Polymer flammability. I

The transport of oxygen by diffusion from the environment into a gas stream was investigated as a model for the analogous process in a diffusion flame. The amount transported at steady‐state conditions depended on the flow rate, diameter, and spatial orientation of the gas stream. A change of the same extrinsic parameters in a diffusion flame caused changes of burner surface temperature, maximum flame temperature, and flame height. These responses were correlated and yielded an overall activation energy of the rate‐controlling reaction step in the combustion process equal to 49 kcal/mole. This value was the same for several types of diffusion flames examined and appeared to be associated with the CO/CO2 conversion process at the high‐temperature flame boundary. Flame quenching was demonstrated to occur at a minimum fuel flow rate and minimum environmental oxygen concentration which were characteristic for a given fuel. Quenching conditions were related to the diffusion rate of oxygen into the product effluent stream. Quenching of a polymer flame by depletion of environmental oxygen was governed by the same processes. The effect of extrinsic parameters on polymer flames is discussed in Part II.