Fabrication and Foaming Behavior of Branched Poly (butylene succinate)

The linear structure, narrow molecular weight distribution, and low molecular weight of poly (butylene succinate) (PBS) result in poor melt viscoelasticity, which significantly affects its supercritical CO₂ foaming performance. In this paper, benzoyl peroxide (BPO) was introduced into PBS via reactive extrusion to prepare PBS with branched structure. Molecular weight test results showed that the molecular weight of PBS increased with increasing BPO concentration, from 103,877 g/mol to 181,409 g/mol. The results of shear and extensional rheology indicated that increasing BPO concentration enhanced the branching degree of PBS and promoted strain hardening behavior. Supercritical CO₂ foaming results showed that the foaming performance of the modified PBS has been significantly improved. The cells are regular and uniform, and the expansion ratio can reach up to 31.9 times, while the unmodified PBS can only reach up to 10.1 times. The method used in this paper is simple, efficient and does not form gel formation, deepening the understanding of the foaming behavior of PBS, and has significant industrial application value for the preparation of PBS materials suitable for foaming.