SCI和EI收录∣中国化工学会会刊

Chin.J.Chem.Eng. ›› 2016, Vol. 24 ›› Issue (1): 180-189.DOI: 10.1016/j.cjche.2015.11.016

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Experiment and simulation of foaming injection molding of polypropylene/nano-calcium carbonate composites by supercritical carbon dioxide

Zhenhao Xi1,2, Jie Chen1,2, Tao Liu1, Ling Zhao1, Lih-Sheng Turng2   

  1. 1 State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China;
    2 Department of Mechanical Engineering, University of Wisconsin-Madison, WI 53706, USA
  • Received:2014-11-26 Revised:2015-07-09 Online:2016-02-23 Published:2016-01-28
  • Contact: Ling Zhao
  • Supported by:

    Supported by the National High Technology Research and Development Program of China (2012AA040211), the National Natural Science Foundation of China (21306043), the Research Fund for the Doctoral Program of Higher Education of China (20120074120019, 20130074110013), and the Fundamental Research Funds for the Central Universities.

Experiment and simulation of foaming injection molding of polypropylene/nano-calcium carbonate composites by supercritical carbon dioxide

Zhenhao Xi1,2, Jie Chen1,2, Tao Liu1, Ling Zhao1, Lih-Sheng Turng2   

  1. 1 State Key Laboratory of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China;
    2 Department of Mechanical Engineering, University of Wisconsin-Madison, WI 53706, USA
  • 通讯作者: Ling Zhao
  • 基金资助:

    Supported by the National High Technology Research and Development Program of China (2012AA040211), the National Natural Science Foundation of China (21306043), the Research Fund for the Doctoral Program of Higher Education of China (20120074120019, 20130074110013), and the Fundamental Research Funds for the Central Universities.

Abstract: Microcellular injection molding of neat isotactic polypropylene (iPP) and isotactic polypropylene/nano-calcium carbonate composites (iPP/nano-CaCO3H) was performed using supercritical carbon dioxide as the physical blowing agent. The influences of filler content and operating conditions on microstructure morphology of iPP and iPP/nano-CaCO3H microcellular samples were studied systematically. The results showed the bubble size of the microcellular samples could be effectively decreased while the cell density increased for iPP/nano-CaCO3H composites, especially at high CO2 concentration and back pressure, low mold temperature and injection speed, and high filler content. Then Moldex 3D was applied to simulate the microcellular injection molding process, with the application of the measured ScCO2 solubility and diffusion data for iPP and iPP/nano-CaCO3H composites respectively. For neat iPP, the simulated bubble size and density distribution in the center section of tensile bars showed a good agreement with the experimental values. However, for iPP/nano-CaCO3H composites, the correction factor for nucleation activation energy F and the pre-exponential factor of nucleation rate f0 were obtained by nonlinear regression on the experimental bubble size and density distribution. The parameters F and f0 can be used to predict the microcellular injection molding process for iPP/nano-CaCO3H composites by Moldex 3D.

Key words: Microcellular injection molding, Isotactic polypropylene/nano-calcium carbonate, Cell morphology, Nucleation activation energy, Numerical simulation

摘要: Microcellular injection molding of neat isotactic polypropylene (iPP) and isotactic polypropylene/nano-calcium carbonate composites (iPP/nano-CaCO3H) was performed using supercritical carbon dioxide as the physical blowing agent. The influences of filler content and operating conditions on microstructure morphology of iPP and iPP/nano-CaCO3H microcellular samples were studied systematically. The results showed the bubble size of the microcellular samples could be effectively decreased while the cell density increased for iPP/nano-CaCO3H composites, especially at high CO2 concentration and back pressure, low mold temperature and injection speed, and high filler content. Then Moldex 3D was applied to simulate the microcellular injection molding process, with the application of the measured ScCO2 solubility and diffusion data for iPP and iPP/nano-CaCO3H composites respectively. For neat iPP, the simulated bubble size and density distribution in the center section of tensile bars showed a good agreement with the experimental values. However, for iPP/nano-CaCO3H composites, the correction factor for nucleation activation energy F and the pre-exponential factor of nucleation rate f0 were obtained by nonlinear regression on the experimental bubble size and density distribution. The parameters F and f0 can be used to predict the microcellular injection molding process for iPP/nano-CaCO3H composites by Moldex 3D.

关键词: Microcellular injection molding, Isotactic polypropylene/nano-calcium carbonate, Cell morphology, Nucleation activation energy, Numerical simulation