Contractive stress of epoxy resin during isothermal curing

Abstract The contractive stresses of an amine curing epoxy resin during isothermal curing are studied by photoelastic and bimetallic methods. The increase in elastic modulus during the curing process of the resin is measured by torsional braid analysis (T.B.A.). The contractive stress in composite systems is observed only after gelation of the resin. The volume contraction after gelation is effective in generating contractive stress; the contraction in the fluid state is not effective. The effective contraction is estimated to be one third of the total contraction in this experiment.