THERMODYNAMIC VERIFICATION OF THE GRADIENT-METHOD FOR SURFACE-AREA ESTIMATION

We present thermodynamic verification of Nonaka's gradient method for surface area estimation. On the basis of calorimetric measurements and integral molar entropy calculations it is shown that the main assumpt ion of this method, when used at around room temperature, is an approx imation. The specific surface areas of Sterling MT graphitized carbon black, obtained on the basis of three methods are compared. It is show n that the gradient method may be used, for its operational convenienc e, in cases where an uncertainty of several per cent may be tolerated.