PARTIALLY-FLUORINATED POLYMERS

Abstract: A polymer whose repeating units include a side-chain and, between the atom or group to which the side-chain is bonded, a backbone chain, in which the chains are each at least four atoms long and are chemically incompatible, one chain being at least predominantly hydrocarbon and the other comprising a C4+ perfluorocarbon group.

Description: PARTIΆLLY-FLUORINΆTED POLYMERS This invention relates to partially-fluorinated polymers that have chemically-incompatible segments; the polymers have interesting and varied properties, including liquid crystallinity. An example of a molecule having two distinct parts that are mutually-immiscible is C 10 H 21 -C 10 F 21 , i.e. (perfluorodecyl)decane, as described by Twieg, Robolt J. Polym. Sci. Polym. Phys. Ed. 22:901(83) , and Mahler, Guillon and Skoulios, Mol. Cryst. Liq. Cryst. 2:111-119 (1985) . That compound was prepared by the reaction of perfluorodecyl iodide with 1-decene, followed by reduction; the a phiphilic product exhibited a smectic B liquid crystalline phase. Hόpken et a , "Integration of Fundamental Polymer Science Technology - 5", ed. Lemstra and Kleintjes, Elsevier Applied Sciences, describe amphiphilic allyl ethers and ethacrylates. Alcohols of the formula F(CF 2 ) n (CH 2 ) m OH, wherein n = 8, 10, 12 and m = 4 , 6, 10, were converted to allyl ethers, and sequentially perfluorinated methacrylates were then prepared. The polymers exhibit a mesomorphic "Schlieren" texture. Budovskaya et a!, Polymer Science USSR 3_2 (3) :502-506 (1990) , disclose comb-like polyfluoroalkyl ( eth) acrylates having side-chains of the formula=COOCH-(CF 2 ) n H, wherein n = 2, 4, 6, 8, 10, 12; the backbone comprises a single -CH 2 - group between the carbonate and the CH or CCH 3 group to which the side-chains are bonded. The polymers are mesomorphic in structure, with a degree of ordering directly related to n; for n = 10, the formation of a liquid crystal state "is proved by an optical method". EP-A-0352718 discloses partially-fluorinated polymers in which repeating units include a sequence of the formula -X 1 -CH 2 CH 2 -R f -CH 2 CH 2 -X 2 - wherein X 1 and X 2 are polymer-forming linkages (e.g. COO or OOC for polyesters, CONH or NHCO for polyamides) and R f is a C.. 40 perfluorinated divalent organic radical. Such S UBSTITUTESHEET polymers are prepared- from dinitriles or ester-nitriles. The polymers are apparently those sold under the registered Trade Mark "Zonyl" as fluoro-surfactants that offer thermal and chemical stability superior to that of hydrocarbon surfactants. The polymers are also suitable for use as non-stick coatings. Surprisingly, it has now been found that polymers having chemically-incompatible segments can be produced that clearly have liquid crystalline properties, as well as offering the properties associated with the polymers described above. The repeating units (of which there may be any number, preferably at least 3, e.g. 3 to 30) of the novel polymers include a side-chain and, between the atom or group to which the side-chain is bonded, a backbone chain: the chains are each at least 4 atoms long and are chemically-incompatible, one chain being at least predominantly hydrocarbon and other comprising a C 4+ perfluorocarbon group. Depending on which of the chains comprises the hydrocarbon and perfluorocarbon groups, representative formulae of repeating units of polymers according to the present invention are -X^ ^-Z (he) -hc 2 -X 2 -fc- -X 1 -hc 1 -Z (fc) -hc 2 -X -hc- wherein X 1 and X 2 are as defined above; Z is the atom or group to which the side-chain is bonded; fc is the perfluorocarbon; and he, he 1 and he 2 are each hydrocarbon (he may also be replaced by a perfluorocarbon group fc 1 that is the same or different from fc) . The atom or group to which the side-chain is bonded, i.e. Z in the formulae given above, may be -CH(-)- or -CH(CH 2 -)-, but is preferably -N(S0 2 -)-; the bracketed hyphen indicates attachment of the side-chain. The preference for -N(S0 2 -)- reflects a preferred process for introducing the side-chain into one of the monomers from which a polymer may be prepared. Thus, for example, the compound fcS0 2 F is reacted with a compound of the formula Y^hc^ZQ-hc^y 1 S UBS TI TUTE SHEET wherein Q is a reactive group and Y 1 is a group reactive with another group Y 2 to form X 1 or X 2 in the ultimate polymer. Y 1 is a substituent such as I or OH, or within he 1 or he 2 , e.g. a C=C bond. In this case, when the side-chain comprises the perfluorocarbon group, the relevant monomer can be synthesised without forming a carbon-carbon bond and without the expense of obtaining or synthesising the appropriate perfluoroalkyl iodide (fcl) . Although the monomers and polymers to which this invention relates may be prepared by procedures that will be readily apparent to those skilled in the art, polyesters of the invention may be prepared by the Stupp method of ester formation, following Moore et al, Macromolecules 2.3:55-70 (1990) . This procedure, and the invention as a whole, are illustrated in the following Examples. The reaction scheme is shown in the Chart headed "Fluorinated Side-chain Polyesters". Examples 1 to 10 In each case, the compound shown in the Chart as "F 8 " and "Cl" in the following table of properties was reacted with a different hydrocarbon dicarboxylic acid, to obtain the polymer enumerated as 2-11 in the tabulated data. More specifically, in each case, 0.587g of "F 8 " was stirred with a stoichiometric amount of the dried diacid in approx. 50 ml dry CH-.C1-. (all reagents were dried), and 0.19 g PTSA and 0.122 g DMAP were added together. Then 0.8-1.2 ml diisopropylcarbodiimide was added to the stirred solution under a positive stream of N 2 . PTSA = paratoluenesulphonic acid DMAP = 4-dimethylaminopyridine After a few hours, a white precipitate formed. After 1 day, the product was precipitated by pouring the solution into a larger volume of ethanol (approx. 150-200 ml) , and the polymer was collected by filtration. The product was washed several times with methanol to remove PTSA/DMAP. IR spectra show ester, -C-F and -C-H. Main peaks at approx. 1730, 1100-1250 and 2800-3000. H NMR shows SUBSTITUTE SHEET N-CH 2 CH 2 -0 at: one multiplet 4.30(2) , 2 multiplets 3.85(1), 3.65(1) and aliphatic diester between 2.8 and 1.2 (aromatic at approx. 8.0 and 7.5) . Yield: usually between 80-88% white solid. See table for details. All the polymers exhibited liquid crystalline properties. SUBSTITUTE SHEET SUBSTITUTE SHEET SUBSTITUTE SHEET SUBSTITUTE SHEET FLUORINATED SIDE-CHAIN POLYESTERS REACTIONS; + ■ H ..O«O■C POLYMER '= F(CF2) 8 SO 2 N(EtOH) 2 C = (CH 2 ) or Ar. EXAMPLES C y = ( S/ ' - 0 2 C -ΛΛΛ C Jl. HOOC, "COOH HOOC, ,COOH HOOC, "COOH HOOC, .COOH HOOC, ALL SHOW L.C. PHASE. "COOH HOOC-(CH 2 ) 2Q -COOH and -OC- (CH 2 ) 20 _COO- (CH., ) 5 - 0 OC- (CH 2 ) 2fJ -CO- SUBSTITUTE SHEET

