A Preliminary Study: Influence of Alkali Treatment on Physical and Mechanical Properties of Agel Leaf Fiber (Corypha gebanga) Hendri Hestiawan a,* , Jamasri b , Kusmono c Department of Mechanical and Industrial Engineering, Gadjah Mada University, Yogyakarta, Indonesia. Jl. Grafika No. 2 Yogyakarta, 55281 a hestiawan1@yahoo.com, b jamasri@ugm.ac.id, c kusmono@ugm.ac.id Keywords: agel leaf fiber, corypha gebanga, alkali treatment, NaOH, tensile strength of single fiber. Abstract. The aim of this research is to investigate the alkali treatment influence on tensile strength physical and mechanical properties of agel leaf fibers (ALF). The presence of surface impurities and the large amount of hydroxyl groups make plant fibers less attractive for polymeric materials reinforcement. ALF were subjected to alkali treatments with 2 and 4% NaOH solutions for different soaking times of 1, 12, and 24 hours at room temperature. The tensile test of single fiber was done according to ASTM D3379-75 standard. The chemical changes and the fiber surface after alkali treatment were investigated by using Fourier transform-infrared (FTIR) and scanning electron microscopy (SEM), respectively. Tensile tests showed the alkali treatment of ALF results in different tensile strength compared to untreated ALF. The highest tensile strength (1464 MPa) is found for ALF immersed in 4% NaOH for 1 hour. FTIR showed that the hemicellulose and lignin components in the ALF are removed by NaOH treatment. SEM observation of the treated ALF showed the removal of impurities and the increase of roughness on the ALF surface with alkalization. These results show that alkali treatment can increase the tensile strength of ALF. Introduction Petroleum and natural gas consumption continue to increase resulting in their reserves will be exhausted in the next 40-60 years, so we must try to look for a replacement them [1]. Due to increase in population, natural resources are being exploited substantially as an alternative to synthetic materials. Natural fiber not only reduces composite weight and cost but also increases productivity and improves mechanical properties of the product [2]. The use of natural fiber for the reinforcement of the composites has received increasing attention both researchers in academia and industry. The commercial natural fibers such as ramie, sisal, rosella, banana, coir, palm, and wood are renewable resources in many developing countries such as Indonesia. Technology development of natural fiber composites in line with government policy to explore the potential of existing local genius. This will improve the empowerment of local natural resources that can be renewed. In fact, the successful development of natural fiber composites will be able to increase the technology and economic value of natural fibers [3]. The natural fibers offer specific benefits such as low cost, low density, low pollutant emissions, acceptable specific properties, renewable characteristics, enhanced energy recovery, and biodegradability [4–6]. They are considered as strong candidates to substitute the conventional glass fibers. These fibers are generally incompatible with hydrophobic plastics. Furthermore, due to the presence of hydroxyl and polar groups in various constituents of fibers, very high water absorption and leads to poor interfacial bonding with the hydrophobic matrix polymers. Therefore, it is necessary to decrease the moisture absorption and hydrophilic character of fibers by suitable chemical modification [7–9]. Applied Mechanics and Materials Submitted: 2016-02-25 ISSN: 1662-7482, Vol. 842, pp 61-66 Accepted: 2016-02-25 doi:10.4028/www.scientific.net/AMM.842.61 Online: 2016-06-21 © 2016 Trans Tech Publications, Switzerland All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, www.ttp.net. (ID: 202.43.93.17-26/04/16,07:55:19)