Mechanical and physical characterization of sodium hydroxide treated Borassus fruit fibers

In order to improve the properties by chemical modification and to optimize the alkali concentration, we treated Borassus fruit fine fibers with aqueous sodium hydroxide solutions of different concentrations. In each case, the tensile properties of the fibers were determined. The morphology of the untreated and alkali treated fibers was observed using scanning electron microscope. The surface of the fibers became rough on alkali treatment. The tensile properties of the fibers improved on alkali treatment. The fibers attained maximum tensile properties when treated with 15% aqueous sodium hydroxide solution and decreased thereafter. The crystallinity index of the fibers showed a similar trend. The thermal stability of the alkali treated fibers was found to be higher than that of untreated fibers. Further, the char content was maximum for fibers treated with alkali having concentration of 15% and above. The chemical composition indicated that the percentageof α-cellulose was maximum when the fibers were treated with 15% aqueous sodium hydroxide solution and then decreased thereafter thus indicating the beginning of degradation of the fibers at higher concentrations. Thus, the optimum concentration of NaOH was established as 15% for alkali treatment of the Borassus fibers. © 2012 Northeast Forestry University and Springer-Verlag Berlin Heidelberg.