Hygrothermal ageing and mechanical degradation behaviour of alkali-treated sunn hemp fibre/bio-epoxy composites

Abstract The long-term durability of natural fibre-reinforced bio-composites under hygrothermal environments remains a major barrier to their deployment in building and construction. This study provides a methodical evaluation of the mechanical, viscoelastic, and chemical degradation mechanisms of bio-epoxy composites reinforced with alkali-treated sunn hemp fibres (SHFs) under accelerated hygrothermal ageing (60 °C, 98% RH, up to 3,000 h). Fibre modification was performed using sodium hydroxide (NaOH) concentrations of 6%, 8%, and 10% for 2 h to investigate the influence of