Mixing and Flow Characteristics of Alumina-Thermoplastic Resins

Effect of the Change of Resin Properties during Heating and Mixing

Abstract

The mixing torque of polypropylene (PP) and polystyrene (PSt) decreased monotonously with the increase in mixing time at 453K, whereas that of polyethylene (PE) decreased up to about 10min and increased afterwards. Fluidity after mixing was improved for PP and PSt, but it deteriorated for PE.
The behavior of an alumina-resin mixture with a high solid volume content of 60% was similar to PE during the initial stage of mixing. This, however, could be attributed to the agglomeration of alumina powders. Addition of a nonionic surfactant lead to smooth mixing and also improved the flow characteristics of this system. The mixing characteristics in the alumina-resin-surfactant system reflected the properties of resins more clearly than in the alumina-resin system. Thus, an apparent constant torque after a sufficient mixing time could be observed only in a special blending ratio of PE, PP and PSt.