p, T Dependence of the Self Diffusion Coefficients and Densities in Liquid Silicone Oils

Technical sil icones have been applied in many fields of science and industry because of their chemical stability and their unique combina t ion of useful properties [1,2] , In the fol lowing the densit ies p and self diffusion coefficients D for a small series of low molecular weight sil icones have been measured in a wide temperature and pressure range. The aim of this study is to compare the density and temperature dependence of D in this class of c o m p o u n d s to the one observed in a similar series of long liquid n-alkanes [3]. In comparison to the alkanes the silicones possess much lower melt ing pressure curves and offer the possibility to study the liquid state in a significantly larger temperature range, thus providing more stringent tests for the applicabil i ty of models for the molecular dynamics .