Fabrication of hydrophobic biocomposite by combining cellulosic fibers with polyhydroxyalkanoate

Due to increasing environmental concerns related to bio-persistence of petroleum based polymers, and the fact that most biopolymers such as polysaccharides or bio-polyesters are hydrophilic, hydrophobic biodegradable composite consisting of natural cellulosic fiber matrix and bio-derived polyhydroxyalkanoate (PHA) were fabricated by dip-coating, in which PHA was grafted using maleic anhydride to improve its compatibility with cellulosic fibers. It was found that there was a balance between the hydrophobicity of the complex and the grafting degree of MA on PHA. The composite film reached the highest contact angle of 130° at the grafting degree of 0.05% and the ratio of biopolymer to fibers 15%, and it was found to withstand the time aging without loss of hydrophobicity. The tensile strength of the composite film was greatly improved as a result of the introduction of PHA. This hydrophobic composite can potentially be used as a substitute for synthetic polymer/cellulose composite materials.