High performance fibers coated with catechol-containing materials

Abstract

The present disclosure relates to high performance fibers (HPFs), fiber reinforced composites, plastics, and other materials. The present disclosure also relates to HPF fibers coated with a material comprising a catechol polymer, more particularly polycatechol styrene (PCS). The present disclosure also relates to methods of functionalizing HPF fiber surfaces using a PCS-type coating. In some embodiments, the fibers are polymeric materials, such as aramid, liquid crystal polymer (LCP), and ultra high molecular weight polyethylene (UHMWPE). In one embodiment, the HPF is a carbon fiber.

Description

[0001] Cross - reference to related patent applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 403,237, filed on September 1, 2022, the entire content of which is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to high - performance fibers (HPFs), fiber - reinforced composites, plastics, and other materials. The present disclosure also relates to HPF fibers coated with a material comprising a catechol polymer, more specifically polycatechol styrene (PCS). The present disclosure also relates to methods of functionalizing the surface of HPF fibers with a PCS - type coating. In some embodiments, the fibers are polymeric materials such as aramids, liquid crystal polymers (LCPs), and ultra - high - molecular - weight polyethylene (UHMWPE). In one embodiment, the HPF is a carbon fiber. Background Art

[0004] High - performance fibers (HPFs) such as high - performance polymer fibers (HPP fibers) are a very important reinforcing fiber for thermosetting materials, thermoplastic materials, and other composite materials. Although, due to their high specific modulus, specific strength, and corrosion resistance, HPP fiber - reinforced plastics (FRPs) can be excellent materials for many applications across a range of industries, the interfacial adhesion between the fiber and the matrix can be weak due to the inert polymer structure on the surface of the HPP fibers, and many HPP - FRPs tend to exhibit failure at the fiber - matrix interface. This phenomenon can greatly affect the overall mechanical properties of the composite, such as flexural properties, interlaminar shear strength (ILSS), etc. Good interfacial adhesion can effectively transfer stress from the matrix to the reinforcing material, which promotes stress dispersion and increases the mechanical strength of the composite.

[0005] Similarly, HPFs such as carbon fibers (CFs) are a very important reinforcing fiber for thermosetting materials, thermoplastic materials, and other composite materials (CFRPs). Due to their high specific modulus, specific strength, and corrosion resistance, CFRPs are excellent materials for many applications across a range of industries. However, due to the inert graphite structure on the surface of the CFs, the interfacial adhesion between the fiber and the matrix tends to be weak, and most CFRPs also tend to exhibit failure at the fiber - matrix interface. This phenomenon can greatly affect the overall mechanical properties of the composite, such as flexural properties, interlaminar shear strength (ILSS), etc. Similar to HPPs, in CFs, good interfacial adhesion can also effectively transfer stress from the matrix to the reinforcing material, which promotes stress dispersion and increases the mechanical strength of the composite.

[0006] In recent years, many methods have been proposed to improve the interfacial adhesion of fiber materials to composite matrices, such as chemical grafting, sizing, carbon black, electrophoretic deposition, and the introduction of nanoparticles. However, many of these processes are highly toxic, consume large amounts of energy, and are carried out under harsh conditions that can damage the fibers themselves. This has limited the development of these processes for industrial applications. Developing an effective, safe, and environmentally friendly process for improving the interfacial properties of HPFs (such as HPP fibers) used in the development of high-performance HPP-FRPs and CFs used in the development of high-performance CFRPs would be very useful.

[0007] One method for improving the interfacial shear strength of fibers to matrix materials is by changing the surface "roughness" and thus the surface energy of the fibers. For example, for carbon fibers, it is by depositing or coating carbon-containing materials such as carbon nanotubes, carbon nanofibers, graphene, and carbon black. This method does not chemically functionalize the surface of the CFs but changes the surface "roughness" and thus the surface energy of the fibers. These carbon-containing materials are deposited by several methods that can be expensive, hazardous, or both. These methods include chemical vapor deposition, spraying, and dip coating. Summary of the Invention

[0008] On the other hand, the present disclosure provides a polycatechol styrenyl coating on HPFs (such as HPP fibers) and CFs, making it an effective adhesion promoter and thus allowing it to be incorporated into various composite materials. This coating is effective not only on a small scale in a laboratory environment but also for large-scale industrial and commercial applications.

[0009] In one embodiment, the present disclosure relates to a coated high-performance fiber (HPF) coated with a catechol-containing material, the catechol-containing material comprising a polymer containing catechol, semiquinone, or quinone.

[0010] In another embodiment, the present disclosure relates to the coated HPF as described above, wherein the catechol-containing material coated on the HPF comprises monomeric, oligomeric, or polymeric catechol or catechol-containing material, wherein the catechol is present as catechol and / or as semiquinone and / or as quinone, but no amine is present; and wherein the polymer layer optionally comprises at least one of the following: a) a reactive substance separated from the catechol or catechol-containing material; and b) a catalyst, cocatalyst, or accelerator.

