摘要:
Use of vinylidenfluoride (VDF) copolymers for preparing electrolyte polymers, wherein the VDF copolymers have the following polymeric structure (I): (CH2—CF2)m—(CXY—C(ORf)Z)n—(CF2—CF(CF3))p) wherein: Rf is a perfluoroalkyl group having from 1 to 3 carbon atoms; X, Y, and Z equal to or different from each other are selected from F, Cl or H; m,n and p are integers, n or p can be 0 but not simultaneously; said VDF copolymers being obtainable by emulsion polymerization at 75-120° C., preferably 95°-120° C., in the presence of organic initiators.
摘要:
Use of amorphous perfluoropolymers based on homopolymers of the TTD dioxole or its amorphous copolymers to prepare solutions in fluoro-containing solvents, to obtain solutions for coatings, wherein TTD has the formula: ##STR1## wherein R.sub.F is a perfluoroalkylic radical with 1-5 carbon atoms, linear or branched when possible; X.sub.1 and X.sub.2 equal to or different from each other being F or CF.sub.3 ; the TTD amount ranges from 40 to 100% by moles.
摘要翻译:使用基于TTD二氧杂环戊烯或其无定形共聚物的均聚物的无定形全氟聚合物在含氟溶剂中制备溶液,以获得涂料溶液,其中TTD具有下式:其中RF是具有1-5个碳的全氟烷基 原子,可以是直链或支链的; X 1和X 2彼此相同或不同,是F或CF 3; TTD量为40-100摩尔%。
摘要:
Fluoroelastic copolymers, suitable for the manufacture of O-rings, comprising by weight:48-65% of VDF units21-36% of HFP units3-9% of PAVE units0-17% of TFE units
摘要:
Fluoroelastomers characterized by the presence of iodine or bromine atoms at the end of the polymeric chain in an amount equal to or lower than 1 iodine or bromine atom per polymeric chain, and by a bromine content in the chain ranging from 0.05 to 2% by weight referred to the total weight of the monomeric units.Said fluoroelastomers exhibit improved characteristics of processability, particularly as regards the utilization in injection molding processes and the detaching from the molds, as well as of stability to heat.A process for preparing fluoroelastomers containing iodine or bromine atoms at the ends of the polymeric chain, in an amount equal to or lower than 1 iodine or bromine atom per polymeric chain, which process comprises polymerizing mixes of fluorinated monomers (VDF, TFE, HFP, FVE) in bulk, in suspension, in aqueous emulsion, or in solution of organic solvents by means of radical starters, in the presence of compounds capable of providing I.sup.- or Br.sup.- ions in the polymerization medium and conditions.
摘要:
Compositions containing fluorinated thermoplastic elastomers with different moelcular weight and with different plastomeric phase/elastomeric phase ratio, essentially formed by: (a) 30-80% by weight, preferably 50-80%, of a fluorinated thermoplastic elastomer, having a block structure of A-B-A type, wherein A is a plastomeric segment and B is an elastomeric segment; (b) 10-50% by weight, preferably 20-40% of a fluorinated thermoplastic elastomer having a block structure of A-B-A type; (c) 0-30% by weight, preferably 0-15%, of a fluorinated plastomer preferably of the same kind as that contained in the component (a) and/or (b).
摘要:
New fluoroelastomers are described, comprising monomeric units deriving from a bis-olefin having general formula: ##STR1## wherein: R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, equal or different from each other, are H or alkyls C.sub.1 -C.sub.5 ; Z is an alkylene or cycloalkylene radical C.sub.1 -C.sub.18, linear or branched, optionally containing oxygen atoms, preferably at least partially fluorinated, or a (per)fluoropolyoxyalkylene radical.Such products are endowed with improved processability, especially during calendering of the vulcanization mixture, along with superior mechanical and workability properties during extrusion and injection molding, with a very good mold release.
摘要:
A polyvinylidenefluoride (PVDF) having high mechanical properties both at room temperature and at high temperatures, having very good processability and high thermochemical resistance to dehydrofluorination, is prepared by means of a polymerization process of vinylidenefluoride in aqueous emulsion at a temperature comprised between 95.degree. and 120.degree. C., in the presence of a chain transfer agent. In this way it is possible to obtain, using non-hazardous peroxidic initiators (for instance diterbutylperoxide), a PVDF particularly suitable for applications where high mechanical and thermochemical resistance properties are required, such as for instance the manufacture of articles for chemical industry (pipes, valves, fittings, tanks, heat exchangers, membranes, flanges, etc.).
摘要:
Fluoroelastomeric copolymers exhibiting high resistance to bases and alcohols, as well as high mechanical properties and low-temperature resistance, comprising, in moles:4-75% of units of vinylidene fluoride;12-40% of units of hexafluoropropene and/or perfluorovinylether and/or hydropentafluoropropene and/or chlorotrifluoroethylene;2-35% of units of an olefin containing up to 4 carbon atoms;2-60% of units of tetrafluoroethylene, provided that, when the sum of the olefin units and the perfluorovinylether units is equal to or greater than 70%, such copolymers possess a molecular weight sufficiently high to exhibit good mechanical characteristics.
摘要:
Use of perfluoropolyethers having perfluoroalkyl end groups with a molecular weight ranging from 500 to 1500, in amounts from 0.5 to 3 parts by weight per 100 parts by weight of elastomer and, optimally, in combination wit polytetrafluoroethylene having a molecular weight lower than about 200,000, as additives to the polymerization latex of rubbers vulcanizable by means of peroxides in order to improve the detachability of the vulcanizate from forming molds.