Study on the Effect of Bleaching Treatment on the Mechanical Properties of Kenaf Fibers

Abstract

Automotive industries are trying to reduce the weight of cars by replacing parts that are made of steel and aluminum with lighter material but equally strong. It is an emerging trend in these industries to utilize polypropylene reinforced with natural fiber as the alternative lightweight material. PP-natural fiber composite is projected to have market growth with compound annual growth rate (CAGR) of 9.5% within 2018-2025. Blending PP with natural fiber is a challenging process considering these two materials are not compatible enough to produce composite with desired mechanical properties. Prior treatment to the fiber is required to improve its compatibility with PP with cautionary that it does not degrading the mechanical strength of the fiber. The aim of this work was to study the effect of chemical treatment on Kenaf fiber to the tensile strength of the fiber. Kenaf fiber was bleached with NaClO solution at various concentration (1-10% v/w), temperature (25-55°C), and duration (1-6 hours). The effect of bleaching treatment to the chemical structure and the tensile strength of the fiber was analyzed using FTIR and UTM respectively. This study showed that the fiber with highest tensile strength was the one that treated with NaClO solution with concentration 1% v/w, at 25°C for 1 hour. This treatment removed impurities for the surface and reduced some amorphous part of the fiber. However further increasing NaClO concentration, mixing temperature and duration will damage the cellulose chain in Kenaf fiber which will decrease the mechanical strength of the fiber.