Development of mechanistic model for Blackglas^TM pyrolysis: Comparison of theory and experiment

The development of a mechanistic model for the transformation of Blackglas^TM polymer to a silicon carboxide glass during pyrolysis was based on the known chemistry and architecture of the polysiloxane precursors. The pyrolysis process and resulting mass loss is due to the occurrence of multiple chemical reactions that lead to the evolution of hydrocarbon gases such as methane, ethane and hydrogen. The kinetic parameters used to fit the model were estimated from literature values on bond energies and chemical kinetics, and results were compared with TGA/RGA experiments obtained on pyrolyzed Blackglas^TM composites. The effects of heating rate, temperature and curing cycle on outgassing kinetics will be explained in terms of the chemistry of decomposition of the polymer, heat transfer, specimen geometry and thermal properties of the composite.