摘要 |
<p>Process for the preparation of a block copolymer comprising at least one polymer block of an anionically polymerizable monomer selected from the group consisting of monovinyl aromatic hydrocarbons, conjugated dienes and mixtures thereof, and one polymer block of polydimethylsiloxane, said process comprising the steps of: (a) polymerizing the anionically polymerizable monomer(s) in the presence of an organoalkali metal initiator in a hydrocarbon solvent until substantial completion; (b) reacting the living polymer chains thus obtained with a cross-over agent selected from the group consisting of strained ring siloxanes, aldehydes, ketones, alkylene oxides and epoxides; (c) reacting the product from step (b) with hexamethylcyclotrisiloxane in the presence of a polar promoter; and (d) terminating the polymerization.</p> |