Evaluation of soil burial biodegradation behavior of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) on the basis of change in copolymer composition monitored by thermally assisted hydrolysis and methylation-gas chromatography

Abstract

Soil burial biodegradation behavior of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)] was studied based on its copolymer composition determined by thermally assisted hydrolysis and methylation-gas chromatography (THM-GC). The change in copolymer composition of P(3HB-co-3HHx) film samples during soil burial degradation test was monitored in detail by THM-GC. As a result, the copolymer compositions of 3HB units gradually increased, while those of 3HHx units decreased with soil burial time, almost correlating with recovery weight. Based on these results, the biodegradation mechanism of P(3HB-co-3HHx) was elucidated with considering the influence of the crystallinity on the biodegradability. Furthermore, local differences in biodegradability of a given P(3HB-co-3HHx) film after soil burial test were also successfully evaluated from the copolymer compositions obtained by THM-GC.