Effect of benzoylation surface treatment on the physical, mechanical and thermal properties of aloe vera fiber reinforced polyester composites

Abstract The growing demand for sustainable materials has driven interest in natural fiber-reinforced composites. Aloe vera fiber is biodegradable and abundant but suffers from poor adhesion with polymer matrices, limiting its structural use. This study aimed to enhance the interfacial bonding of aloe vera fiber-reinforced polyester composites through chemical surface modifications. Fibers were subjected to alkali treatment using sodium hydroxide and subsequently benzoylated with benzoyl chloride at concentrations of 5, 10, 15, and 20 %. The composites were evaluated for hardness, tensile, flexural, impact, and shear strengths, along with water absorption and thermal conductivity. Results showed that alkali treatment improved adhesion and reduced moisture uptake, while benzoylation further enhanced mechanical performance. The AVF-B20 composite exhibited superior properties, including a hardness of 66.98, impact strength of 6.62 J, tensile strength of 67.30 MPa, tensile modulus of 4.9 GPa, flexural strength of 88.68 MPa, flexural modulus of 4.05 GPa, shear strength of 13.96 MPa, and the lowest water absorption of 3.62 percent. A slight rise in thermal conductivity was observed with increasing benzoylation levels. Overall, combined alkali and benzoylation treatments effectively improved the strength, durability, and dimensional stability of Aloe Vera fiber composites, making them suitable for sustainable engineering applications.