"Weak links" in polystyrene-thermal degradation of polymers prepared with AIBN or benzoyl peroxide as initiator

Abstract

Polystyrene has been prepared with 13C-labelled initiators and 13C NMR spectroscopy used to evaluate the role of initiator-derived functionality in the thermal degradation at 300°C. Changes in the molecular weight and molecular weight distribution were measured by GPC. For polymers prepared with benzoyl-carbonyl-13C peroxide or benzoyl-α-13C peroxide, the end groups incorporated by head addition or transfer to initiator/primary radical termination (secondary benzoate esters) undergo rapid elimination at 300° and must be considered potential "weak links". However, benzoate end groups formed by "tail" addition to monomer (primary benzoates) are relatively stable at 300° and are not "weak links..