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CN-122003460-A - Thermoplastic prepreg, corresponding green body, carbon-carbon composite article and carbon fiber

CN122003460ACN 122003460 ACN122003460 ACN 122003460ACN-122003460-A

Abstract

Thermoplastic prepregs comprising an organic polymer matrix and a carbon fiber substrate are described herein. The polymer matrix comprises a polyphenylene polymer as described in detail below. Thermoplastic prepregs are particularly suitable for carbon-carbon composites ("C/C composites"). In particular, the polyphenylene polymers described herein provide improved C/C composites both structurally and based on processing efficiency due, at least in part, to the significantly improved char yield and conversion of graphitic carbon into the transverse order during pyrolysis. Also described herein are methods for making thermoplastic prepregs and green bodies and C/C composites made therefrom.

Inventors

  • N. Tritter
  • J. Polino
  • S. Heinz
  • M. JACKSON
  • J. Moscow Witz

Assignees

  • 塞特工业公司

Dates

Publication Date
20260508
Application Date
20241008
Priority Date
20240126

Claims (17)

  1. 1. A thermoplastic prepreg, comprising: -a polymer matrix comprising a polyphenylene polymer, and -A carbon fiber substrate impregnated with the polyphenylene polymer; Wherein the method comprises the steps of The polyphenylene polymer comprises repeating units (R PP1 ) and (R PP2 ) each represented by the formula (1) And (2); - Wherein each of R 1 to R 8 is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl, aryl, alkoxy or aryloxy, alkylthio or arylthio, ketone, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkylsulfonate, alkali or alkaline earth metal phosphonate, alkylphosphonate, amine, and quaternary ammonium; - R 1 At least one of R 4 is represented by the formula A-T-, wherein - T is selected from the group ：CH 2 -;-O-;-SO 2 -;-S-;-C(O)-;C(CH 3 ) 2 -;-C(CF 3 ) 2 -;-C(=CCl 2 )-;-C(CH 3 )(CH 2 CH 2 COOH)-;-N=N-;-R a C=CR b -, consisting of R a and R b are each independently selected from the group consisting of hydrogen, C 1 -C 12 -alkyl, C 1 -C 12 -alkoxy or C 6 -C 18 -aryl groups, and a straight or branched aliphatic divalent group of 1to 6 carbon atoms, and- (CF 2 ) n ) -wherein n is an integer of 1to 6, and - A is represented by a formula selected from the group of formulas: (3)、 (4)、 - (5) And - (6), - Wherein each of R 9 to R 17 is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl, aryl, ether, thioether, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkyl sulfonate, alkali or alkaline earth metal phosphonate, alkyl phosphonate, amine, and quaternary amine, and - The concentration of the repeating unit (R PP2 ) is at least 15.0 mol% ("relative (R PP2 ) concentration") relative to the total moles of repeating units (R PP1 ) and (R PP2 ).
  2. 2. The prepreg according to claim 1, wherein a is represented by formula (3), or T is-C (O) -.
  3. 3. A prepreg according to claim 1 or claim 2 wherein the repeating unit (R PP1 ) is represented by the formula: (7), Wherein R 1 、R 3 、R 4 、R 9 to R 13 are as defined in claim 1 or 2.
  4. 4. A prepreg according to any one of claims 1 to 3 wherein R 1 、R 3 、R 4 、R 9 to R 13 and, if present, R 14 to R 17 are all hydrogen.
  5. 5. The prepreg of any one of claims 1-4 wherein R 5 to R 8 are all hydrogen.
  6. 6. The prepreg of any one of claims 1-5, wherein the relative (R PP2 ) concentration is at least 50.0 mol%.
  7. 7. The prepreg of any one of claims 1-6, wherein the relative (R PP2 ) concentration is not more than 95.0 mol% or not more than 90.0 mol%.
  8. 8. The prepreg of any one of claims 1-7, wherein the volume fraction of the polyphenylene polymer in the prepreg is at least 15.0% and not more than 70.0%.
