A Brief Study on Toxic Combustion Products of the Polymers Used in High-Pressure Oxygen Systems
One likely cause of polymer ignition in a high-pressure oxygen system is the adiabatic-compression heating of polymers caused by pneumatic impact. Oxidative pyrolysis or combustion of polymers in a high-pressure oxygen system could generate toxic gases. This paper investigates the feasibility of using the NASA pneumatic-impact system to conduct adiabatic-compression combustion tests and determines the toxic combustion products produced from the burning of five selected polymers. Five polymers commonly used in high-pressure oxygen systems, Zytel(Registered TradeMark) 42 (Nylon 6/6), Buna N (nitrile rubber), Witon(Registered TradeMark) A (copolymer of vinylidene fluoride and hexafluoropropylene), Neoflon(Registered TradeMark) (polychlorotrifluoroethylene), and Teflon(Registered TradeMark) (polytetrafluoroethylene), were tested in the NASA pneumatic-impact test system at 17.2-MPa oxygen pressure. The polymers were ignited and burned; combustion products were collected in a stainless-steel sample bottle and analyzed using various methods. The results show that the NASA pneumatic-impact system is an appropriate test system to conduct adiabatic-compression combustion tests and to collect combustion products for further chemical analysis. The composition of the combustion product gas generated from burning the five selected polymers are presented and discussed.
Pneumatic impact ignition of selected polymers in high‐pressure oxygen environments
One likely cause of polymer ignition in high‐pressure oxygen systems is adiabatic‐compression heating of polymers, caused by pneumatic impact. This study investigates ignition by pneumatic impact of selected polymers in high‐pressure oxygen environments. Six polymers commonly used in high‐pressure oxygen systems were tested in a pneumatic‐impact test system at 8.3–37.9 MPa oxygen pressures. The six polymers tested were Teflon®(polytetrafluoroethylene), Neoflon®(polychlorotrifluoroethylene), PEEK (polyetheretherketone), Zytel® 42 (Nylon 6/6), Buna N (nitrile rubber), and Viton® A (copolymer of vinylidene fluoride and hexafluoropropylene). This study shows that the ignition of polymers due to pneumatic impact could be initiated by a local heterogeneous reaction between the hot oxygen and the oxidation sites of the polymer, and proposes an ignition mechanism. Ignition susceptibility of a material to the pneumatic impact can be expressed by its ignition probability. The ignition probabilities of the six polymers at the various oxygen pressures are presented. There is no good correlation between the ignition probability and the autoignition temperature. Copyright © 2006 John Wiley & Sons, Ltd.
Energy
Energy is often defined as the ability to do work. There are many forms of energy. A few examples include; Gravitational energy, Kinetic energy (energy of motion), Thermal energy (heat energy), Potential energy. Potential energy is the energy something has based on its position in the universe. A stretched elastic band has potential energy. A rock held up in the air has potential energy based on its position.