Characterization, weathering and modeling of natural fibre based composites

Abstract

Natural fibre based composite materials find their use in the manufacture of a large number of products and this makes them commercially valuable. In this study, a hybrid 3 ply jute/coir-epoxy composite was used to study the effect of natural fibres on the mechanical properties of the composites. Mechanical testing revealed that the properties enhanced with increasing fibre content as the stronger fibres contribute to a stronger and stiffer composite. Additionally, analytical analysis using the Halpin-Tsai method was employed to calculate elastic constants of the composites. Comparative analysis revealed better properties for hybrid composites than single fibre (jute or coir) composites due to the additive properties added by the two fibres. Moreover, increasing the fibre content led to the enhancement of the elastic constants except Poisson’s ratio which decreased with increasing fibre loading. Finite element modelling using ANSYS was simulated for tensile and flexural loading conditions for a 3 ply jute/coir/jute–epoxy composite (oriented 0°/90°/0°). It was found that the modelling results correlated well with the experimental results for 15 wt% fibre content in the composites. Composite materials since they are widely used, they may come into contact with harsh environmental conditions that may cause weathering. Hence weathering studies were conducted to study the water absorption at room temperature and under boiling conditions. It was found that the composites with lime sludge filler material had a higher water absorption rate than the jute and wood dust reinforced polyester composites. This was due to presence of CaCO3 which is a good water absorbent in lime sludge filler material. Moreover, jute fibres being hollow in nature, absorbed more water than wood dust with increasing time leading to more water absorption in case of jute-polyester composites than wood-polyester composites.