As a relatively new source of processing energy, microwave energy offers many compelling advantages in materials processing over conventional heat sources. These advantages include greater flexibility, greater speed and energy savings, improved product quality and properties, and synthesis of new materials that cannot be produced by other heating methods. Studies of microwave processing of polymeric materials in the early 1960s led to a successful industrial application in the rubber industry. Since the mid-1980's, there has been a great deal of interest in microwave processing of polymeric materials worldwide. The discipline can be categorized in two major fields: microwave-assisted polymer physics (MAPP) and microwave assisted polymer chemistry (MAPC). This paper offers an overview of the state-of-the-art research on the field of MAPC, including polymer processing (curing of thermosets, processing of thermoplastics, and joining), polymer synthesis, plasma modification of polymer surfaces, plasma polymerization, polymer degradation, and production of nanomaterials. Most of these studies have focused on laboratory-scale, exploratory efforts. Challenges and possible future directions for the commercialization of microwave processing technologies are discussed.

The dielectric properties of a curing epoxy/amine system have been studied from 25 to 120°C at 2.45 GHz. The epoxy resins at different extents of curing exhibit a ␥ 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. A simple model is proposed to represent the temperature dependence of the dielectric properties. A complete description of the evolution of the parameters during the polymerization has been obtained. The nature of the information yielded by dielectrometry on the dynamics of the system is discussed.

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The dielectric properties of a curing diglycidyl ether of bisphenol A (DGEBA)/Jeffamine D-230 system have been studied over the temperature range of 20 -90°C at 2.45 GHz. It was found that, generally, both the dielectric constant and the dielectric loss factor of the system increased with temperature and decreased as the reaction proceeded. The epoxy resins at different extents of cure exhibited the ␥ relaxation, which can be described by the Arrhenius Rate Law. The relaxation is attributed to the motions of the dipolar groups associated with the reactants. The Davidson-Cole model can represent the temperature dependencies of the dielectric properties. The nature of the information yielded by dielectrometry on the dynamics of the system is discussed. The evolution of the parameters of the models during the polymerization was mainly affected by the decreasing number of the dipolar groups involved in the reaction and increasing medium viscosity. POLYM. ENG. SCI., 45:1576 -1580, 2005.

This paper presents a self-consistent 3D marching-in-time multiphysics model, which includes electromagnetic field distribution, microwave power absorption, heat transfer, and polymer curing kinetics. Temperature-and cure-dependent permittivity and curing kinetics for DGEBA/DDS based on experimental data are explicitly included in the model. An edgebased finite element method (FEM) is implemented for the electromagnetic model, whereas node-based FEM is used in the heat transfer model. The numerical results can be used to determine the time-dependent temperature distribution and curing profile across the polymer sample, as well as the electromagnetic field distribution within the cavity applicator. The numerical results are compared with the measured data and a good agreement is achieved.