tThe kinetic behavior of innovative photopolymerizable UV-cured methacrylic–silica hybrid formula-tions, previously developed, was studied and compared to that of a reference control system. Theorganic–inorganic (O–I) hybrids proposed in this study are obtained from organic precursors with a highsiloxane content mixed with tetraethoxysilane (TEOS) in such a way to produce co-continuous silicanano-domains dispersed within a cross-linked organic phase, as a result of the hydrolysis and condensa-tion reactions. The kinetics of the radical photopolymerization mechanism induced by UV-radiations, inpresence of a suitable photoinitiator, was studied by calorimetric, FTIR and Raman spectroscopic analy-ses, by varying the composition of the mixtures and the atmosphere for reactions. The well known effectof oxygen on the kinetic mechanism of the free radical photopolymerization of the methacrylic–siloxanebased monomers was found to be strongly reduced in the hybrid system, especially when a properthiol was used. The experimental calorimetric data were fitted using a simple kinetic model for radicalphotopolymerization reactions, obtaining a good agreement between the experimental data and the the-oretical model. From the comparison of the kinetic constants calculated for control and hybrid systems,it was possible to assess the effect of the composition, as well as of the atmosphere used during thephoto-polymerization process, on the kinetic of photopolymerization reaction.
UV-cured methacrylic-silica hybrids: Effect of oxygen inhibition on photo-curing kinetics
ESPOSITO CORCIONE, Carola;STRIANI, RAFFAELLA;FRIGIONE, Mariaenrica
2014-01-01
Abstract
tThe kinetic behavior of innovative photopolymerizable UV-cured methacrylic–silica hybrid formula-tions, previously developed, was studied and compared to that of a reference control system. Theorganic–inorganic (O–I) hybrids proposed in this study are obtained from organic precursors with a highsiloxane content mixed with tetraethoxysilane (TEOS) in such a way to produce co-continuous silicanano-domains dispersed within a cross-linked organic phase, as a result of the hydrolysis and condensa-tion reactions. The kinetics of the radical photopolymerization mechanism induced by UV-radiations, inpresence of a suitable photoinitiator, was studied by calorimetric, FTIR and Raman spectroscopic analy-ses, by varying the composition of the mixtures and the atmosphere for reactions. The well known effectof oxygen on the kinetic mechanism of the free radical photopolymerization of the methacrylic–siloxanebased monomers was found to be strongly reduced in the hybrid system, especially when a properthiol was used. The experimental calorimetric data were fitted using a simple kinetic model for radicalphotopolymerization reactions, obtaining a good agreement between the experimental data and the the-oretical model. From the comparison of the kinetic constants calculated for control and hybrid systems,it was possible to assess the effect of the composition, as well as of the atmosphere used during thephoto-polymerization process, on the kinetic of photopolymerization reaction.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
