Modified polysiloxanes, rubber compositions and tire tread rubber compositions containing the same, and reactive plasticizer

摘要

A polysiloxane having a siloxane structure of the following formulas (1) and (2): ##STR1## wherein, R.sup.1 is a C.sub.1 to C.sub.6 alkyl group or C.sub.1 to C.sub.21 acyl group, a is 1 to 200, b is 1 to 200, t is 2 or 3 and r is 1 to 100, and a rubber composition containing the same.