Abstract: A melt-mixed composition of non-melt flowable polytetrafluoroethylene (PTFE) and melt-fabricable perfluoropolymer is provided that exhibits thixotropy at increasing shear rate in the molten state and high elongation at break even at PTFE concentrations well above 4 wt %, based on the combined weight of the PTFE and the perfluoropolymer, e.g. at least 200% up to at least 30 wt % PTFE, the composition also exhibiting the structure of a dispersion of submicrometer-size particles of the PTFE in a continuous phase of the melt-fabricable perfluoropolymer.

Abstract: In the formation of a fluoropolymer non-stick layer on a substrate such as of cookware and bakeware, improved adhesion of the layer is obtained by co-grinding at least the polymer binder component with the pigment component. In an aqueous system, this co-grinding is carried out in water which contains a surfactant and the polymer binder is soluble in the water or water organic solvent mixture the resultant co-ground aqueous dispersion/solution is blended with aqueous dispersion of fluoropolymer to form the coating composition. Addition of inorganic filler film hardener to the co-grinding step also improves the scratch resistance of the of the non-stick layer.

Abstract: A tetrafluoroethylene/fluoroalkoxy trifluoroethylene copolymer (PFA) composition which has finer spherulite diameters compared to a conventional PFA is provided, so as to give fabricated articles having excellent surface smoothness, and which are free from problems, such as process contamination and the like, caused by leaching. This effect is obtained by incorporating into the composition prior to fabrication a polytetrafluoroethylene having a crystallization temperature of at least 305.degree. C. and a heat of crystallization of at least 50 J/g.

Abstract: A fluid medium such as a gas and a liquid medium are interacted within a convoluted array of tubes, wherein the liquid medium is present as "rain-fall" rather than flooding the array of tubes, with a heat transfer medium being passed through the tubes to heat or cool the liquid medium, as the case may be, to drive the mass transfer occurring in the interaction between gas and liquid medium.

Abstract: Copolymers of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP) having high HFP content and end-of-melting temperature, T.sub.m (end), as low as 200.degree. C. are disclosed. Exceptional performance as a processing aid in polyolefins results from having T.sub.m (end) of the TFE/HFP copolymer close to the processing temperature of the polyolefin. These TFE/HFP copolymers are soluble in fluorinated cyclic solvents. Copolymer/solvent systems copolymer at significant concentrations in selected solvents are fluid and stable at room temperature.

Abstract: Seals capable of containing corrosive liquid and/or vapor of, e.g., HCFCs, are made of cured blends of (a) CTFE/VF.sub.2 elastomer, (b) chlorine-free fluoroelastomer, and (c) 1 to 20 wt % of hydrocarbon polymer, based on the combined weight of (a) and (b). The blends are homogeneous and coherent wherein the hydrocarbon polymer is not visible at 165.times. magnification as a separate phase within the matrix of the blend of (a) and (b) and the blend is free of internal cracks and voids.

Abstract: A single step, vapor phase process for the chlorofluorination of methane forms trifluoromethane and/or tetrafluoromethane in high yield. A Cr.sub.2 O.sub.3 catalyst is preferred.

Abstract: Halogen-containing organic compounds are reacted with alkali metal or earth alkaline metal carbonate and/or oxide to convert the halogen component of the compound to halide of the metal, thus converting a liquid or gaseous compound to a solid halogen-containing compound for use or safe landfill disposal.

Abstract: This invention is a melt processible fluoropolymer composition having a thermally stable, non-volatile, non-fugitive coagent. The fluoropolymer is made from ethylene, tetrafluoroethylene and at least one monomer. The coagent preferably is a salt of an acrylic acid such as dimethacrylate or diacrylate. The composition is useful as a wire and cable coating, chemically resistant lining for pipes or vessels or a film or membrane. The fluoropolymer composition has good tensile strength particularly at high temperatures and has good heat aging properties. The composition may be crosslinked with low doses of radiation. A shaped article made from the composition and a method of making the shaped article are also claimed.

