International Journal of Research in Advent Technology, Vol.6, No.8, September 2018 E-ISSN: 2321-9637 Available online at www.ijrat.org 2191 Influence on Mechanical Properties of Epoxy Polymer Matrix Composites reinforced with Surface Treated Woven Strand Mat E-Glass fibers Guruprasad H.L 1 , Dr. J.N. Prakash 2 Department of Mechanical Engineering 1,2 , East West Institute of Technology 1,2 , Bangalore-560091 Email: gurugowdahl@gmail.com 1 ,prakash69jnp09ace@gmail.com 2 Abstract-In the present days composite materials are the popular materials in demand because of their high strength to weight ratio. In the present work an attempt has been made to evaluate the Fiber Surface Treatment of Woven Strand Mat (WSM) E-glass fiber reinforced with Epoxy Polymer Matrix Composites. The hand lay-up technique was used to fabricate the epoxy matrix composites reinforced with treated WSM E-glass fibers of volume fraction of 3.42%. WSM E-glass fibers used to evaluate the mechanical properties of the epoxy composites were treated in three different types. First is the manufacturer supplied E-glass fiber coated with lubricating oil and polyvinyl acetate, second is the surface heat treatment and the last one was Ethyl Silicate coating on heat treated E-glass fibers. Tensile, flexural and impact strength of the composite were determined to study the mechanical properties. The results showed the improvement in mechanical properties of surface treated WSM E-glass fiber reinforced with epoxy polymer matrix composites. The heat treated WSM E-Glass Fibers coated with Ethyl silicate showed the excellent improvement in mechanical properties. Experimental results of mechanical properties for different surface treatment of E-glass fiber were evaluated and compared to conclude. Index Terms- Epoxy, Woven strand mat, WSM, E-glass fiber, Mechanical Properties, Composites 1. INTRODUCTION Polymer matrix composites are in great demand as they are the advanced materials with better properties replacing the existing materials. Due to some of the disadvantages with respect to matrix materials, composites are limited to some applications hence creating the need of research to develop the new varieties. Many metals and pure polymer have been replaced my fiber reinforced polymer matrix composites in many applications because of their high strength to weight ratio. The fiber reinforced composites exhibits the excellent mechanical properties which are the most essential parameters to design the long sustainable structures or components [1]. To improve the properties of the composites the use of fillers and reinforcement of fibers are done. This improves the properties like toughness, hardness, stiffness, mould shrinkage and distortion temperature with reduction in processing cost. The organic or inorganic fillers are used to achieve the desired mechanical properties [2]. Glass fibers are the reinforcing materials with polymer matrix composites, they are used in wide range of application from aerospace to circuit boards, as the single fiber of glass with small diameter exhibits the tensile strength of 3.5 GPa [3]. The application of commercially available glass fibers have been limited due to the reduction in the mechanical properties caused by the damages on glass fibers by contact abrasion between the fibers while handling and humidity degradation [4]. The coupling agent, lubricant and a film former are mixed and applied as a solution or aqueous emulsion is generally called as sizing [5]. To improve the wettability of the fiber surface, the commercially available glass fibers are been surface treated with the liquid resin in the manufacturing process known as sizing [6]. The adequate researches in the direction of surface treatment of glass fiber have been made. Many researchers have been reported with increase in strength by 90% with the fiber surface treatment. This increase in strength is due to sizing, which protects the fiber from contact abrasion and improves the load transferring capability between the matrix and fibers [7,8]. The increase in the strength of glass fibers are dependent on the type of surface treatment, gauge length of fibers, fiber diameter and strain rate [9,10]. The life expectancy, toughness, fatigue resistance and strength of the composite materials are defined by the stability and the strength of the interface between the matrix and glass fibers [11]. The enhancement in the mechanical properties of the polymer matrix composites is possible with the surface treatment of glass fibers only with the proper selection of the treatment [12]. The morphology of the matrix will be modified as there will be a change in the physical property of the matrix due to the chemical reaction at the matrix/fiber interface caused by coupling agent