Effect of expandable Graphite/Hexaphenoxycyclotriphosphazene beads on the flame retardancy of silicone rubber foam

Abstract

Silicone rubber foam (SiF) with EG/HPCTP was prepared by high-temperature vulcanization. The flame retardancy of SiF was evaluated using the LOI (limiting oxygen index), UL-94, cone calorimetry test (CCT), thermogravimetric analysis (TGA), and mechanical properties. The results showed that EG/HPCTP could improve the LOI of SiF, and the SiF could pass the UL-94 V-0 rating. Compared with pristine SiF, EG/HPCTP could reduce the total heat release rate (THR), heat release rate (PHRR). Digital images of the char residues showed that the HPCTP was beneficial to promote the strength of SiF with EG. TGA showed that the branched decomposition temperature and main chain pyrolysis temperature of SiF were delayed. Mechanical properties analysis showed that EG and HPCTP could improve the mechanical properties of SiF. These indicated that the addition of EG/HPCTP was a good approach to prepare high effective flame-retarding SiF.

Improving the Ablation Properties of Liquid Silicone Rubber Composites by Incorporating Hexaphenoxycyclotriphosphonitrile

“…Moreover, the thermal conductivity and density are increased as well, which are not favorable for their practical application as flexible ablative composites [ 18 , 19 , 20 , 21 ]. Hexaphenoxycyclotriphosphonitrile (HPCTP), which contains a molecular skeleton structure with alternating P and N atoms and multiple external aromatic units, has been widely employed to improve the flame retardancy of silicone rubber [ 22 ] and many other polymers [ 23 , 24 , 25 ]. To the best of the author’s knowledge, very few studies have been conducted to improve the ablative properties of silicone rubber-based materials by incorporating the HPCTP.…”

Lightweight and flame retardant fluorosilicone rubber composited foam prepared by supercritical nitrogen

“…When the composite polymer comes into contact with a heat source, the contained EG is broken down and expanded about 100 times in volume to form a non-flammable "worm-like" structure that prevents further flame damage. 7,8 However, the "worm-like" structural layer usually lacks sufficient adhesion and thus is easily damaged by thermal convection and flame pressure during combustion. 9 Chen et al 10 synthesized functional expandable graphite (FEG) and blended it with silicone rubber to obtain an organic-inorganic hybrid flame retardant system, the results showed that the limit oxygen index (LOI) reached 53.8% with 15 wt% FEG.…”

Improving the Heat Resistance and Flame Retardancy of Epoxy Resin Composites by Novel Multifunctional Cyclophosphazene Derivatives

“…Recently, some fillers available in the commercial market, such as carbon nanotubes [ 13 ], multiwalled carbon nanotubes [ 14 ], functionalized graphene [ 15 , 16 ] and hexachlorocyclotriphosphazene (HCCP) [ 17 , 18 ], have been used to improve the flame retardancy of epoxy resin, and excellent results have been obtained. Qu [ 16 ] synthesized reactive cyclophosphazene and grafted it onto graphene oxide to prepare flame-retardant graphene oxide (fGO) nano sheets for EP nanocomposites.…”