Polymer-derived ceramic fibers and methods of preparing the same

Patent metadata

Field	Value
Publication number	US-2022340494-A1
Application number	US-202017642326-A
Country	US
Kind code	A1
Filing date	Sep 10, 2020
Priority date	Sep 13, 2019
Publication date	Oct 27, 2022
Grant date	—

Abstract

Ceramic matrix composite (CMC) materials are a desired solution for lightweight and high temperature applications. CMC materials can be reinforced with polymer-derived ceramic (PDC) fibers, which advantageously possess intrinsic thermal stability and high mechanical strength. Carbon-rich SiOC and SiOCN fibers were synthesized via hand-drawing and electrospinning polymer pyrolysis of a hybrid precursor materials with the aid of a spinning reagent. The prepared fibers are crosslinked and pyrolyzed for polymer-to-ceramic conversion.

First claim

1 . A method of producing ceramic fiber materials comprising:
forming a reaction mixture comprising a liquid preceramic composition and a spinning reagent; spinning preceramic polymer fibers from the reaction mixture; crosslinking the preceramic polymer fibers to form crosslinked preceramic polymer fibers; and pyrolyzing the crosslinked preceramic polymer fibers to form the ceramic fiber materials.

2 . The method of claim 1 , wherein the liquid preceramic composition comprises a siloxane and/or a silazane, and wherein said spinning reagent comprises polyacrylic acid, polyvinylpyrrolidone, and/or polyacrylonitrile.

3 . The method of claim 2 , wherein the liquid preceramic composition comprises one or more materials selected from the group consisting of 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane, Pt-1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetra-siloxane complex, 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane, 1,3-divinyltetramethyl-disiloxane, and 1,3,5,7-tetramethyl-1,3,5,7-tetravinyl-cyclotetrasilazane.

4 . The method of claim 1 , wherein the spinning reagent comprises an organic polymer solution and is prepared by mixing the organic polymer with a solvent in a weight ratio of from about 0.1:1 to about 10:1 to form a gel.

5 . The method of claim 4 , wherein the solvent comprises water and/or an alcohol.

6 . The method of claim 1 , wherein the liquid preceramic composition comprises from about 2% to about 25% by weight of a crosslinking agent.

7 . The method of claim 5 , wherein the crosslinking agent is dicumyl peroxide.

8 . The method of claim 1 , wherein the reaction mixtures comprises a weight ratio of the spinning reagent to the liquid preceramic composition of from about 1:5 to about 5:1.

9 . The method of claim 1 , wherein the spinning step comprises a wet spinning, a melt spinning, a gel spinning, or an electrospinning process.

10 . The method of claim 1 , wherein the crosslinking step comprises heating the preceramic polymer fibers to a temperature of from about 100° C. to about 200° C., for about 1 hour to about 48 hours.

11 . The method of claim 1 , wherein the pyrolyzing step comprises heating the crosslinked preceramic polymer fibers to a temperature of at least 400° C.

12 . A method of producing silicon oxycarbide fibers comprising:
forming a reaction mixture comprising a liquid preceramic composition and a spinning reagent, the liquid preceramic composition comprising a siloxane and/or a silazane, the spinning reagent comprising polyacrylic acid, polyvinylpyrrolidone, and/or polyacrylonitrile; spinning preceramic polymer fibers from the reaction mixture using a wet spinning, a melt spinning, a gel spinning, or an electrospinning process; heating the preceramic polymer fibers to form crosslinked preceramic polymer fibers; and pyrolyzing the crosslinked preceramic polymer fibers to form the silicon oxycarbide fibers.

13 . The method of claim 12 , wherein the siloxane and/or silazane is selected from the group consisting of 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetra-siloxane, Pt-1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetra-siloxane complex, 1,3,5-trivinyl-1,3,5-trimethylcyclotrisiloxane, 1,3-divinyltetramethyl-disiloxane, and 1,3,5,7-tetramethyl-1,3,5,7-tetravinyl-cyclotetrasilazane.

14 . The method of claim 12 , wherein the step of heating the preceramic polymer fibers comprises heating the preceramic polymer fibers to a temperature of from about 100° C. to about 200° C., for about 1 hour to about 48 hours.

15 . The method of claim 12 , wherein the step of pyrolyzing the crosslinked preceramic polymer fibers comprises heating the crosslinked preceramic polymer fibers to a temperature of at least 600° C. under an inert atmosphere.

16 . A ceramic fiber material comprising:
from about 1% to about 90% by weight silicon; from about 1% to about 90% by weight oxygen; and from about 1% to about 90% by weight carbon, wherein at least a portion of the carbon is present as free carbon, wherein the ceramic fiber material comprises a plurality of ceramic fibers having a average diameter of from about 0.1 to about 50 μm.

17 . The ceramic fiber material of claim 16 , wherein the ceramic fibers comprise from about 0.05 to about 2% by weight nitrogen.

18 . The ceramic fiber material of claim 16 , wherein the ceramic fibers are substantially uniform in diameter and have a porous outer surface.

19 . The ceramic fiber of claim 16 , wherein the ceramic fibers exhibit thermal stability at a temperature of at least 1000° C.

Assignees

• Univ Kansas State

Inventors

• Singh Gurpreet
• Ren Zhongkan

Classifications

• C04B2235/48

  Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins · CPC title

• D01F11/08

  of macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• C04B2235/5264

  characterised by the diameter of the fibers · CPC title

• D01F6/16

  from polymers of unsaturated carboxylic acids or unsaturated organic esters, e.g. polyacrylic esters, polyvinyl acetate · CPC title

• C04B35/64

  Burning or sintering processes (C04B33/32 takes precedence {; powder metallurgy B22F}) · CPC title