Numerical study of reaction process for preparing PP/TiO₂ nanocomposites in an internal batch mixer

Abstract

When the nanosize particles of titanium dioxide (TiO 2 ) are well dispersed into the polypropylene (PP) matrix, the inorganic nanocomposites, PP/TiO 2 , has more significant material properties than the net PP polymer. Based on the finite element method, the sol-gel reaction process of preparation PP/TiO 2 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.

3D Numerical Simulation of Reactive Extrusion Processes for Preparing PP/TiO2 Nanocomposites in a Corotating Twin Screw Extruder

“…As for research on PP/TiO 2 nanocomposites, most of it has focused on the properties of experimental products using several techniques, such as XRD, TEM micrographs, Raman spectroscopy, X-ray diffraction and mechanical analysis [ 5 , 30 , 31 ]. However, studies on the mixing and reaction process of PP/TiO 2 nanocomposites by means of numerical simulation based on Computational Fluid Dynamics (CFD) are few and are limited to 1D or 2D models [ 32 , 33 ]. In the present paper, the reaction process of preparing PP/TiO 2 nanocomposites in a corotating TSE with two combined screws was investigated via 3D numerical simulation based on FEM.…”

Fluid transportation and heat transfer analysis of PP/TiO2 nanocomposites in an internal mixer

“…On the other hand, for the reaction in the mixer, most studies focused on the experiment product performance by experimental techniques. [17][18][19][20] More recently, Zhu and Sun 21 studied the influences of chaotic flow fields induced by rotor speed ratios on the local and overall reactive rates in the mixer with Haake rotors. However, the information of complex reactive temperatures dominated by the fluid transportation and mixing efficiency in the internal mixers is relatively absent.…”