Effect of gamma radiation on compressive properties of Kevlar/oil palm empty fruit bunch hybrid composites

The compressive strength of irradiated hybrid composite materials was investigated via compression testing. The hybrid composites consisted of Kevlar fibre, oil palm empty fruit bunch (EFB) fibre, and epoxy. The hand lay-up method was used to fabricate the samples. The samples were then irradiated with different gamma radiation doses: 25 kGy, 50 kGy, and 150 kGy. Compression tests were performed in accordance with ASTM D695 (2015). Compressive strength in Group 1 increased to 30.4 MPa at 25 kGy. At 50 kGy, the compressive strength further increased to 39.6 MPa. Compressive strength for Group 2 also increased to 58.7 MPa when the radiation increased to 50 kGy. The compressive modulus showed the same trend in compressive strength for both Group 1 and Group 2. It was observed that the exposure of hybrid Kevlar/oil palm EFB/epoxy hybrid composites improved the compressive properties of the materials. Furthermore, a difference in the thickness and layering pattern also influenced the compressive strength with different doses. At 150 kGy, both layering patterns showed a degradation of compressive properties.