Multifunctionality of Silk Fibroin-Based Rigid Polyurethane Foam to Improve Thermal Stability, Flame Retardancy, and Mechanical Properties

Abstract

Rigid polyurethane foam (RPUF) is widely used as building materials, automotive protective materials, etc. However, its flammability and the environmental impact of traditional flame retardants limit its further development. As a cellulose biomass flame retardant, silk fibroin can effectively reduce environmental impact. The current work used silk fibroin as a modifying material, leveraging its compatibility with the honeycomb structure of the material and its excellent flame retardancy to prepare multifunctional RPUF with superior flame retardancy, thermal stability, and mechanical properties. The material properties were characterized through thermogravimetric experiments and cone calorimeter tests. The results showed that the initial decomposition temperature of the modified RPUF (RPUF-SF5) decreased by 10.73°C, the heat release rate (HRR) decreased by 45.62 kW/m², and the smoke density (Ds) decreased by 7.88%, verifying the fire safety of the modified RPUF as a construction engineering material. Additionally, this study constructed a research method combining Abaqus simulation experiments with quasi-static compression, overcoming the limitations of single evaluation methods, which indicated that RPUF-SF5 had the highest compressive strength of 0.07 MPa, avoiding the impact of flame retardants on its mechanical property. These results provided new ideas for the research of the multifunctional RPUF.