Effect of cyclic moisture absorption desorption on the mechanical properties of silanized jute-epoxy composites

The goal of this paper is to discuss the influence of water absorption-deso rption cycles on the mechanical properties of natural fiber reinforced plas tics. Therefore, epoxy resins with jute wovens as reinforcement with untrea ted and silane treated fibers were investigated. Silane treatment of fibers led to increased tensile, flexural strength, and Young's modulus of compos ites with up to 30%. Absorption-desorption cycles of fibers changed the fra cture mechanisms of fibers without having significant effects on the tensil e strength of the fibers. Light microscopic investigations showed that abso rption-desorption cycles of composites led to the debonding of resin from f ibers as well as to cracks in the adjacent resin. Because of these mechanis ms, tensile strength and Young's modulus decrease, independent of the quali ty of fiber resin adhesion. For dynamic loadings, storage cycle induces dam ages, further bringing about a decreased dynamic modulus and an increased p rogress in damage with increasing load cycles during the first two environm ental cycles, being constant afterwards.