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Phosphonic acids are known to be useful mono- mers in dental restorative materials because of their good potential to provide enhanced adhesion to hydroxyapatite and their high hydrolytic stability. In this study, the photopolymeri- zation of phosphonic acid-based monomer via the camphorqui- none (CQ)/ethyl-4-(dimethylaminobenzoate) (EDAB) photoredox system is compared with a ternary system composed of iodo- nium hexafluorophosphate and CQ/EDAB. Photocalorimetry shows that the ternary system does not provide a significant acceleration of the polymerization with either acrylamide or methacrylate phosphonic acids. The complexation of the iodo- nium by the phosphonic moiety of the acidic monomers leads to a lowered iodonium reactivity and reduced polarizability of the medium and as a consequence limits the rate enhancement effect normally observed by phosphonic acids on the polymer- ization rate. V C 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 5046-5055 |
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