Addition Copolymerization of Silicon-Containing Tricyclononene with 2,5-Norbornadiene Dimer

A series of addition copolymers of 3-trimethylsilyltricyclo[4.2.1.02.5]non-7-ene with a bifunctional comonomer—2,5-norbornadiene dimer—are synthesized. It is shown that, with the introduction of a small amount of the 2,5-norbornadiene dimer (up to 0.3 mol %), the molecular weight of the polymer increases. When using a large amount of the 2,5-norbornadiene dimer, crosslinked insoluble polymers are formed. As exemplified by a copolymer containing 0.3 mol % 2,5-norbornadiene dimer units, the introduction of the bifunctional comonomer does not lead to a significant decrease in gas permeability, and the developed method can be used to increase the molecular weights of polymers, improve their mechanical properties, and make polymers resistant against plasticization.