Synthesis, Characterization and Clay-Reinforcement of Epoxy Cured with Benzoxazine

Epoxy resin (EP) was cured with in situ polymerized monofunctional benzoxazine monomer, Pa, in the absence and presence of organically modified montmorillonite (OMMT). DSC showed that the onset and maximum of the exotherm due to copolymerization of EP and Pa, at 223 'C and at 262 'C, respectively, without OMMT, decreased as large as 60 'C in the presence of OMMT The XRD patterns and transparency of the films suggested nanoscale dispersion of the clay layers into the EP/Pa copolymer. Dynamic mechanical analyses indicated that the Tgs of the hybrid materials were higher than that of the pristine resin and the Tg shifted to higher temperature when the OMMT surfaces contain reactive functionalities. Isothermal and dynamic TGA showed that the dispersion of the clay nanolayers into the EP/Pa network gave better thermal properties.