[0011] In yet another embodiment, the present disclosure relates to the coated HPF as described above, wherein the polymeric material comprises a reactive substance separated from the catechol-containing polymer or oligomer; and the reactive substance is a polyurethane component, an epoxy resin, an acrylate monomer or oligomer, a methacrylate monomer or oligomer, a silane, or a combination thereof.

[0012] In one embodiment, the present disclosure relates to the coated HPF as described above, wherein the reactive substance is:

[0013] (i) a polyurethane component;

[0014] (ii) a polyurethane component, which is a polyol or an organic compound containing multiple hydroxyl groups, and wherein the polyurethane is linear or branched;

[0015] (iii) a polyurethane component, which is 1,6 - hexanediol, glycerol, Stepanpol PDC - 279 ® or polycaprolactone triol;

[0016] (iv) an epoxy resin;

[0017] (v) an epoxy resin, which is an epoxy monomer, an epoxy oligomer, a polyepoxide or a combination thereof; and wherein the epoxy resin is linear or branched;

[0018] (vi) an epoxy resin, which is bisphenol A diglycidyl ether, bisphenol A epoxy resin, bis(4 - glycidyloxyphenyl)methane, bisphenol E diglycidyl ether (DGEBE), 2,2’ - [l,l - ethylenebis(4,1 - phenyleneoxymethylene)] bisoxirane, bisphenol F diglycidyl ether (DGEBF), poly(bisphenol A - co - epichlorohydrin) or a combination thereof;

[0019] (vii) an acrylate monomer or oligomer;

[0020] (viii) an acrylate monomer or oligomer, which is an acrylate monomer containing at least one of a carboxylate and a carbonitrile and a vinyl group; and wherein the acrylate is linear or branched; or

[0021] (ix) an acrylate monomer or oligomer, which is ethyl acrylate, ethylene - methyl acrylate, methyl methacrylate, 2 - chloroethyl vinyl ether, 2 - hydroxyethyl acrylate, 2 - hydroxyethyl methacrylate, butyl acrylate, trimethylolpropane triacrylate (TMPTA) or a combination thereof.

[0022] In another embodiment, the present disclosure relates to the coated HPF as described above, wherein the polymer layer contains the catalyst, the cocatalyst or the accelerator; and the catalyst, the cocatalyst or the accelerator is a polyurethane catalyst that promotes the polyurethane polymerization reaction, an epoxy resin catalyst that promotes the epoxy resin polymerization reaction, an acrylate catalyst that promotes the acrylate polymerization reaction or a combination thereof.

[0023] In yet another embodiment, the present disclosure relates to the coated HPF as described above, wherein the catalyst, the cocatalyst, or the accelerator is:

[0024] (i) a polyurethane catalyst that promotes polyurethane polymerization;

[0025] (ii) a polyurethane catalyst that promotes polyurethane polymerization, and the polyurethane catalyst is 1,4-diazabicyclo[2.2.2]octane, K-KAT 6212, benzyldimethylamine, or a combination thereof;

[0026] (iii) an epoxy resin catalyst that promotes epoxy resin polymerization;

[0027] (iv) an epoxy resin catalyst that is 1,4-diazabicyclo[2.2.2]octane;

[0028] (v) an acrylate catalyst that promotes acrylate polymerization; or

[0029] (vi) an acrylate catalyst that is acrylic acid or a free radical polymerization promoter.

[0030] In one embodiment, the present disclosure relates to the coated HPF as described above, wherein the coating of the polymeric material has a thickness of:

[0031] (i) from about 5 nanometers to about 100 micrometers;

[0032] (ii) from about 15 nanometers to about 50 micrometers;

[0033] (iii) from about 15 nanometers to about 15 micrometers;

[0034] (iv) from about 50 nanometers to less than about 15 micrometers; or

[0035] (v) from about 50 nanometers to about 1.5 micrometers.

[0036] In another embodiment, the present disclosure relates to the coated HPF as described above, wherein the catechol-containing polymer or oligomer comprises polycatechol styrene (PCS).

[0037] In yet another embodiment, the present disclosure relates to the coated HPF as described above, wherein the molecular weight is in the range of 100 to 1,000,000.

[0038] In one embodiment, the present disclosure relates to the coated HPF as described above, wherein the PCS comprises from about 15% to about 85% catechol.

[0039] In another embodiment, the present disclosure relates to a coated HPF as described above, wherein the PCS comprises about 25% catechol or about 35% catechol.

[0040] In yet another embodiment, the present disclosure relates to a coated HPF as described above, wherein the HPF is a polymer.

