Abstract: A copolymer has low levels of cyclic oligomeric compounds, which are undesirable impurities in certain applications. The cyclic oligomeric compounds are provided in an advantageously low ratio of C21/C13 oligomers. The C13 oligomers are extractable using steam to further reduce the total amount of cyclic oligomers. A process for producing the copolymer having low levels of cyclic oligomers involves contacting at least one isoolefin monomer with at least one multiolefin and/or ?-pinene monomer in the presence of at least one Lewis acid and at least one initiator in a diluent. The diluent contains 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.

Abstract: A bicone antenna and methods for manufacture therefor can include a feed portion, a top section and a bottom section that can be centered on a vertical axis. The top section and bottom sections can each have a respective conical surface, which can extend radially outward from the vertical axis at an inner portion at a constant angle ?1 with respect to a horizontal antenna axis of the antenna. For both sections, the inner portion can merge into an outer portion that can have a curved surface, with the curved surface extending radially outward from the conical surface so that the curved surface has a logarithmic profile when viewed in side profile. The above structure can allow for a multi-directional antenna with a minimum of moving parts, which can be easily manufactured, including by additive manufacturing techniques.

Abstract: A bicone antenna and methods for manufacture therefor can include a feed portion, a top section and a bottom section that can be centered on a vertical axis. The top section and bottom sections can each have a respective conical surface, which can extend radially outward from the vertical axis at an inner portion at a constant angle ?1 with respect to a horizontal antenna axis of the antenna. For both sections, the inner portion can merge into an outer portion that can have a curved surface, with the curved surface extending radially outward from the conical surface so that the curved surface has a logarithmic profile when viewed in side profile. The above structure can allow for a multi-directional antenna with a minimum of moving parts, which can be easily manufactured, including by additive manufacturing techniques.

Abstract: A copolymer has high levels of multolefin incorporation. A process for producing the copolymer having high levels of multiolefin incorporation involves contacting at least one isoolefin monomer with at least one multiolefin and/or ?-pinene monomer in the presence of at least one Lewis acid and at least one initiator in a diluent. The diluent contains a hydrofluor-Mated 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 hydro-fluorocarbons.

Abstract: The invention relates to an efficient polymerization process and its use to produce novel copolymers with a specific micro structure. In particular, the invention relates to butyl rubbers with novel micro structure, preferably those obtainable by copolymerization of monomer mixtures comprising isobutylene and isoprene in diluents comprising 2,3,3,3 -tetrafluoro-1-propene. In a further aspect the invention relates to halogenated copolymers obtainable from such novel copolymers by halogenation.

Abstract: 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 ?-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.

Abstract: A process for producing a copolymer involves contacting at least one isoolefin monomer with at least one multiolefin and/or ?-pinene monomer in the presence of at least one Lewis acid and at least one initiator in a diluent. The diluent contains a hydrofluorinated olefin (HFO) comprising a tetrafluorinated propene. Copolymers produced by a process of the present invention have a cyclic oligomer content lower than comparable polymers produced in a butyl rubber slurry process using 1,1,1,2-tetrafluoroethane and/or methyl chloride as a diluent as well as a more favorable ratio of C21/C13. Hydrofluorinated olefins used in the present invention are better diluents for butyl slurry cationic polymerization than saturated hydro fluorocarbons.

Abstract: A copolymer has high levels of multolefin incorporation. A process for producing the copolymer having high levels of multiolefin incorporation involves contacting at least one isoolefin monomer with at least one multiolefin and/or ?-pinene monomer in the presence of at least one Lewis acid and at least one initiator in a diluent. The diluent contains a hydrofluor-Mated 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 hydro-fluorocarbons.

Abstract: 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 ?-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.

Abstract: A process for producing a copolymer involves contacting at least one isoolefin monomer with at least one multiolefin and/or ?-pinene monomer in the presence of at least one Lewis acid and at least one initiator in a diluent. The diluent contains a hydrofluorinated olefin (HFO) comprising a tetrafluorinated propene. Copolymers produced by a process of the present invention have a cyclic oligomer content lower than comparable polymers produced in a butyl rubber slurry process using 1,1,1,2-tetrafluoroethane and/or methyl chloride as a diluent as well as a more favourable ratio of C21/C13. Hydrofluorinated olefins used in the present invention are better diluents for butyl slurry cationic polymerization than saturated hydrofluorocarbons.

Abstract: The invention relates to an efficient polymerization process and its use to produce novel copolymers with a specific microstructure. In particular, the invention relates to butyl rubbers with novel microstructure, preferably those obtainable by copolymerization of monomer mixtures comprising isobutylene and isoprene in diluents comprising 2,3,3,3-tetrafluoro-1-propene. In a further aspect the invention relates to halogenated copolymers obtainable from such novel copolymers by halogenation.

Abstract: A copolymer has low levels of cyclic oligomeric compounds, which are undesirable impurities in certain applications. The cyclic oligomeric compounds are provided in an advantageously low ratio of C21/C13 oligomers. The C13 oligomers are extractable using steam to further reduce the total amount of cyclic oligomers. A process for producing the copolymer having low levels of cyclic oligomers involves contacting at least one isoolefin monomer with at least one multiolefin and/or ?-pinene monomer in the presence of at least one Lewis acid and at least one initiator in a diluent. The diluent contains 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.

Abstract: A hair sleeve for maintaining a collection of the free end portions of a user's hair in a substantially dry state. The hair sleeve has a flexible and substantially waterproof body that extends from an open end to a closed end. The body defines an interior cavity that is sized for receiving the collection of free end portions through an opening in the body. A closure assembly selectively constricts the opening against the rooted portions of the user's hair to seal the collection of tip portions within the interior cavity, leaving the user's scalp exposed for washing.