Enzymatic degradation of poly (butylene succinate-co-hexamethylene succinate)

Poly (butylene succinate) (PBS) is an important bio-based and biodegradable polymer and attracts lots of attention stemming from its good mechanical properties that are complementary to other biobased polyesters. PBS has relatively slow biodegradation due to its high degree of crystallinity, which limits its utility in targeted applications. It is known that enzymatic degradation depends on polymer chemistry, solid-state morphology (i.e. crystallinity), molecular weight and other structural factors. In this paper, PBS-based copolyesters were synthesized through a melt polycondensation process and enzymatic degradation was carried out using lipase from Candida rugosa. Rate of enzymatic degradation and thermal properties were found to vary depending on the ratio of butanediol to hexanediol in the copolymer. The combined analysis of the enzymatic degradation rate and change in the morphology and molecular weight of a series of PBS-based copolyesters demonstrated the relative contributions of polymer chemistry, thermal properties and crystallinity. PBS-based copolyesters with tunable enzymatic degradation show promise as a more sustainable substitute for non-biodegradable plastics in agriculture and packaging industries. This paper explores the use of copolymerization to tune the kinetics of enzymatic degradation in biobased aliphatic polyesters. The work also and investigates the effects of polymer crystallinity, molecular weight, and melting temperature on properties of both homo- and co-polyesters and discusses the relative contributions of the material attributes to environmental degradation. [Display omitted] •Copolymerization is an effective method to enhance enzymatic degradation rate of succinate-based polymers•Concentration of lipase in buffer solution didn't affect the enzymatic degradation rate but did alter the lag period prior to steady mass loss•From wide-angle x-ray scattering analysis, total crystallinity was lower for copolymers than homopolymers, and the compositionally dependent crystallinity affected degradation rate as predicted.