Influence of chemical treatment on the physico-mechanical characteristics of Tamarind and Borassus fruit fibres-a comparative assessment

Natural fibers are to be treated before using it as reinforcement in composites to make it compatible with the polymer matrix. Treatment brings about several changes in the properties of the fibers which have a direct influence on the properties of the composites. It is necessary to have a knowledge of effect of treatment on the physical and mechanical properties of the fiber. Treatment should bring about positive changes in the properties of the fibers at a very low cost and also by not harming the environment. In the present work, Tamarind and Borassus fibers are treated with three different chemical solutions viz., 10% by wt. Sodium bicarbonate (NaHCO₃) solution, for 24 h, 72 h and 96 h; with Chromium sulphate (Cr₂(SO₄)₃) for 3 h and with Potassium permanganate (KMnO₄) for 10 min separately to observe trends in physico-mechanical properties and deduce the best possible treatment. Variation in diameter, density, tensile strength are determined experimentally. Surface morphology of the fibers, is analyzed using Scanning Electron Microscopy (SEM), functional group modifications are determined Fourier Transform Infrared Spectroscopy (FTIR) analysis are conducted. It is observed that these chemical treatments led to changes in physical and mechanical properties of fiber. With NaHCO₃ optimum removal of hemicellulose and lignin layers was seen in case of 72 h treatment; KMnO₄ treatment had a similar effect with treatment for a short span of time and (Cr₂(SO₄)₃) treatment led to formation of layer on the fiber surface all of which aiding to the increase of fibers' mechanical properties.