Development Of Kenaf Woven Fabric Reinforced Epoxy And Polypropylene Composite With Different Stitching Pattern

Natural fibres, due to their eco-friendly nature and sustainability, receive attention from researchers and academics to be used in polymer composites. In this study, the effect of stitching pattern on properties of woven kenaf fabric reinforced polymer (thermoset and thermoplastic) composites was analysed. The hand lay-up followed by a vacuum baggage technique was used to fabricate thermoset composite and a hot pressing technique was used to produce thermoplastic composites. The materials used were epoxy resin and polypropylene, which acted as matrices and woven kenaf fibre as a reinforcement. The composites were made in different patterns of stitches which were divided into two categories, basic patterns which were stitched together by a single cross, including Vertical (V), Horizontal (H), Tilt 30° (T30) and Tilt 60° (T60). The other was a complex pattern, stitch with a double cross, including Box, Tilt 45°/90° (T45/90), Tilt 30°/30° (T30/30) and Tilt 60°/60° (T60/60). Tensile test, impact test and hemisphere test of the composites were evaluated in accordance with an ASTM standard. The highest specific strength for single and double stitching was found in samples V and T60/60 of 9.53 MPa/g and 12.75 MPa/g respectively, with an improvement of 14.41% and 53.06% compared to unstitched samples. It was also found that the double stitch patterns show good agreement in improving the tensile and impact performance, either for reinforced thermoset or thermoplastic composite. The results also show that the composite samples reinforced thermoset matrix have better specific strength performance, approximately 3.58 MPa/g to 10.49 MPa/g compared to the composite reinforced thermoplastic matrix. This is due to the thermosetting matrix is generally tougher and stronger than thermoplastics. However, in impact performance, thermoplastic reinforced composite samples show higher impact strength, approximately 3.73 J/cm2 to 4.25 J/cm2 compared to thermoset composites due to excellent impact resistance and damage tolerance by reducing crack propagation and better stress distribution throughout the structure. The evidence from this study suggested that the stitching patterns and stitching angle gave significant effect to the performance of woven stitch kenaf composite compared to the unstitched ones. Implications of the results and future research direction were also presented