The effect of free radical initiators on poly (butylene adipate-co-terephthalate) (PBAT) and its foaming performance

Poly (butylene adipate-co-terephthalate) (PBAT) is a biodegradable polyester, which has commonly utilized in film products. As an application of biodegradable plastic foam, the shrinkage problem of PBAT foam severely limits its development and application, so it is necessary to improve the physical and mechanical properties of PBAT while taking into account the biodegradability and foaming properties. In this paper, benzoyl peroxide (BPO) was introduced into PBAT, and the modified PBAT was foamed using supercritical CO₂ foaming technology. The chain reaction between PBAT and BPO, the mechanical properties, crystallization, rheological properties, and anti-shrinkage were investigated. The experimental results show that when 0.2 phr BPO was introduced, the gel content of the modified PBAT material was only 0.44%, the tensile strength of the sample plates can reach 23.2 MPa, their crystallization temperature rose from 81.4 to 89.2 ℃. The expansion ratio of the modified PBAT foam can reach 13.28, and the foam demonstrates a certain degree of resistance to shrinkage, and shows good mechanical properties with a rebound rate of 87.7% and a maximum compressive strength of 535.9 kPa. This research provides balance in terms of plastic foam improving the shrinkage resistance and foaming properties as well as its biodegradability. An effective strategy for manufacturing PBAT foams with shrinkage resistance and excellent mechanical properties would be suggested.