| abstract |
A sulfur-vulcanizable rubber composition which in vulcanized state is of improved hysteresis, comprising silica as reinforcing filler and a polymer which is coupled and/or starred by means of an agent having the general formula:(Y)m-R1-Si(OR2)3-n-R3nin which Y represents the radical R1 represents an alkyl, cycloalkyl, or aryl radical having 1 to 10 carbon atoms, R2 represents an alkyl, aryl, cycloalkyl, alkaryl or aralkyl radical having from 1 to 12 carbon atoms, R3 represents an alkyl, aryl or alkaryl radical having 1 to 12 carbon atoms, R4 represents a hydrocarbon radical having 1 to 6 carbon atoms and may comprise one or more oxygen atoms in the hydrocarbon chain, n is a whole number selected from among the values 0 and 1, m is a whole number selected from among the values 1 and 2, p and q are whole numbers selected from among the values 0, 1, 2, 3 and 4, it being understood that the sum of p+q must represent a whole number between 2 and 5 inclusive. |