Fire‐resistant elastomers

Abstract

SUMMARYThe molecular design of semi-inorganic polymers has produced polysilphenylene-siloxane and polyphosphazene elastomers having comparable fire safety to heat resistant engineering plastics. In flaming combustion a polyphosphazene rubber had a four times lower peak heat release rate than the polyurethane elastomer currently used in fire-blocked aircraft seat cushions. Figure 1. In 1987 the Federal Aviation Administration (FAA) imposed federal airworthiness regulation (FAR) 25.853c on the flammability of aircraft seat cushions to delay their involvement in cabin fires [4,5]. This test for flammability of seat cushions involves subjecting a fully constructed seat cushion (e.g. Figure 2) to an oil burner flame for 2 min (Figure 3) and recording the mass loss of the cushion and the burn length. The FAA requirements are that the burn length of the cushion should not exceed 43 cm ð17 inÞ and the mass loss should not exceed 10% of the original weight. Manufacturers responded to these regulations by wrapping the polyurethane seat cushion in a fire resistant barrier fabric [3,5] (Figure 2). Seat fire blocking allowed manufacturers to pass the 2 min FAA certification test but the polyurethane foam burns vigorously when the fire blocking layer has been consumed (Figure 1). More recently, combustion-modified polyurethane foam rubbers have been developed [6], some of which pass the FAA seat cushion flammability test without the need for a fire blocking layer [7,8]. These second-generation aircraft seat cushions

Methoxyethoxyethoxyphosphazenes as ionic conductive fire retardant additives for lithium battery systems

“…Liquid MEE trimer (3.5771 g, 3 ml), pre-dissolved in THF (5 ml), was mixed with LiCF 3 SO 3 in 1.3, 2.6, 3.7, 6, 9.3, 11.3, 28.7, 37.7, and 44.7 wt% ratios [14,20,23,25]. Stirring was applied to ensure proper mixing.…”

“…MEE trimer (2) and MEEP polymer (1) were synthesized using previously reported procedures [23], with improvements to the purification processes.…”

“…2). It was also reported that these polymers have a high onset temperature of thermal degradation (235 • C) together with a modest heat release capacity [23]. Moreover, small molecule cyclic phosphazenes with the same ethyleneoxy side groups have been used either as stand-alone electrolytes or as plasticizers for gel electrolytes, and they are known to function well as solvents and as additives that increase the ionic conductivity of the base macromolecular electrolyte [24,25] (Fig.…”

Recent Research Progress in the Synthesis of Polyphosphazene and Their Applications

“…Polyphosphazenes and polysilphenylene-siloxane, semi-inorganic polymers are used as heat-resistant elastomers and for fire safety. However, in combustion polyphosphazene rubber had a lower peak heat release rate than the polyurethane elastomer and these elastomers are currently used in fire-blocking aircraft seat cushions [80]. An aircraft which is used on commercial flights contains about two tonnes of elastomers as seat cushions, pillows and flexible sealants [81].…”

Synthesis of vinyl substitute poly(silphenylene‐siloxane) via silyl hydride‐dialkoxysilane process

“…1 In conventional technologies, polymers containing halogens, nitrogen or phosphorous, such as fluorocarbon polymers, polyimide, polyphosphazenes, 2 and so on, are widely used as heat-resistant or fire-retardant polymers. However, the drawback of these materials in practical applications is the possible emission of toxic and corrosive gasses during combustion.…”