Estimation of the vapor pressure of PFPEs by TGA

The vapor pressure of a series of perfluoropolyethers (PFPEs) was estimated from the weight loss measured in a standard thermogravimetric analyzer (TGA). A relation linking the coefficients describing the vapor pressure dependence on temperature to the molecular weight was obtained from the data measured on fractions with a narrow molecular weight distribution. Based on this relation, a simple method predicting the vapor pressure of a mixture of PFPEs from the molecular weight distribution can be applied to the whole range of grades.

► TGA standard equipment can be used to estimate vapor pressure and enthalpy of vaporization.
► The vapor pressure of a series of PFPEs was measured to obtain the enthalpies of vaporization.
► A general Clausius Clapeyron's relation can be established with parameters depending on the molecular weight.
► The obtained relation is checked on samples with broad molecular weight distribution.