Effects of cross-linking units on the heat resistance and heat insulation properties of polysilsesquioxane-based materials

Heat insulators are key materials for efficient energy use and reduction of CO₂ emissions. Recently, we examined cross-linked polymethylsilsesquioxane (MSQ) for use as the basic structure of heat-resistant insulation materials. In this study, we prepared MSQs with different cross-linking units and examined the effects of their structures on the heat resistance and heat insulation properties. Among those, MSQ linked by diethynylbenzene had sufficiently low thermal diffusivity and moderately high heat resistance. We also showed their structure–thermal property relationships. Although other influencing factors could exist, the rigidity, π‒π interactions, and bulkiness of the cross-linking units were found to predominantly influence the thermal properties. These findings will lead to new molecular designs for polysilsesquioxane (PSQ)-based heat-resistant heat insulators with high performance.