Rheological Modeling for Production of High Quality Polymeric

The fundamental defect inherent to the thermoforming technology is wall-thickness variation of the products due to inadequate thermal processing during production of polymer. A nonlinear viscoelastic rheological model is implemented for developing the process model. This model describes deformation process of a sheet in thermoforming process. Because of relaxation pause after plug-assist stage and also implementation of two stage thermoforming process have minor wall-thickness variation and consequently better mechanical properties of polymeric articles. For model validation, a comparative analysis of the theoretical and experimental data is presented.

Authors:

• H.Hosseini
• A.A. Azemati

Keywords:

• High-quality polymeric article
• Thermal Processing
• Rheological model
• Minor wall-thickness variation.

References:

[1] J.L Throne, Thermoforming. Hanser publishers, Munich (1987).
[2] N. Rosenzweig, , M. Narkis, and Z. Tadmor, "wall thickness
distribution in thermoforming", Polym. Eng. Sci. 19, 946,1979.
[3] Nam, G.J., Ahn K.H. and Lee, J.W.: "Three-dimensional simulation of
thermoforming process and its comparison with experiments"
Polym. Eng. Sci., 40, 2232 , 2000.
[4] Ayhan, Z., and Zhang, Q.H.: "Wall thickness distribution in
thermoformed food containers produced by a Benco aseptic packaging
machine", Polym. Eng. Sci. 40, 1, 2000.
[5] Aroujalian, A., Ngadi, M. O. and Emond, J.P.: Wall thickness
distribution in plug-assist vacuum formed strawberry containers, Polym.
Eng. Sci., 37, 178 1997.
[6] Chung, Y., et al., "Prediction Of Temperature, Viscosity And Shear
Stress during Steady State Of Vibation Welding Of Polyamide-6 W.R.
SPE ANTEC Tech. Papers 38, 117, 1992.
[7] Hosseini, H., Berdyshev B.V. and Mehrabani, A.: "Rheological
Modeling of Plug-assist Thermoforming", J. Appl. Poly. Sci., 101,4148,
2006.
[8] Hosseini, H., Berdyshev B.V. and Mehrabani, A.: "Solution of warpage
in Thermoforming Proceses", Euro. Poly. J., 42, 1836 , 2006.
[9] Oden, J.T., Finite Elements of Non-Linear Continua, McGraw-Hill, New
York, 1972.
[10] Rosenzweig, N., Narkis, M. and Tadmor, Z.: "Wall thickness
distribution in thermoforming", Polym. Eng. Sci., 19, 946, 1979.
[11] Ghafur, M.O., Koziey, B., and Vlachopoulos, J., Simulation of
thermoforming and blowmolding- theory and experiments, Kluwer
Academic Publishers, 1995.
[12] Igl, S.A., et al., SPE ANTEC Tech Papers 38, 122, 1992.
[13] Charrier, J.M., Shrivastava, S., and Wu, R." Free and constrained
inflation of elastic membranes in relation to thermoforming -
axisymmetric problems", J. Strain Anal., 22, 115, 1987.
[14] Leonov, A.I., Prokunin, A.N. "Nonequilibrium thermodynamics and
rheology of viscoelastic polymer media", Rheo.Acta, 15, 85, 1976.
[15] Borisov, A.A., Garasimchuk, I.A., Kuzmin a, M.S., and A.N.
Mikhailov, Theses of the Internet Conference,(In Russian), Moscow,
2003.