On the behaviour of jute and flax fibre epoxy composites with alkali-treated fibres after exposure to water

Investigations on the influence of exposure to water on the physical proper ties of untreated and alkali-treated jute and flax fibers and their composi tes with an epoxy resin were carried out. The moisture uptake led to a stro ng anisotropic swelling which was more significant for the alkali treated f ibers. In general, jute fibers lost roughly 30% of their tenacity after thi s water exposure, while the tenacity of flax fibers remained unaffected. Du e to this, the tensile strength of jute-epoxy composites decreases with inc reasing water content, while the strength of comparable flax-epoxy composit es increases slightly. The dynamic strength of the composites was improved by the use of alkali-treated fibers, the loss of this characteristic value after a 49-days water storage was influenced by the type of fiber and their treatment.