Dimethacrylates derived from hydroxybenzoic acids.

Since the color stabilities and durabilities of current composite and pit and fissure sealant resins need improvement, it is worthwhile to evaluate innovations that might accomplish this goal. Accordingly, three crystalline dimethacrylate monomers with low melting points were prepared from the isomeric hydroxybenzoic acids and 2-bromo-ethyl methacrylate. These monomers can be purified by crystallization and liquified by admixture in various proportions to obtain a polymerizable liquid of suitable viscosity at room temperature. In contrast to the analogous dimethacrylate monomers that were derived from the phthalic acid isomers, these aromatic ether-ester dimethacrylates do not form colored charge-transfer complexes with tertiary aromatic amine accelerators. These monomers and their polymers should be elevated for use in composites and pit and fissure sealant formulations.