The Effect of Stretch on Multi-Pore-Structure of Ultrahigh Molecular Weight Polyethylene/SiO 2 Hybrid Hollow Fiber Membranes

Abstract

Ultrahigh molecular weight polyethylene/SiO₂ hybrid hollow fiber membranes were prepared by thermally induced phase separation (TIPS), using mineral oil as the diluent and SiO₂ as the additive. The influences of heat-treatment, drawing ratio and drawing temperature on melting behavior, crystallization, multi-pore-structure (MPS) and porosity were investigated. The results of this study demonstrated that the original crystal grains became more perfect and that new micro crystallites were produced through heat treatment. Defects were more easily formed by the micro crystallites in cold stretching. Heat treatment also made the pores contract. The MPS including TIPS pore, stretching pore and interfacial microvoid was constructed after stretching. A model of interfacial microvoid was built. The model indicated that the area of interfacial microvoid increased as the drawing ratio became larger, reaching a maximum at a certain drawing ratio. Values above this maximum drawing ratio made no contribution to further increase the triangular area of interfacial microvoid but made many TIPS pores close. As the drawing ratio increased, the pore diameter (PD) and total pore fraction (TPF ) of the stretched pores increased whereas the TPF of the TIPS pores decreased. The pore diameter distribution (PDD) and the porosity resulted from the joint effect of multiple pores. Without stretching, the porosity was slight due to the pores contracting, and it increased as the drawing ratio became larger, reaching a maximum at a drawing ratio of 5 times.

Keywords

Ultrahigh molecular weight polyethylene (UHMWPE)SiO2 hybrid membrane model of interface introduced microvoid multi-pore-structure (MPS)

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References

Turell, M.B. and Bellare, A. ( 2004). A Study of the Nanostructure and Tensile Properties of Ultra-High Molecular Weight Polyethylene, Biomaterials, 25: 3389-3398.

Kurtz, S.M. , Muratoglu, O.K. and Evans, M. ( 1999). Advances in the Processing, Sterilization, and Crosslinking of Ultra-High Molecular Weight Polyethylene for Total Joint Arthroplasty, Biomaterials, 20: 1659-1688.

Atkinson, P.M. and Lloyd, D.R. (2000). Anisotropic Flat Sheet Membrane Formation via TIPS: Atmospheric Convection and Polymer Molecular Weight Effects, J. Membr. Sci., 175: 225-238.

Lopatin, G. and Yen, L.Y. ( 1988). Microporous Membranes of Ultrahigh Molecular Weight Polyethylene , US Patent 4778601.

Ding, H.Y. , Tian, Y. and Wang, L.H. (2007). Preparation of Ultrahigh-Molecular-Weight Polyethylene Membranes via a Thermally Induce Phase-Separation Method, J. Appl. Polym. Sci., 105: 3355-3362.

Jun, K. , Takayuki, H. and Hiroshi, T. ( 1992). Porous Polypropylene Hollow Fiber Membrane of Large Pore Diameter, Production Process Thereof, and Hydrophilized Porous Polypropylene Hollow Fiber Membranes. Eur Patent 0498414.

Kim, J.J. , Jang, T.S. , Kwon, Y.D. , Kim , U.Y. and Kim , S.S. (1994). Structural Study of Microporous Polypropylene Hollow Fiber Membranes Made by the Melt-Spinning and Cold-stretching Method, J. Membr. Sci., 93: 209-215.

Wang, D.L. , Li, K. and Teo , W.K. (2000). Preparation and Characterization of Polyvinylidene Fluoride (PVDF) Hollow Fiber Membranes, J. Membr. Sci., 163: 211-220.

Braun, D.L. and Lira, R. ( 2001). Diffusional Gas Transfer System and Method of Using Same , US Patent 6248153.

10.

Shipman, G.H. (1985). Microporous Sheet Materia1. Method of Making and Articles Made Therewith, US Patent 4539256.

11.

