Molecular Configuration and Pyrolysis Reactions of Phenolic-Novolaks

Abstract

The mechanism for heat rejection of char-forming, ablative heat shields is well known [1]. However, the data needed by the engineer to design heat shields have often been determined by laboratory experiments [2–4]. The fraction of heat shield which remains as char after pyrolysis and the thermokinetic parameters for thepyrolysis process have been estimated from thermogravimetric measurements [5,6]. This empirical approach to determining the char yield of phenolic heat shields and the fraction of polymer involved in the pyrolysis reactions has been the result of lack of definitive information on the mechanism of high-temperature decomposition of the polymers used in compounding the heat shield.