Determination of Tert-Butoxy Endgroups in Polymers: The Mode of Reaction of Tert-Butoxy Radicals with Methyl Methacrylate and Styrene

Abstract

A simple technique has been devised for the determination of tert-butoxy endgroups in poly(methyl methacrylate) and polystyrene. The method is based on cleavage of the tert-butyl ether with boron trichloride and analysis of the resulting tert-butyl chloride by gas-liquid chromatography. In polystyrene, tert-butoxy endgroups were also determined by dealkylation with trifluoroacetic acid, followed by reaction of the resulting hydroxy endgroups with o-sulfobenzoic anhydride and analysis for sulfonate by the dye-partition technique with methylene blue reagent. From these analyses it was possible to conclude that tert-butoxy radicals, derived from the decomposition of di-tert-butyl peroxalate (DB..