Processing of microcellular polyester composites

Abstract

Abstract A new method of producing microcellular polyester composites is developed. The microcellular foam which is produced by supersaturating the polyester resin with nitrogen is cured by dielectric heating. The lightweight composite contains about 10 μm size bubbles. By substituting the microcells for the particulate fillers of the conventional composites, the weight of the composite is reduced by 30 to 40 percent. A theoretical analysis based on classical nucleation theory is applied to predict the rate of nucleation. The diffusion controlled bubble growth is modeled and the theoretical prediction is in good agreement with experiment. The mechanical behavior of the microcellular composite has also been examined. Toughness is improved significantly whereas the flexural strength remains the same as that of a conventional sheet molding compound.