Authors:Andrei Jitianu, Kristin Lammers, Georgia A. Arbuckle-Kiel, and Lisa C. Klein
Hybrid melting gels were prepared by a sol–gel process, starting with a mono-substituted siloxane and a di-substituted siloxane, methyltrimethoxysilane (MTES) together with dimethyldimethoxysilane (DMDES). Five gel compositions were prepared with concentrations between 50% MTES–50% DMDES and 75% MTES–25% DMDES (in mol.%). The consolidation temperature, the treatment temperature after which the melting gel no longer softens, increased from 135 to 160 °C with a decrease in the amount of the mono-substituted siloxane. The glass transition temperature, recorded with differential scanning calorimetry, decreased from −0.3 to −56.7 °C with a decrease in the amount of the mono-substituted siloxane. When a sample was heat treated isothermally for 2 h at the consolidation temperature, the glass transition temperature increased by about 15°, indicating further crosslinking of the siloxane network.