Tetrafluoroethylene peroxide

Photooxidation of tetrafluoroethylene (TFE) and hexafluoropropylene (HEP) yield peroxides that can be decomposed to esters and ultimately long-chain ether-containing carboxyUc acids. Equation 6 shows a simplified version of what occurs during photooxidation and workup (TFE R = F,... 

Tetrafluoroethylene undergoes addition reactions typical of an olefin. It bums in air to form carbon tetrafluoride, carbonyl fluoride, and carbon dioxide (24). Under controlled conditions, oxygenation produces an epoxide (25) or an explosive polymeric peroxide (24). Trifluorovinyl ethers,... 

Copolymerization is effected by suspension or emulsion techniques under such conditions that tetrafluoroethylene, but not ethylene, may homopolymerize. Bulk polymerization is not commercially feasible, because of heat-transfer limitations and explosion hazard of the comonomer mixture. Polymerizations typically take place below 100°C and 5 MPa (50 atm). Initiators include peroxides, redox systems (10), free-radical sources (11), and ionizing radiation (12). 

Eor curing copolymers of tetrafluoroethylene and perfluorovinyl ether, addition of ca 4% TAG has been proposed (118). TEE—propylene copolymers have been cured by TAG and organic peroxide (119). Copolymers of TEE-propylene-vinyUdene fluoride are cured with TAG by heating at 200°C. 

Silastic LS 420, possessing approximately Q.6%-0.9% pendant vinyl groups, was blended with Kynar 7201, a vinylidene fluoride copolymer with tetrafluoroethylene (Atochem), in the presence of triallylisocyanurate (TAIC) and DAP containing a small amount of benzoyl peroxide in the DAP fraction. 

A terpene inhibitor is usually added to the monomer to prevent spontaneous polymerisation, and in its absence, the monomer will spontaneously explode at pressures above 2.7 bar. The inhibited monomer will explode if ignited [1]. Explosion under thermal initiation is now held to be a disproportionation, that to tetrafluo-romethane and carbon gives 3.2 kJ/g, the same energy as black powder [3], Liquid tetrafluoroethylene, being collected in a liquid nitrogen-cooled trap open to air, formed a peroxidic polymer which exploded [2]. 

Accidental admixture of oxygen gas with unstabilised liquid tetrafluoroethylene produced a polymeric peroxide which was powerfully explosive, and sensitive to heat, impact or friction [1], Removal of oxygen by treatment with pyrophoric copper to prevent explosion of tetrafluoroethylene has been claimed [2],... 

Hazardous when exposed to oxygen due to peroxide formation and subsequent peroxide initiation of polymerization Styrene Butadiene Tetrafluoroethylene Chlorotrifluoroethylene Vinyl acetylene Vinyl acetate Vinyl chloride Vinyl pyridine Chloroprene... 

Propynol, Mercury(II) sulfate, Sulfuric acid, Water, 4479 Styrene, Air, Polymerising styrene, 2945 Styrene, Butyllithium, 2945 Styrene, Dibenzoyl peroxide, 2945 Styrene, Initiators, 2945 f Tetrafluoroethylene, 0628... 

The first free radical initiated copolymerization was described by Brubakerl) in a patent. A variety of peroxides and hydroperoxides, as well as, 02, were used as initiators. Olefins that were copolymerized with CO included ethylene, propylene, butadiene, CH2=CHX (X—Cl, OAc, CN) and tetrafluoroethylene. A similar procedure was also used to form terpolymers which incorporated CO, C2H4 and a second olefin such as propylene, isobutylene, butadiene, vinyl acetate, tetrafluoroethylene and diethyl maleate. In a subsequent paper, Brubaker 2), Coffman and Hoehn described in detail their procedure for the free radical initiated copolymerization of CO and C2H4. Di(tert-butyl)peroxide was the typical initiator. Combined gas pressures of up to 103 MPa (= 15,000 psi) and reaction temperatures of 120—165 °C were employed. Copolymers of molecular weight up to 8000 were obtained. The percentage of CO present in the C2H4—CO copolymer was dependent on several factors which included reaction temperature, pressure and composition of reaction mixture. Close to 50 mol % incorporation of CO in the copolymer may be achieved by using a monomer mixture that is >70 mol% CO. Other related procedures for the free radical... 

