Effects of Chemical Treatments on Mechanical and Physical Properties of Flax Fiber-reinforced Rotationally Molded Composites

Abstract

Biofibers have an outstanding potential as a reinforcement in thermoplastics. The advantages of natural fibers over traditional reinforcing materials, such as glass fibers, are low density, relatively high toughness, high strength and stiffness, good thermal properties and biodegradability. Nature fibers are recyclable and renewable raw materials. Natural fiber-reinforced composites have attracted increasing interests because of these advantages of fibers. However, there are disadvantages in the broad use of these fibers in thermoplastics, such as poor compatibility between the fibers and the matrix, the inherent high moisture sorption which brings about dimensional changes in the fiber-based composites and quality variations and low thermal stability. Flax fibers were derived from Saskatchewan-grown flax straws for use in fiber-reinforced composite. In order to improve their interfacial properties, fibers were subjected to different chemical modifications, such as mercerization, peroxide treatment, benzoylation and peroxide treatment. The modified fibers were then extruded with the polymer matrix to form the composite. It is expected to improve the interfacial adhesion significantly as opposed to simple mixing of the two components. These composite blends were then rotation molded for mechanical characterization. The effects of the different chemical treatments and the fiber content on the mechanical properties and the physical properties of natural fiber-reinforced composites were studied.