Unsaturated polyesters from benzofuro[2,3-b] benzofuran-2,9-dicarboxylic acid

Unsaturated polyesters because of their valuable applications and versatile preparation are the most interesting resins among the cross-linkable polymers and a huge volume of works is completed or currently running on this type of polymers. This work is of those kinds resembling the incorporation of new monomers into the ordinary unsaturated polyester resins and investigating the influence of this monomer on the resin properties. By this way the monomer, which is of interest in this work constitutes benzofuro[2,3-b]benzofuran-2,9-dicarboxylic acid. This monomer was synthesized by the authors in 1996 for first time. For polymerization, this molecule, maleic anhydride and several diols were reacted in a polycondensation reaction to yield the unsaturated resins. The produced resins were characterized subsequently by H-1 NMR and IR spectra, measuring molecular weight, and inherent viscosity. On the other hand, thermal and environmental resistance (resistance to acidic and alkaline moiety) was investigated on the cured resins with styrene 30% (by weight), as are described in the paper. Their thermal and chemical stability show an acceptable range of properties.