| 摘要 |
A heterogeneous blend of elastomers having a stabilized morphology, as well as the method of making the same, comprises at least two radiation cross-linkable elastomers which form a heterogeneous blend. The radiation cross-linkable elastomer components are selected from the class consisting of conjugated dienes having from 4 to 12 carbon atoms, natural rubber, polyalkenamers such as polypentenamer, chlorinated polyolefinic elastomers having from 2 to 8 carbon atoms such as chlorinated polyethylene, ethylenepropylene terpolymers, polysiloxanes, nitrile rubber, butadiene-acrylic copolymers, chlorosulfonated polyethylene, butadiene vinyl pyridine copolymers, substituted phosphazenes, aliphatic polyesters which are substantially non-crystalline and have 6 carbon atoms or more in the repeating unit, preferably from 6 to 12 carbon atoms, butyl copolymers containing groups with unsaturation, a butadiene-styrene copolymer and a copolymer, terpolymer, etc., made from a conjugated diene having from 4 to 12 carbon atoms and from monomers selected from the class consisting of a vinyl aromatic having from 8 to 15 carbon atoms, acrylonitrile, and olefins having from 2 to 8 carbon atoms. The morphology of the heterogeneoous blend is greatly improved or fully stabilized by irradiating to a point below to slightly above the gel dose of the blend, that is up to a point where the blend has 15 percent and preferably up to 5 percent gel. The greatly improved or fully stabilized morphology permits conventional processing steps to be carried out where shear is involved such as in milling, extruding, compression or injection molding, and the like such that the final morphology of the blend, after processing, is substantially the same as the initial morphology. Examples of specific heterogeneous elastomeric blends include nitrile rubber blended with an EPDM polymer, styrene-butadiene blended with an EPDM polymer, and polybutadiene blended with an EPDM polymer. |
