Experimental Investigation of Polymer Pellets Melting Mechanisms in Vane Extruders

Vane extruders are novel polymer-processing equipments, which are composed of a number of vane plasticizing and conveying units (VPCUs). With the vane extruder and the visualization VPCU device, the melting phenomenon of high-density polyethylene (HDPE) pellets under different operation conditions was investigated. It was shown that the positive displacement conveying mechanism and mandatory deformation of particles made the melting evolution in vane extruders totally different from screw extruders. The length of solid conveying and melting zone in vane extruders was much shorter, and the island-sea melting model was formed instead of Tadmor's melting model. Plastic energy dissipation, friction energy dissipation, and viscous energy dissipation were very important sources of heat energy for polymer particles melting in vane extruders. The eccentricity of VPCU, leading to the compression and deformation of particles, was a decisive factor in polymer melting in vane extrusion. Owing to the eccentricity, mechanical energy was dissipated into heat via the deformation of HDPE particles and the thermo-mechanical history was shortened remarkably. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21336; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21336

[1]  Xiaochun Yin,et al.  Solid conveying in vane extruder for polymer processing: Effects on pressure establishment , 2012 .

[2]  James L White,et al.  Melting model for intermeshing counter‐rotating twin‐screw extruders , 2003 .

[3]  C. White,et al.  Probe Segregation and Tg Determination of a Supported Ultra-Thin Polystyrene Film Studied by X-ray and Neutron Reflectivity, and SIMS , 2003 .

[4]  C. Gogos,et al.  Plastic energy dissipation during compressive deformation of individual polymer pellets and polymer particulate assemblies , 2002 .

[5]  Linjie Zhu,et al.  Experimental investigation of polymer pellets melting mechanisms in corotating twin‐screw extrusion , 2002 .

[6]  C. Gogos,et al.  The importance of plastic energy dissipation (PED) to the heating and melting of polymer particulates in intermeshing co‐rotating twin‐screw extruders , 2000 .

[7]  Z. Tadmor,et al.  Melting phenomena and mechanisms in polymer processing equipment , 1998 .

[8]  James L White,et al.  Melting model for modular self wiping co-rotating twin screw extruders , 1998 .

[9]  Liqin Chen,et al.  Studies on the theory of single screw plasticating extrusion. Part I: A new experimental method for extrusion , 1991 .

[10]  I. Bruker,et al.  Melting mechanism in single screw extrusion , 1989 .

[11]  J. T. Lindt.  Pressure development in the melting zone of a single‐screw extruder , 1981 .

[12]  R. T. Fenner,et al.  Melting performance in the single screw extrusion of thermoplastics , 1980 .

[13]  J. T. Lindt.  A dynamic melting model for a single-screw extruder† , 1976 .