  9. 9. The prepreg of any one of claims 1-8, wherein the carbon fibers of the carbon fiber substrate have an average length of at least 10cm.
  10. 10. The prepreg of any one of claims 1-8, wherein the carbon fiber substrate is a woven fabric.
  11. 11. The prepreg of any one of claims 1-8, wherein the carbon fiber substrate is a tape having a width of 0.3 cm to 185 cm.
  12. 12. A method of making the prepreg of any one of claims 1 to 10, the method comprising impregnating the carbon fiber substrate with the polyphenylene resin, wherein the impregnating is selected from the group consisting of resin film infusion, slurry impregnation, melt impregnation, solution impregnation, and combinations of any two or more thereof.
  13. 13. A green body comprising a laminate consolidated by the thermoplastic prepreg of any one of claims 1 to 11.
  14. 14. A method of making the green body of claim 13, the method comprising forming a laminate by consolidating the prepreg.
  15. 15. A method according to claim 14 comprising the steps of laying up two or more prepregs according to any one of claims 1 to 11 such that each prepreg is in contact with one or two other prepregs and consolidating the laid thermoplastic prepregs by heating, optionally at a pressure above atmospheric pressure.
  16. 16. A method of making a carbon-carbon composite ("C/C composite") article, the method comprising pyrolyzing the green body of claim 13, wherein the pyrolyzing comprises heating the green body at a temperature of at least 1000 ℃ for at least 10 h.
  17. 17. A method for preparing carbon fibers, the method comprising: -melt spinning a polyphenylene polymer to form filaments comprising a first average circular cross-section; -stretching the filaments to form stretched filaments having a second average circular cross-section, wherein the second average circular cross-section is smaller than the first average circular cross-section; stabilizing the drawn filaments to form stabilized filaments, and -Pyrolyzing the stabilized filaments to form the carbon fibers; Wherein the method comprises the steps of The polyphenylene polymer comprises repeating units (R PP1 ) and (R PP2 ) each represented by the formula (1) And (2); - Wherein each of R 1 to R 8 is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl, aryl, alkoxy or aryloxy, alkylthio or arylthio, ketone, carboxylic acid, ester, amide, imide, alkali or alkaline earth metal sulfonate, alkylsulfonate, alkali or alkaline earth metal phosphonate, alkylphosphonate, amine, and quaternary ammonium; - R 1 At least one of R 4 is represented by the formula A-T-, wherein - T is selected from the group ：CH 2 -;-O-;-SO 2 -;-S-;-C(O)-;C(CH 3 ) 2 -;-C(CF 3 ) 2 -;-C(=CCl 2 )-;-C(CH 3 )(CH 2 CH 2 COOH)-;-N=N-;-R a C=CR b -, consisting of R a and R b are each independently selected from the group consisting of hydrogen, C 1 -C 12 -alkyl, C 1 -C 12 -alkoxy or C 6 -C 18 -aryl groups, and a straight or branched aliphatic divalent group of 1to 6 carbon atoms, and- (CF 2 ) n ) -wherein n is an integer of 1to 6, and - A is represented by a formula selected from the group of formulas: (3)、 (4)、 - (5) And - (6), - Wherein each of R 9 to R 17 is independently selected from the group consisting of hydrogen, halogen, alkyl, alkenyl, alkynyl, aryl, alkoxy or aryloxy, alkylthio or arylthio, carboxylic acid, ester, amide, imide, alkali metal or alkaline earth metal sulfonate, alkylsulfonate, alkali metal or alkaline earth metal phosphonate, alkylphosphonate, amine and quaternary ammonium, and - The concentration of the repeating unit (R PP2 ) is at least 15.0 mol% ("relative (R PP2 ) concentration") relative to the total moles of repeating units (R PP1 ) and (R PP2 ).

