EFFECT OF CRYOGENIC TREATMENT ON THERMAL AND MECHANICAL PROPERTIES OF HEMP FIBER COMPOSITE PANELS

Abstract

Natural fibres have been outstanding materials which are feasible and amble substitute for expensive, non-bio degradable and non-renewable synthetic materials so these organic/natural fibres can be used as replacement for synthetic fibers for various applications. Cryogenic treatment is a type of heat treatment process applied to materials at low temperatures in which fiber is treated at cryogenic temperatures, at this low temperature conditions, materials showcase some physiochemical changes The main objective of these works is to conduct cryogenic treatment on hemp fiber and to study the effect of cryogenic treatment on thermal, mechanical and water absorption properties of hemp fiber reinforced epoxy composite panels. Physical properties such as functional groups of fabrics were studied and compared using Fourier Transform Infrared Spectroscopy (FTIR). It shows treatment on fiber have substantially increased the number of hydrogen bonding in cellulose, which lead to increase in stiffness of the fabric. The thermal behaviour of untreated and treated hemp fiber was studied using the techniques of thermo gravimetric analysis (TGA) and differential thermo gravimetric analysis (DTG). It is observed that after cryogenic treatment, hemp fiber's thermal stability has been significantly enhanced. Mechanical properties such as tensile and flexural strength of Hemp/epoxy panels are studied under untreated and cryogenic treated condition and the result show improvement in mechanical properties under cryogenic treatment. Improvement in mechanical properties was observed in cryogenic treated hemp composite due to increased frictional bond in the composite interface. Thermal conductivity of panels was measured using guarded hot plate method and the results shows decrease in thermal conductivity after cryogenic treatment. Water absorption rate of the fiber increases with time due to hygroscopic nature of fiber.Cryogenic treated hemp fiber shows 12% reduction in percentage of water absorption compared to untreated hemp fiber. These findings indicate hemp fabric as an alternative bio degradable material with greater thermal stability and physical qualities than synthetic materials for engineering applications