H-1 AND C-13 NMR SIGNAL ASSIGNMENT FOR THE 4-PHENYL-1,2,3,4-TETRAHYDRO-1-NAPHTHYL END-GROUP OF AUTOPOLYMERIZED POLYSTYRENE

Most of the H-1 and C-13 NMR signals of the 4-phenyl-1,2,3,4-tetrahydr o-1-naphthyl end-group of polystyrene are assigned. An oligostyrene sy nthesized by thermally initiated ''living'' free-radical polymerizatio n of styrene in the presence of 2,2,6,6-tetramethylpiperidine-N-oxyl ( TEMPO) is used as a model compound. The TEMPO end-group is eliminated under formation of a benzophenone end-group prior to spectroscopical a nalysis. The tacticity of the backbone and probably the presence of th e cis-and trans-stereoisomer result in a signal splitting of the end-g roup signals. The absence of a methyl end-group indicates that the sta rting radical is formed by H-abstraction from the Diels-Alder styrene dimer by TEMPO according to a mechanism proposed by Mead et al.