of about 20 7 at about 10 9 parts per hundred teta having an equivalent weight of about 24 5 at about 12 9 parts per hundred tris dimethyl amino methyl phenol at about 10 parts per hundred tepa having an equivalent weight of about 27 at about 14 2 parts per hundred and ethylenediamine having an equivalent weight of about 60 at about 31 6 parts per hundred any combination of these amines may be used to cure an epoxy resin having an equivalent weight of approximately 190 so long as the equivalent weights of the amines add up to the amount needed to react with the resin thus various blends of the listed amines can be used to develop the cure cycle and physical properties that are desired in the finished polymer a preferred embodiment of the modified epoxy resin may also contain a filler material the filler material can have a density ranging from about 0 009 g ml such as a thermoplastic microballoon to about 11 3 g ml such as lead powder and may comprise from about 0 2 percent to about 30 percent by volume of the total polymer composition preferred examples of the filler material include solid glass spheres.