Parameters relevant to bubble detachment when gas-injecting into polymer melt flow field

Abstract

The bubble deformation processes were reported when gas was injected into polymer melt flow field in another paper, the experiments showed that the deformation was severely affected by the volume of the bubble, and in turn, for the different bubbles, several different deformation processes were presented during their movement along the flow channel. In addition, we could find that the magnitude of the bubble volume was dependent upon the pressure difference of the gas injection pressure and the melt pressure. In this paper, more experimental conditions were changed to investigate the parameters relevant to the detachment of bubbles from the injection nozzle. The experimental results show that the pressure difference, the melt flow velocity as well as the melt pressure were all critical for the parameters, such as the bubble detachment time, the maximum bubble diameters and the magnitude of the bubble volume. The morphology changes of bubble were very large when the flow field was abruptly changed, and the situations were more complicated.

Keywords

bubble / morphology / detachment time / geometry parameters / flow field

References

[1] Chen L, Wang X, Straff R, Blizard K. Shear Stress Nucleation in Microcellular Foaming Process. Polym. Eng. Sci., 2002, 42(6): 1151-1158.

[2] Li S N, Song S Z, Yu T Q. Properties and Structure of Magnesium Matrix Composite Reinforced with CNTs. J. Wuhan University of Technology-Mater. Sci. Ed., 2004, 19(1): 65-68.

[3] Yu J Y, Sun T, Sun Y B, Zhou H. Influence of Matrixes on Microstructure and Properties of CTBN Toughened Epoxy Resins. J. Wuhan University of Technology-Mater. Sci. Ed., 2001, 16(2): 17-20.

[4] Biesenberger J A, Lee S T. A Fundamental Study of Polymer Melt Devolatilization: III More Experiments on Foam-enhanced DV, Polymer. Polym. Eng. Sci., 1987, 27(7): 510-510.

[5] Shan S G, Gao D S, Chen W. The Layered-nanocomposite Film of Polymer Intercalation in V₂O₅ Xerogel. J. Wuhan University of Technology-Mater. Sci. Ed., 2000, 15(3): 1-5.

[6] Favelukis M, Tadmor Z, Semiat R. Bubble Growth in a Viscous Liquid in a Simple Shear Flow. AIChE. J., 1999, 45: 691-691.

[7] Peng Y C, Guo M C, Li L, Li K L. Research of Bubble Bhape and Interfacial Characteristics when CO₂ Injected into HDPE Melt. J. Mater. SCI. Lett., 2003, 22(8): 639-641.

[8] Guo M C, Peng Y C, Li K L. Mathematical Simulation of the Shape for Bubbles Injected into Polymer Melt, Polymer Engineering and Science. Polym. Eng. Sci., 2003, 68(4): 445-449.

[9] Chen Z L. Analysis of Interfaual Mophology and Mation during Gos-injecting into Polymermelt, 2000 Changsha: South China University of Technology. 89-101.

[10] Y B Cai, M C Guo, Z L Chen, Y C Peng. Study on the Interface Deformation when Gas Injected into Polymer Melt Flow Field, to be Published