Improvement of the performance of epoxy-amine thermosets by antiplasticizer-induced nano-scale phase separation during cure

Interest in the addition of an antiplasticizer to epoxy-amine resin formulations was strongly enhanced by selecting a chemical species which is miscible in the monomer mixture but gives rise to nano-scale phase separation along the network construction. As a result, small domains, consisting of additive molecules trapping some network chains, are dispersed in the polymer matrix, which is plasticized by residual additive molecules. The main effects of this special morphology on the network properties were the depression of the main relaxation temperature, Tα, of the matrix and the appearance of some damping (so-called μ relaxation) in the intermediate temperature range between the secondary relaxation and Tα. The networks prepared in this way exhibit higher modulus and toughness around room temperature than the unmodified systems. In addition, they exhibit lower moisture absorption at equilibrium than their conventional homologues.