Hybrid Composite Materials from Crotalaria and Borassus Fibers: Mechanical and Water Absorption Properties

Agricultural waste is one of the major concerns in present society. The present work investigates the possibility of agricultural waste materials, Crotalaria and Borassus short fibers, as hybrid reinforcement in composite materials. The study examines a novel approach by investigating the combined effect of hybridization and random fiber orientation on the mechanical and water absorption properties of untreated Crotalaria Juncea (CJ) and Borassus Flabellifier (BF) fibre reinforced hybrid polyester resin composites. The outcomes provide awareness into the possibility of utilizing agricultural waste for sustainable and eco-friendly hybrid composite materials. Hybrid composites were developed through the hand lay-up method, incorporating two distinct short fibres. These composites were then evaluated for their mechanical properties and water absorption characteristics, following the guidelines set by ASTM standards. A hybrid composite (HC20CJ30BF) composed of 20g of CJ and 30g of BF exhibits the highest tensile strength of 22.59 MPa, which is a notable improvement of 96.26% compared to single reinforced composites. An enhanced flexural strength of 47.46% was achieved, surpassing the performance of the single reinforced composite materials. The water absorption resistance of the hybrid composite, HC20CJ30BF, is demonstrated by its least absorption rate of 1.65% after 24 h of immersion. The fractographic analysis exposed fiber pull-out as well as rough surfaces in tensile tests, and fiber bending with matrix cracks during flexural loads, emphasizing the significant role of fiber orientation in enhancing composite performance. Such work provides valuable insight into the fabrication of highly efficient and durable hybrid composite materials employing natural fibers.