N.m.r. studies of butadiene - styrene copolymers

An analysis of the ¹³C nuclear magnetic resonance spectra of copolymers of butadiene—styrene, both block or random type, shows the possibility of observing the microstructure of the copolymers themselves. The microstructure of the copolymers was analysed in terms of triads of monomeric sequences. The units present in the copolymers are of the type: trans-1,4-butadiene, cis-1,4-butadiene, 1,2-butadiene and styrene. An assignment for all the experimental bands observed is proposed on the basis of correlation with homopolymers as well as on the basis of the frequencies for the single triads, calculated by additivity rules.