[0041] In one embodiment, the present disclosure relates to a coated HPF as described above, wherein the HPF is an aramid, super aramid, aramid copolymer, meta-aramid, LCP, UHMWPE polymer, polyamide, polyester, polyolefin, or a combination thereof.

[0042] In another embodiment, the present disclosure relates to a coated HPF as described above, wherein the HPF is carbon fiber.

[0043] In yet another embodiment, the present disclosure relates to a fiber-reinforced composite comprising one or more of the above HPFs.

[0044] In one embodiment, the present disclosure relates to a fiber-reinforced composite as described above, wherein the matrix polymer is selected from:

[0045] Polypropylene, polyethylene, polycarbonate, polyvinyl chloride, polyether ether ketone, polyether sulfone, polyphenylene sulfide, polyamide, polymethyl methacrylate, polyetherimide, acetal, sulfone polymer, ethylene-vinyl acetate, liquid crystal polymer, polybutylene terephthalate, acrylonitrile-butadiene-styrene, fluoropolymer, thermoplastic elastomer, thermoplastic polyurethane, cyclohexanedimethanol terephthalate, epoxy resin, polyester resin, vinyl ester resin, phenolic resin, polyimide, polyurethane, polystyrene, silicone resin, cyanate ester, melamine-formaldehyde resin, polydicyclopentadiene, polyarylate, polybenzimidazole, polychlorotrifluoroethylene, methyl methacrylate-butadiene-styrene, polyacrylonitrile, polyhydroxyalkanoate, polylactic acid, polyhydroxybutyrate, polyoxymethylene copolymer.

[0046] In another embodiment, the present disclosure relates to a method for preparing an HPF as described above, the method comprising: exposing the HPF to a prepolymerized catechol-containing polymer dissolved in one or more solvents.

[0047] In yet another embodiment, the present disclosure relates to a method for functionalizing the surface of an HPF as described above, the method comprising: exposing the HPF to a prepolymerized catechol-containing polymer dissolved in one or more solvents.

[0048] In one embodiment, the present disclosure relates to a coated HPF as described above, wherein the HPF is completely or partially covered with a material comprising a PCS polymer.

[0049] In another embodiment, the present disclosure relates to an article comprising the fiber-reinforced composite material as described above.

[0050] In yet another embodiment, the present disclosure relates to a method for applying a coating to at least one surface of a substrate made of the fiber-reinforced composite as described above, wherein the method comprises:

[0051] applying a PCS layer filled with graphene particles or zinc particles as a primer to the at least one surface of the substrate, and

[0052] applying a coating to the PCS layer filled with zinc particles or graphene particles.

[0053] In one embodiment, the present disclosure relates to a method as described above, wherein:

[0054] the viscous PCS layer filled with zinc particles or graphene particles has a thickness between 200 nm and 100 µm; and / or

[0055] the PCS layer is filled with graphene particles and contains 0.5 wt% to 2 wt% of graphene.

[0056] In another embodiment, the present disclosure relates to a substrate comprising a coating applied to at least one surface by implementing the method as described above.

[0057] In yet another embodiment, the present disclosure relates to an aircraft component comprising the substrate as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 A and Figure 1 B show high-performance fibers (HPFs) coated with at least one layer of a catechol-containing material and other optional layers comprising one or more layers of a catechol-containing layer.

[0059] FIG. 2 shows SEM micrographs of the following aramid fibers: aramid fibers without any coating treatment (2A, 2D, 2G); aramid fibers with a 6% ZnCl2 bath (2B, 2E, 2H); and aramid fibers treated in a ZnCl2 bath and a PCS coating (2C, 2F, 2I).

[0060] FIG. 3 shows SEM images of carbon fibers (CFs) coated with polycatechol styrene (PCS): Figure 3A , Figure 3B and Figure 3C corresponding to magnifications of 7Kx, 2x, and 700x, respectively.

[0061] Figure 4 shows SEM images of both untreated Teijin Tenax chopped carbon fibers and PCS-coated chopped carbon fibers: SEM micrographs of carbon fibers without any coating treatment (4A, 4C, 4E) or carbon fibers with a PCS coating (4B, 4D, 4F).

[0062] Figure 5 shows SEM micrographs of recycled carbon fibers coated with PCS: Figures 5 (5A, 5C) are recycled carbon fibers cleaned with acetone, and Figures (5B, 5D) are recycled carbon fibers treated with a poly(catechol-styrene) (PCS) coating.

[0063] Figure 6 shows SEM micrographs of recycled carbon fibers coated with poly(catechol-styrene) (PCS): Figures (6A, 6C) relate to fibers in which carbon fibers were coated with a 0.5% PCS solution; and Figures (5B, 5D) relate to a 3% PCS solution used for coating carbon fibers, which coated the fibers with a thick PCS coating.

