COPOLYMER HAVING LOW ISOPRENOID CONTENT

摘要

A copolymer has low levels of isoprenoid (short chain branching) structures. A process for producing the copolymer having low isoprenoid content involves contacting at least one isoolefin monomer with at least one multiolefin and/or β-pinene monomer in the presence of at least one Lewis acid and at least one initiator in a diluent. The diluent may contain a hydrofluorinated olefin (HFO) comprising at least three carbon atoms and at least three fluorine atoms. Hydrofluorinated olefins used in the present invention are better diluents for butyl slurry cationic polymerization than saturated hydrofluorocarbons. Blends of saturated hydrofluorocarbons (e.g. 1,1,1,2-tetrafluoroethane) with an inert solvent (e.g. methyl chloride) may also be used as diluents.