Supercritical Carbon Dioxide Treated Kenaf Bast Pulp Fiber Reinforcement in Epoxy Composite

Due to environmental concerns, green composites have become a highly researched material. In the present study, kenaf fiber was used as reinforcement in epoxy-based composite with weight fraction ranges from 0, 5, 10, and 15% (w/w of resin). The ratio of epoxy to hardener was 65: 32.5. Prior to incorporation, kenaf bast fiber underwent Soda-AQ pulping followed by total chlorine-free bleaching (OAZP sequence). The obtained pulp was then subjected to supercritical carbon dioxide extraction (SCE) treatment. It was observed that epoxy composite with 10% of fiber loading demonstrated the highest mechanical properties with a tensile strength of 64 MPa, tensile modulus of 1.64 GPa, flexural strength of 83 MPa, and flexural modulus of elasticity of 2.94 GPa. The observed improvement was due to the SCE process which enhanced the wetting process of fiber. However, at 15% mechanical properties decreased due to void formation since fiber could not be dispersed properly in epoxy matrix at high concentration.