[0064] Figure 7 relates to a method of dip-coating carbon fibers with a PCS sizing solution. The carbon fibers ( Figure 7A ) were immersed in the solution ( Figure 7B and Figure 7C ). The air-dried samples are shown in ( Figure 7D ).

[0065] Figure 7.1 Shows the FTIR transmittance as a function of wavenumber for a PCS polymer of 240K molecular weight, with the same polymer at a concentration of 1% in acetone, and acetone was used for dip-coating for 5 minutes, 15 minutes, and 30 minutes.

[0066] Figure 7E 、 Figure 7F and Figure 7G Show two layers of ready-to-use Chomarat ® carbon fibers (0 / 90) at three different magnifications. Figure 7H Shows the carbon fibers before burnout, and Figure 7I and Figure 7J Show the carbon fibers after burnout. Figure 7K 、 Figure 7L and Figure 7M Are SEM micrographs of carbon fibers after burnout in a furnace.

[0067] Figure 8 Shows the FTIR scans of ready-to-use and burned-out carbon fibers.

[0068] Figure 9A 、 Figure 9B and Figure 9CThis is a SEM of a ready-to-use carbon fiber coated with 0.5% PCS polymer in acetone solution, which was dip coated for 30 minutes. The PCS used was a 240K Dalton molecular weight material.

[0069] Figure 10A , Figure 10B and Figure 10C This is a SEM of a ready-to-use carbon fiber coated with 1.0% PCS polymer in acetone solution, which was dip coated for 30 minutes. The PCS used was a 240K Dalton molecular weight material.

[0070] Figure 11 FTIR scans of ready-to-use carbon fibers coated with 1% PCS in acetone solvent are shown, with dip coating for 5 minutes, 15 minutes, and 30 minutes. The PCS used was a 240K Dalton molecular weight material.

[0071] Figure 12A , Figure 12B and Figure 12C is a SEM of a ready-to-use carbon fiber coated with 1.5% PCS polymer in acetone, which was dip coated for 5 minutes.

[0072] Figure 13A , Figure 13B and Figure 13C is a SEM of a ready-to-use carbon fiber coated with 1.5% PCS polymer in acetone, which was dip coated for 15 minutes.

[0073] Figure 14A , Figure 14B and Figure 14C is a SEM of a ready-to-use carbon fiber coated with 1.5% PCS polymer in acetone, which was dip coated for 30 minutes.

[0074] Figure 15 FTIR scans of ready-to-use carbon fibers coated with 1.5% PCS in acetone solvent for 5, 15, and 30 minutes of dip coating are shown. The PCS used was a 240K Dalton molecular weight material.

[0075] Figure 16A , Figure 16B and Figure 16C is a SEM of a ready-to-use carbon fiber coated with a 2.0% PCS polymer solution in acetone, which was dip coated for 5 minutes.

[0076] Figure 17A , Figure 17B and Figure 17Cis a SEM of a ready-to-use carbon fiber coated with a 2.0% PCS polymer solution in acetone, which was dip coated for 15 minutes.

[0077] Figure 18A , Figure 18B and Figure 18C is a SEM of a ready-to-use carbon fiber coated with a 2.0% PCS polymer solution in acetone, which was dip coated for 30 minutes.

[0078] Figure 19 Shown is the FTIR scan of ready-to-use carbon fiber coated with 2.0% PCS in acetone solvent, where dip coating was for 5 minutes, 15 minutes and 30 minutes. The PCS used was a 240K Dalton molecular weight material.

[0079] Figure 20A Shown are the upper surfaces of the carbon fibers after 5 minutes, 15 minutes, and 30 minutes of dip coating. Figure 20B The bottom surface of the carbon fiber after 5 minutes, 15 minutes and 30 minutes of dip coating is shown.

[0080] Figure 21 Carbon fibers that have been sized with PCS via dip coating are shown and then used to prepare a laminate with a PEEK matrix. DETAILED DESCRIPTION

[0081] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present disclosure belongs. The terms used in this specification are for the purpose of describing particular embodiments only and are not intended to limit the present disclosure.

[0082] The following terms are used to describe the present disclosure. Where a term is not specifically defined herein, the term is given the art-recognized meaning by one of ordinary skill in the art in which the term is applied to the context in which it is used to describe the present disclosure.

[0083] In this disclosure, the singular forms "a," "an," and "the" include plural references, and reference to a specific value includes at least that specific value unless the context clearly dictates otherwise. Thus, for example, reference to "a material" refers to at least one such material and equivalents thereof known to those skilled in the art, and so forth.

