Synergistic effects of in situ fibrillated polytetrafluoroethylene and polystyrene–butadiene block on the microcellular foaming behaviors of polyphenylene oxide modified by high‐impact polystyrene

Abstract Microcellular foams of polyphenylene oxide/high‐impact polystyrene (PPO/HIPS) with high strength are prepared using supercritical CO 2 foaming technology. The study focuses on examining the influence of polytetrafluoroethylene (PTFE) and polystyrene–butadiene block (SEBS) polymers in PPO/HIPS blends. Compared with the pure PPO/HIPS blend, the PPO/HIPS blend with 1 phr PTFE exhibits higher impact strength (7.62 kJ/m 2 ), and the foam compressive strength is 5% larger. The PPO/HIPS foams with 1 phr PTFE (as a nucleating agent) and 5 phr SEBS (as a toughening agent) display a small cell diameter (13.73 μm) and the highest cell density (2.02 × 10 9 cells/cm 3 ) compared to the pure PPO/HIPS blend. Moreover, the compressive strength of the PPO/HIPS/PTFE‐1/SEBS‐5 foam (1.63 MPa at a 5% strain) demonstrates a remarkable increase of 92% compared to that of the PPO/HIPS/PTFE‐1 foam.