Investigation on mechanical properties of novel natural fiber-epoxy resin hybrid composites for engineering structural applications

Polymers and fibers are the main components of cementitious composite materials to reinforce concrete. The synthetic fibers used in concrete composites typically weigh and also, and they are easily subjected to thermal degradation. To tackle the above issues, researchers developed various natural fiber-based composites. In the paper, the mechanical characteristics of hybrid composites were examined. The hybrid composites were developed using Madar, Gongura, and Hibiscus cannabinus fibers. The polyester resin was the matrix. The fibers were treated chemically using a 5% sodium hydroxide (NaOH) solution. The fibers were then carefully cleaned with distilled water twice and baked for 70 minutes at 60°C. For the evaluation of the tensile, flexural, and impact properties of the hybrid composites, specimens were made in accordance with ASTM standards. The treated composite sample (S3) specimen exhibits a tensile strength (TS) of approximately 34.720 N/mm2, flexural strength (FS) of 77.957 MPa, and flexural modulus (FM) of 1548.588 GPa. The average water absorption of the sample is only 2.45%. The hardness and impact strength (IS) of the samples are also superior to those of several other composites studied in the literature. Hence, the proposed hybrid composites could be a potential material for reinforcing the concrete composites to provide a higher service rate and greater durability to the structures.