expandable microspheres (EnEMs). During the foaming process of PBS, the heat release from AC was tailored by optimizing the EnEMs/AC loading ratio and related theoretical calculation was established. The closed-cell fraction of PBS foams was improved from 21% to almost 100%. The thermal conductivity of PBS foams decreased from 58 to 22 mW/(m·K). In addition, the flexural strength was enhanced from 3 to 21 MPa and the flexural modulus from 106 to 278 MPa. This strategy was verified to be feasible in theory and practice.