The universal temperature parameter of rigid PVC gelation in Brabender kneader

Course of gelation of rigid PVC Polanvil S of K-value 52, 58, 61, 67 or 70, in the chamber of Brabender kneader at temperature range 160-185 degreesC and rotation speed of the rotors 10-50 min(-1), has been investigated. On the basis of torque and temperature changes as functions of process time the curves of torque changes versus real temperature of gelating blend were received. It has been observed that maximal torque value always occurred in the narrow temperature range, independently on chamber wall temperature or shear rate, and was dependent on PVC K-value. It was found that temperature related to torque maximum (T-EG) could be universal parameter characterizing PVC gelation. The proposed new way of analysis facilitates more precise comparison of torque curves obtained at various set temperature and rotational speeds of rotors.