Mechanical Ball Milling-Assisted Synthesis of Esterified Starch for Polybutylene Succinate Blend with Improved Performance

Polybutylene succinate (PBS), as one of the most promising multi-application polymer, still suffers from low toughness, poor miscibility, and high crystallinity. Blending with starch is an effective strategy to improve the properties of PBS, but the compatibility and dispersity between starch and PBS still need to be optimized. In this study, mechanical ball milling was carried out to synthesize esterified starch and the subsequent PBS/esterified starch blend. The FT-IR and XPS analyses confirmed the existence of molecular interactions between PBS and esterified starch. SEM images showed a homogeneous surface for the PBS/esterified starch blend, highlighting the favorable compatibility and good dispersion of starch within the PBS matrix. TGA, DSC, and VSP tests indicated that the introduction of esterified starch into PBS lowered the thermal transition temperatures, thereby enhancing the processability. WCA measurements displayed that the water contact angle of the PBS/esterified starch blends gradually decreased with increasing esterified starch content, proving the improved hydrophilicity of PBS/esterified starch blends. Mechanical testing indicated that incorporating 5 wt% esterified starch into PBS significantly improved the tensile strength to 36.35 ± 2.16 MPa and the breaking elongation to 27.18 ± 5.08%, surpassing those of the pure PBS, PBS/esterified starch mixture, and PBS/starch blend. Our study indicates that mechanical ball milling is an efficient method to improve the properties of PBS composites.