NMR characterization of postcure temperature effects on the microstructures of Blackglas™ resin and ceramic

Abstract Blackglas™ is a novel siliconoxycarbide ceramic material with high levels of carbon incorporated in the atomic structure. This material has potential in the fabrication of low cost ceramic matrix composites with high temperature capability. Here we study the relationship between the microstructure of Blackglas™ resins and ceramics and the postcure temperature using solid-state NMR to determine explicitly the microstructure evolution from resin to ceramic. In this study, 29 Si solid-state NMR reveals a dependence between the postcure temperature and the microstructure of the resin, which then effects the resulting ceramic structure. The postcure temperature that appears to give optimal mechanical and oxidative properties of Blackglas™ ceramic is around 150°C. For a resin postcured at 250°C, the incorporation of oxygen into the resin network, and thermal redistribution reactions between Si–H and Si–O bonds, results in a dramatic and detrimental change of microstructure compared to that of resins postcured at 100°C and 150°C.