Influence of silane-treated lignin and Celosia argentea stem fiber on load bearing, tribology and flame retardant behavior of vinyl ester composites

The primary objective of the study is to examine the mechanical, wear, flammability and thermal properties of the vinyl ester biocomposite reinforced with silane-treated lignin biopolymer and Celosia argentea microfiber. Thus, the reinforcement of lignin biopolymer as filler particle into matrix by extracting from waste biomass along with natural fiber reinforcement provides better strength properties and which creates a novelty to this study. The composite VCL2, which contained 2 vol% lignin and 40 vol% microfiber, outperformed the other examined specimens in terms of mechanical parameters, including tensile strength (146 MPa), flexural strength (173 MPa), compression strength (160 MPa) and impact strength (5.98 J). This VCL2 exhibits improvements of 87.17%, 57.27%, 63.26% and 88% in comparison with the basic specimen. Conversely, the specimen VCL3, which contains 40% microfiber and 4% lignin, has a maximum specific wear rate, COF and hardness of 0.0096 mm³/Nm, 0.21 and 85 shore-D, respectively. There were improvements of 254%, 90% and 10.38% when compared to the base specimen VC. Similar way, the maximum thermal conductivity of 0.21 W/mK is attained for the specimen VCL3 with 4 vol% of lignin addition. Being robust, lightweight and thermally stable, this composite could be used in variety of engineering sectors, including biomedical, construction, packaging, aerospace, automotive and marine.