Synthesis and properties of an intrinsic flame retardant silicone rubber containing phosphaphenanthrene structure

Abstract

A novel intrinsic flame retardant silicone rubber (SR) containing phosphaphenanthrene structure was synthesized in the present research. A series of characterizations including vertical burning testing, limiting oxygen index (LOI), microscale combustion calorimetry (MCC), thermogravimetric (TG) analysis and scanning electronic microscopy (SEM) showed that this SR possessed much quicker self-extinguishment, lower heat release rate, higher LOI and thermal stability as well as better charring capacity compared with unmodified SR. The char residues of the materials had been investigated in detail by Fourier transform infrared spectra (FT-IR) and X-ray photoelectron spectroscopy (XPS) to reveal the interactions between phosphaphenanthrene group and siloxane in the condensed phase. In addition, the corresponding physical properties such as transparence, dynamic and static mechanical performances were also evaluated.