Jp. Dumas et al., HEAT-TRANSFER INSIDE EMULSIONS - DETERMINATION OF THE DSC THERMOGRAMS.1. CRYSTALLIZATION OF THE UNDERCOOLED DROPLETS, Thermochimica acta, 236, 1994, pp. 227-237
A general study of the heat transfers inside the cell of a differentia
l scanning calorimeter is presented. In Part 1 of this study, the crys
tallization of undercooled droplets of an emulsion is analysed. It is
demonstrated that the classical assumption of a uniform temperature in
the cell cannot explain the shape of the thermogram. The model, which
considers the local heating due to the exothermic transformations of
the droplets and the erratic character of the crystallizations, shows,
despite the small size of the cell, important temperature gradients a
nd explains the shape of the thermogram upon cooling. The analysis ind
icates that the undercooling is well characterized by the beginning of
the peak and not by the peak minimum as suggested before.