Ethylene-propene copolymerization in the presence of a 13C enriched catalyst: End group analysis and monomer reactivities in the first insertion steps

Ethylene and propene were copolymerized in the presence of an isotactic specific 13C enriched catalyst. The 13C enriched end groups in the copolymers were detected by 13C NMR analysis. The resonances of the enriched carbons of the end groups could be assigned and the relative reactivities of the monomers in the insertion steps occurring at the beginning of the copolymerization were determined.