Modification on PBS using epoxy-functionalized core–shell starch particles

Polybutylene succinate (PBS) is an aliphatic linear polyester that is known for its excellent biodegradability and biocompatibility, making it one of the most promising application polymers. However, its disadvantages of poor toughness, low thermostability, and high crystallinity limit its large-scale commercial applications. In this article, a novel epoxy-functionalized core–shell starch particle (CSP-GMA) is successfully synthesized by virtue of soap-free emulsion polymerization, which consists of a "hard" starch (St) core and a "soft" ethyl acrylate (EA) shell grafted with glycidyl methacrylate (GMA). A binary blend of biodegradable polymers is prepared via a melt blend process with CSP-GMA as a core–shell particle modifier and PBS as a polymer matrix. The mechanical properties, thermal behavior, crystallization properties, stability and microscopic morphology of PBS/CSP-GMA blends are thoroughly studied. The incorporation of 20 wt% CSP-GMA into the PBS blend promotes an increase in the impact strength by 55% and the elongation at break by 173% higher than that of pure PBS respectively, which indicates that our work proposes an efficient strategy for fabricating PBS blends with good comprehensive properties and low cost. The DSC testing shows that the crystallinity of PBS blend is reduced in comparison to PBS, while the crystallization temperature is also decreased, confirming that CSP-GMA can facilitate the crystallization of PBS. The SEM observation reveals that owing to the compatibility arising between two phases interface due to the presence of epoxy group on core–shell starch particle surface, CSP-GMA is better dispersed in the PBS matrix, resulting in the improvement for performance of PBS blends.