Study On The Mixing Properties And Preparation Of Carbon Nanotubes/Epoxy Resin Composites Of Continuous Mixer

Continuous mixers, kind of high efficiency mixing equipment, have gained more and more attention in the domain of difficlty mixing polymer processing owing to their excellent mixing characteristics and wide adaptability for various kinds of polymer. In this paper, mixing properties of continuous mixers and the application of which in the preparation of carbon nanotubes (CNTs)/epoxy resin composites were studied.In this paper, the mixing theory of polymers together with the operating principle of continuous mixers, were used to develop a quantitative evaluation system. This system consisted of dispersion mixing, distribution mixing and the residence time distribution. The flow and three-dimensional dynamic mixing process in the continuous mixer were studied using the professional polymer processing finite element software package Polyflow. From these results, the influences of operating conditions and material viscosity on mixing properties were analyzed. The primary geometric characteristics influencing the mixing properties were evaluated in accordance with mixing and the design theory of rotors geometrical structure. The influences of phase angle, cross-section shape, peak position and peak region of rotor on the mixing properties were studied by numerical simulation. Design suggestions about those geometric characteristics are provided according to the simulation results.Based on above simulation results, the application of continuous mixer in preparation of CNTs/epoxy resin composites was studied. CNTs are considered to be a perfect reinforcing material for advanced polymeric matrix composites due to their remarkable properties and unique nanostructure. However, the unique nanostructure of CNTs also causes CNTs to easily aggregate, making them difficult to homogeneously disperse in a polymeric matrix. This makes it difficult to realise the full potential of CNTs reinforcement. The question of how to reduce CNTs aggregation, homogeneously dispersing them in the epoxy resin is one of the key problems when preparing CNTs/epoxy resin composites.This paper focuses on solving the problems in the melt-mixing of CNTs/epoxy resin using continuous mixers. Firstly, employing mixing theory and the dispersion model of solid powders in polymers, the melt-mixing theory of CNTs and epoxy resin was studied, and a multi factor accumulative scale distribution function was established. The mixing processes of CNTs/epoxy resin in continuous mixers were studied using three-dimension numerical simulation, and the influence of operating conditions on the dispersion of CNTs was analyzed. Based on the numerical simulation results, a set of experiments about the influence of various operating conditions on dispersion of CNTs in epoxy resin were carried out. The results show that an adequate dispersion of CNTs/epoxy resin composites could be achieved using a continuous mixer, indicate that the numerical simulation of CNTs dispersion is feasible. Finally, for practical application, study on the relationship between the content of CNTs with the mechanical and rheological properties of CNTs/epoxy resin composites was carried out.