摘要:
An improved procedure is provided for increasing the electrical conductivity of graphite via intercalation. It has been found that fully halogenated hydrocarbons (as described) have the ability to substantially aid the intercalation of graphite by previously known intercalant mixtures of (a) fluorosulfonic acid, chlorosulfonic acid, or mixtures thereof, and (b) a boron trihalide, a tetrahalide of a Group IV element, a pentahalide of a Group V element, or mixtures thereof. The presence of a fully halogenated hydrocarbon, such as carbon tetrachloride, during the graphite intercalation reaction has been found to expedite the rate at which intercalation takes place and possibly enables the achievement of a greater electrical conductivity than would have otherwise been obtained. In a preferred embodiment the graphite carbon is present within a carbonaceous fibrous material at the time of its intercalation and the resulting product is substantially electrically oriented along the axis of the fiber.
摘要:
An improved procedure is provided for increasing the electrical conductivity of graphite via intercalation. It has been found that sulfur trioxide has the ability to substantially aid the intercalation of graphite by previously known intercalants such as (a) fluorosulfonic acid, chlorosulfonic acid, or mixtures thereof, (b) a boron trihalide, a tetrahalide of a Group IV element, a pentahalide of a Group V element, or mixtures thereof, and (c) mixtures of (a) and (b). Such presence of sulfur trioxide during the graphite intercalation reaction has been found to expedite the rate at which intercalation takes place and possibly enables the achievement of a greater electrical conductivity than would have otherwise been obtained. In a preferred embodiment the graphitic carbon is present within a carbonaceous fibrous material at the time of its intercalation and the resulting product is substantially electrically oriented along the axis of the fiber.
摘要:
An electrical device is made by partially pyrolyzing polymer material by heating the material to between 500.degree. C. and 800.degree. C. Electrodes are applied to the material at two different locations to define an electrically active element therebetween. Devices made according to the teachings of the disclosure exhibit negative resistance in a portion of their voltage current domain and function as bi-directional electrical switches.
摘要:
Temperature detectors are disclosed which employ, as their active elements, pieces of partially pyrolyzed polymer material which switch to a more highly conductive state under appropriate imposed electrical bias conditions when the ambient temperature increases above the switching temperature of the detector.
摘要:
Ceramic fibers formed by the pyrolysis of organosilicon preceramic polymers are provided with increased resistivity by treating the fibers in air at temperatures of less than 1,000.degree. C. to oxidize the free carbon content of the fibers.
摘要:
The present invention provides a rechargeable electric storage battery comprising an electrolyte containing charge-transporting positive ions and negative ions capable of intercalating into graphitic carbon, and oppositely charged graphitic carbon electrodes which are simultaneously intercalated by the positive ions and negative ions present in such electrolyte. The graphitic carbon electrodes may be provided in a variety of physical configurations. Such battery is believed to provide reasonably high power density and energy density characteristics, fabrication simplicity, a relatively long lifetime, and potential economic advantages.
摘要:
An electrical device is made by partially pyrolyzing polymer material by heating the material to between 500.degree. C. and 800.degree. C. Electrodes are applied to the material at two different locations to define an electrically active element therebetween. The device exhibits negative resistance in a portion of its voltage current domain and function as bi-directional electrical switches.This application is a continuation of application Ser. No. 859,709, filed May 5, 1986, now abandoned, which is a divisional application of application ser. No. 487,401, filed Apr. 21, 1983, now U.S. Pat. No. 4,642,644.
摘要:
Films or other articles having a barrier coating derived from a concentrated nanocomposite dispersion which includes a silicate filler and a matrix polymer dispersed in an aqueous medium. The dispersions are condensed by selectively removing liquid therefrom to provide high solids coating formulations.
摘要:
An evacuated container assembly suitable for use in connection with blood collection including: (a) a container member formed of a first polymeric material and having a sidewall and one or more openings; (b) a nanocomposite barrier coating disposed on the container member having a thickness of up to about 30 microns and being derived from an aqueous dispersion including (i) a dispersed barrier matrix polymer; and (ii) a substantially exfoliated silicate filler having an aspect ratio of more than 50; and (c) one or more sealing members disposed in the opening(s) operative to hermetically seal the cavity; wherein the cavity is evacuated and maintains a pressure below atmospheric pressure and exhibits a draw volume loss lower than that of a like assembly without a nanocomposite barrier film by a factor of at least 1.5.
摘要:
Barrier coating mixtures include (a) a non-butyl elastomeric polymer; (b) an acid or base treated dispersed, substantially exfoliated silicate filler material that has not been functionalized with organic cations having an aspect ratio greater than 25; and (c) at least one additive, wherein the total solids content is less than 30% and the amount of filler is between 5% to about 60% of the total solids content. The coating retains its permeability properties under strain and has a strain to first damage of at least 5% biaxial elongation at 0% RH.