ИСТИНА

Currently, a large number of glassy polymers are known for membrane gas separation: polyacetylenes, polymers of intrinsic microporosity etc. However, the search for new materials and methods for their synthesis continues actively. Polynorbornenes are convenient objects for the study of the relationships between structure and properties. However, the orientation of the substituent in norbornene monomer plays an important role in the polymerization of substituted norbornenes: exo-isomers have higher polymerization reactivity, and polymers based on them exhibit a higher level of gas permeability unlike polymers synthesized from endo-isomers or exo-/endo mixture. The traditional methods for the synthesis of norbornene-type monomers based on cycloaddition reactions are multistage or non-selective. In this study, we propose a new, simple and more efficient one-step approach to the selective synthesis of exo-silicon-substituted norbornenes, based on the reaction of the hydrosilylation of 2,5-norbornadiene by commercially available hydrosilanes, for the synthesis of new polymeric materials. Synthesized exo-substituted norbornenes were highly reactive in metathesis and vinyl-addition polymerization. Gas transport properties of the synthesized silicon-substituted polynorbornenes were investigated. It has been found that polymers containing Si–O–Si fragments have high solubility-controlled hydrocarbon separation selectivity. The permeability of the synthesized polymers turned out to be higher than the level of the permeability of polymers previously obtained from a mixture of exo-/endo-isomers. New relationships between the polymer structure and gas transport properties were found.