THERMAL AND NONTHERMAL INTERACTION OF MICROWAVE-RADIATION WITH MATERIALS

Industrial use of microwave radiation as an alternative to conventiona l thermal heating has generated interest recently mainly because of th e drastic reduction in the processing ti me. In spite of its wide appl ication, its chemical mechanism of interaction with materials has not been well understood. The current debate on the alternative use of mic rowave radiation to conventional thermal heating is on the involvement of a ''microwave specific effect'' other than the well accepted diele ctric heating. There are reports of various reactions which show simil ar kinetics under both microwave and thermal methods at similar temper atures suggesting simple dielectric heating of materials by microwaves . There are also reports which show a clear reaction rate enhancement under microwave radiation compared to the thermal method under similar reaction conditions and temperatures indicating a ''microwave specifi c effect'' other than the simple dielectric heating of materials. This paper will discuss the above conflicting results reported in the lite rature.