THERMAL-DEGRADATION OF POLY(ALPHA-METHYLSTYRENE) IN SOLUTION

The thermal degradation of poly(alpha-methylstyrene) in solution was i nvestigated at various temperatures (150-225 degrees C) and polymer co ncentrations (2.00-20.0 g/l) at 6.8 MPa (1000 psig). The molecular wei ght distributions (MWDs) of the reacted polymer at these conditions we re examined at four different residence times. Experimental data indic ated that the polymer degraded to its monomer, cu-methylstyrene. No ot her degradation products were observed. Continuous-mixture kinetics wa s used to examine the MWDs and to obtain the rate coefficient for degr adation and its activation energy. The rate was first order in polymer concentration with a rate coefficient at 225 degrees C of 0.01 min(-1 ) and an activation energy of 66.5 kJ/mol (16.0 kcal/mol). The maximum conversion observed at 275 degrees C was 1.2%. Hydrogen-donor solvent , tetralin, had no effect on the degradation. (C) 1996 Published by El sevier Science Limited