Hostname: page-component-77c89778f8-m8s7h Total loading time: 0 Render date: 2024-07-20T14:27:23.230Z Has data issue: false hasContentIssue false

Transport kinetics of methanol in hydroxyethyl methacrylate homopolymer and its copolymers

Published online by Cambridge University Press:  01 November 2004

C-S. Tsai
Affiliation:
Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
Sanboh Lee
Affiliation:
Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
Tinh Nguyen
Affiliation:
National Institute of Standards and Technology, Gaithersburg, Maryland 20899
Get access

Abstract

The kinetics of methanol transport in 2-hydroxyethyl methacrylate (HEMA) homopolymer and 75/25 and 50/50 mol fraction HEMA/DHPMA (2,3-dihydroxypropyl methacrylate) copolymers at five different temperatures has been investigated using the sorption experiment technique. A combined case I and case II diffusion model was used to describe the transport processes. Four replicates for each temperature of each material having a nominal thickness of 0.1 mm were immersed in methanol maintained at 35, 40, 45, 50, and 55 °C, and the mass uptake as a function of time was measured gravimetrically. Experimental results are found to be in good agreement with model prediction at all temperatures and for all three materials. Both the diffusion coefficients of case I transport and velocity of case II transport increase with increasing temperature. D values at low temperatures (35 and 40 °C), which are in the 10−9 cm2/s range, of the HEMA homopolymer are less than those of the copolymers. On the other hand, the activation energies of case I transport of the copolymers are substantially higher than those of the HEMA homopolymer; however, the level of DHPMA loading in the copolymer does not seem to affect the activation energy. In addition, thermodynamic heat and free energy of mixing values indicate heat is released when HEMA/DHPMA copolymers are exposed to methanol and that the solvent/copolymer systems exist as a continuous phase. In contrast, the methanol/HEMA homopolymer system exists as separate phases.

Type
Articles
Copyright
Copyright © Materials Research Society 2004

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1Refojo, M.F.: In Encyclopedia of Polymer Science and Technology, Supplement 1, edited by N.M. Bikales. (Wiley, New York, 1976), p. 195Google Scholar
2Wichterle, O. and Linn, D.: Hydrophilic gels for biological use. Nature 185, 117 (1960).CrossRefGoogle Scholar
3Huglin, M.B. and Sloan, D.J.: Release of ergotamine from poly(2-hydroxyethyl methacrylate). Br. Polym. J. 15, 165 (1983).CrossRefGoogle Scholar
4Teijon, J.M., Trigo, R.M., Garcia, O. and Blanco, M.D.: Cytarabine trapping in poly(2-hydroxyethyl methacrylate) hydrogels. Drug Delivery Studies, Biomaterials 18, 383 (1997).Google ScholarPubMed
5Chou, K.F., Han, C.C. and Lee, S.: Buffer transport in hydroxyethyl methacrylate copolymer irradiated by gamma rays. Polymer 42, 4989 (2001).CrossRefGoogle Scholar
6Lu, K.P., Lee, S. and Han, C.C.: Transmittance in irradiated poly(2-hydroxyethyl methacrylate) copolymer at elevated temperatures. J. Mater. Res. 17, 2260 (2002).CrossRefGoogle Scholar
7Brandrup, J., Immergut, E.H., Grulke, E.A. and editors, : Polymer Handbook, 4th ed. (Wiley-Interscience, New York, 1999), Vol. 2, 692Google Scholar
8Caykara, T., Ozyurex, C., Kantoglu, O. and Guven, O.: Influence of gel composition on the solubility parameter of poly(2-hydroxyethyl methacrylate-itaconic acid) hydrogels. J. Polym. Sci.: Part B: Polym. Phys. 40, 1995 (2002).CrossRefGoogle Scholar
9Wang, T.T. and Kwei, T.K.: Diffusion in glassy polymers: Reexamination of vapor sorption data. Macromolecules 6, 919 (1975).CrossRefGoogle Scholar
10Harmon, J.P., Lee, S. and Li, J.C.M.: Methanol transport in PMMA: The effect of mechanical deformation, J. Polym. Sci. Part A: Polym. Chem. 25, 3215 (1987).CrossRefGoogle Scholar
11Chiang, I.J., Chau, C.C. and Lee, S.: Ethyl acetate transport in syndiotactic polystyrene. Polym. Eng. Sci. 42, 724 (2000).CrossRefGoogle Scholar
12Lee, S., Nguyen, T., Byrd, E. and Martin, J.: A quantitative study of water transport during the hydrolysis of coatings exposed to water vapor. J. Mater. Res. 18, 2268 (2003).CrossRefGoogle Scholar
13van Krevelen, D.W.: Properties of Polymers, 2nd ed. (Elsevier, New York, 1976), p. 447Google Scholar
14Castellan, G.W.: Physical Chemistry, 2nd ed. (Addison-Wesley, Menlo Park, CA, 1971), pp. 235236.Google Scholar