Influence of water ageing on mechanical properties and damage events of two reinforced composite materials: Flax-fibres and glass-fibres

Moisture absorption and durability in water environment are major concerns for natural fibres as reinforcement in composites. This paper presents a study on the influence of water ageing on mechanical properties and damage events of flax-fibre composites, compared with glass-fibre composites. The effects of the immersion treatment on the tensile characteristics, water absorption and acoustic emission (AE) recording were investigated. The water absorption results for the flax-fibre composites show that the evolution appears to be Fickian and the saturated weight gain is 12 times as high that the glass-fibre composites. Decreasing continuously with increasing water immersion time, the tensile modulus and the failure strain of flax-fibre composites are hardly affected by water ageing whereas only the tensile stress is reduced regarding the glass-fibre composites. AE indicate that matrix-fibres interface weakening is the main damage mechanism induced by water ageing for both composites. (C) 2010 Elsevier Ltd. All rights reserved.