Water uptake at 25°C is measured for unsaturated polyester matrix and glass fiber composites as a function of time. Dielectric measurement in the frequency range of 1 MHz-1 GHz has been performed on the specimens during the water absorption process. The dielectric constant decreases as the frequency increases for matrix and composites. The dielectric constant of unsaturated polyester is lower than their composites based on glass fibers. A Fickian diffusion model is applied for water absorption studies, and the effective diffusion coefficient is calculated for each sample. An empirical model describing the increase in dielectric constant with water absorption is proposed.
Fraga, A. N., Alvarez, V. A., de la Osa, O. and Vazquez, A. (2003). Relationship between Dynamic Mechanical Properties and Water Absorption Unsaturated Polyester and Vinyl-ester Glass Fiber Composites, Journal of Composite Materials, 37(17): 1553-1573.
2.
Alvarez, V. A., Fraga, A. N. and Vazquez, A. (2004). Effect of the Humidity and Fiber Content on the Mechanical Properties of MaterBi-Y and Sisal Short Fibers Biocomposites, Journal of Applied Polymer Science, 91(6): 4007-4016.
3.
Pethrick, R. A. and Hayward, D. (2002). Real Time Dielectric Relaxation Studies of Dynamic Polymeric Systems, Progress in Polymer Science, 27(9): 1983-2017.
4.
Manffezzoli, A. M., Peterson, L., Seferis, J. C., Kenny, J. M. and Nicolais, L. (1993). Dielectric Characterization of Water Sorption in Epoxy Resin Matrices, Polymer Engineering and Science, 33(2): 75-81.
5.
Boinard, E., Pethick, R. A. and MacFarlane, C. J. (2000). The Influence of Thermal History on the Dynamic Mechanical and Dielectric Studies of Polyetherketone Exposed to Water and Brine, Polymer, 41(3): 1063-1076.
6.
Li, Y., Cordobes, M. and Karbhari, V. M. (2003). Dielectric and Mechanical Characterization of Processing and Moisture Uptake Effects in E-glass/Epoxy Composites, Composites Part B: Engineering, 34(4): 383-390.
7.
Mac Ewan, I., Pethrick, R. A. and Shaw, S. J. (1999). Water Absorption in a Rubber-modified Epoxy Resin, Carboxy Terminated Butadiene Acrylonitrile-amine Cured Epoxy Resin System, Polymer, 40(15): 4213-4222.
8.
Ivanova, K. I., Pethrick, R. A. and Affrossman, S. (2000). Investigation of Hydrothermal Ageing of a Filled Rubber Toughened Epoxy Resin using Dynamic Mechanical Thermal Analysis and Dielectric Spectroscopy, Polymer, 41(18): 6787-6796.
9.
Kchaou, B., Turki, C., Salvia, M., Fakhfakh, Z. and Treheux, D. (2004). Role of Fibre-matrix Interface and Fibre Direction on Dielectric Behavior of Epoxy Composites, Composites Science and Technology, 64(9): 1467-1475.
10.
Xue, Qingzhong (2001). Study on Dielectric Properties of Oil/Water Random Composites, Journal of Electrostatics, 50(3): 169-175.
11.
Gonon, P., Sylvestre, A., Teysseyre, J. and Prior, C. (2001). Combined Effects of Humidity and Thermal Stress on the Dielectric Properties of Epoxy-silica Composites, Materials Science and Engineering B, 83(1): 158-164.
12.
Logsdon, S. D. and Laird, D. A. (2002). Dielectric Spectra of Bound Water in Hydrated Ca-smectite, Journal of Non-Crystalline Solids, 305(1-3): 243-246.
