Effect of oxygen concentration on pyrolytic and combustion characteristics of flame-retardant EPDM Rubber
Fire-resistant EPDM rubber is widely used in public buildings,transport and other areas where the oxygen concentra-tion changes during a fire.In order to study such materials in real fires,this paper uses a flame-retardant EPDM flooring rubber as a sample and experiments are carried out using a FPA and TG-DTG-DSC analyzer under different oxygen volume fraction to study the effect of oxygen concentration on pyrolysis and combus-tion behavior.The results show that the rate of weight loss,heat release and activation energy decrease when the oxygen concentra-tion decreases in an aerobic atmosphere,but the reaction model remains unchanged.The oxygen volume fraction of the sample that can cause open flame combustion ranges from 15%to 18%.In the presence of open flame combustion,the decrease in oxygen concentration resulted in a lower flame,a decrease in the amount of irritating black smoke,a decrease in the amount of greyish-white areas and cracks on the surface of the residue,and a shal-lower fissure;an increase in the critical heat radiation flux,equiva-lent convective heat transfer coefficient,and ignition tempera-ture,and a decrease in the first peak of the HRR curve and in the rate of fire propagation;the second peak in the CO production rate,and an increase in the CO/CO2 value.In the case of combus-tion without open flame,the samples released a large amount of grey smoke,the middle of the residue was raised,the middle of the surface was grey-black,metallic,with yellow-brown viscous liquid at the bottom,and the CO and CO2 yields were much lower than those of flaming combustion.
flame retardant EPDM rubberoxygen volume frac-tioncombustionresiduesweight loss rateheat release rateacti-vation energy