Effect of water ageing on nanoindentation response of single hemp yarn/epoxy composites

This paper aims to evaluate the influence of water ageing on nanoindentation response of the in situ components of hemp/epoxy composites. Specific samples have been tested, made of single hemp yarn composites with two different epoxy resins. Analysis of indentation points depending on their location in the yarn microstructure has been performed. Measurements showed the influence of neighbouring fibres on the reduced modulus in the confined resin. Water induces a decrease in nanoindentation properties, and maximum decrease in reduced modulus takes place in the interfacial zone, which shows the significant degradation of the fibre/matrix interface caused by water ageing. Evolutions in the indentation properties induced by water are similar for both partially bio-based and fully synthetic epoxy resin composites. All these results bring insights into the influence of water ageing of each constituent of hemp fibre reinforced composites and give interesting data for developing eco-composite materials.