Physicomechanical Properties of Treated Oil Palm-Broom Fibers for Cementitious Composites

The use of natural fibers such as oil palm broom fibers (OPBF) for reinforcing cementitious composites, although reported to be beneficial from economic and environmental standpoints, has generated durability concerns that have caused investigations into possible fiber treatments. In this study, three types of treatments were carried out on OPBF. These include alkalization, silanization, and hot-water treatments. For alkalization, OPBF was treated with solutions of 2%, 4%, 6%, and 10% sodium hydroxide each for 30, 60, 120, 240, 480, 1,440, and 2,880 min. For silanization, OPBF were treated with solutions of 1% and 3% triethoxyvinylsilane each for 60, 120, 240, 480, 1,440, and 2,880 min. For hot-water treatment, OPBF were treated with water at 100°C for 15, 30, 60, and 120 min. The effects of treatments on the fibers were analyzed through tensile strength, X-ray diffraction, electron microscopy, and water absorption tests. The results indicate improvements in tensile strength and modulus of elasticity of 60% and 65%, respectively. Although the average reduction in water absorption of 4% was recorded for silanization, increases of 40% and 9% were recorded for alkalization and hot-water treatment, respectively. The changes in the physical and mechanical properties of treated OPBF are attributed to the elimination of impurities, lignin, and wax, a reduction in the microfibrillar angle, alteration of fiber surface, and improvement in fiber crystallinity. The reported pretreatments could enhance the durability of composites incorporating OPBF as a reinforcement.