[0084] When values are presented as approximations by use of the descriptor "about" or "substantially", it should be understood that the particular value forms another embodiment. In general, the use of the term "about" or "substantially" indicates an approximation that may vary depending on the desired characteristics sought to be obtained from the disclosed subject matter and is to be interpreted in the context in which it is used based on its function. A person skilled in the art will be able to interpret this in a conventional manner. In some cases, the number of significant digits used for a particular value may be a non-limiting method for determining the degree of the term "about" or "substantially". In other cases, the gradations used in a series of values may be used to determine the expected range available for the term "about" or "substantially" for each value. Where ranges are provided, all ranges include the end values and are combinable. That is, a reference to a value within a range includes each value within that range.

[0085] When a list is presented, unless otherwise stated, it should be understood that each individual element of the list and each combination of the list should be construed as a separate embodiment. For example, a list of embodiments presented as "A, B, or C" should be construed as including the embodiments "A", "B", "C", "A or B", "A or C", "B or C", or "A, B, or C".

[0086] It should be understood that certain features of the present disclosure that are described in the context of separate embodiments herein may also be provided in combination in a single embodiment. That is, each individual embodiment is considered combinable with any other embodiment unless clearly incompatible or excluded, and such combinations are considered another embodiment. Conversely, various features of the present disclosure that are described in the context of a single embodiment for brevity may also be provided separately or in any sub-combination. It should also be noted that the claims may be drafted to exclude any optional elements. Thus, this statement is intended to serve as a basis antecedent to the use of exclusive terms such as "alone", "only", etc. or the use of "negative" limitations in connection with the recitation of claim elements. Finally, although an embodiment may be described as part of a series of steps or part of a more general structure, each of the recited steps may itself be considered an independent embodiment.

[0087] Exemplary embodiments of the present disclosure are described below in the context of high performance fibers (HPFs). The present disclosure relates to HPFs coated with a catechol-containing material. Preferred catechol-containing materials include polycatechol-styrene (PCS) as described below. Although the various embodiments disclosed below may relate to PCS or PCS-type materials, it should be understood that PCS is used as an example of a catechol-containing material. The term PCS-type is also used to denote materials that contain catechol and are similar to PCS.

[0088] In one embodiment, the high-performance fibers or superfibers for the coatings in the present disclosure include polyaramids (aromatic polyamides), e.g., Kevlar ™ , gel-spun high-modulus polyethylene (UHMWPE), super aromatic polyamides and aromatic polyamide copolymers, melt-spun liquid crystal aromatic polyesters (LCP), and carbon fibers.

[0089] In another embodiment, other HPP fibers for the present disclosure include polyamides, polyolefins, and polyesters. These include melt-spun commercial fibers (such as nylon 6 and nylon 6,6), high-performance polyaramids or aromatic polyamides spun from monomeric acids, or meta-aramids (such as Nomex ® ), and their copolymers. Examples of polyolefins include melt-spun commercial fibers from LLDPE or polypropylene, and gel-spun high-performance polyethylene and polypropylene fibers. Examples of polyesters include melt-spun commercial fibers from polyesters (such as PET, PTT, and PBT), and high-performance aromatic polyesters including lightning arrester polymers or liquid crystal polymers (LCP) and / or their copolymers.

[0090] I. Polyarylamide or Aromatic Polyamide

[0091] The aromatic polyamide fibers for the coatings in the present disclosure include those aromatic polyamide fibers for aerospace and military applications, for bulletproof-grade body armor fabrics and bulletproof composites, for marine ropes, marine hull reinforcement, and as heat-resistant and strong synthetic fibers as an asbestos substitute. The chain molecules in the fibers are highly oriented along the fiber axis. Therefore, a higher proportion of chemical bonds contribute more to the fiber strength compared to many other synthetic fibers. Aromatic polyamides have a very high melting point (>500 °C). Common aromatic polyamide trade names include Kevlar ® , Nomex ® and Twaron ® . Aromatic polyamides share a high degree of orientation with other fibers (such as ultra-high molecular weight polyethylene), which is a characteristic that dominates their properties. Other examples of aromatic polyamides include Technora ® and Vectran ® .

[0092] Aromatic polyamides have one or more of the following properties:

[0093] ● High tensile strength

[0094] ● High abrasion resistance

[0095] ● Lightweight

[0096] ● High chemical resistance and good resistance to organic solvents

[0097] ● Excellent durability

[0098] ● Thermal stability

[0099] ● Heat resistant / flame retardant

[0100] ● Low moisture absorption

[0101] ● Cut resistant / hack resistant / impact resistant

[0102] ● Non-conductive

[0103] ● Extremely high melting point (>500 °C)

[0104] ● Good fabric integrity at high temperatures

[0105] ● Sensitive to acids and salts

[0106] ● Sensitive to ultraviolet radiation

[0107] ● Prone to static charge accumulation unless treated

[0108] ● Para-aramid fibers (such as Kevlar ® and Twaron ® ) offer excellent strength-to-weight ratio characteristics

[0109] ● High chord modulus

[0110] ● Low creep

[0111] ● Low elongation at break (about 3.5%)

