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Natalya K Gladkova

Nikolai S Nametkin

Eduard Grigorievich Novitsky

Valentina G Filippova

Vladimir V Teplyakov

Sergei G Durgarian

Block-copolymers of vinyltrialkylsilane-hexaorganocyclotrisiloxane of the formula: ##STR1## wherein R, R' are the same or different and each R.sub.3 represent methyl, phenyl; R.sub.1, R.sub.2, R.sub.3 --are each an aliphatic radical containing 1 to 4 carbon atoms, Z is a residue of a dilithium initiator of polymerization of a vinyltrialkylsilane K is a residue of a monolithium initiator, which is a hydrocarbon radical- normal or iso-alkyl; K' is hydrogen, an (R.sub.3) Si silcarbonic group wherein R is a C.sub.1 -C.sub.4 alkyl radical, or a hydrocarbon radical; a=0 to 10.sup.4 ; b=0 to 10.sup.4 ; C=10 to 10.sup.4 ; d=10 to 10.sup.4 ; f=0 to 1; g=0 to 1, x.gtoreq.1, with a molecular mass of from 10.sup.3 to 10.sup.6. A method for preparing these block-copolymers comprises polymerization of vinyltrialkylsilanes in the presence of mono- or dilithiumorganic initiators, whereafter a solution of a hexaorganocyclotrisiloxane is added to the reaction mixture and polymerization is effected to give intermediate block-copolymers, whereafter the polymerization is stopped or the intermediate block-copolymers are combined by means of a cross-linking agent, followed by recovery of the desired product. The block-copolymers according to the present invention feature a high selectivity of permeation for certain gases. Thus, the ratio of permeability constants for oxygen and nitrogen (P.sub.O.sbsb.2 /P.sub.N.sbsb.2) is as high as 3.5. At the same time, the absolute value of gas-permeability constants is also high, i.e. P.sub.O.sbsb.2 is as high as 1.4.times.10.sup.-8 cm.sup.3.cm/cm.sup.2 cm Hg.sec.

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Moscow, Russia

Natalya K Gladkova