Relationship between composite matrix molecular structure and properties

The synthesis of three novel dimethacrylate esters for use as the monomer p hase in dental composites was studied. The monomers were prepared by the re action of glycidyl methacrylate with phthalic, isophthalic and terephthalic acids, respectively, and the reaction products were found to be mixtures o f isomers. The monomers obtained from the reaction of phthalic and isophtha lic acids were low-viscosity liquids and the relationship between viscosity and molecular structure was studied. The low viscosity of these di-hydroxy l containing monomers was shown to be due to intramolecular hydrogen bondin g. This reduced monomer viscosity compared with BisGMA allowed a reduction in the quantity of diluent monomer triethyleneglycoldimethacrylate (TEGDMA) required to give standard viscosities of 1 and 2 Pas resulting in a modest decrease (ca. 10%) in polymerization shrinkage compared with that exhibite d by BisGMA/TEGDMA solutions of equivalent viscosities. A number of propert ies relevant to the use of these as potential core monomers in dental compo sites were determined for both monomer and polymer systems. (C) 1998 Publis hed by Elsevier Science Ltd. All rights reserved.