Thermal degradation kinetics of poly(n-butyl acrylate) initiated by lactams and thiols

The thermal degradation of poly(n-butyl acrylate) (PBA) has been studied by using thermogravimetry under nitrogen atmosphere. It is found that the thermal degradation of PBA initiated by thiols and epsilon-caprolactam has only a one-step degradation mechanism, and the degradation temperatures (360-370degreesC) are higher than AIBN system (304 and 361degreesC). FT-IR, H-1 NMR, and C-13 NMR are applied to characterize the polymer structures. The terminal group of the PBA chain has a great influence on the degradation, and the initial degradation does not appear to be ester group scission. In order to determine the effect of terminal groups, several approaches (such as Flynn, Flynn-Wall-Ozawa, and Kissinger methods) have been applied to evaluate the kinetic parameters, including activation energy, frequency factor, and rate constants. These values are compared with those obtained for PBA initiated by AIBN. These results indicate that the end groups do have an influence on thermal stability, and the strength of the effect follows the order -R-12 > -COOH > -OH > -AIBN. (C) 2004 Elsevier Ltd. All rights reserved.