| abstract |
Intervulcanized compositions having improved curing efficiency are prepared by the free radical curing of a mixture of an ethylenically unsaturated diolefin polymer such as natural or synthetic rubber and a saturated or low unsaturation polymer such as an isobutylene/para-methylstyrene copolymer which contains functional groups pendant to the polymer chain. These functional groups contain an olefinic or vinyl double bond positioned alpha, beta to a substituent group which activates the double bond towards free radical addition reactions with the diolefin polymer. Preferred functionality includes benzylic ester functionality represented by structure (1), wherein R2 and R3 are indenpendently selected from hydrogen or C1 to C6 alkyl, and R4 is selected from hydrogen, C1 to C28 alkyl, aryl or C2 to C28 alkenyl. |