Chemical inequivalence behavior of the protons attached to the same carbon in ethylene–propylene copolymer (EPC)

Six ethylene–propylene copolymer samples with different structural parameters were analyzed by 1H NMR, 13C NMR and 1H–13C COSY in this paper. With the aid of the 1H–13C COSY spectra of ethylene–propylene copolymer, the chemical inequivalence behavior of the protons attached to the same carbon in the ethylene–propylene copolymer could be observed. Four basic types of chemical bonds were divided, and two kinds of main conformations were proposed to explain this phenomenon. Based on the calculation of conformation distribution, it can be proved that the explanation of this phenomenon was reasonable.