Flame Retardancy and Smoke Suppression of Silicone Rubber Foams with Chitosan and Cyclodextrin

Abstract

ABSTRACT Flame‐retardant silicone rubber foams (SRF) were prepared by dehydrogenation at room temperature with chitosan (CS) and cyclodextrin (CD) as flame retardants. The flame retardancy, smoke suppression, mechanical properties, and thermal stability of SRF with CS and CD were tested using the UL-94 test, limiting oxygen index (LOI), cone calorimeter test (CCT), compression test, field emission scanning electron microscope (FESEM), and thermogravimetry analysis (TGA). The results indicated that the fire behavior was good when the content of CS and CD was 1 wt%, and the CD had a flame-retardant efficiency better than CS. The combination of 0.6 wt% CS and 0.4 wt% CD had the best synergistic flame-retardant efficiency, smoke suppression, and excellent thermal stability. The 0.6%CS/0.4%CD/SRF achieved an LOI value of 30% and a UL-94 V-0 rating and did not drip. Compared with pure SRF, the peak heat release rate (pHRR), the total heat release (THR), the peak smoke production rate (pSPR), and the total smoke production (TSP) decreased by 60.00%, 55.52%, 53.82%, and 55.00%, and the char residue increased by 17.40%. However, the addition of CS and CD slightly worsened the mechanical properties of SRF, and the compressive strength of 0.6%CS/0.4%CD/SRF was reduced by 3.62%.