ELEVATED-TEMPERATURE OXYGEN INDEX APPARATUS AND MEASUREMENTS

An apparatus that performs elevated temperature (300-800-degrees-C Oxy gen Index (OI) measurements using radiant heating has been developed a nd used to perform OI measurements on a variety of high-OI composite m aterials. Comparisons of data with OI values obtained using a gas preh eat device indicate reasonable agreement. Flame propagation down the e dges o the samples dominated the burning behavior for many high temper ature samples. The physical mechanism of volatile release was identifi ed as the con trolling factor for the OI value for high-OI materials. Delamination, cracking, matrix penetration, foaming, and blistering al l led to different burning behavior and different OI characteristics. Long-term aging of composite materials is also a very important contri butor to the OI of the material. At temperatures above 300-degrees-C O I values were found to be very high as a result of the stable nature o f the carbon char remaining after decomposition of the polymeric binde r material.