| 摘要 |
<p>1485185 Alternating block copolymers BASF AG 14 Jan 1975 [15 Jan 1974] 1497/75 Heading C3P A block copolymer is obtained by (1) polymerizing monomer(s) to form an elastomeric block B in the presence of a mono- or bifunctional anionic initiator, (2) either (a) reaching the "living" chain ends with a monomer comprising two vinyl and/or vinylidene groups attached to an aromatic nucleus or (b) including such a monomer in the initial polymerization step (1) (in which case some branches may be formed), (3) terminating the living polymer and (4) effecting an alternating copolymerization of an unsaturated polar monomer and an alkenyl aromatic monomer in the presence of a Lewis acid catalyst which is capable of complexing with the polar monomer and is preferably a typical metal halide cationic catalyst. Typical polar monomers are (meth) acrylic acids, their nitriles and esters, and vinyl ketones. Examples refer to (1) the polymerization of butadiene in the presence of BuLi or alphamethylstyrene tetramer dipotassium, (2) treatment of the living polymer with diisopropenyl benzene or inclusion of vinyl-isopropenylbenzene in stage (1), (3) termination with methanol, and (4) copolymerization of segments of alternating structure of styrene/acrylonitrile in the presence of ZnCl 2 / diisobutyronitrile or Et 3 Al 2 Cl 3 .</p> |
