摘要 |
Polymers containing a monomeric unit of the formula …<IMAGE>… in which R<1> is hydrogen, methyl, ethyl, fluorine, chlorine, bromine, cyano or phenyl; X<1> is oxygen, sulphur, -NH- or -N(CH3)-; R<2> is alkylene having 3-15 carbon atoms in which a non-terminal methylene group may optionally be replaced by oxygen or sulphur; X<2> is a single covalent bond, oxygen or sulphur; the rings A and B, independently of one another, are 1,4-phenylene which is unsubstituted or substituted by halogen, methyl, methoxy and/or cyano and in which one or two CH groups are optionally replaced by nitrogen; ring C is 1,4-phenylene which is unsubstituted or substituted by halogen, methyl, methoxy and/or cyano and in which one or two CH groups are optionally replaced by nitrogen, or is trans-1,4-cyclohexylene; n is the number 0 and Z<1> is -CONH- or -NHCO-; or n is the number 1, one of the groups Z<1> and Z<2> is -CONH- or -NHCO- and the other of the groups Z<1> and Z<2> is a single covalent bond, -CH2CH2-, -CH2O-, -OCH2-, -N=N-, -CONH- or -NHCO-; and R<3> is hydrogen, halogen, cyano, nitro or an alkyl group in which one or two non-adjacent methylene groups are optionally replaced by oxygen and/or sulphur,… are used in optics and for separating mixtures of substances. |