Epoxy Polymer Gasification under Combustion

Abstract

The processes taking place in the preflame zone at flame spread over the surface of epoxy polymer have been investigated in the present work. It has been shown that heating of yet unignited polymer ahead of flame spreading over the thermally thick samples is done mainly by the heat conduction through condensed phase. The compositions of highly- and hardly-volatile products of gasification are determined in conditions of the preflame zone. It is shown that the main combustible product of gasification is CO (ca. 85 %). The mass rates of gasification and the linear velocities of an injection of gasification products into gas phase of preflame zone have been determined. The complicated aerodynamic structure of the preflame zone with a vortex formation is shown to exist. As a result oxygen gets a free access to a polymer surface and can participate in gasification processes. Experimental simulation of the epoxy polymer gasification processes was carried out in the oxygen-18 enriched atmosphere. The main oxygen-containing product of gasification is shown to be generated both as a result of pyrolysis, and a result of thermooxidation. More than 75% of carbon dioxide is formed only due to thermooxidative destruction, and 75 - 90% of carbon oxide is formed only due to pyrolysis. It has been shown that in a course of epoxy polymer gasification in preflame zone the main mass of combustible products is generated by pyrolysis, but an energy for this is mostly supplied by simultaneously occurred exothermal processes of thermooxidation of the near-surface layers of epoxy polymer.