摘要:
A fluoropolymer composition is provided. The polymer comprises interpolymerized units derived from (i) tetrafluoroethylene, (ii) vinylidene fluoride, (iii) at least one ethylenically unsaturated monomer of the formula CF2═CFRf where Rf is a perfluoroalkyl or a perfluoroalkoxy of 1 to 8 carbon atoms, and (iv) a perfluorovinyl ether of the formula CF2═CF—(OCF2CF(Rf))aORf where Rf is as described in (iii), Rf is a perfluoroaliphatic, preferably a perfluoroalkyl or a perfluoroalkoxy, of 1 to 8, preferably 1 to 3, carbon atoms, and a has a value of 0 to 3.
摘要:
Fluoroelastomers having copolymerized units of vinylidene fluoride major monomer, at least one other fluorinated major monomer, and at least one cure site monomer are prepared in an aqueous suspension polymerization process using an initiator consisting essentially of a solution of an oil soluble peroxide in a water-soluble hydrocarbon solvent.
摘要:
A method for forming a fluoropolymer comprises providing a reaction mixture comprising carbon dioxide, at least one fluoromonomer, and an initiator; and reacting the at least one fluoromonomer in the reaction mixture to form a fluoropolymer. The fluoropolymer has a multimodal molecular weight distribution.
摘要:
Random copolymers including vinylidene fluoride and hexafluoropropylene that exhibit a large electrostrictive response when subjected to an electric field, articles including such polymers, and methods of preparing the polymers and articles. Electrostrictive responses greater than about 4 percent are obtainable at electric field strengths of 50 megavolts per meter.
摘要:
A fluoroelastomer comprising constituent units derived from vinylidene fluoride (a) and constituent units derived from perfluoro(methoxypropyl vinyl ether) (b), optionally together with constituent units derived from tetrafluoroethylene (c) and/or constituent units derived from a perfluoroalkyl vinyl ether (d), wherein the constituent units (a) are contained in an amount of 65 to 85 mol %, the constituent units (b) in an amount of 0.5 to 30 mol %, the constituent units (c) in an amount of 0 to 10 mol % and the constituent units (d) in an amount of 0 to 25 mol %. The fluoroelastomer can be produced by a process comprising copolymerizing vinylidene fluoride and perfluoro(methoxypropyl vinyl ether), optionally together with tetrafluoroethylene and/or a perfluoroalkyl vinyl ether, in the presence of an iodated brominated compound represented by the general formula RBrnIm [I]. Further, there is provided a crosslinkable composition comprising the above fluoroelastomer and a peroxide crosslinking agent. Still further, there is provided a curing product produced by curing the above crosslinkable composition, and having excellent resistances to heat, cold and solvents.
摘要:
A new class of ferroelectric terpolymers having an exceptionally large electrostrictive response (>3%) induced by external electric field at ambient temperature comprise 50-80 mole % of vinylidene fluoride (VDF), 15-40 mole % of trifluoroethylene (TrFE) and 2-20 mole % of at least one bulky monomer, such as chlorotrifluoroethylene (CTFE) or hexafluoropropene (HFP). These semicrystalline terpolymers behave like a ferroelectric relaxor having a rapid electric field-induced mechanical response, due to a low Curie temperature (phase transition between polar and nonpolar crystalline domains at or near ambient temperature) and high dielectric constant. A combination of bulk polymerization and free radical polymerization using oxidation adducts of an organoborane as the free radical initiator may be used to prepare the terpolymers, such that the terpolymers are characterized by good processibility, high purity and uniform molecular structure.
摘要:
Curable fluoroelastomers comprising monomeric units formed by a triazine iodinated derivative having general formula: wherein Y′ is independently H, Cl, F, CH3, or CF3, m′ and t′ are 0 or 1, and m′+t′=0 or 1, preferably m′+t′=0; p′ is an integer and is equal to 1 when t′=1, or p′=0; X′ is independently H, Cl, F, alkyl or perfluoroalkyl C1-C3, preferably F; n′ is an integer between 2 and 20, preferably between 4 and 12, more preferably between 4 and 8.
摘要:
Peroxide curable fluoroelastomers having copolymerized units of vinylidene fluoride or tetrafluoroethylene major monomer, at least one other fluorinated major monomer, a cure site monomer having the general formula CH2═CH—(CF2)nI, where n is an integer between 2 and 8, and iodine bound at the terminal positions of polymer chains, process well and have excellent tensile properties.
摘要:
A carboxyl group-containing fluorine copolymer is produced safely at a low cost by treating a vinylidene fluoride copolymer with a base and a peroxide, preferably in the presence of a phase-transfer catalyst such as a quaternary ammonium salt or a quaternary phosphonium salt.
摘要:
Vinylidene fluoride and chlorotrifluoroethylene are copolymerized in the presence of a compound represented by the general formula I: InBrmR (I) wherein R represents a fluorohydrocarbon group, a chlorofluorohydrocarbon group, a chlorohydrocarbon group or a hydrocarbon group, and n is 0, 1 or 2 and m is 0, 1 or 2 provided that n+m≧2. This provides a process for producing a fluorinated copolymer which enables providing a fluorinated copolymer crosslinking product having mechanical properties satisfactory for practical use as sealants even if no inorganic additive is added thereto.