| abstract |
A diorganosiloxane polymer suitable for modifying thermosetting resins and its preparation are disclosed, said polymer being terminated at each molecular end with an epoxy group-containing organopolysiloxane residue of the following general formula ##STR1## wherein R 1 is a monovalent hydrocarbon group free of alkenyl groups, R 2 is selected from the group consisting of hydrogen and a monovalent hydrocarbon group free of alkenyl groups, R 3 is a monovalent group selected from the group consisting of an epoxy group-containing organic group and an alkoxysilylalkyl group, with the proviso that at least one R 3 group is an epoxy group-containing organic group, R 4 is a divalent hydrocarbon group, a is zero or a positive number, b is a positive number, c is a positive number, a/c is a positive number in the range of zero to 4, b/c is a positive number in the range of 0.05 to 4, and (a+b)/c is a positive number in the range of 0.2 to 4. |