Abstract
A new type molecular composites, copolymers of methyl methacrylate and rigid siloxane oligomers, which have a ladder-like structure, have been developed for resins for dental use, for example, hard crown and bridge, composite and denture base resins. The oligomers made from a variety ratio of γ-methacryloxypropyl trimethoxysilane and phenyl triethoxysilane were lucid and viscous liquids, with molecular weight of about 1100. The viscosity of the oligomers increased with the number of phenyl substitutes, and were lower than that of Bis-GMA.
Compressive strength of the various MMA-copolymer, which contained 20 wt% of the oligomers, were higher than that of the copolymers with same weight of polyfunctional monomers, such as 3G and Bis-GMA.
Based on considerations of the degree of crosslink in the various copolymers and structure of siloxane bond, it is assumed that the copolymer is reinforced not only by crosslinkage involved with the polyfunctional substances, but by the contribution of rigid structure of the siloxane oligomers.
