Experimental Analysis on Thermo Gravimetric and Thermal Conductivity Behaviors of <i>Cocos nucifera</i> -Reinforced Plasticized Polyvinyl Chloride Composites

The development of natural fiber-reinforced polymer (NFRP) composites has significantly influenced polymer composite research and innovation over the past decade. Various parameters, influencing the performance of NFRP composites make it a challenge to optimize their thermal behavior. This study introduces a novel approach to optimize the thermal behavior of coir fiber (Cocos nucifera)-reinforced polyvinyl chloride (PVC) composites. The optimization considers three key parameter ranges: coir fiber particle content (2–6 wt.%), coir particle size (100–200 μm) and fiber surface treatments. The coir fiber surface treatments include silane, sodium hydroxide (NaOH) and potassium hydroxide (KOH). Using a response surface methodology (RSM)-based Box–Behnken design (BBD), the optimal combination for thermal behavior is identified. The thermogravimetric analysis (TGA) results identify three stages of degradation. The test results show that there is a lot of residual mass loss at a factor of 6%, 225 μm, for the triethoxy (ethyl) silane treatment. The thermal conductivity of all coir/PVC composite samples is observed in the range of 0.72–0.78 W/m·K. According to optimization and confirmation tests, KOH treatment, 2 wt.% coir and a 75 μm powder diameter result in high thermal conductivity. Thus, it is concluded that the developed coir/PVC composites are well suited for thermal insulation applications.