Effects of accelerated weathering on the mechanical properties of hemp fibre/polybenzoxazine based green composites

In the current study, three different kinds of hemp fibre treated polybenzoxazine composites were exposed to accelerated weathering at 30 °C and 80% relative humidity (RH), till the saturated moisture uptake. The tensile, flexural, and impact properties of saturated samples were evaluated and results were compared with the unconditioned samples. The silane treated hemp fibre (STHF) composites showed the lowest decline in the properties. Afterwards, the STHF composites were exposed to various accelerated weathering conditions, in the range of 25–35 °C and 40–80% RH. Moisture uptake was slightly increased and tensile and flexural properties were gradually decreased as the exposure temperature and RH were increased. Highest decline was observed in the samples exposed at 35 °C and 80% RH. Furthermore, the slightly higher impact values were observed for the exposed composites. The composites colour was slightly lost and changes to lower shaded as the temperature and RH were raised.