Synthesis of BISGMA derivatives, properties of their polymers and composites.

2,2-Bis[4-(2 hydroxy-3-methacryloyloxy propoxy) phenyl] propane (BisGMA) is commonly the main component of the organic matrix of dental filling materials. Derivatives of BisGMA were synthesized from the diglycidyl ether of Bisphenol A (DGEBA) by the parallel reaction with methacrylic acid (MAA) and isophthalic acid as well as mixtures of methacrylic anhydride with palmitic acid and acetic anhydride, respectively, whereby MAA was partially substituted by the latter components. By this technique the structure of BisGMA monomer could be varied with regard to weight content of C=C double bonds, the hydrophilicity of the molecule as well as its flexibility or stiffness. Free-radical initiated homopolymerization of the monomers was carried out at 80 degrees C. Composites, prepared from mixtures of monomers with triethylene glycol dimethacrylate (TEGDMA) filled with 76% silica were room temperature polymerized using both redox and photoinitiated techniques. The polymerization shrinkage, diffusion coefficients of water in the crosslinked polymer, and some thermal properties of the homopolymers were determined. Mechanical properties of the resulting polymers and composites are compared to those of BisGMA itself.