Formulation optimization and performance enhancement of polyvinyl chloride-silica micropowder composites with a promising flooring application

Filler agglomeration, single filler type, poor filler-matrix compatibility, and lack of toughness are the main problems that restrict the development of the polyvinyl chloride (PVC) manufacturing industry. In this work, PVC composites were prepared with silica micropowder (SMP) as a filler. Titanate coupling agent (TCA-KTTO) modification and chlorinated polyethylene (CPE) toughening treatment were utilized to enhance the composites performance. Herein, we successfully obtained SMP/PVC composites with high strength, high toughness, and outstanding heat resistance. The optimal dosage of titanate coupling agent for SMP surface modification was determined to be 1.5 wt% by mechanical and thermal conductivity tests. With an increase in the filling content of modified silica micropowder (mSMP), the density, surface hardness, Young's modulus, flexural modulus, thermal conductivity, and thermal stability of mSMP/PVC composites were significantly improved. The notched impact strength of mSMP/PVC composites shows a significant increase with the addition of CPE. At a CPE dosage of 7.5 parts per hundred parts of resin (phr), the notched impact strength of mSMP/PVC composites was enhanced by 59.15%, and the glass transition temperature was improved by 6.1 °C. The co-extruded hollow flooring, fabricated by the SMP reinforced PVC composites, meets Chinese standard GB/T 24508-2020, which has a wide range of applications in panels and profiles, such as seaside boardwalks and outdoor parks.