ected from the group consisting of(i) a diorganosiloxane having its formula selected from R3R1 2 SiO(R1 2 SiO)p SiR1 2 R3 or R3 R1 2 SiOSiR1 2 R3 wherein R1 is as defined above, R3 is an alkenyl group having from 2 to carbon atoms, and p is an integer having a value of greater than zero, (ii) an unsaturated aliphatic hydrocarbon compound having from 3 to 10 carbon atoms and having at least 2 carbo