Long-term water aging of composites with bamboo fiber and montmorillonite filler

Abstract

This article examines the degradation mechanisms and mechanical properties of unfilled and montmorillonite-filled bamboo fiber-composites, under long-term water aging (up to 120 days) at room temperature. The main findings show that the water absorption and hydrolysis processes simultaneously occur during aging. The presence of clay fillers (3 wt %) reduces the water absorption content of composites from 18.69% to 15.68% after 120 aging days. However, their moisture absorption rate increases after adding particles. Scanning electron microscope images confirm the development of structural damage induced by the extra-swelling of particles, enabling more water absorption after long-term aging. Interestingly, the unfilled composites lose about 18.7% and 17.94% of their initial tensile strength and modulus after 120 aging days, which is attributed to the swelling/plasticization mechanisms and the chemical degradation at the interface, respectively. However, the tensile strength and modulus of montmorillonite-filled composites drop by 35.78% and 32.47%, respectively. This poor resilience to aging is attributed to the development of microstructural damage. The results of this work provide a clear insight into the long-term mechanical properties of composite materials and shed light on their systematic aging mechanisms, with a view to their application in harsh environments.