Synthesis and microstructure of polymers from o-methacryloyloxybenzoic acid

The free radical polymerization of o-methacryloyloxybenzoic acid using acetone and benzene as solvents, in the interval 30–120°C, is investigated. The polymerization in benzene has a precipitant character. However, when acetone is used as solvent, at reaction temperatures higher than 60–70°C, the polymerization deviates from the classic free radical mechanism and, beside the addition of monomer molecules to growing chain ends, the release of salicylic acid and the formation of cyclic anhydride structures of glutaric type in the main chain has been detected. The microstructure of polymers obtained has also been studied by the transformation into the corresponding poly(methyl methacrylate)s.