Development of lightweight rigid polyvinyl chloride foam for insulation and cushioning using supercritical <scp> CO ₂ </scp> and water as co‐foaming agents

Abstract In this work, polyvinyl chloride (PVC) was plasticized using an epoxy silane coupling agent (KH560), subsequently foamed with supercritical CO 2 and water, resulting in lightweight, insulating, and cushioning rigid PVC foam. When the catalyst‐to‐KH560 ratio was 1, the foam exhibited the highest thermal and mechanical properties. The triethanolamine (TEOA) catalytic system produced more uniform cells (20–25 μm) than NaHSO 3 . When there was 5 phr KH560, the stiffness and compressive strength of the foam increased by 8 × 10 5 N/m and 1.0 MPa. When 15 phr KH560 was added, the foam density and conductivity were as low as 76.1 kg/m 3 and 36.3 mW/m K, respectively. Additionally, the foam absorbed accounts for 76%–87% of the total impact energy. This work presented an eco‐friendly and efficient method for preparing rigid PVC foam with thermal insulation and impact cushioning properties. Highlights Supercritical CO 2 and water co‐foaming were used to prepare rigid PVC foam. The density was as low as 76.1 kg/m 3 . The thermal conductivity was 36.3 mW/m K. The impact energy absorption rate ranging from 76% to 87%.