THERMAL-PROPERTIES OF SILICATE ESTERS

Fourteen dimethyldialkoxysilanes are prepared by reacting dimethyldich lorosilane with corresponding alcohols in the liquid phase. Their phys icochemical properties are determined by standard methods and their te ntative empirical formulae are elucidated. The thermal conductivity va lues of dimethyldialkoxysilanes are determined using a two slab guarde d hot plate apparatus over a temperature range of 30-190-degrees-C. Th e thermal conductivity values of dimethyldialkoxysilanes calculated fr om empirical equations are found to vary from -14% to +19%. Because th ermal conductivity is an important parameter in heat transfer calculat ions, and to minimise the deviation of the values, new equations invol ving easily measurable ultrasonic parameters have been formulated. The proposed equations have been tested for the series of dimethyldialkox ysilanes, tetraalkoxysilanes and polydimethylsiloxanes. The thermal co nductivity values computed from the proposed equations are comparable with experimental thermal conductivity values. Further, an equation in volving the calculation of thermal conductivity values at varying temp eratures is also proposed.