DETERMINATION OF THE DIMENSIONS OF THE CONJUGATION REGION IN COPOLYMERS OF ETHYLENE AND ACETYLENE BY RESONANCE RAMAN-SCATTERING

Resonance Raman scattering is used to determine the sizes and size dis persion of defect-free conjugation regions in copolymers of ethylene a nd acetylene containing 2-24 mol % of a rigid polyacetylene fragment. In addition to extended sequences containing up to 70-100 double C=C b onds, there is a substantial fraction of short (15-25 C=C) conjugated fragments. The size distribution of the conjugation regions in the eth ylene-acetylene copolymer is close to that observed in pure polyacetyl ene synthesized in the conventional way. A model is proposed for the d istribution of these sequences in hypermolecular ethylene-acetylene co polymer formations. (C) 1997 American Institute of Physics.