Surface modifications of natural fibers and performance of the resulting biocomposites: An overview

A review of biocomposites highlighting recent studies and developments in natural fibers, bio-polymers, and various surface modifications of natural fibers to improve fiber-matrix adhesion is presented. One of the most important factors which determine the final performance of the composite materials is the quality of the fiber-matrix interface. A sufficient degree of adhesion between the surface of hydrophilic ligno-cellulosic natural fibers and the polymer matrix resin is usually desired to achieve optimum performance of the biocomposite. Dewaxing, alkali treatment, isocyanate treatment, peroxide treatment, vinyl grafting, bleaching, acetylation, and treatment with coupling agents are useful ways to improve fiber-matrix adhesion in natural fiber composites. Two major areas of biocomposites will be discussed in this article. One is the most predominant biocomposite currently being commercialized for semi-structural use in the durable goods industries, e.g. auto-industries, i.e. natural fiber-polypropylene composites. The second type is the biocomposites from natural fibers and biodegradable plastics. Two major classes of biodegradable plastics are available, one being derived from renewable resources and the second type being synthesized in the laboratory from petrochemical sources which can also be used as matrix materials to make value-added biocomposites.