Description

Thermoplastic prepreg, corresponding green body, carbon-carbon composite article and carbon fiber Citation of related application The application claims priority from U.S. provisional application number 63/589542 filed on day 10 and 11 of 2023 and european patent application number 24154273.7 filed on day 1 and 26 of 2024, the entire contents of each of these applications are incorporated herein by reference for all purposes. Technical Field The present invention relates to a prepreg comprising a thermoplastic polymer matrix comprising a polyphenylene polymer. The prepreg has improved char yield and graphitic carbon conversion. The invention further relates to a method for preparing the prepreg and to a method for preparing green bodies and carbon-carbon composites therefrom. The invention also relates to carbon fibers prepared from the polyphenylene polymer. Background Carbon-carbon composites are a unique class of materials capable of retaining strength at temperatures greater than 1000 ℃. Carbon-carbon composites are typically composed of a carbon fiber substrate embedded in a graphite matrix and exhibit low density, high modulus, and high thermal stability. There are several proven methods of manufacturing carbon-carbon materials, but the general process involves initial impregnation of an organic matrix into the carbon fibers followed by multiple pyrolysis and re-infiltration cycles until a sufficient density is reached. The mass retention of the organic matrix resins of the current state of the art is about 50% and therefore requires six or more re-permeation/pyrolysis cycles, where each cycle may take about one month. Disclosure of Invention In one aspect, the present invention relates to a thermoplastic prepreg comprising a polymer matrix comprising a polyphenylene polymer and a carbon fiber substrate impregnated with the polyphenylene polymer. The polyphenylene polymer comprises recurring units (R PP1) and (R PP2) represented by formulae (1) and (2), respectively, as detailed below, wherein the concentration of recurring units (R PP2) is at least 15 mol% ("relative (R PP2) concentration") relative to the total number of moles of recurring units (R PP1) and (R PP2). In some embodiments, a is represented by formula (3), or T is-C (O) -. In some embodiments, the repeating unit (R PP1) is represented by the formula: (7)。 In some embodiments, R 1、R3、R4、R9 to R 13, and R 14 to R 17, if present, are all hydrogen. In some embodiments, R 5 to R 8 are all hydrogen. In some embodiments, the relative (R PP2) concentration is at least 50 mol%. In some embodiments, the relative (R PP2) concentration is no more than 95% or no more than 90%. In some embodiments, the carbon fibers of the carbon fiber substrate have an average length of at least 10 cm. In some embodiments, the carbon fiber substrate is a woven fabric. In some alternative embodiments, the carbon fiber substrate is a tape having a width of at least 0.3 cm to 185.0 cm. In another aspect, the present invention relates to a method of making a prepreg comprising impregnating a carbon fiber substrate with a polyphenylene resin, wherein the impregnation is selected from the group consisting of resin film infusion, slurry impregnation, melt impregnation, solution impregnation, and combinations of any two or more thereof. In a further aspect, the invention relates to a green body comprising a laminate consolidated by a thermoplastic prepreg. In a further aspect, the invention relates to a method for preparing a green body, the method comprising forming a laminate by consolidating a prepreg. In another aspect, the invention relates to a method of making a carbon-carbon composite ("C/C composite") article, the method comprising pyrolyzing a green body, wherein the pyrolyzing comprises heating the green body at a temperature of at least 1000 ℃ for at least 10 h. In yet another aspect, the present invention is directed to a method for making carbon fibers comprising melt spinning a polyphenylene polymer to form filaments comprising a first average circular cross-section, drawing the filaments to form drawn filaments having a second average circular cross-section, wherein the second average circular cross-section is less than the first average circular cross-section, stabilizing the drawn filaments to form stabilized filaments, and pyrolyzing the stabilized filaments to form carbon fibers, wherein the polyphenylene polymer comprises recurring units (R PP1) and (R PP2) represented by formulas (1) and (2), respectively, detailed below, and the concentration of recurring units (R PP2) is at least 15 mol% relative to the total moles of recurring units (R PP1) and (R PP2). Detailed Description Thermoplastic prepregs comprising an organic polymer matrix and a carbon fiber substrate are described herein. The polymer matrix comprises a polyphenylene polymer as described in detail below. Thermoplastic prepregs are particularly suitable for carbon-carbon composites ("C/C co