Spatial and temporal control of the degree of cure in polymer composite structures

This paper describes current efforts to apply spatially and temporally loca lized microwave processing techniques to ensure uniformity of material prop erties in polymer composite materials. In large polymer composite structure s, high temperatures caused by exothermic resin cure can degrade the mechan ical properties of the composite. In this work, resin cure temperature data was obtained during microwave processing from a series of thermocouples em bedded at various lateral locations relative to the microwave source and un iformly through the thickness of the composite structure. Using this temper ature information, the potential for localized microwave-accelerated cure t o reduce the occurrence of material degradation from resin over-temperature was evaluated. In addition, a theoretical model is presented that helps el ucidate the influence of the microwave parameters on the temperature prove.