Melting and Shear Heating

Since dissipation of mechanical energy into heat is strongly dependent on the rheology of the polymer medium, the presence of fillers will increase viscosity and exacerbate shear heating. 

In other forms of compounding plant, such as internal mixers, dissipation of mechanical energy is normally the dominating factor determining the rate of heating, both for material in solid form, from inter-particle frictional effects and subsequently as the polymer melts [8]. 

The influence of fillers on melting mechanism has not been considered in detail. However, at low or modest filler levels it is imlikely to be changed much. Increased rates of heating are likely from particle attrition and increases in polymer melt viscosity. Set against this will be the additional heat required to compensate for heat absorption by the filler component depending on its specific heat capacity. 

A requirement central to most compounding situations is intimate blending of the components, both at the micro and macro level. This is strongly influenced by machinery design and to a large degree by material formulation. 

The overall process of dispersion can be considered as a munber of stages  

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