[0112] ● Difficult to dye - usually solution dyed

[0113] These fibers include the following end uses:

[0114] ● Protective textiles and clothing / PPE

[0115] ● Industrial special fabrics

[0116] ● Ropes / cables

[0117] ● Aerospace / military / law enforcement

[0118] ● Heavy lift slings / straps

[0119] ● Professional electronics

[0120] ● Flexible composites / inflatables

[0121] ● Fireproof clothing

[0122] ● Heat protective clothing and helmets

[0123] ● Body armor

[0124] ● Composite materials

[0125] ● Asbestos substitutes (e.g., brake linings)

[0126] ● Hot air filtration fabrics

[0127] ● Tires, new name Sulfron ® (Sulfur-modified Twaron ® )

[0128] ● Reinforcing materials for mechanical rubber goods

[0129] ● Ropes and cables

[0130] ● V-belts (for automobiles, machinery, equipment, etc.)

[0131] ● Wick for fire extinguishing

[0132] ● Optical cable systems

[0133] ● Canvas

[0134] ● Sporting goods

[0135] ● Eardrums

[0136] ● Reed for wind instruments

[0137] ● Speaker diaphragms

[0138] ● Hull materials

[0139] ● Fiber-reinforced concrete

[0140] ● Reinforced thermoplastic pipes

[0141] ● Tennis strings

[0142] ● Hockey sticks

[0143] ● Ski boards

[0144] ● Jet engine casings

[0145] ● Fishing reel drag systems

[0146] ● Asphalt reinforcing materials

[0147] ● Prusik knots for climbers

[0148]

[0149] In one embodiment, the aromatic polyamide of the present disclosure for PCS-type coatings has the molecular structure as shown above, where generally hexagonal rings are alternately attached to two NH groups or two CO groups. The attachment points on each ring are diametrically opposite to each other, which means this is classified as a para-aramid. In aromatic polyamides, the aromatic rings are connected by amide bonds, and each amide bond contains a CO group attached to an NH group. Depending on the position where the bond is attached to the ring, aromatic polyamides are divided into two main types. Numbering the carbon atoms around the ring sequentially, para-aramids have bonds attached at positions 1 and 4, while meta-aramids have bonds attached at positions 1 and 3. That is, in para-aramids, the attachment points are diametrically opposite to each other, and in meta-aramids, the two atoms are separated. This illustration thus shows a para-aramid.

[0150] The meta-aramid fiber Nomex for PCS-type coatings in the present disclosure ® is characterized by its excellent heat resistance as it neither melts nor catches fire under normal oxygen levels. It is widely used in the production of protective clothing, air filtration, thermal insulation and electrical insulation, as well as substitutes for asbestos. Meta-aramids include Teijinconex ® , Arawin ® , New Star ® , X-Fiper ® and variants of the meta-aramid Kermel ® .

[0151] The para-aramid fibers for PCS-type coatings in the present disclosure include Kevlar ® , Twaron ® , Heracron ® and Taparan ® . Para-aramids are used in many high-tech applications such as aerospace and military applications for "bulletproof" body armor fabrics. Both meta-aramid fibers and para-aramid fibers can be used to prepare aramid paper. Aramid paper is used as an electrical insulation material and a building material to prepare honeycomb structure cores. Aramid paper includes meta-aramid paper and para-aramid paper, such as Nomex ® paper and Metastar ® paper. Aramid fibers can be made into fibers, staple fibers, powders or pulps.

[0152] In addition to meta-aramids such as Nomex ® , other variants for PCS-type coatings in the present disclosure also fall within the scope of aramid fibers. These are mainly copolyamide types, the most well-known being the trade name Technora ® .

[0153] II. Liquid Crystal Polymer (LCP) Fibers

[0154]

[0155]

[0156] Molecular and Crystal Orientations in Spun Polymers

[0157] For use in the PCS-type coating in the present disclosure, in one embodiment, an LCP based on a p-hydroxybenzoic acid (HBA) and 2-hydroxy-6-naphthoic acid (HNA) HBA / HNA copolymer can be used, which has been used to produce Vectran ® HT LCP fibers. When liquid crystal polymers are spun into fibers, as schematically shown above, some alignment of the crystalline domains occurs. Some alignment with the spinning direction also occurs in amorphous polymers such as PET, but in LCPs, the aligned crystalline domains result in much higher tensile properties such as strength and modulus.

[0158] The polyester-based LCP fibers for use in the PCS-type coating in the present disclosure can achieve a toughness of over 3.5 GPa (>28 gpd) and an elongation at failure of <4%. The main advantages of LCPs over competing high-performance fibers include dimensional and property stability over a wide temperature range, and a long service life due to enhanced durability against repeated wear, flex fatigue, and chemical exposure. Such fibers have been found to be increasingly used in demanding aerospace, military, and industrial applications in a wide range of environments.

