RELATING THE PROPERTIES OF FOAM TO THE PROPERTIES OF THE SOLID FROM WHICH IT IS MADE

Properties of foam and the solid (neat resin) from which it was derive d were compared experimentally for polymethacrylimide (PMI). Viscoelas tic properties of the foam and neat resin differed significantly in th e range 50 Hz to 5 kHz. No significant differences in thermal properti es were observed in differential scanning calorimetry. However, it was observed that the stiffness of the solid material from which the foam was made was increased after heat treatments. It is therefore likely that the properties of the solid material in the foam are changed by t he foaming process, which involves elevated temperature. The propertie s of the solid material in the foam were also inferred from the measur ed foam properties substituted into the given foam structure-property relations.