Unsaturated polyester/montmorillonite nanocomposites prepared by in situ intercalative copolyaddition

New approach to the synthesis of unsaturated polyester/day nanocomposites is described. Various forms of organically modified montmorillonite (OMMT) were introduced in situ during the copolyaddition of epichlorohydrin, maleic anhydride and phthalic anhydride. The catalytic effect of OMMT containing quaternary ammonium ions was observed. The introduction of clay leads to the increase in softening temperature, as well as melt or solution viscosity of unsaturated polyester. Cured unsaturated polyester/clay compositions exhibit increased hardness and heat resistance and, in some cases, decreased flammability. The best properties, including limiting oxygen index (LOI) values in the range of 27-29 %, were obtained for the compositions with OMMT functionalized with hydroxyl group. In that case, covalent bonds between clay surface and unsaturated polyester are likely to be formed. The dispersion of OMMT in the polyester matrix in form of exfoliated nanocomposite was indicated by X-ray diffraction study.