THE INFLUENCE OF THE MOLECULAR-STRUCTURE ON THE CHEMICAL RESISTIVITY OF SOLVENTLESS AND HIGH-SOLID EPOXY-RESINS

The chemical resistance of solventless and high-solid epoxy compositio ns has been studied. The compositions have been cured at normal temper ature and the chemical resistivity has been studied as a function of v arious resin types, solvent types and hardener types. The chemical res istance increases slightly with increasing epoxy equivalent weight. Th is is especially pronounced for this type of dependence relative to lo w molecular weight organic acids. The resistance of diluents to hydrol ysis is more important than the reactivity of the diluent used. Also t he capacity to swell plays an important role for a given solvent and r esin system. The highest resistances have been determined for styrene as a reactive diluent and for 1,1-diphenylethane as the non-reactive d iluent. The differences due to polyamine hardeners are decreased with the use of epoxy resin of higher epoxy equivalent weight.