VOL. 11, NO. 23, DECEMBER 2016 ISSN 1819-6608 ARPN Journal of Engineering and Applied Sciences © 2006-2016 Asian Research Publishing Network (ARPN). All rights reserved. www.arpnjournals.com 13681 SURFACE MORPHOLOGY AND INTERFACIAL BONDING BETWEEN PALM FIBER TREATED WITH SEA WATER AND SAGO MATRIX Mardin Husen, Muhammad Balfas, Kusno Kamil Departement of Mechanical Engineering, Universitas Muslim Indonesia, Makassar, Indonesia E-mail: mardin@umi.ac.id ABSTRACT Surface morphology, roughness and bonding among palm fibers and sago matrix were observed. The sugar palm fiber was treated by sea water immersion with duration of 1, 2, 3 and 4 weeks, before naturally dried under the sun for 3 hours then continued by 6 hours oven at 80°C. SEM, XRD and roughness arithmetic tests are applied to see the surface morphology, roughness and bonding among fibers and the matrix. The result shows that fibers morphology and roughness changes with immersion duration. At longer immersion duration the roughness increases and the fiber-matrix quality is better. The best interlocking of matrix and fibers occurred after duration of 4 weeks fiber immersion, where no more gaps seen between the fiber and matrix. Keywords: palm fiber, submersion, surface morphology, sago matrix, bonding. INTRODUCTION Cellulose-based natural fibers become a challenge for researchers to reveal their advantages compare to synthetic fibers, including the application possibilities to the global construction and engineering technology [1]. Natural palm fibers (Arenga pinata) have the prospect to be developed as reinforcement substance in composite material due to its flexural properties, salt water resistance, environmentally friendly and relatively high tensile strength [2]. Most of natural fibers are hydrophilic in nature, strongly opposite to the hydrophobic properties of polymer. Hence, soaking natural fiber in ocean water is intended to reduce the hydrophilic characteristic of natural fibers and presume to be more hydrophobic compatible to the polymer materials [2, 3]. Sea water immersion cleans the extractive media off the natural fibers such as lignin, pectin, wax and dirt (impurities) in order to obtain surface with relatively uniform topography. Topography of fiber surface affected by soaking treatment is reviewed qualitatively through observation by Scanning Electron Microscopy [4]. While quantitative characteristics of the fiber surface were observed by direct measurement of Roughness Arithmetic Surface Area, which provides information about porosity and roughness [5]. Change on the surface shapes were observed by comparing the differences of roughness patterns between the immersed fibers (treatment) and the untreated fibers (green fiber). Fiber characteristics on morphology and surface roughness are crucial information for composite reinforcement applications [6]. With the increasing awareness of environmental protection, natural fibers should contribute to a cleaner environment while meet today’s considerable demand of composites [7]. Natural fibers such as flax, hemp and jute are some of the most commonly used reinforcement material of fiber composite. Composites of polymers-reinforced natural fibers should be more eco-friendly as the reinforcement and matrix material (eg. polylactide - PLA) are degradable, as this bio-composites commonly named as "green composites" [8-9]. Although environmentally friendly, natural fibers have a major drawback associated with application for reinforcement of polymer matrix, such as problems associated with surface of natural fibers and polylactide. Several approaches have been made to the surface modification of cellulose (e.g. esterification of cellulose and cellulose substrate to graft copolymerization) and the use of multiple adjustments, i.e. maleated polylactide and isocyanate [7-9]. Several studies have been done to give more utilization of natural fibers focusing the issues of adhesion among natural fibers and the polymer matrix including opposite chemical properties of hydrophilic natural fibers and hydrophobic polymer matrix. Other factors include surface area, surface structures and porosity of the fiber relatively neglected in consideration of adhesion among surface fiber and the matrix [9]. The morphology and roughness of the surface of the natural fiber has been recognized as a significant factor for composite reinforcement. Its effects on the performance of composites have been investigated by the interfacial shear strength of fiber surface roughness through Scanning Electron Microscope [10]. Characteristics of natural fiber differenced from commercial synthetic fibers in terms of geometry, morphology, and surface profiles. This study observe the effects of sea water on fiber surface morphology and roughness so that the interface of sugar palm fiber of sago matrix may be improved to be considered as bio-composite material. SEM and roughness arithmetic are utilized to analyze the surface morphology and roughness of the fiber surfaces. Most of natural fibers consist of high cellulose with difference in particular micro structure. These particular microstructure have strong bonds of intra- and intermolecular hydrogen which are various in sizes. The larger the molecule size, the weaker the bond, and the smaller the molecular size, the stronger their bonds. Hence, microstructures affect the tensile strength of fibers. As microstructures of palm sugar fiber consist of 85% cellulose, and covering almost the whole fibers surface, the fibril bonds then become stronger.