Preparation and stability of silica sol/TPGDA dispersions and its application in the UV-curable hybrid coatings for fire protection

A series of silica sols modified by γ-methacryloxypropyltrimethoxysilane (MPS) were synthesized by the acid-catalyzed sol–gel method, and then the solvent in these sols were extracted under several vacuum distillation conditions. The stability of the sol after the distillation can be improved by means of increasing the dosage of MPS and incorporating reactive diluent TPGDA into the sol as new dispersion medium. Optimized samples have maintained stable for over 180 days. The sol dispersions and UV-curable organic compounds were mixed to form the hybrid coatings for fire protection. Effects of the distillation treatment and the cosolvent anhydrous ethanol added into the reaction solution on thermal and combustion performances and physical properties of the hybrid coatings were studied by thermogravimetric analysis, microscale combustion calorimeter, limit oxygen index test and UL-94 horizontal test, etc. The results showed that the distillation treatment for the sol was necessary to improve thermal performance and physical properties of the hybrid coatings. In addition, in the flammability experiment, hybrid coatings showed a quick and efficient protection of the substrate.