[0159] Specific applications for the LCP fibers for use in the PCS-type coating in the present disclosure include low-creep ropes, multi-component cables and umbilicals, and technical fabrics. Flexible composites using coated Vectran ® fabrics are used in many technical end-uses such as rapidly deployable inflatable structures, lighter-than-air vehicles, and air-supported tension members. LCP fibers are used in applications similar to UHMWPE (ultra-high molecular weight polyethylene) and aramid fibers. For example, while rope handlers in heavy marine environments prefer the lighter weight of UHMWPE fibers, LCP fibers are used at elevated temperatures, which can cause dimensional instability in UHMWPE. In cables and coated fabrics, the near-zero moisture content of LCP eliminates fiber outgassing, which can cause polymer coatings or sheaths to blister during extrusion. In industrial fabrics, the improved flex-fold and abrasion resistance of LCP compared to aramids reduces premature fatigue failure in coated fabrics and personal protective equipment.

[0160] LCPs are classified according to the position of the liquid crystal cores. Main-chain liquid crystal polymers (MCLCPs) have liquid crystal cores in the main chain. Side-chain liquid crystal polymers (SCLCPs) have side chains containing liquid crystal cores. Main-chain LCPs have rigid, rod-like mesogens in the polymer main chain, which indirectly results in the high melting temperature of such LCPs. In side-chain LCPs, the mesogens are in the polymer side chains. The mesogens are usually connected to the main chain by flexible spacers.

[0161] The mesogens in LCPs can self-organize to form liquid crystal regions under different conditions. Based on the mechanisms of aggregation and alignment, LCPs can be roughly divided into two subclasses: lyotropic systems and thermotropic systems.

[0162] Lyotropic main-chain LCPs have rigid mesogen cores (such as aromatic rings) in the main chain. Lyotropic main-chain LCPs are mainly used for producing high-strength fibers (such as Kevlar). Lyotropic side-chain LCPs attached to polysiloxane polymers (such as alkyl polyoxyethylene surfactants) can be applied to personal care products (such as liquid soaps, etc.).

[0163] When the melting temperature is much lower than the decomposition temperature, thermotropic LCPs can be processed. Above the melting temperature and the glass transition temperature and below the clearing point, thermotropic LCPs will form liquid crystals. There are other systems, such as phototropic systems.

[0164] The present disclosure also relates to a method of coating the above-mentioned HPF with a catechol-containing material.

[0165] III. Carbon Fibers

[0166] Carbon fibers are lightweight and have excellent strength and elastic modulus, so they are combined with various matrix resins to form composite materials, which are used in various fields, including aircraft components, spacecraft components, automotive components, marine components, building materials, and sporting goods. In order to endow the composite materials containing carbon fibers with the excellent properties of carbon fibers, excellent adhesion between the carbon fibers and the matrix resin is important.

[0167] In order to improve the adhesion between carbon fibers and matrix resins, carbon fibers are usually oxidized (such as gas-phase oxidation and liquid-phase oxidation), thereby introducing oxygen-containing functional groups on the surface of the carbon fibers. For example, the disclosed methods include: improving the interlaminar shear strength as an adhesion index by electrolyzing carbon fibers. However, in recent years, due to the requirement of higher properties for composite materials, the adhesion achieved only by such oxidation has become insufficient.

[0168] Carbon fibers are brittle and have poor adhesion and wear resistance, so they are prone to generate fluff or broken wires in high-order processing steps. To solve this problem, methods of coating carbon fibers have been disclosed.

[0169] In one embodiment, the present disclosure relates to individual and multiple carbon fibers coated with a thin poly(catechol-styrene) (PCS) film. The thin polymer film functionalizes the previously inert carbon fiber surface with catechol moieties that can assist in bonding to the matrix of various thermosetting, thermoplastic, and other composite materials. The coating method includes: stirring raw carbon fibers in an organic solvent containing dissolved PCS. The PCS in the solution forms bonds with the carbon fiber surface, leaving a thin film deposited on the carbon fiber surface. After the coating reaction, the fibers are filtered, rinsed with isopropyl alcohol and DI water, and dried, preferably in a vacuum chamber to remove any residual solvent.

[0170] This one-step coating process has advantages over many other coating processes. In one embodiment, an advantage of PCS is that it is pre-polymerized, and thus in one embodiment of the coating process, the pre-formed catechol-containing polymer interacts with the carbon fiber surface.

[0171] The carbon fibers can be chopped filaments and can be of any of the PAN type, pitch type, and other types, and there are no restrictions on their starting materials and their production methods. The length of the chopped carbon fiber filaments is not critical, but in one embodiment, it is from 5 microns to 50 mm. The diameter and number of the filaments constituting the chopped carbon fiber filaments are also not critical, but in one embodiment, the diameter is typically from 500 nm to 50 microns. The number of filaments is typically from 100 to 100,000. The chopped carbon fiber filaments may be pre-coated with a sizing agent.

