Unsaturated structures in polyolefinpolymers are important inmany respects. In this work, new vinyl and vinylidene structures wereidentified in poly(ethylene-co-1-octene) copolymers.The combination of careful sample selection and model compounds providedclear evidence for the assignment of these structures. More importantly,a new method was developed to differentiate and quantify for the firsttime terminal and internal unsaturations in ethylene-co-1-octene copolymers. The method described here will be generallyapplicable to many different polyolefins. [ABSTRACT FROM AUTHOR]