Binary systems of chlorinated polyethylene (CPE) and chlorinated paraffin (CP) or 3,9-bis[1,1-dimethyl-2{beta-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy}-ethyl]-2,4,8,10-tetraoxaspiro[5,5]-undecane (AO-80) and their ternary systems were investigated by dynamic mechanical analysis, thermal analysis, and infrared spectrum analysis. Adding CP into CPE/AO-80, in which one novel relaxation appears above the glass-transition temperature of CPE, can increase not only the peak height but also the minimum value between two peaks. The tan delta value in the middle of the two peaks for CPE/CP/CPE was found to be proportional to the slope (d In E'/dT) of the E' curve at an identical temperature. The addition of CP caused changes in many of the hydrogen bonds: a decrease in hydrogen bonds between the hydroxyl groups of AO-80, a reinforcement of hydrogen bonds between the hydroxyl groups of AO-80 and alpha -hydrogens of CPE, and the formation of other hydrogen bonds between the carbonyl groups of AO-80 and alpha -hydrogens of CPE. Those changes are useful to improve the temperature dependence of tan delta and to enhance the stability of the dynamic mechanical properties. (C) 2000 John Wiley & Sons, Inc.