摘要 |
<p>Block copolymers are prepared by coupling a poly- alpha -methylstyrene block with a polydiorganosiloxane block through a small amount of coupling units of the formula <IMAGE> where R denotes an alkyl radical of 1 to 4 carbon atoms. The resulting block copolymers have an improved glass transition temperature, reaching a value of approximately the glass transition temperature of an analogous poly- alpha -methylstyrene when R is tertiary-butyl.</p> |