New thermosetting nanocomposites prepared from diglycidyl ether of bisphenol and gamma-valerolactone initiated by rare earth triflate initiators

Mixtures of diglycidyl ether of bisphenol A (DGEBA) with gamma-valerolactone (gamma-VL) 2:1 (mol/mol) with different organically modified clays were cationically copolymerized in the presence of scandium, ytterbium or lanthanum triflates as initiators. The cure process was followed by calorimetry and theological techniques. The differences in the gelation time on adding clays were studied by rheological measurements. These methods, in addition to FTIR studies of the cure process allowed selection of the best initiator and its concentration to achieve creation of the nanocomposite. The enhanced thermal stability of the nanocomposites was confirmed by thermogravimetric analysis (TGA). The intercalated morphology of the nanocomposites obtained was confirmed by transmission electron microscopy. The nanocomposites prepared showed a more plastic fracture surface than the unfilled material. Thermomechanical characteristics were also studied. (C) 2009 Elsevier Ltd. All rights reserved.