Study On Influence Of Rotor Stuctrue Of A Double-Rotor Mixer On Mixing Performance Of Solid Powders

Polymer filling modification is an effective way to improve the physical and chemical performance of polymer matrix, and it is also an important method to obtain polymer composites with excellent performance. Solid powders are common additives used in polymer modification, since the specific surface area of their primary particles is rather big, which makes the primary particles easy to aggregate, solid powders always exist in polymer matrix in the form of agglomerates. The dispersion state of solid powder agglomerates in polymer matrix is closely related with the performance of the final polymer composites. When adding particular solid powders into polymer, the dispersion state of solid powder agglomerates has a lot to do with the selection of mixing equipment. Double-rotor continuous mixer has attracted more and more attention in polymer processing where dispersive mixing is difficult due to its excellent dispersive and distribution mixing performance and strong ability of mixing solid powders. The mixing of solid powders using double-rotor continuous mixer was studied in this paper, based on the conventional quantitative indicators evaluating mixing performance, the cumulative particle size distribution function was put forward to represent the dispersion state of agglomerates in polymer directly using the numerical simulation method combined with the polymer mixing theory and the dispersion mechanism of solid powder agglomerates in polymer flow field. In the detailed study, the effects of rotor structure parameters were simulated using the finite element analysis software POLYFLOW, and the effect law of rotor structure parameters on mixing performance was analyzed, providing certain theoretical guidance for structure design of the rotors. The simulation results showed that the three-wing rotors had the most outstanding mixing performance, and the reasonable range of the wedge angle was15°～20°. The three-wing rotors would gain better dispersing and distribution mixing performance with a peak position of about3/5the whole length of the rotors and a lead3times of the peak position. Slotting in the rotor wings was beneficial to improve the dispersing and distribution mixing performance of rotors, while designing the rotor wing as a ladder type would reduce the dispersing mixing performance of rotors.Based on the theoretical research, the mixing experiments of solid powders adding into polymer were carried out using the S-type double-rotor continuous mixer, and PS/MH, PS/CB and PS/MH/CB composites were prepared respectively. The mixing process was explored and the properties of the composites were studied. The experimental results showed that within a certain range, improving the rotor speed could improve the dispersion of solid powder agglomerates in the polymer matrix, as well as improve the macro-properties of the composites. The properties of the composites not only related with the dispersion state of solid powder additives in the polymer matrix, but also related with the species, ratio and particle size of solid powder additives.