The Polymer Society of Korea

Abstract

Controlling polymer chain mobility, which governs the glass transition temperature (T_g), remains a key challenge in designing biodegradable polyesters with balanced thermal and mechanical performance. Conventional approaches often rely on compositional modification or post-blending, offering limited control over chain dynamics.
In this work, kraft lignin was introduced as a biomass-based rigid aromatic component to modulate chain mobility in poly(butylene succinate-co-terephthalate) (PBST), yielding PBST and PBST–kraft lignin composites via in-situ  polymerization. The presence of kraft lignin restricted segmental motion of PBST chains through structural constraints arising from its rigid aromatic nature and intermolecular interactions. This study provides insight into structure–mobility relationships in kraft lignin-containing biodegradable polyesters and suggests a molecularly informed approach for tuning thermal and mechanical properties.