Kinzer, K.E. ( 1989). Oriented Microporous Film, US Patent 4867881, 1989.

12.

Gu, B. , Cao, Y. and Du , G.Q. (1999). Hollow Fiber Micro porous Polypropylene (PP) Membranes Prepared from Solid-Liquid Phase Separation in a Stress Field, J. Funct. Polym. (chinese) , 12: 281-284.

13.

Aoyama, M. , Ito, M. and Tsuji, S. ( 1989). Preparation of Gas Permeable Porous Film, US Patent 4814124.

14.

Hetzler, K.G. and Jacobs, R.L. (1999). Oriented Polymeric Microporous Films with Flexible Polyolefins, US Patent 5910136.

15.

Hu, X.Y. , Xiao, C.F. and An , S.L. (2006). Structure and Properties of Polyurethane/Polyvinylidene Difluoride Blending Hollow Fiber, J. Dong. Hila. Unv., 23: 76-79.

16.

Vandeweerdt. P. , Cooman. R.D. and Berghmans . H. (1994). Gel Spinning of Porous Poly(methy methacrylate) Fibers, Polym. , 35: 5141-5143.

17.

Wang, Z. ( 2000). Foundation of Membrane Separation Technology, Beijing: Chemical Industry Press, pp. 281-287.

18.

Yang, M.C. and Liu, T.Y. (2003). The Permeation Performance of Polyacrylonitrile/Polyvinylidine Fluoride Blend Membranes, J. Membr. Sci., 226: 119-130.

19.

Chiu, H.C. , Huang, J.J. , Liu , C.H. and Suen, S.Y. (2006). Batch Adsorption Performance of Methyl Methacrylate/Styrene Copolymer Membranes, React. Funct. Polym., 66: 1515-1524.

20.

Wünderlich, B. and Cormier, C. (1967). Heat of Fusion of Polyethylene , J. Polym. Sci., 5, 987-988.

21.

Brown, R.G. and Eby, R.K. (2004). Effect of Crystallization Conditions and Heat Treatment on Polyethylene: Lamellar Thickness, Melting Temperature, and Density, J. Appl. Polym. Sci, 15: 1156-1165.

22.

Van Hutten, P.F. , Koning, C.E. and Pennings, A.J. (1985). The Plastic Deformation of Ultra-High Molecular Weight Polyethylene, J. Mater. Sci. , 20: 1556-1570.

23.

Peterlin, A. ( 1987). Drawing and Extrusion of Semi-Crystalline Polymers, Colloid . Polym. Sci., 265: 357-382.

24.

Smook, J. , Flinterman, M. and Pennings, A.J. ( 1980) Influence of Spinning/Hot Drawing Conditions on the Tensile Strength of Porous High Molecular Weight Polyethylene, Polym. Bull, 2: 775-783.

25.

Smook, J. and Pennings, A.J. ( 1984). Influence of Draw Ratio on Morphological and Structural Changes in Hot-Drawing of UHMW Polyethylene Fibres as Revealed by DSC, Colloid Polym. Sci., 262: 712-722.

26.

He, M.J. , Chen, W.X. , and Dong, X.X. ( 1990). Polymer Physics, 2nd ed, Shanghai: Fudan University Press, pp. 80-100.

27.

Peterlin, A. ( 1987). Drawing and Extrusion of Semi-Crystalline Polymers, Colloid Polym. Sci., 265: 357- 382.

28.

Popli, R. and Mandelkern, L. ( 1987). Influence of Structural and Morphological Factors on the Mechanical Properties of the Polyethylenes, J. Polym. Sci., Polym Phys Ed, 25: 441-483.

29.

Matsuo, M. , Sawatari, C. , Iida , M. and Yoneda, M. (1985). Ultradrawing of High Molecular Weight Polyethylene Films Produced by Gelation/Crystallization from Solution: Effect of the Number of Entanglements, Polym. J. , 17: 1197-1208.