Polymerisation of N-vinylcarbazole. Part 1.—End-group studies on polymers prepared using azobisisobutyronitrile and benzoyl peroxide

End-group studies have been made on poly-N-vinylcarbazole prepared by polymerization at 60°C in benzene with either azobisisobutyronitrile or benzoyl peroxide as initiator. The azo-nitrile gives polymers having on average 1.35 initiator fragments per molecule, suggesting that combination and disproportionation occur with approximately equal frequencies. The peroxide gives polymers of unexpectedly low molecular weight and having close to two initiator fragments per molecule; benzoyloxy groups form a high proportion of these fragments. It appears that benzoyl peroxide does not promote a true radical polymerisation of N-vinylcarbazole.