Thermal degradation studies of cyclic olefin copolymers

The influences of the chemical composition and microstructure on the degradation behaviors of 3-series cyclic olefin copolymers (COCs) were investigated by using non-isothermal thermogravimetric analysis (TGA). Kinetic parameters of degradation were evaluated by using the Flynn-Wall-Ozawa iso-conversional method and the pseudo first-order method. Compared with conventional polyolefins, e.g. HDPE, COCs have lower peak temperatures of degradation, narrower degradation temperature ranges and higher amount of residual weights at the end of the degradation, which should be attributed to the chemical structure and microstructure features of COCs including the branching effect and the steric effect. The values of the reaction order of COCs determined by the Kissinger method are close to I in the non-isothermal degradation process. Although the values of E-a in region 11 calculated by using the pseudo first-order method are much higher than those calculated by using the Flynn-Wall-Ozawa method, there is a similar change trend of E-a between these two methods. However, there is a good correlation between the E-a in region 11 and the peak temperature of degradation for COCs. The theoretical weight loss versus temperature curves, generated by using the estimated kinetic parameters, well fit the experimental data, which indicates that the analysis method used in this work is valid. (C) 2003 Elsevier Science Ltd. All rights reserved.