Branched macromonomers and their application in dental composites. Monomers for low-shrinking composites, 3

Branched macromonomers were synthesized by esterification of epoxy-carboxylic acid macromonomers with long aliphatic monocarboxylic acids. The molar masses of the resulting branched epoxy-carboxylic acid macromonomers varied between 1200 and 1700 g mol–1. Such branched macromonomers composed of aliphatic dicarboxylic acids in the main chain exhibit a very low viscosity (20 to 45 Pa · s) and a relatively low volumetric shrinkage (ΔV = 2.3 to 3.4%) during photoinitiated cure. Dental composites with a volumetric shrinkage of 1.0% were based on the blends of these branched macromonomers. Due to the flexible structure of the macromonomers a relatively low mechanical stiffness of the composites was found.