Dynamic Mechanical Analysis of Randomly Oriented Short Bagasse/Coir Hybrid Fibre-Reinforced Epoxy Novolac Composites

Hybrid composites of epoxy novolac reinforced with short bagasse fibres and short coir fibres were prepared. The mechanical and dynamic mechanical properties of these bagasse-coir hybrid fibres reinforced epoxy novolac composites were investigated with reference to different layering patterns of the composites. The tensile properties of the tri-layer composites are recorded higher than those of the bi-layer composites, whereas the flexural properties of the tri-layer composites are lower than bi-layer composites. The tensile strength of the intimate mix composite is comparable with tri-layer composite having bagasse as skin material. The effect of layering pattern on storage modulus (E), damping behavior (tan delta), and loss modulus (E) was studied as a function of temperature and frequency. The E' values of the bi-layer composites are recorded lower than those of tri-layer (bagasse/coir/bagasse) and intimately mixed hybrid composites. The minimum E' value is obtained for the composites made with coir as skin layer. Bi-layer composite shows maximum damping property. The theoretical modeling showed good correlation with experimental results at above glass transition temperature (T-g), while theoretical model deviates experimental data at lower T-g. The Arrhenius relationship has been used to calculate the activation energy of the glass transition of the composites.