Preparation and Characterization of Polyhydroxyalkanoate Bioplastic-Based Green Renewable Composites from Rice Husk

The biodegradability, morphology, and mechanical properties of composite materials consisting of acrylic acid-grafted poly(hydroxyalkanoate) (PHA-g-AA) and rice husk (RH) were evaluated. Composites containing PHA-g-AA (PHA-g-AA/RH) exhibited noticeably superior mechanical properties compared with those of PHA/RH because of greater compatibility with RH. The dispersion of RH in the PHA-g-AA matrix was homogeneous because of ester formation and the consequent creation of branched and crosslinked macromolecules, between the carboxyl groups of PHA-g-AA and hydroxyl groups in RH. The water resistance of PHA-g-AA/RH was higher than that of PHA/RH, although the weight loss of composites buried in soil compost indicated that both were biodegradable, especially at high levels of RH substitution. After 60 days, the weight loss of the PHA-g-AA/RH (40 wt%) composite was greater than 90 %. PHA/RH exhibited a weight loss of approximately 4-8 wt% more than PHA-g-AA/RH. The PHA/RH and PHA-g-AA/RH composites were more biodegradable than pure PHA, which implies a strong connection between RH content and biodegradability.