VISCOSITY, GLASS-TRANSITION AND INTERMOLE CULAR DISTANCE OF 1,2-PROPANEDIOL-PROPANETRIOL SYSTEMS

The viscosity of x (propanediol 1,2); (1 - x) (propanetriol) systems h as been investigated over about 13 orders of magnitude, to 5 degrees C above the glass-transition temperature. It has been fitted to the Vog el relation, to a linear relation as T-3 and to the (H) hyperbolic rel ation : log eta = A + B/(d - d(0)), d is the mean intermolecular dista nce. The cut-off length d(0) is identical to the minimum distance r(0) reached in the glassy state at 0 K. Its variations are linear between 4.769 Angstrom (x = 1) and 4.803 Angstrom (x = 0) and can be attribut ed to the different dimensions of diol and triol molecules. The relati on (H) is also valid for aqueous solutions and other liquids with smal l molecules (maltitol). The identity between d(0) and r(0) is respecte d in the whole interval 3.3 -7.2 Angstrom.