Physical properties of four α, ω-dimethoxyfluoropolyethers

Several physical properties of four samples of linear alpha, omega-dimethoxyfluoropolyethers, varying in length from 6 to 14 chain atoms, i.e. carbon plus oxygen atoms, are reported and discussed. Among them are boiling points, glass and melting transition temperatures, specific volumes and their temperature coefficients, refractive indices and thermodynamic data such as cohesive energy density and melting enthalpies. The experimental data have been analysed, when possible, on the basis of the group contribution method, the results of which are in agreement with literature data. The above results are compared with those of two analogous series of fluoropolyethers whose chain ends are, respectively, -OCF2H and -OCF3. As expected, with increasing chain length, the effect of the OCF2H and OCH3 ends decreases progressively so that for chains longer than approximately 15-20 atoms, the differences among the three series should disappear. (c) 2004 Elsevier B.V. All rights reserved.