Utilization of peanut husks as a filler in aliphatic-aromatic polyesters: Preparation, characterization, and biodegradability

The biodegradability, morphology, and mechanical properties of composite materials made of poly(butylene adipate-co-terephthalate) (PBAT) and peanut husks (PH) were evaluated. Composites containing maleic anhydride-grafted PBAT (PBAT-g-MA/PH) exhibited noticeably superior mechanical properties because of greater compatibility between the two components. The dispersion of PH in the PBAT-g-MA matrix was highly homogeneous as a result of ester formation between the anhydride carboxyl groups of PBAT-g-MA and hydroxyl groups in PH and the consequent creation of branched and cross-linked macromolecules. Each composite was subjected to biodegradation tests in Aminobacter aminovorans compost. Morphological observations indicated severe disruption of film structure after 60 days of incubation, and both the PBAT and the PBAT-g-MA/PH composite films were eventually completely degraded. Water resistance of PBAT-g-MA/PH was higher than that of PBAT/PH, although the weight loss of composites buried in A. aminovorans compost indicated that both were biodegradable, even at high levels of PH substitution. The PBAT-g-MA/PH films were more biodegradable than those made of PBAT, implying a strong connection between these characteristics and biodegradability.