EQUATION OF STATE OF POLY(DIMETHYLSILOXANE) MELTS

The pressure-volume-temperature (PVT) properties of three commercial s amples of poly( dimethylsiloxane) are studied experimentally and theor etically in the temperature range 25-150 degrees C and for pressure to similar to 3 kbar. The Tait equation is employed to represent the dat a at elevated pressure. Isothermal compressibilities are computed for the three samples. The melt data are analyzed in terms of the Simha-So mcynsky hole theory, and scaling parameters of pressure, volume, and t emperature are obtained. Satisfactory agreement between theory and exp eriment is found over the entire range of experimental pressures. (C) 1998 John Wiley & Sons, Inc.