Enhanced Thermal Stability, Heat Retention Performance, Mechanical, and Flame‐Retardant Properties of Castor Oil‐Based Modified Rigid Polyurethane Foam

ABSTRACT The castor oil (CTO)‐based modified rigid polyurethane (RPUF) was successfully prepared by adding CTO to modify the polyols. The experimental results showed that RPUF‐CTO9 (accompanied 10 wt% CTO) exhibited excellent thermal stability and flame retardancy in the series samples, and compared with the original RPUF, the pyrolysis temperature increased by 8.67°C, the activation energy (E) increased by 16.57 kJ/mol, the peak heat release rate (HRR) decreased by 20.82 kW/m 2 , the total heat release (THR) decreased by 35.09%, and the smoke density (Ds) decreased by 10.67. In addition, RPUF‐CTO9 had excellent thermal insulation properties, with temperature variations ranging from 5.8°C (during cooling) and 1.5°C (during heating) less than the original RPUF, respectively. Furthermore, RPUF‐CTO9 also excelled in terms of mechanical properties, with the highest compressive strength (0.02 MPa) and energy absorption efficiency (34%). The current study was important for the wide application of multifunctional foams.