Surface modification of human hair by grafting poly(methyl methacrylate)

Human hair is a slow-degrading nanocomposite biological fiber. In the present work, the surface of human hair has been modified via grafting of poly(methyl methacrylate). The grafting has been done via free radical polymerization using graft from approach. The percent grafting calculated from thermo-gravimetric analysis data was in good agreement with the percent grafting calculated from gravimetric method. The scanning electron microscopy images showed that the hair surface got completely covered when the weight of methyl methacrylate was twice that of human hair in the feed. The ultimate tensile strength and modulus were found to be 1099 MPa and 20 GPa, respectively, when hair was grafted with feed ratio of 2:1 for methyl methacrylate and hair, as compared to 795 MPa and 16 GPa, respectively, for virgin human hair. An improvement in chemical stability was also observed on grafting, under both basic and acidic conditions. The effect of grafting on swelling and adsorption properties has also been studied. For a lower contact time, the removal efficiency was found to be more for anionic dye, methyl orange as compared to cationic dye, methylene blue, but as the contact time increased, the removal efficiency of grafted copolymers for methylene blue increased significantly. The effect of contact time, pH, adsorbent dosage, initial dye concentration on absorption and desorption studies has also been done. The adsorption behavior was studied using isotherm models Langmuir, Freundlich and Temkin model, and adsorption kinetics were investigated using pseudo-first-order and pseudo-second-order model.