Investigation of the Melting Mechanism in a Twin-Screw Extruder Using a Pulse Method and Online Measurement

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• 作者：Hongbing Chen ; Uttandaraman Sundararaj ; K. Nandakumar ; and Mark D. Wetzel
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2004
• 出版时间：October 13, 2004
• 年：2004
• 卷：43
• 期：21
• 页码：6822 - 6831
• 全文大小：675K
• 年卷期：v.43,no.21(October 13, 2004)
• ISSN：1520-5045

文摘

A perturbation (or pulse) method was used to investigate the melting of a polystyrene/polypropylene (PS/PP) blend in a 40-mm twin-screw extruder (TSE). A sliding-barrel techniquewas used to visualize the melting processes, map the temperature and pressure profiles alongthe channel, and obtain the residence time distribution (RTD) at different locations in theextruder. Pressure, pulse, and visualization results were used to determine where meltingoccurred. Three runs with ratios of the flow rate/screw speed (Q/N) varying from 5.0 to 11.3g/revolution were studied. It was found that the melting of the PS/PP blend in the TSE hadthree distinct regions. Most of the melting occurred in a narrow transition region (~50 mm)from the partially filled region to the fully filled region. The location of the transition regionwas found using four different techniques: visualization, pressure, temperature, and combinedpulse/RTD methods. High-speed video of the extrusion processes shows that the solid polymerpellets melted through an "erosion" mechanism. Mechanical energy consumption for meltingcan be obtained through this perturbation method.