THE EFFECT OF CHAIN-END GROUPS ON THE THERMAL-STABILITY OF POLY(ETHYLMETHACRYLATE)

The thermal degradation behavior of poly(ethyl methacrylate) homopolym ers, synthesized by using a sulfur dioxide-tert-butyl hydroperoxide (S O2-TBHP) redox pair at different temperatures (12-35 degrees C) was in vestigated. The thermal behavior of samples was followed by dynamic th ermogravimetry in a nitrogen atmosphere. Contrary to some reports in t he literature, the thermal degradation of polymers has been observed t o take place in multi-steps. These are assigned to the loss of labile end groups, side chain scission, anhydride formation and main chain de gradation steps. The thermal stability of the polymer samples synthesi zed by using a SO2-TBHP redox pair has been compared with the thermal stability of the polymers synthesized by using azo-bis-isobutyronitril e (AIBN), tert-butyl hydroperoxide (TBHP), and benzoyl peroxide (BPO). The polymers synthesized by using the SO2-TBHP redox pair showed grea ter stability against thermal degration. (C) 1997 Elsevier Science Lim ited.