Method of making mixture of polymers

A method for the synthesis of a mixture of polymers comprising a partially fluorinated polyether backbone having two chain ends, each of said chain ends being linked to an opposite side of said backbone, wherein each of the first chain end and the second chain end is independently selected from the group consisting of —CRH1RH2—OC(═O)F, —C(═O)F, and —CRH1RH2F, with RH1 and RH2, equal to or different from each other, are each independently H or a C1-C6 hydrocarbon group;

• said process comprising:
• Step (I):
• a step of contacting:
• at least one perfluoro compound comprising at least two acyl-fluoride groups;
• and
• at least one hydrogenated compound comprising at least two fluoroformate groups of formula —CRH1RH2—O—C(O)F,
• in the presence of at least one fluoride-containing compound,
• to provide a mixtures of polymers comprising a partially fluorinated polyether backbone having two chain ends,
• wherein said backbone comprises recurring unit(s) derived from said at least one compound (F) alternately arranged with recurring unit(s) derived from said at least one compound (H), and
• wherein each of said chain ends, equal to or different from each other, is selected from the group consisting of a group —CRH1RH2—OC(═O)F and a group —C(═O)F;
• Step (II):
• a step of heating said polymer (FHFOR) obtained in step (I) above at a temperature exceeding 120° C., preferably in the range from 130° C. to 210° C., for a duration of at least 4 hours and in the presence of a fluoride-containing compound, optionally in the presence of a fluoride-containing compound comprising at least one of (i) a metal fluoride of formula MeFy, with Me being a metal having y valence, y being 1 or 2;
• and (ii) an (alkyl)ammonium fluoride of formula NRHN4F, with each of RHN , equal to or different from each other being, independently, a H or an alkyl group, in particular tetrabutylammonium fluoride,
• wherein the heating tconverts at least a fraction of the chain ends of polymer (FHFOR) of formula —CRH1RH2—OC(═O)F to groups —CRH1RH2—F,
• to provide the polymer mixture (FHCH2F).

A polymer mixture (FHCH2F) comprising (preferably essentially consisting of) variable amounts of any of compounds of formula:

• (a) F—CRH1RH2—EH—CRH1RH2—O—[CF2—Rf—CF2O—CRH1RH2—EH—CRH1RH2—O]n*—CF2—Rf—CF2O—CRH1RH2—EH—CRH1RH2—F [formula (FHCH2F-CH2F)];
• (b) F—CRH1RH2—EH—CRH1RH2—O—[CF2—Rf—CF2O—CRH1RH2—EH—CRH1RH2—O]n**—CF2—Rf—C(O)—F [formula (FHCOF-CH2F)];
• (c) F—C(O)—OCRH1RH2—EH—CRH1RH2—O—[CF2—Rf—CF2O—CRH1RH2—EH—CRH1RH2—O]n′—C(O)—F [formula (FHFOR-FOR)];
• (d) F—CRH1RH2—EH—CRH1RH2—O—[CF2—Rf—CF2—CRH1RH2—EH—CRH1RH2—O]n′—C(O)—F [formula (FHCH2F-FOR)];
• (e) F—C(O)—OCRH1RH2—EH—CRH1RH2—O—[CF2—Rf—CF2O—CRH1RH2—EH—CRH1RH2—O]n″—CF2—Rf—C(O)—F [formula (FHCOF-FOR)]
• (f) F—C(O)Rf—CF2OCRH1RH2—EH—CRH1RH2—O—[CF2—Rf—CF2O—CRH1RH2—EH—CRH1RH2—O]n′″—CF2—Rf—C(O)—F [formula (FHCOF-COF)]
• wherein:
• n*, n**, n′, n″, and n′″ are integers such that the molecular weight as measured by NMR analysis of the polymer mixture (FHCH2F) is from 210 to 50,000;
• Rf has the same meanings defined above for compound (F);
• EH is selected from a bond, a —O— group and a divalent linear or branched (oxy)alkylene group, wherein said (oxy)alkylene group comprises from 1 to 8 carbon atoms and is optionally interrupted by one or more than one ethereal oxygen atom;
• each of RH1 and RH2, equal to or different from each other at each occurrence, is independently H or a C1-C6 hydrocarbon group;
• and
• wherein in polymer mixture (FHCH2F):
• the concentration of compound of formula (FHCH2F-CH2F), is higher than the concentration of compound of formula (FHFOR-FOR);
• and/or
• the concentration of compound of formula (FHCOF-CH2F), is higher than the concentration of compound of formula (FHCOF-FOR).

