摘要 |
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 the structure: <IMAGE> wherein R2 and R3 are independently selected from hydrogen or C1 to C6 alkyl, and R4 is selected from hydrogen, C1 to C28 alkyl, aryl or C2 to C28 alkenyl. |