1 - Natural fiber reinforcements: classification, extraction, treatment, and properties

Abstract

Synthetic fibers such as glass fibers, aramid fibers, and carbon fibers are commonly used as reinforcement in composite materials because of their outstanding properties. However, the production of these man-made fibers requires the use of a large amount of chemicals, which results in the generation of toxic waste and emissions, posing serious environmental risks. Many researchers have proven the significant potential of natural fibers as alternative reinforcements, due to their advantages over synthetic fibers including low cost, low density, eco-environmentally friendly, biodegradability, and large availability in nature, as well as their ability to improve the mechanical properties of composite materials. Despite these many considerable advantages of natural fibers, they have weaknesses such as low thermal stability and high moisture absorption which leads to lack of good interfacial adhesion with the matrix, making the resulting composites less attractive for application. This chapter provides a detailed classification of natural fibers in terms of their origin, composition, and structure. It also gathers the different methods used for natural fiber extraction. Finally, the principle of the physical and chemical treatments is explained, and then their role in improving the surface characteristics of natural fibers, and thus their thermal and mechanical properties is reported.