| 摘要 |
A copolymer is formed by emulsion polymerization and then hydrogenated to obtain a thermooxidatively stable composition. The copolymer is prepared from two monomer classes. The first monomeric class comprises a fluorodiene of the structure <IMAGE> <IMAGE> <IMAGE> wherein substituent a is independently hydrogen or fluorine, R is hydrogen or a fluoro alkyl group containing from 1 to about 4 carbon atoms and containing at least three fluoro atoms, with the proviso that both R's are not hydrogen, R1 and R2 are independently fluorine, hydrogen or a fluoro alkyl group containing from 1 to about 4 carbon atoms and containing at least three fluorine atoms. The second monomeric class is (a) a hydrocarbon diene comprising a conjugated diene, a branched conjugated diene or mixtures thereof containing from 4 to about 8 carbon atoms or a mixture of (a) with (b) a monomer of the general formula CH2=CR3X wherein R3 is hydrogen or an alkyl group containing from 1 to 4 carbon atoms, and X is 2-pyridyl, 4-pyridyl, -COOR4, CONR5R6 or -COOR7OR4 wherein R4 is an alkyl group containing from 1 to about 4 carbon atoms, -CH2CF3 or -CH2CF2CF2H, R5 and R6 are alkyl groups containing from 1 to about 4 carbon atoms and R7 is an alkylene group containing from 1 to about 4 carbon atoms. The mole ratio of hydrocarbon diene (a): CH2=CR3X (b), when (b) is present, is from 1:7 to about 7:1 and the mole ratio of first monomer:second monomer is from about 4:3 to about 2:3. The copolymer thus obtained is hydrogenated in the presence of a transition metal catalyst and a trialkyl aluminum wherein the alkyl group contains from 1 to about 4 carbon atoms and further in the absence of boron trifluoride or boron trifluoride etherate. Additionally, a complexing agent for said transition metal catalyst is employed and said transition metal catalyst is deactivated after hydrogenation by the use of a second complexing agent, in the absence of air.
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