Natural fiber reinforced composite has been the topic of recent studies and is preferred in various fields of engineering for the specific properties and bio-friendly nature. Surface modification of the natural fibers has been recommended to achieve good bonding. The performance of fiber reinforced polymer composites has been enhanced by the addition of nanofillers. The present work investigates the effect of surface modification of fibers by alkali treatment and the surface roughness and drilling forces in jute fiber reinforced nano-phased epoxy composite are also studied by changing the content of graphene. Graphene has enhanced the quality of hole in nanocomposites.

Keywords: jute fibre, graphene, drilling, thrust, torque, surface roughness

Natural fibre reinforced composite materials are being employed in consumer products, automotive and structural industries. Natural fibres such as jute, hemp, agave, bamboo, coir etc. are found to be suitable alternative to synthetic fibres.^1-3 These fibres are bio-degradable, renewable and available in abundance. They require less energy during manufacture and possess high specific strength.⁴ Hemi-cellulose, cellulose, pectin, lignin, and water-soluble wax are present in natural fibres.⁵ Natural fibres have found to be hydrophilic in nature, which result in poor bonding capability with the matrix. Treatment of these natural fibres by different methods such as alkali treatment, bleaching etc., to modify their surface has been reported to be effective in enhancing bonding.⁶ Nanofillers can help achieve improvement in mechanical, thermal and other properties of a composite. The nanofillers can be of metals, carbon, oxides etc. Carbon-based nanofillers such as carbon nanotubes (CNT), nanofibres and graphene are widely used in composites. Graphene is cheaper and graphenebased composites have better mechanical and thermal properties than CNT.⁷ Level of dispersion of nanofillers in matrix highly influences these properties. The better dispersion can be achieved by methods like grafting, use of ultra sonic waves, rollers, in-situ polymerisation.^7,8 Sonication assisted by a solvent provides homogenous dispersion and increases the strength and toughness.⁹ The addition of multi-walled carbon nanotubes as filler improved the mechanical properties such as tensile strength, modulus, flexural strength, and glass transition temperature.¹⁰
Composite materials processed in the form of a laminate or frame or channel is drilled to be employed in applications. Many types of researches have been done to analyse the drilling of synthetic fibre reinforced composites. Study of drilling characteristics of natural fibre reinforced composites is still at the early stage. Kishore et al. studied the effect of process parameters on thrust, torque and surface finish of holes drilled in sisal fibre reinforced composites.¹¹ The surface roughness of the drilled hole has drawn much attention as it has significant effect on the life of the material. Nanofiller has improved the surface roughness quality of the drilled hole.¹²
Torque should be minimized to avoid damage and ensure the roundness of the hole drilled.¹³ Output characteristics like thrust force, torque, surface roughness, cylindricity, circularity, and perpendicularity have been studied to investigate the hole quality after drilling.¹⁴ In this study, the effect of alkali treatment and graphene on quality characteristics such as thrust force, torque, and surface roughness have been investigated and reported.