A novel epoxy resin/CaCO₃ nanocomposite and its mechanism of toughness improvement

In this work, epoxy resin/CaCO₃ nanocomposites were prepared by in situ and inclusion polymerization. Nanoparticles with a size of 30-40 nm were dispersed efficiently in bisphenol-A alkaline solution before polymerization and the dispersion could be kept in the resultant composite by a reaction that took place at the nanoparticle surface and among the nanoparticles when epichlorohydrin was added. Furthermore, the slightly conglomerated nanoparticles could even be separated by epoxy resin growing among them. This method showed a better dispersion of nanoparticles compared with solution-blending as observed with TEM. Owing to better combination of epoxy resin and nanoparticles, the resultant nanocomposite showed a 12°C increase in T_g compared to the nanocomposite prepared by solution-blending. Tensile test revealed that the tensile strain of nunocomposites rises as the nano-CaCO₃ content increases.