Degradation kinetics enhancement of polystyrene by peroxide addition

An experimental study combined with theory based on distribution kinetics s hows how polystyrene degradation is enhanced by continuous addition of pero xide. We investigated polystyrene oxidative degradation kinetics by di-tert -butyl peroxide in the solvent trichlorobenzene at temperatures from 100 to 150 degrees C. The basic experimental data consisted of the time dependenc e of the polystyrene molecular-weight distribution (MWD). The model. accoun ts for the rate of peroxide dissociation to radicals that rapidly abstract hydrogen from the polymer backbone. The model also includes random hydrogen transfer among polymer molecules and their radicals, and describes p-sciss ion of radicals. For the case that all polymer rate coefficients increase l inearly with MW, an analytical (similarity) solution is formulated for the MWD. Experimental data support the general form of the model results, inclu ding the Induction time for peroxide decomposition, and provide estimates o f rates for peroxide dissociation, hydrogen abstraction, and random scissio n. Rate coefficient temperature dependences yield activation energies.