ABSTRACT
The low density of glass micro spheres makes them attractive in manufacture of syntactic foams for weight critical structural applications. The mechanical properties of a new class of three phase syntactic foam manufactured by embedding glass microspheres in epoxy resin with a deliberately introduced high fraction of void content, is investigated here. A technique developed by the University of Newcastle using acetone to manufacture this ultra light syntactic foam was employed in this study. The compression and flexural properties of the material manufactured with varying filer to resin ratio providing a range of density values were determined using ASTM standard test methods. The fracture surfaces of the failed specimens were examined using Scanning electron microscopy to develop an understanding of the observed variations in material properties with increasing resin content. While at low values of resin content the properties are primarily determined by the strength of the glass micro-spheres, it is seen that with increasing resin content, the compressive and flexural strength of the material become more dependent on the resin characteristics. The density decreases with increasing void fraction to a greater extend than the reduction in strength values. However, it is found that the specific properties of the material, strength and stiffness per unit weight, is almost an order of magnitude lower than the corresponding properties of two phase glass microsphere filled composites (without voids). This is attributed to the weakening of the matrix properties by the acetone employed to produce the voids in the three phase system.
