Thermal decomposition of copolymers used in dental resins formulations photocured by ultra blue IS

Abstract

Kinetics of thermal decomposition of acrylates copolymers used in dental resins formulations were studied with dynamic thermogravimetric analysis experiments. The kinetic parameters, including activation energy, pre-exponential factor, and 60 min half-life temperature, which were calculated by the Flynn and Wall method, are presented. The results indicate that thermal decomposition of the material occurred in three different stages characterized by different mechanism. These three events were separated and the kinetics parameters were determined. The loss mass was observed in the onset of the thermal decomposition for the all of copolymers studied. When the copolymers were submitted to thermal treatment before of thermal analysis was not observed the loss mass in the beginning of the process. The analysis of intermediates by GC of the condensed material extracted after thermal treatment at TB copolymers showed the presence of the methacrylic acid and 2-hydroxyethyl methacrylate, which are products of decomposition of BisGMA and triethyleneglycol dimethacrylate monomers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007