401 results about "Poly tetra fluoro ethylene" patented technology

The invention relates to medical devices and methods of using them. The devices are prostheses which can be percutaneously deliverable with (or on) an endovascular catheter or via other surgical or other techniques and then expanded. The prostheses are configured to have a lattice resistant to dilation and creep, which is defined by a plurality of openings. The prosthesis may also optionally have a stent disposed proximal to the lattice. In exemplary embodiments, the fluoropolymer is expanded polytetrafluoroethylene. The composite materials exhibit high elongation while substantially retaining the strength properties of the fluoropolymer membrane. In at least one embodiment, the lattice is made of a composite material that includes a least one fluoropolymer membrane including serpentine fibrils and an elastomer. A lattice including a generally tubular member formed of a composite material including a least one fluoropolymer membrane containing serpentine fibrils and an elastomer is also provided.

The present invention discloses a composite conductive carbon fiber paper. Its preparation process includes the following steps: using acrylonitrile carbon fiber and other carbon material as raw material, adopting polyphenylamine, conventional polyvinyl alcohol and water-soluble phenolic resin and mixing them, and using their mixture as adhesive, the polyphenylamine is conductive high-molecular polymer; mixing sodium alginate and conventional dispersing agent; adopting wet-process paper-making technique to make paper; vacuum drying the obtained carbon paper, then using Teflon emulsion whose concentration is 5%-20% to make treatment; finally, introducing nitrogen gas and making carbonization, carbonization temperature is higher than 1000 deg.C, so as to obtain the invented composite conductive carbon fiber paper. Said composite conductive carbon fiber paper mainly is used in fuel cell field.

The invention discloses a method for preparing hollow fiber membranes and tubular membranes with a microporous PTFE hybrid flat membrane wrapping method. Dispersed PTFE resin and polyvinylidene fluoride resin are mixed with a liquid lubricant, and microporous PTFE hybrid flat membranes are prepared from the mixture through extrusion, calendaring, stretching and sintering. Then the microporous PTFE hybrid flat membranes are cut into membrane strips which wrap around supporting tubes, and finally the wrapped supporting tubes are sintered to obtain the hollow fiber membranes and the tubular membranes. The polyvinylidene fluoride resin added into the products of the invention has a melting point around 160 DEG C, fuses while sintered at a temperature between 250 and 340 DEG C, and can largely increase the hardness of the flat membranes after solidification, which facilitates slitting of the flat membranes. During the process of sintering after wrapping, the polyvinylidene fluoride resin contained in the flat membranes fuses again when sintered at a temperature between 260 and 340 DEG C, and thus can be used as overlapping parts between the wrapped flat membranes and as binders between the flat membranes and the microporous supporting tubes, so that the bonding strength is substantially improved.

Polymer electrolyte for an electrochemical generator based on at least a four branched polymer, at least a poly(vinylyldienefluoride), a poly(vinyldiene fluoro-co-hexafluoropropene copolymer), a poly(tetrafluoroethylene), a poly(ethylene-co-propylene-co-5-methylene-2-norbornene) or an ethylene propylene-diene copolymer, a polyol, a poly(methylmethacrylate, a poly(acrylonitrile), SiO2Al2O3, or nano TiO2 non coated or coated with an organic material. This electrolyte allows to prepare electrolytic compositions that can be used in high performance electrochemical devices.

An upcoated optical fiber includes an optical fiber having a ultra-violet (UV) curable upcoating and a slip layer disposed between the optical fiber and the upcoating. The upcoating is mechanically strippable from the optical fiber and may be colored for identification of the optical fiber. In one embodiment, the slip layer and upcoating both have predetermined glass transition temperatures that are within about 15° C. of each other for improving mechanical characteristics. The slip layer may be essentially the same color as the upcoating for identification of the optical fiber after the upcoating is removed or it may be uncolored. In suitable embodiments, the slip layer may include a micronized poly-tetra-fluoro-ethylene (PTFE), a silicone, and / or a dispersing agent for enhancing the strip performance of the upcoating over a range of temperatures.

A workpiece is transported using a porous belt, which belt delivers a workpiece to a chuck, upon which the workpiece is held by vacuum. The belt can be porous PTFE. A flexible stamp is preheated, before it is applied to a workpiece, by drawing the stamp toward a heated plate, for instance by vacuum.