Catalyst selection and polymerization optimization of biobased poly(butylene succinate) for sustainable applications

Poly(butylene succinate) (PBS) is a biobased and biodegradable polyester with strong potential as a sustainable coating binder. However, its application in coatings requires prcise control over molecular weight, crystallinity, thermal transitions, mechanical integrity, and biodegradoin behavior. These properties are directly governed by polycondensation kinetics, which are highly sensitive to catalyst selection and reaction conditions. This study investigates the catalytic synthesis and optimization of PBS from biobased succinic acid and 1,4-butanediol, focusing on catalyst-driven structure-property relationships relevant to coating performance. Specifically, titanium butoxide, titanium isopropoxide, and antimony trioxide were utilized as polycondensation catalysts and systematically compared. The effect of catalyst type on chain growth, crystallization behavior, and degradation phenomena were examined. PBS samples were collected at defined intervals during the polycondensation step to monitor polymer evolution. Fourier transform infrared spectroscopy (FTIR) was used to track ester bond formation, X-ray diffraction (XRD) to assess crystalline structure, and differential scanning calorimetry (DSC) to evaluate melting and crystallization behavior. Enzymatic hydrolysis provided insight into structure-biodegradability relationships, while tensile testing correlated molecular architecture with mechanical performance. Distinct catalytic behaviors were observed, with titanium-based catalysts promoting faster polycondensation and antimony trioxide offering improved control over molecular weight development. Optimized PBS materials demonstrated a favorable combination of thermal stability, mechanical performance, and controlled biodegradation, supporting their applicability in sustainable coating systems.