The first report of the polymerization of tetrafluoroethylene was by Plunkett in 1941, who had a cylinder of tetrafluoroethylene cut open to see why the expected amount of gas was not released when the valve was opened. His perspicacity led to the discovery of an inert, white, opaque solid with a waxy feel. Various methods of polymerization were tried after the adventitious discovery and the preferred methods for polymerization now involve aqueous media and super-atmospheric pressures. Suitable initiators (Hanford and Joyce) include ammonium, sodium, or potassium persulfate, hydrogen peroxide, oxygen, and some organic peroxy compounds. Oxidation-reduction initiation systems involving the use of persulfate with either ferrous ion or bisulfite or the use of bisulfite with ferric ion are also useful and have been discussed by Berry and Peterson. 

Polymerization of tetrafluoroethylene with dibasic acid peroxide catalysts. U. S. Patent 2,534,058 (Dec. 12, 1950). 

List C contains peroxidisable monomers, where the presence of peroxide may initiate exothermic polymerisation of the bulk of material. Precautions and procedures for storage and use of monomers with or without the presence of inhibitors are discussed in detail. Examples cited are acrylic acid, acrylonitrile, butadiene, 2-chlorobutadiene, chlorotrifluoroethylene, methyl methacrylate, styrene, tetrafluoroethylene, vinyl acetate, vinylacetylene, vinyl chloride, vinylidene chloride and vinylpyridine [1],... 

Perfluoroether monomers 3,5-dioxa-l-heptene, (I), and 3,5,8-trioxa-l-nonene, (II), were prepared by the author [1] and polymerized with tetrafluoroethylene using perfluoropropionyl-peroxide as the reaction initiator. 

The first reported polymerization of fluoroolefins in carbon dioxide was by Fukui and coworkers [39,40]. Tetrafluoroethylene, chlorotrifluoroethylene,and other fluoroolefins were polymerized in the presence of CO2 using ionizing radiation [39, 40] and free-radical initiators [40]. DeSimone and coworkers reported the homogeneous telomerization of tetrafluoroethylene [41] and vinylidene fluoride [42] in CO2 using AIBN as an initiator. The kinetics of AIBN decomposition in CO2 is well understood [4]. However, peroxide initiators are preferred over azo initiators for producing stable endgroups in fluoroolefins... 

Many solvents form dangerous levels of peroxides during storage e.g., dipropyl ether, divinylacetylene, vinylidene chloride, potassium amide, sodium amide. Other compounds form peroxides in storage but concentration is required to reach dangerous levels e.g., diethyl ether, ethyl vinyl ether, tetrahydrofuran, p-dioxane, l,l-diethox) eth-ane, ethylene glycol dimethyl ether, propyne, butadiene, dicyclopentadiene, cyclohexene, tetrahydronaphthalenes, deca-hydrona-phthalenes. Some monomeric materials can form peroxides that catalyze hazardous polymerization reactions e.g., acr) lic acid, acr)Ionitrile, butadiene, 2-chlorobutadiene, chlorotrifluoroethylene, methyl methacrylate, styrene, tetrafluoroethylene,... 

PTFE is produced by free-radical polymerization mechanism in an aqueous media via addition polymerization of tetrafluoroethylene in a batch process. The initiator for the polymerization is usually a water-soluble peroxide, such as ammonium persulfate or disuccinic peroxide. A redox catalyst is used for low temperature polymerization. PTFE is produced by suspension (or slurry) polymerization without a surfactant to obtain granular resins or with a perfluori-nated surfactant emulsion polymerization) to produce fine powder and dispersion products. Polymerization temperature and pressure usually range from 0 to 100°C and 0.7 to 3.5 MPa. 

This plastic is a partially fluorinated straight-chain polymer with a very high molecular weight. It is produced by free-radical polymerization mechanism in a solvent or a hybrid (a solvent/aqueous mixture) media, using an organic peroxide initiator. Copolymerization of tetrafluoroethylene and ethylene (CH2=CH2, molecular weight 28, CAS number 74-85-1) proceeds by an addition mechanism. 

I Methyl methacrylate, 1915 Oxy gen (Gas), Cyclooctatetraene, 4831 Oxygen (Gas). Tetrafluoroethylene, 4831 Poly(l,3-butadiene peroxide). 1533 Poly (1,3-cyclohexadiene peroxide), 2386 Poly (dimetlryIketene peroxide). 1536 Poly (ethylidene peroxide). 0835... 

---