ASSIGNMENT OF C-13 NMR RESONANCES TO ALIPHATIC CARBON-ATOMS OF POLYBUTADIENE

High-frequency (125 MHz) high-resolution C-13 NMR spectra of polybutad iene with varying amounts of 1,2 units were studied. Methine and methy lene subspectra were separated using DEFT (Distortionless Enhancement by Polarization Transfer) techniques. Comparison of the NMR spectra of polyalkenamers, linear polybutadiene, and related structures made it possible to calculate the substituent parameters for the carbons that are up to four bonds away from the branching junction. The assignment of C-13 NMR resonances to aliphatic carbons incorporated into the diad s or triads of 1,2 or 1,4-units was made.