EFFECT OF ALKALI TREATMENT ON THE WATER ABSORPTION OF PINEAPPLE LEAF FIBER

Abstract

To develop a high strength biocomposite material, it is highly required to make a good interfacial adhesion between the natural fiber and polymeric resin. Due to the presence of a hydroxyl (OH) and other polar groups in various constituents of cellulosic fibers, the biocomposite materials absorb moisture in humid environment condition which leads to poor interfacial adhesion, dimensional instability and loss of mechanical properties. Therefore, it becomes requisite to impart hydrophobicity in cellulosic fibers by employing an appropriate chemical treatment process. In this work, experiments were performed to analyze the effect of an alkali treatment of various concentrations (2%, 4%, 6%, 8%, and 10%) on the water absorption behavior of pineapple leaf fiber. Characterization of fibers (both untreated and alkali treated) have done by using FTIR and FE-SEM techniques. The results show that an alkali treated fibers look cleaner, and fiber bundles are more separated with a highly serrated surface due to the removal of wax, adhesives, hemicellulose, and gummy substances. Changes in the peak at 1730, 1525, and 1244 cm-1 in FTIR spectra corresponds to the partial removal of hemicellulose and lignin after alkaline treatment. The results indicate that the 8% NaOH treated pineapple leaf fiber absorbs maximum water in distilled and river water and fibers treated with 10% NaOH shows maximum water absorption in hand pump water. This was due to the presence of cavity, holes, and micro-pores on the surface of PALF after alkali treatment.