Summary: The heat of pyrolysis of phenolic resin is a required input parameter to charring ablator thermal response codes which are used to predict the performance of thermal protection systems. Conventional simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA/DSC) was used to investigate the thermal behaviour of cured phenolic resin using a Mettler Toledo TGA/DSC 1 STARe analyser. Samples around 20 mg were thermally decomposed in a crucible with a pierced lid at a heating rate of 10°C/min to a maximum temperature of 850°C. Specific heat capacities of the virgin and char samples were measured through DSC analyses. The heat of pyrolysis was obtained from the difference in the enthalpy associated with the thermal decomposition minus the sensible enthalpy of the remaining solid. The experimental results were compared to a heat of pyrolysis calculation representing the difference between the enthalpies of the products and reactants as a function of temperature. The enthalpy of the products was based on two different gas compositions. One composition was based on assumed chemical equilibrium as a function of temperature, at a pressure of one atmosphere and the other was based on an analytically derived composition from the literature.
Authors: Sacha Wason, Matthew Parry, and David Payne
Keywords: Heat, Pyrolysis, Phenolic, Decomposition, Enthalpy