Degradation behavior of polybutylene succinate with fillers

Abstract

The degradation profiles of poly(butylene succinate) (PBS) with filler were quantitatively evaluated with respect to the degradation rate and the effect of filler content. The types of fillers examined were activated carbon (AC), mesoporous silica, and cellulose nanofiber. Compost degradation and temperature-elevated hydrolysis were performed, and the rate of molecular weight reduction was found to be independent of filler type and content. The ISO 14,855–1 protocol showed no effect of microbial degradation on the molecular weight change profile but did reveal degradation by hydrolysis. The low filler content did not affect the crystallinity or polydispersity index, which suggests that the degradation proceeded uniformly in the crystalline and amorphous phases. However, the crystallinity was lower when the content was high, and the weight decreased at a higher rate. These results suggest that crystallization was inhibited by AC during sample molding, thus promoted the elution of low-molecular-weight components, which were stuck in crystalline regime, from amorphous regime. No AC discharge was observed during temperature-elevated hydrolysis, which was quantitatively confirmed by carbon balance analysis. This finding suggested that the hydrolysis rate of PBS around the AC was very small. The kinetic analysis of the molecular weight change profile of PBS was conducted, and the activation energy of degradation was determined to be 73 kJ/mol. The parameters determined in this study enable the prediction of the time change in the molecular weight of PBS resulting from hydrolysis.