Mechanical, dynamic mechanical, vibration, and moisture absorption on alkali-treated Phoenix sp. reinforced vinyl ester composites

In this research work, Phoenix sp. reinforced vinyl ester composites (PRVC) 30 wt.% and 20 mm in length were made by the compression molding method and characterized for their mechanical, dynamic mechanical, free vibration, and sorption behavior to study the influence of fiber treatment with alkali (NaOH) of concentrations (5%, 10%, 15%, and 20%). Additionally, vertical flammability and limited oxygen index experiments were also performed. The findings show that composites with 15% alkali-treated fibers perform maximum in the mechanical and vibration analysis. The recorded score of 32.84 MPa tensile strength, 2086.64 MPa tensile modulus, 62.89 MPa flexural strength, 2820.20 MPa flexural modulus, 0.584 J impact energy, 81 Shore D hardness, and 37.15 Hz natural frequency is observed. The improvement in properties is justified with superior fiber matrix bonding confirmed through FESEM examinations. The vertical flammability tests revealed that no samples ignited, indicating inherent ignition resistance unaffected by alkali treatment. Furthermore, a limiting oxygen index (LOI) of 21% achieved with 20 wt.% NaOH suggested that higher alkali concentrations enhance combustion resistance. Based on the above findings, the 15% NaOH-treated 20 mm Phoenix sp. fiber-reinforced vinyl ester composites are recommended for interiors in the automotive and packaging sectors.