ORIENTAL JOURNAL OF CHEMISTRY www.orientjchem.org An International Open Access, Peer Reviewed Research Journal ISSN: 0970-020 X CODEN: OJCHEG 2021, Vol. 37, No.(3): Pg. 531-540 This is an Open Access article licensed under a Creative Commons license: Attribution 4.0 International (CC- BY). Published by Oriental Scientifc Publishing Company © 2018 Effect of Kevlar Fiber and Nano SiO 2 on Mechanical and Thermal Properties of Hybrid Composites P. S. YAdAv 1 , RAJESH PUROHIT 2 *, ANIL KOTHARI 3 and R. S. RAJPUT 4 1,3,4 Department of Mechanical Engineering, Rajiv Gandhi Proudyogiki Vishwavidyalaya, Bhopal, (M.P.), India. 2 Department of Mechanical Engineering, Maulana Azad National Institute of Technology Bhopal, (M.P.), India. *Corresponding author E-mail: rpurohit73@gmail.com http://dx.doi.org/10.13005/ojc/370303 (Received: May 24, 2021; Accepted: June 25, 2021) AbSTRACT The aim of the current investigation is an analysis of the mechanical and thermal properties of epoxy/nano-silica/Kevlar fber hybrid composites. The ultrasonic vibration-assisted hand layup process was used for the preparation of composite with different weight percentages (1%, 2%, 3%, and 4%) of Nano SiO 2 particles and 2 layers of the Kevlar fber. For the evolution of mechanical properties tensile tests, hardness tests, impact tests, and fexural tests were done. For evaluation of morphological analysis Field Emission-Scanning Electron Microscopy, XRD, and FT-IR tests were performed. A heat defection temperature test was performed for the evaluation of the thermal characteristic of the hybrid composite. The results show the improvement of mechanical and thermal properties of the hybrid composite with increasing wt.% of nano SiO 2 particles in the hybrid composites. As per the observation of experimental results, the Field Emission-Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and X-ray diffraction test also show the enhancement of surface morphology and chemical structure of hybrid composites. The heat diffraction test shows the improvement of thermal resistance and heat absorption capability. As per the observation of experimental results, the tensile strength, hardness, and impact strength increased up to 98%, 16%, and 42% respectively. The fexural test shows the improvement of fexural modulus and stresses 46% and 35% respectively. The heat defection temperature of hybrid composite improves up to 30%. Keywords: Nanocomposites, Hardness, Impact strength, tensile strength, fexural modulus. INTROdUCTION A composites material has excellent mechanical, thermal and tribological properties. Composite materials are characterized by high strength, high stiffness, or modulus of elasticity characteristics, compared to other materials. Filler and fbers enhance the performance of the composites. Epoxy and glass fber hybrid composites show better tribological and mechanical properties as compared to carbon-epoxy (C-E) composites in different loading conditions and speeds 1 . Nano-silica particles improve the wear behavior and thermal performance of the nomex fber composites 2 . The tensile strength and wear resistance behavior of hybrid composite enhanced by the use of Glass fber