The Model Study Of Polymer Transforming From Solid-melt System To Viscous State In Vane Plastication Conveying

Extrusion is an earlier molding method and it is important in polymer processing. In thelast decades, extrusion molding principles and techniques in the production practice havebeen continuously deepen and expanded, also extrusion processing equipment has beencontinuously improved and innovated. The Vane Plastic Extruder based on elongation stressfield is newly developed by Prof. Qu Jinping in SCUT. The mandatory plasticizationconveying mechanism of Vane Plastic Extruder is fundamentally different from dragconveying mechanism of the traditional screw extruder. Since melting process of polymerconsumes most energy of the total process, and it directly affects the production and quality ofextruded products, it is important to explore the melting mechanism of the Vane PlasticExtruder.In this paper, large numbers of cooling experiments were conducted in Vane PlasticExtruder, and analysis and conclusions were made about melting phenomenon of polymermaterial. Also, the influence of the rotator speed and kinds of polymer on the meltingprocessing, energy sources and melting mechanism of polymer materials in Vane PlasticExtruder were analyzed. At last, appropriate physical models and mathematical theoryformula of the melting mechanism of Vane Plastic Extruder were established and comparedwith experiment results.The result shows: the Vane Plastic Extruder has excellent melting ability, the meltinglength increase as the rotator speed increase, but the increment of it is not large, and allpolymer material melts in the first five Vane Plastic Conveying Units. Materials in VanePlastic Extruder are mainly experienced from compressed solid-bed to solid-rich suspensionsystem and melt-rich suspension system. When the rotator speed is low, melting pool is foundin the discharging side of the VPCU. At the same rotate speed, PP has the longer meltinglength then HDPE, and HIPS has the shortest melting length. The decrescence of materialfriction coefficient makes the melting process of Vane Plastic Extruder increasing while haslittle effect on the conveying characteristic. Thermal conduction, friction energy dissipation(FED), plastic energy dissipation(PED) and viscous energy dissipation (VED) are the mainmelting mechanism of Vane Plastic Extruder. When the rotator speed is low, the effect ofthermal conduction to the melting process is large, while PED is large when the rotor speed ishigh. The two melting model established in this paper can well reflect the melting conditionof Vane Plastic Extruder.The research of melting mechanism in this paper provides direct and reliable theoretical basis for the design and improvement of Vane Plastic Extruder.