Physical modification of natural fibers and thermoplastic films for composites : a review

The article throws light on the physical methods to modify natural fibers to be used in composites. Physical methods in natural fiber processing are used to separate natural fiber bundles into individual filaments and to modify the surface structure of the fibers so as to improve the use of natural fibers in composites. Steam explosion and thermomechanical processes fall in the first category while plasma, dielectric barrier techniques and corona fall in the second. The physical treatments have also been used to modify the thermoplastic polymeric films like polyethylene and polypropylene in a bid to impart reactivity. Reviewing such developments, the areas for further research are suggested.One of the authors, Dr S Mukhopadhyay acknowledges the financial support of FCT, Fundacao do Ministerio de Ciencia e Tecnologia i.e., The Science and Technology Foundation of Portugal, for the post doctoral grant SFRH/BPD/27231/2006 on natural fiber-reinforced composites