Preparation, characterization and biodegradability of crosslinked tea plant-fibre-reinforced polyhydroxyalkanoate composites

The biodegradability, morphology, and mechanical properties of composite materials made from maleic anhydride-grafted poly(hydroxyalkanoate) (PHA-g-MA) and treated (crosslinked) tea plant fibre (t-TPF) were evaluated. Composites containing PHA-g-MA (PHA-g-MA/t-TPF) had noticeably superior mechanical properties compared with those of PHA/TPF because of greater compatibility with TPF. The dispersion of t-TPF in the PHA-g-MA matrix was more homogeneous because of ester formation and the consequent creation of branched and crosslinked macromolecules between the anhydride carboxyl groups of PHA-g-MA and hydroxyl groups in t-TPF. Additionally, the PHA-g-MA/t-TPF composites were more easily processed because of their lower melt viscosities. The water resistance of PHA-g-MA/t-TPF was higher than that of PHA/TPF, although the weight loss of composites buried in soil compost indicated that both were biodegradable, especially at high levels of TPF substitution. The PHA/TPF and PHA-g-MA/t-TPF composites were more biodegradable than pure PHA, which implied a strong connection between TPF content and biodegradability.