Renewable Sugar-Based Diols with Different Rigid Structure: Comparable Investigation on Improving Poly(butylene succinate) Performance

In order to improve the mechanical and oxygen barrier properties of poly(butylene succinate) (PBS), two series of sugar-containing PBS copolyesters with different molecular stiffness were synthesized and comparatively investigated, in which a cyclic alditol, isosorbide (Is) or 2,3-O-isopropylidene-l-threitol (ITh) was, respectively, used as a comonomer. Both cyclic alditols were easily available from biomass feedstock, such that Is is a bicyclic compound derived from d-glucose, and ITh is a monocyclic acetalized compound coming from naturally occurring l-tartaric acid. All these copolyesters containing up to 30 mol % of sugar-based units had satisfactory number-average molecular weights in the 16 000–83 000 g mol–1 range, and presented a random microstructure together with excellent thermal stability. The sugar-containing copolyesters were all semicrystalline and still possessed the monoclinic crystal structure of PBS. The incorporation of either Is or ITh units with rigid cyclic structure into PBS chain ...