Thermal degradation and fire performance of polysilazane-based coatings

This paper deals with the thermal degradation and fire performance of polysilazane (PZane) based coatings. PZanes are silicon–nitrogen backbone polymers and can be used in a wide range of applications. In this study, the fire performance of PZane coating as virgin or formulated materials were evaluated using a homemade fire testing methodology similar to the “Torch Test” fire testing method. It was shown that the performance of the PZane coating can be improved incorporating fire retardant additives. Degradation of the coating is then investigated. The mechanism of degradation of the PZane was elucidated analyzing the gas and condensed phases during the degradation. It was shown that the degradation occurs in three steps leading to the formation of SiN4 and charring at high temperature. The kinetics of degradation of the three steps of degradation was also modeled in order to predict the degradation of the PZane coating in a fire scenario.