Coeficiente de transferência de calor em misturador interno para diferentes polímeros e condições de processamento.

Abstract

Polymer processing involves the heat transfer between the material and the walls of the processing chamber in any type of equipment used. The objective of this work is to study this heat transfer in internal mixers with different operating conditions and different polymers, blends and composites, and experimentally determine the corresponding heat transfer coefficient. Tests with five different neat polymers, two different blends and one composite were conducted on the Haake Rheomix 3000 and Haake Rheomix 600 internal laboratory mixers with two different types of rotors. The coefficient of heat transfer per unit area was determined from the temperature and torque values recorded by the equipment. In all cases the dispersion of the experimental results was significant. The results showed that the coefficient of heat transfer in internal mixers is higher than that common mono screw extruders and similar to the values found for corrotational twin screw extruders. The coefficient in internal mixers is practically independent of the size of the internal mixer, the type of rotor used, the processing temperature and the type of neat polymer processed. In contrast, it is dependent on the nominal speed of the rotors, the material for incompatible polymer blends and for composites with polymer matrix and solid filler. Since the purpose of this research was to evaluate the heat transfer coefficient experimentally, the intention of the work was reached.