Optimal Post-Curing Process on Palm Fiber-Based Composites Panel Towards Flexural and Impact Strength Using RSM Method

In composite materials, extending the post-curing period helps achieve more uniform heat distribution within the structure. This promotes stronger bonding between the resin and the Empty Fruit Bunch (EFB) fibers from oil palms, resulting in improved bending strength. Nevertheless, excessive heating can damage the fibers or the resin matrix, leading to a decline in mechanical performance, particularly in flexural and impact strength. This research examines the effect of varying post-curing durations and temperatures on the flexural and impact properties of palm fiber-based composite ceiling panels. The composites have been produced using a press molding technique with a resin-to-fiber volume ratio of 60:40. Specimens have been prepared according to ASTM D790-02 for flexural testing and ASTM D5942-96 for impact testing. Experimental results, supported by statistical analysis, have revealed that the best flexural and impact strength values have been achieved at the lowest post-curing temperature with the longest curing time. Gradual heating at lower temperatures minimizes residual thermal stresses, enabling the composite to adapt and relax during curing, which enhances its mechanical performance. Specifically, post-curing at 35 °C for 6 hours has produced impact and flexural strengths of 0.0245 Nm/mm2 and 25.89 N/mm2, respectively, compared to 0.0150 Nm/mm2 and 20.50 N/mm2 for untreated samples.