Abstract: The comonomers are perfluorocyclic unsaturated compounds, copolymerized to form amorphous copolymer. Such copolymer forms optically clear tough coating and films.

Abstract: A process for suspension polymerization of tetrafluoroethylene to polytetrafluoroethylene is characterized by starting reaction at low temperature and increasing temperature to higher temperature during the reaction.

Abstract: Copolymers of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP) having high HFP content and end-of-melting temperature, T.sub.m (end), as low as 200.degree. C. are disclosed. Exceptional performance as a processing aid in polyolefins results from having T.sub.m (end) of the TFE/HFP copolymer close to the processing temperature of the polyolefin. These TFE/HFP copolymers are soluble in fluorinated cyclic solvents. Copolymer/solvent systems copolymer at significant concentrations in selected solvents are fluid and stable at room temperature.

Abstract: This invention provides a tetrafluoroethylene (TFE) copolymer resin powder composition capable, upon rotational lining, of generating a corrosion-resistant, nonstick film, which is a thick film on a metal or a like substrate, essentially free of gas bubbles, and excellent in adhesion and peel resistance. The TFE-copolymer resin powder composition comprises granules which comprise particles of a TFE/perfluoro(alkyl vinyl ether) copolymer (PFA), polyphenylene sulfide (PPS) particles having an average particle size of 0.3-50 .mu.m, and a heat resistant filler. This invention also provides a process for manufacturing the TFE copolymer resin powder composition comprising either (1) granulating a mixture of PFA particles, PPS and a heat resistant filler in the presence of water and an organic liquid, or (2) mixing PFA, PPS, and a heat-resistant filler, compression-molding, and pulverizing.

Abstract: Polytetrafluoroethylene coagulate obtained from aqueous dispersion polymerization of tetrafluoroethylene in the presence of volatile initiator, surfactant, and possibly wax, is purified of these contaminants by exposing the coagulate to heated air with the coagulate being formed as a shallow bed on a fabric of polymer filament, the heated air passing through the bed from top to bottom to volatilize the contaminants including the water content of the coagulate and thereby cause them to leave the bed through openings in the fabric.

Abstract: Copolymers of tetrafluoroethylene (TFE) and hexafluoropropylene (HFP) having high HFP content and end-of-melting temperature, T.sub.m (end), as low as 200.degree. C. are disclosed. These copolymers contain one or more additional fluoromonomers such as perfluoro(alkyl vinyl)ether. These TFE/HFP copolymers are soluble in fluorinated cyclic solvents.

Abstract: Fluoroelastomers and fluoroplastics are plasticized with high-boiling fluorinated aliphatic cyclic structures to enhance processibility or to improve final properties.

Abstract: Repeat units having pendant functional groups increase the solubility of polymers containing repeat units of perfluoro-2,2-dimethyl-1,3-dioxole.

Abstract: An optical fiber cladding made of copolymers of perfluoro( 1,3 -dimethyl-2,2-dioxole) with perfluoro(butenyl vinyl ether) and, optionally, with a third comonmer are amorphous in all monomer proportions, and soluble in perfluoro(2-butyl tetrahydrofuran). Dipolymers of the present invention have lower glass transition temperatures than dipolymers of perfluoro(1,3-dimethyl-2,2-dioxole) with tetrafluoroethylene having the same monomer proportions.

Abstract: Tetrafluoroethylene is made safe (non-explosive) to handle by forming a liquid solution of tetrafluoroethylene and carbon dioxide, one in the other, in a pressurized container.

Abstract: A downcomer used to direct hot flue gases from oxidative combusion of halocarbons into an aqueous medium in a quench tank has improved corrosion resistance when made of rhenuim, molybdenum, or an alloy containing at least 50 wt % molybdenum and having a corrosion rate not exceeding 0.254 mm/yr.