摘要:
Process for working up aqueous dispersions of fluoropolymers. Fluoropolymer dispersions, in particular of fluoroelasomers, can be coagulated without adding chemicals, by compression with the aid of a gas and release through one or more small apertures.
摘要:
Non-free flowable, non-dusting molding powders with a bulk density of more than 450 g/l are obtained when a suspension polymer of tetrafluoroethylene with a content of 0.01 to 1% by weight of units of at least one perfluoro(alkyl-vinyl) ether is ground to a particle diameter of 10 to 50 &mgr;m and agglomerated in water.
摘要:
A multimodal fluoroplastic terpolymer composition is provided. The terpolymer can be extruded at high extrusion speeds without having to reduce its molecular weight. The terpolymer is useful by itself; in combination with conductive fillers to provide an electrostatically dissipative composition; and as a polymer processing aid. The polymer has a low molecular weight component, a high molecular weight component and, optionally an ultra-high molecular weight component.
摘要:
Aqueous dispersions of fluoropolymers which are obtained by emulsion polymerization, are not processsable from the melt and form a film on sintering, which comprise a fluoropolymer A) having an average particle size (number average) of from 180 to 400 nm and a fluoropolymer B) having an average particle size which is lower by a factor of from about 0.3 to about 0.7, so that the total dispersion has a non-monomadal number distribution of the particle diameter, are suitable for soaking, impregnating or coating surfaces, for example of fibers or planiform articles of fibers or porous materials, in particular for coating fiberglass fabrics, and also for the formulation of metal coating systems.
摘要:
Polymerizing tetrafluoroethylene with modifying amounts of a perfluoro(alkyl vinyl ether) at temperatures below 60.degree. C. using permanganate or similar initiators by the suspension process and milling the raw polymer to an average particle size of from 10 to 50 .mu.m gives molding powders which are suitable for the preform free-sintering technique.
摘要:
A transparent thermoplastic molding compound consisting of 40 to 90% by weight of units derived from tetrafluoroethylene, and 60 to 10% by weight of units derived from compounds of formula I or II:CF.sub.2 .dbd.CF--O--(CF.sub.2 --CF(CF.sub.3)--O).sub.m --(CF.sub.2).sub.n --CF.sub.3 (I)CF.sub.2 .dbd.CF--O--(CF.sub.2 --CF(CF.sub.3)--O).sub.p --(CF.sub.2).sub.q --COO--R (II)is particularly suitable for manufacturing the sheath of beam waveguides whose core has a higher transparency than polymethyl methacrylate.
摘要:
Process for the preparation of fluorinated carboxylic acid fluoridesFluorinated carboxylic acid fluorides of the Formula I ##STR1## can be prepared from fluorinated vinyl ethers of the Formula II ##STR2## by heating the vinyl ethers to a temperature of 100.degree. to 350.degree. C.Perfluorinated carboxylic acids and derivatives thereof can be prepared from the carboxylic acid fluorides by secondary reactions, for example hydrolysis, esterification or aminolysis.
摘要:
Described herein is a polymerizable composition substantially free of an organic emulsifier, methods of making, and articles thereof. The polymerizable composition comprises: a continuous phase; a polymerizable monomer; an initiator; and inorganic nanoparticles, wherein the inorganic nanoparticles are substantially free of groups that will copolymerize with the polymerizable monomer.
摘要:
Provided are methods of bonding a fluoroelastomer to a metal substrate; fluoropolymer compounds comprising a fluoroelastomer, a curing agent and a bonding promoter; and composite materials obtained by curing the compound. Further provided is the use of bonding promoters for increasing the bond strength between a fluoroelastomer and a metal substrate.
摘要:
Described herein is a composition comprising an aqueous polymerization reaction product of fluorinated monomers and wherein the polymerization is initiated (i) in the absence of a fluorinated emulsifier and whereby no fluorinated emulsifier is added during polymerization or (ii) in the presence of an fluorinated emulsifier selected from: [Rf—O-L-COO-]i Xi+ (I) wherein L represents a linear or branched, non-fluorinated, partially fluorinated, or fully fluorinated alkylene group, Rf represents a linear or branched partially or fully fluorinated aliphatic group or a linear or branched partially or fully fluorinated aliphatic group interrupted with at least one oxygen atom, Xi+ represents a cation having the valence i and i is 1, 2 or 3; wherein the reaction product and/or the resulting aqueous phase are substantially free of di- and tri-alkylamines and substantially free of low molecular weight fluoroorganic compounds and methods thereof.
摘要翻译:本文描述的是包含氟化单体的水性聚合反应产物的组合物,其中聚合反应开始于(i)在不存在氟化乳化剂的情况下,并且由此在聚合过程中不加入氟化乳化剂,或(ii)在氟化乳化剂存在下 选自:[Rf-OL-COO-] i Xi +(I)其中L表示直链或支链,非氟化,部分氟化或完全氟化的亚烷基,Rf表示直链或支链部分或完全氟化的脂族基团或 间隔有至少一个氧原子的直链或支链部分或完全氟化的脂肪族基团,X i +表示i为i且i为1,2或3的阳离子; 其中所述反应产物和/或所得水相基本上不含二烷基胺和三烷基胺,并且基本上不含低分子量氟代有机化合物及其方法。