Poly(trialkoxysilyltricyclononenes): A New Type of Polymers for Membrane Gas Separation

New metathesis and addition polymers containing Si–O–C groups were synthesized from 3-tri(n-propoxy) silyltricyclo[4.2.1.02.5]non-7-ene. It was shown for the first time that metathesis polymer was more permeable than the addition polymer. The prepared polymers showed high selectivity in the butane/methane separation controlled by solubility; therefore, they are promising for membrane separation of hydrocarbon mixtures.