Claims: CLAIMS 1. A polymer whose repeating units include a side-chain and, between the atom or group to which the side-chain is bonded, a backbone chain, in which the chains are each at least four atoms long and are chemically incompatible, one chain being at least predominantly hydrocarbon and the other comprising a C 4+ perfluorocarbon group. 2. A polymer according to claim 1, wherein the repeating units have the formula -X l -hc 1 -Z(hc)-hc 2 -X 2 -fc- wherein X 1 and X 2 are absent or are polymer-forming linkages (e.g. COO or OOC for polyesters, CONH or NHCO for polyamides) ; Z is the atom or group to which the side-chain is bonded; fc is the perfluorocarbon; and he, he 1 and he 2 are each hydrocarbon. 3. A polymer according to claim 1, wherein the side-chain is the perfluorocarbon group. 4. A polymer according to claim 3, wherein the repeating units have the formula -X 1 -hc 1 -Z(fc)-hc -X 2 -hc- wherein X 1 , X 2 ,- Z, fc, he, he 1 and he 2 are as defined in claim 2, or in which he is replaced by another perfluorocarbon fc 1 . 5. A polymer according to claim 2 or claim 4, wherein he 1 and he 2 are each -(CH 2 ) ._-.-. 6. A polymer according to any preceding claim, wherein said atom or group is -N-(S0 2 -)-, -CH(-)- or -CH(CH--)-, the bracketed hyphen • indicating attachment of the side-chain. 7. A polymer according to any preceding claim, which is a polyester. 8. A polymer according to any preceding claim, wherein the perfluorocarbon group has 6 to 20 C atoms. 9. A polymer according to any preceding claim, wherein either chain includes a hydrocarbon unit of 6 to 20 C atoms. 10. A polymer according to any preceding claim, which has liquid crystalline properties. SUBSTITUTE SHEET 11. A substrate coated with a polymer according to any preceding claim. 12. A process for preparing a polymer according to any of claims 1 to 10, which comprises reacting together corresponding compounds of the formulae y 1 -hc 1 -Z(fc)-hc 2 -Y 1 and Y 2 -hc-Y 2 or Y 2 -fc 1 -Y 2 or Y 1 -hc l -Z(hc)-hc 2 -Y 1 and Y 2 -fc-Y 2 wherein Y 1 and Y 2 are mutually-reactive functional groups, on or within the he to which they are shown attached, that together form X 1 and X 2 . SUBSTITUTE SHEET

Inventors: GRIFFIN ANSELM CLYDE, WILSON LADISLAV MARIO, GRIFFIN, ANSELM, CLYDE, WILSON, LADISLAV, MARIO
Applicants: GRIFFIN ANSELM CLYDE, MINNESOTA MINING & MFG, WILSON LADISLAV MARIO, MINNESOTA MINING AND MANUFACTURING COMPANY
Application year: 1993
Main classification: C08G63
IPC codes: C08G63, C08G64, C08G69