Enhanced thermo-mechanical performance of PVC/calcium carbonate composites for electrical insulation

Polyvinyl chloride (PVC) composites reinforced with calcium carbonate (CaCO 3 ) have gained significant attention as efficient electrical insulating materials owing to their enhanced thermo-mechanical performance, improved durability and cost-effectiveness. In this study, the influence of CaCO 3 loading on the PVC composites as cable insulation was examined. Various formulations (10%–70% CaCO 3 ) and varying lubricant levels were prepared by dry mixing at 110–120 °C, followed by twin-screw extrusion, and then applied to copper conductors. Standard thermoplastic insulation tests, including heat-shock and cold-bend assessments, confirmed excellent structural integrity, without the formation. Water uptake increased marginally with higher CaCO 3 content; however, even at 70% CaCO 3 , the maximum absorption value (0.636 mg/cm 2 ) remained within permissible limits, which confirmed a uniform filler dispersion. Incorporation of CaCO 3 enhanced thermal stability and reduced mass loss during the aging, reflecting improved resistance to thermal degradation. Mechanical testing revealed that the tensile strength increased with 20% CaCO 3 , thereafter declining, while elongation at break decreased progressively with increased filler loading. Unaged tensile strength retention peaked at 93.50% for PVC/20%CaCO 3 , whereas the highest unaged elongation (104%) was recorded for PVC/10%CaCO 3 . These results demonstrate that PVC/CaCO 3 composites maintain robust thermo-mechanical performance even at elevated filler levels, highlighting their potential for electrical insulation applications where material efficiency, performance reliability and economic considerations are critical.