Dual cantilever creep and recovery behavior of sisal/hemp fibre reinforced hybrid biocomposites: Effects of layering sequence, accelerated weathering and temperature

In this work, the influence of weathering on the creep behavior of the sisal (SSSS), hemp (HHHH), and their hybrid composites (HSSH, and HSHS) was investigated. Composites were exposed to accelerated weathering for 2222 h, which replicates conditions equivalent to 1 year of outdoor exposure. Bio-epoxy based composites were fabricated by the hot press technique. Creep study was performed in a dynamic mechanical analyzer under the dual cantilever creep mode at 30 °C and 50 °C testing temperature under a load of 5 N. The creep-recovery behavior of the weathered composite specimens was evaluated and compared with the unweathered specimens. The investigation revealed that creep strain decreased with the incorporation of the sisal and hemp fibres into the bio-epoxy matrix. The experimental creep response of the composites was also in good agreement with the analytical results from Burger’s model. Both the weathering and testing conditions at elevated temperature (50 °C) had a significant impact on the creep resistance of the composites. The creep resistance of the hybrid composites was found to be dependent on the layering sequence. HSHS configuration almost displayed similar creep properties before and after weathering. HSSH configuration was found to have lower creep resistance after weathering. Scanning electron microscopy was used out to examine the fibre-matrix interface of the composites.