A polymer mixture (FFCF3) comprising variable amounts of any of compounds of formula:

• (a″) F—CRF1RF2—EF—CRF1RF2—O—[CF2—Rf—CF2O—CRF1RF2—EF—CRF1RF2—O]n*—CF2—Rf—CF2O—CRF1RF2—EF—CRF1RF2—F [formula (FFCF3-CF3)];
• (b″) F—CRF1RF2—EF—CRF1RF2—O—[CF2—Rf—CF2O—CRF1RF2—EF—CRF1RF2—O]n**—CF2—Rf—C(O)—F [formula (FFCOF-CF3)];
• (c″) F—C(O)—OCRF1RF2—EF—CRF1RF2—O—[CF2—Rf—CF2O—CRF1RF2—EF—CRF1RF2—O]n′—C(O)—F [formula (FFFOR-FOR)];
• (d″) F—CRF1RF2—EF—CRF1RF2—O—[CF2—Rf—CF2O—CRF1RF2—EF—CRF1RF2—O]n′—C(O)—F [formula (FFCF3-FOR)];
• (e″) F—C(O)—OCRF1RF2—EF—CRF1RF2—O—[CF2—Rf—CF2O—CRF1RF2—EF—CRF1RF2—O]n″—CF2—Rf—C(O)—F [formula (FFCOF-FOR)]
• (f″) F—C(O)Rf—CF2—O—CRF1RF2—EF—CRF1RF2—O—[CF2—Rf—CF2O—CRF1RF2—EF—CRF1RF2—O]n′″—CF2—Rf—C(O)—F [formula (FFCOF-COF)];
• and optionally further comprising one or more of the following compounds:
• (b″decarb) F—CRF1RF2—EF—CRF1RF2—O—[CF2—Rf—CF2O—CRF1RF2—EF—CRF1RF2—O]n**—CF2—Rf—F [formula (FFF-CF3)];
• (e″decarb) F—C(O)—OCRF1RF2—EF—CRF1RF2—O—[CF2—Rf—CF2O—CRF1RF2—EF—CRF1RF2—O]n″—CF2—Rf—F [formula (FFF-FOR)]
• (f″decarb) F—Rf—CF2—O—CRF1RF2—EF—CRF1RF2—O—[CF2—Rf—CF2O—CRF1RF2—EF—CRF1RF2—O]n′″—CF2—Rf—F [formula (FFF-F)],
• wherein:
• n*, n**, n′, n″, and n′″ are integers such that the molecular weight as measured by NMR analysis of the polymer mixture (FFCF3) is of from 210 to 50,000, —Rf is a divalent, perfluoro linear or branched (oxy)alkylene chain, wherein said alkylene chain comprises from 1 to 10 carbon atoms and is optionally interrupted by one or more oxygen atoms;
• EF is selected from a bond, a —O— group and a divalent linear or branched perfluoro(oxy)alkylene group, wherein said perfluoro(oxy)alkylene group comprises from 1 to 8 carbon atoms and is optionally interrupted by one or more than one ethereal oxygen atom, and
• each of RF1 and RF2, equal to or different from each other, is independently F or a C1-C6 fluorocarbon group;
• and
• wherein in polymer mixture (FFCF3):
• the concentration of compound of formula (FFCF3-CF3) is higher than the concentration of compound of formula (FFFOR-FOR);
• and/or
• the concentration of compound of formula (FFCOF-CF3) is higher than the concentration of compound of formula (FFCOF-FOR).