Mechanical Properties of Hemp Textile Composites Made by VaRTM Method

Abstract

In this study, we aimed to improve the strength of textile composites by applying surface treatment on natural fibers. Natural fibers used were flax and hemp, and the matrix was an epoxy acrylate resin. The flax fiber textile was treated with acetone, laundry detergent and aqueous solution of sodium hydroxide, because water repellent substances were adhered to the fibers. Hemp fiber textile was chemically-treated with aqueous solution of sodium hydroxide or coated by PVA (polyvinyl alcohol). Natural fiber textile composites were made by a VaRTM (Vacuum assisted Resin Transfer Molding) method. The most effective washing process was alkali-treatment with an aqueous solution of sodium hydroxide. The alkali-treated flax fiber composite had its tensile strength improved by 19.7% and bending strength by 12.8%, relative to the untreated fiber composite. However, the tensile and bending strengths of alkali-treated hemp fiber composite were reduced. In addition, the strength of PVA coated hemp fiber composites was also reduced. The effect of PVA coating was examined by using a micro-droplet method. Interfacial shear strength of PVA-coated hemp fiber was reduced compared to that of untreated hemp fiber. In addition, the interfacial shear strength was reduced with increasing PVA conte