The dielectric behavior of a curing system of diglycidyl ether of bisphenol A and m-phenylenediamine has been studied over the temperature range of 20—100°C under 2.45 GHz microwave radiation. The dielectric constant and the dielectric loss factor of the system increase as temperature increases while they decrease as the curing reaction progresses. The epoxy resins at different extents of cure exhibit the g relaxation, which can be described by the Arrhenius rate law. The relaxation is attributed to the motions of the dipolar groups associated with the crosslinking system. The Davidson—Cole model is used to represent the temperature dependency of the dielectric properties.
Zong, L., Zhou, S., Sgriccia, N., Hawley, M.C. and Kempel, L.C. (2003). A Review of Microwave-assisted Polymer Chemistry (MAPC), J. Microwave Power E E, 38: 49-74.
2.
Debye, P. (1945). Polar Molecules, Dover Publications , New York.
3.
Cole, K.S. and Cole, R.H. (1941). Dispersion and Absorption in Dielectrics, J. Chem. Phys., 9: 341-351.
4.
Davidson, D.W. and Cole, R.H. (1951). Dielectric Relaxation in Glycerol, Propylene Glycol, and n-Propanol, J. Chem. Phys. , 19: 1484-1490.
5.
Zong, L., Zhou, S., Sun, R., Kempel, L.C. and Hawley, M.C. (2004). Dielectric Analysis of a Crosslinking Epoxy Resin at a High Microwave Frequency, J. Polym. Sci. Part B: Polym. Phys., 42: 2871-2877.
6.
Eloundou, J.P. , Gerard, J.F., Pascault , J.P. and Kranbuehl , D. (1947). Modeling Complex Permittivity of an Epoxy-amine System Using Simultaneous Kinetic and Microdielectric Studies, Macrmol. Chem. Phys. , 203: 1974-1982.
7.
Pochan, J.M. , Gruber, R.J. and Pochan, D.F. (1981). Dielectric Relaxation Phenomena in a Series of Polyhydroxyether Copolymers of Bisphenol-A Endcapped Polyethylene Glycol with Epichlorohydrin, J. Polym. Sci.: Polym. Phys., 19: 143-149.
8.
Casalini, R. , Fioretto, D., Livi, A., Lucchesi, M. and Rolla, P.A. (1997). Influence of the Glass Transition on the Secondary Relaxation of an Epoxy Resin, Phys. Rev. B, 56: 3016-3021.
9.
Koike, T. and Tanaka, R. (1991). Dielectric Properties Above the Glass Transition for a Series of Epoxide Prepolymers, J. Appl. Polym. Sci. , 42: 1333-1340.
10.
Gallone, G., Capaccioli, S., Levita, G., Rolla, R.A. and Corezzi, S. (2001). Dielectric Analysis of the Linear Polymerization of an Epoxy Resin, Polym. Int., 50: 545-551.
11.
Zong, L. (2005). Ph.D. Dissertation, Michigan State University, East Lansing, MI.
12.
Lee, H. and Neville, K. (1957). Epoxy Resins: Their Applications and Technology, p. 41, McGraw-Hill, New York.
13.
Kauzmann, W. (1942). Dielectric Relaxation as a Chemical Rate Process, Rev. Mod. Phys., 14: 12-44.
14.
Schonhals, A. and Schlosser, E. (1989). Dielectric Relaxation in Polymeric Solids Part 1. A New Model for the Interpretation of the Shape of the Dielectric Relaxation Function, Colloid. Polym. Sci. , 267: 125-132.
