Numerical study of reaction process for preparing PP/TiO 2 nanocomposites in an internal batch mixer

Abstract

When the nanosize particles of titanium dioxide (TiO₂) are well dispersed into the polypropylene (PP) matrix, the inorganic nanocomposites, PP/TiO₂, has more significant material properties than the net PP polymer. Based on the finite element method, the sol–gel reaction process of preparation PP/TiO₂ nanocomposites in an internal batch mixer with Haake rotors was simulated with user defined functions (UDFs) of Polyflow software. In order to better understand the effect of chaotic flow strength induced by asymmetric flow field on the reaction rate, the Poincaré maps, the line stretch and stretching mixing efficiency in the batch mixer were calculated under different speed ratios. Moreover, the effects of rotor speed ratio, temperature rise by viscous heating, and precursor concentration on the overall conversion rates in the mixer were discussed, respectively. Especially, the effect of chaotic strength by different speed ratios on the part and overall reaction rate within the mixer were carried out. It is found that the chaotic mixing intensity and average conversion rate increase gradually with the increase of the speed ratios in the mixer. Interestingly, the greater the intensity of the chaotic flow field in the internal mixer, the more sensitive of the average conversion rate to the temperature rise.

Keywords

Internal batch mixer speed ratios chaotic mixing reaction rate simulation

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