Synthesis of shrinkage-controlled acrylic copolymers

Acrylic copolymer systems consisting of methyl methacrylate and triethylene glycol dimethacrylate with different chemical compositions were synthesize d through bulk polymerization using N,N-dimethyl-p-toluidine as an acelerat or to obtain nonshrinkable polymers. The use of the tertiary amine on this formulation produces an increase on the volume of the material due to a pha se separation in the copolymer, which compensates the volume reduction upon curing. The specific volumes of all materials were determined by volume di latometry using a dilatometer specially constructed for this purpose. (C) 2 000 John Wiley & Sons, Inc.