One-Pot Synthesis of Silicone–Urethane Hybrid Foam and Comparison of Flame Retardant, Rheological, and Mechanical Properties with Polyurethane Foam

This study presents the design and fabrication of silicone–urethane hybrid foam (SUF) to improve fire safety in transportation seating. Tin(II) 2-ethylhexanoate (Sn(OCT)2) was used to catalyze reactions between bifunctional isocyanates, polyols, and vinyl-terminated PDMS, enabling simultaneous curing and foaming. Sn(OCT)2 effectively facilitated both the foaming and gelation processes of silicone and urethane chemistries. The resulting SUF demonstrated a 44.55% reduction in peak heat release rate (PHRR) compared to UF, due to the PDMS network’s synergistic flame-retardant and barrier effects. Additionally, the crosslinked PDMS structure maintained strong mechanical integrity. This study offers a simple and effective approach for producing SUF with enhanced fire safety.