Photopolymerization of poly(melamine-co-formaldehyde) acrylate for dental restorative resins

This paper describes the investigation of photoinitiated polymerization of poly(melamine-co-formaldehyde) acrylate (PMFA) by camphorquinone (CQ) and a mines (AMH) by visible light (lambda > 400 nm). It was shown that as the co ncentration of CQ and/or AMH increases, the rate of polymerization reaches a maximum and then decreases. The double bond conversion of PMFA was 20-35% , whereas monomer conversion was 90-96%, depending on the polymerization co nditions. Addition of inorganic filler up to 70 wt% did not significantly i nfluence the polymerization kinetics. The final hardness of the photocured samples (with 70 wt% filler) was about half that found in a commercial dent al restorative composite. The shrinkage of a composite with 70 wt% filler w as 2.12%. Dental formulations based on photocuring of PFMA can be considere d for clinical applications, after biological and toxicological evaluation. (C) 1999 Society of Chemical Industry.