Effect of Aging and UV Exposure on Mechanical Properties of Natural Fiber Composites

Abstract

The natural fiber-reinforced composites (NFCs) are used to make sustainable eco-friendly products with properties comparable to synthetic materials. However, NFCs are susceptible to aging-induced degradation in environmental conditions such as moisture and ultra violet (UV) exposure. Therefore, it is imperative to understand the aging phenomenon of NFCs and the mechanical properties degradation due to aging and UV exposure. This chapter provides an insight into the effects of aging and UV exposure on the mechanical properties of NFCs. The chapter consists of a comprehensive literature review, simplified procedure for aging and UV exposure tests, a case study and a finite element method (FEM) based model for studying the effect of aging and UV exposure on NFCs. It was evident that with an increase in UV exposure time, the mechanical properties deteriorate significantly as a result of matrix erosion, cracking, and photo-degradation. A further insight into the previous work of one of the authors was provided to understand aging in wood-plastic composites (WPCs). The wood-plastic composites (WPCs) experience a noticeable reduction in the tensile strength (TS), bending strength (BS) and wear resistance after weathering for 13 weeks. In the present work, the sugarcane dry leaves composites (SDLRPCs) also showed a reduction in the TS, BS, and Mode I plane strain fracture toughness (K1C) after 80 h of UV exposure. The FEM-based micromechanical model was constituted to visualize the state of stress within the NFCs. It predicted that after UV exposure, the NFCs such as SDLRPCs have a higher tendency to undergo matrix shear yielding near the crack tip.