Sliding-friction wear of a seashell particulate reinforced polymer matrix composite: modeling and optimization through RSM and Grey Wolf optimizer

In this work we investigated the friction wear of a thermoplastic polymer (nylon-6) reinforced with particles of seashell. Seashells are made of calcium carbonate in the mineral form of calcite or aragonite, which makes them one of the most robust materials known. A twin-screw extruder was used to blend the seashell particles (SPs) and nylon-6, and an injection molding machine was used to fabricate the composite. Various proportions of SPs (12%, 15%, and 18%, by weight) were added to the nylon-6. We studied the wear of the polymer composites as per the standard ASTM G99, focusing on the loss of material due to wear, the friction coefficient, and the interface temperature. We used a response surface methodology (RSM) based Box-Behnken method (BBD) for our experimental design, and multiobjective analyses were performed incorporating desirability analysis. Our results show the following: the interface temperature was highly influenced by rotational speed (41.61%); the reinforcement with SPs (%) significantly (35.71%) affected the loss of material due to wear; and, the coefficient of friction (CoF) was significantly affected by rotational speed (41.48%) and reinforcement with SPs (18.18% w/w). A novel metaheuristic algorithm (Grey Wolf Optimizer) was used to constrain our optimizations, and the results showed that with CoF = 0.3 and an interface temperature of 25 degrees C as constraints, the loss due to wear was 35.77 mu m for 15.09% w/w reinforcement with SPs, but at CoF = 0.3 and an interface temperature of 30 degrees C, the loss due to wear was 28.99 mu m for 18% w/w reinforcement with SP.