A mixing device with phase transition for enhanced exfoliation and dispersion in composites fabrication

Abstract

In this study, a novel mixing device under convergent–divergent elongational flow is developed, mainly contains vane conveying unit and wedge channel unit, generating multi-source pulsating pressure in the mixing procedure to induce phase transition. During the design process, some mathematical works and simulations are conducted to optimize the structural design. High-density polyethylene (HDPE)/expanded graphite (EG) composites are fabricated by phase transition assisted melting mixing. The composites feature lower melt resistance and improved tensile modulus. Furtherly, the prepared HDPE/EG composites exhibit a greater increment of dielectric constant when adding more EG, but always maintain low dielectric loss about 0.05 in low frequency. These results show the excellent exfoliation and dispersion effect, confirming that this new designed equipment and phase transition effect complement each other with fabulous effect in the preparation of filler reinforced polymer.