| Abstract: | Polyesters containing bicyclo2.2.2]octane and bicyclo3.2.2]nonane rings are prepared from 1,4-bis(carboethoxy)bicyclo2.2.2]octane, 1,4-bis(hydroxymethyl)bicyclo2.2.2]-octane and the 1,5-disubstituted bicyclo3.2.2]nonane analogs. These polyesters are compared to the related polymers containing 1,4-phenylene and trans-1,4-cyclohexylene rings in terms of their melting point, thermal stabilities and oxidative stabilities. The lower symmetry of the bicyclo3.2.2]nonane ring produces lower-melting polymers than the other ring systems. The remaining three rings are approximately equivalent in their effect on the melting point of a polymer provided that no more than one bicyclo2.2.2]octane ring is present per polymer repeat unit. Two such rings produce a highermelting polymer than any other combination. Both the thermal and oxidative stabilities of the polyesters is improved by the presence of the bicyclo rings. This is attributed to the rings providing an approximation of a ladder polymer. |
