Regulation of the degree of blockiness of the norbornene–cyclooctene copolymer synthesized via the cross-metathesis reaction

The kinetics of the polymer cross-metathesis reaction in a mixture of polynorbornene and polycyclooctene catalyzed by the Grubbs first-generation ruthenium catalyst at room temperature is studied. The structure of the reaction product, a multiblock copolymer of norbornene and cyclooctene, is determined by a number of factors typical for a mixture of polymers reacting with each other via the interchange reaction with the participation of terminal groups. The addition of 5 mol % catalyst transforms the mixture into an almost random copolymer over a day. At a lower content of the catalyst, the maximum conversion is reached in a mixture enriched with polynorbornene. The interchain exchange results in an increase in the fraction of trans C=C bonds in polycyclooctene and cyclooctene–norbornene copolymers to 80%.