Functional peroxides and peroxy oligoesters on the basis of pyromellitic dianhydride

A series of peroxy oligomers has been synthesized on the basis of pyromellitic dianhydride and tetrachloroanhydride of pyromellitic acid by condensation with polyethylene glycols and tert-butylhydroperoxide. The resulting oligoesters contain two types of functional groups: carboxylic - which can participate in ionic reactions and peroxide - able to initiate certain radical processes. Concentrations of these groups depend on the method of synthesis, the nature of starting monomers, and the molecular mass of polyethylene glycol. Structures of oligoesters have been determined by IR and H-1-NMR spectroscopy. The oligoesters are able to form three-dimensional networks when heated to 400 K. A mechanism of the network formation is proposed. These materials can be used as curing agents for unsaturated polyesters and also for epoxy + unsaturated polyester resin compositions.