Polymer separation membrane

A separation membrane comprising a polyether polymer having a weight-average molecular weight of 104 to 107 and obtained by polymerizing an oxirane compound of the formula:

• wherein R is a hydrogen atom;
• an alkyl group, an alkyl group having a halogen atom, or —CH2O(CH2CH2O)k—R′, where R′ is a group selected from an alkyl group having 1 to 12 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, an aryl group having 6 to 14 carbon atoms and an aralkyl group having 7 to 12 carbon atoms;
• k is from 0 to 12;
• or
• an ethylenically unsaturated group, a reactive silicon-containing group or a methylepoxy-containing group, and
• a branched-chain ether compound exhibiting liquid properties at normal temperature and selected from the group consisting of the formulas (i), (ii) and (iii):
• wherein R11, R12 and R13 are a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms;
• l, m and n are from 0 to 12, provided that all of l, m and n are not simultaneously 0,
• wherein R14, R15, R16 and R17 are a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms;
• o, p, q and r are from 0 to 12, provided that all of o, p, q and r are not simultaneously 0,
• wherein R18, R19, R20 and R21 are a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or an alkenyl group having 2 to 6 carbon atoms;
• s, t, u and v are from 0 to 12, provided that s, t, u and v are not simultaneously 0;
• R22 is a methylene group or —(OCH2CH2)x, x is from 0 to 12 and w is 0 or 1.