Green composites made of polyhydroxybutyrate and long-chain fatty acid esterified microcrystalline cellulose from pineapple leaf
Pitchanun Sinsukudomchai, Duangdao Aht‐Ong, Kohsuke Honda, Suchada Chanprateep Napathorn
Abstract
Pineapple leaf fibres are an abundant agricultural waste product that contains 26.9% cellulose. The objective of this study was to prepare fully degradable green biocomposites made of polyhydroxybutyrate (PHB) and microcrystalline cellulose from pineapple leaf fibres (PALF-MCC). To improve compatibility with PHB, the PALF-MCC was surface modified using lauroyl chloride as an esterifying agent. The influence of the esterified PALF-MCC laurate content and changes in the film surface morphology on biocomposite properties was studied. The thermal properties obtained by differential scanning calorimetry revealed a decrease in crystallinity for all biocomposites, with 100 wt% PHB displaying the highest values, whereas 100 wt% esterified PALF-MCC laurate showed no crystallinity. The addition of esterified PALF-MCC laurate increased the degradation temperature. The maximum tensile strength and elongation at break were exhibited when adding 5% of PALF-MCC. The results demonstrated that adding esterified PALF-MCC laurate as a filler in the biocomposite film could retain a pleasant value of tensile strength and elastic modulus whereas a slight increase in elongation can help to enhance flexibility. For soil burial testing, PHB/ esterified PALF-MCC laurate films with 5-20% (w/w) PALF-MCC laurate ester had higher degradation than films consisting of 100% PHB or 100% esterified PALF-MCC laurate. PHB and esterified PALF-MCC laurate derived from pineapple agricultural wastes are particularly suitable for the production of relatively low-cost biocomposite films that are 100% compostable in soil.