[0172] IV. Coating of High-Performance Fibers with Catechol-Containing Materials

[0173] The above-mentioned high-performance fibers (HPF) can be coated with at least one layer containing a catechol-containing material such as PCS, as described below.

[0174] In one aspect, the present disclosure relates to HPF coated with a catechol-containing material such as PCS, the HPF comprising a catechol-containing polymer or oligomer, wherein the catechol is present as catechol and / or as a semiquinone and / or as a quinone, but no primary or secondary amines are present; and wherein the polymeric material optionally comprises at least one of the following: a) a reactive substance separated from the catechol-containing polymer or oligomer; and b) a catalyst, co-catalyst, or accelerator.

[0175] In some embodiments, the catechol-containing material coated on the HPF comprises a catechol-containing polymer or oligomer, wherein the catechol is present as catechol and / or as a semiquinone and / or as a quinone, but no primary or secondary amines are present.

[0176] In some embodiments, the catechol-containing material coated on the HPF comprises a catechol-containing polymer or oligomer, wherein the catechol is present as catechol and / or as semiquinone and / or as quinone, but no primary or secondary amines are present; and further comprises a reactive material separated from the catechol-containing polymer or oligomer.

[0177] In some embodiments, the catechol-containing material coated on the HPF comprises a catechol-containing polymer or oligomer, wherein the catechol is present as catechol and / or as semiquinone and / or as quinone, but no primary or secondary amines are present; and further comprises a catalyst, a cocatalyst, or an accelerator.

[0178] In some embodiments, the catechol-containing material coated on the HPF comprises a catechol-containing polymer or oligomer, wherein the catechol is present as catechol and / or as semiquinone and / or as quinone, but no primary or secondary amines are present; and further comprises a reactive material separated from the catechol-containing polymer or oligomer and a catalyst, a cocatalyst, or an accelerator.

[0179] Figure 1 A general schematic diagram of the catechol-containing material 20 coated on the HPF 20 comprising a catechol-containing polymer or oligomer and the layered HPF 100 comprising the catechol-containing material described herein is shown. The coated HPF 100 comprises an HPF core 10 and the catechol-containing material 20 coated on the HPF 10.

[0180] The coated HPF 100 may also optionally comprise another polymer 30, which is disposed on and in contact with the catechol-containing material coated on the HPF 20. The coated HPF 100 may also comprise a second catechol-containing material coated on the HPF, and the second catechol-containing material comprises a catechol-containing polymer or oligomer 40 disposed on and in contact with the polymer 30. In one embodiment, the coated HPF 100 may also comprise a second polymer layer 50, which is disposed on and in contact with the second catechol-containing material coated on the HPF 40. The polymer 30 or the second polymer 50 may be a catechol-containing polymer or oligomer, or another polymer.

[0181] In some embodiments, the catechol-containing polymer or oligomer in the catechol-containing material coated on the HPF 20 is oligomeric. In some embodiments, the catechol-containing polymer or oligomer in the catechol-containing material coated on the HPF 20 is polymeric.

[0182] In one aspect, the catechol-containing material coated on the HPF 20 includes a reactive substance separated from the catechol-containing polymer or oligomer. In one aspect, the reactive substance is a polyurethane component, an epoxy resin, an acrylate monomer or oligomer, a methacrylate monomer or oligomer, a silane, or a combination thereof.

[0183] In some embodiments, the reactive substance separated from the catechol-containing polymer or oligomer is a polyurethane component. In some embodiments, the polyurethane component is a polyol or an organic compound containing multiple hydroxyl groups; and wherein the polyurethane is linear or branched.

[0184] In some embodiments, the polyurethane component is 1,6-hexanediol, glycerol, Stepanpol PDC-279 ® or polycaprolactone triol. In some embodiments, the polyurethane component is 1,6-hexanediol. In some embodiments, the polyurethane component is glycerol. In some embodiments, the polyurethane component is Stepanpol PDC-279 ® . In some embodiments, the polyurethane component is polycaprolactone triol.

[0185] In one aspect, the reactive substance separated from the catechol-containing polymer or oligomer is an epoxy resin. In some embodiments, the epoxy resin is an epoxy monomer, an epoxy oligomer, a polyepoxide, or a combination thereof, and wherein the epoxy resin is linear or branched. In some embodiments, the epoxy resin is an epoxy monomer. In some embodiments, the epoxy resin is an epoxy oligomer. In some embodiments, the epoxy resin is a polyepoxide.

[0186] In some embodiments, the epoxy resin is bisphenol A diglycidyl ether, bisphenol A epoxy resin, bis(4-glycidyloxyphenyl)methane, bisphenol E diglycidyl ether (DGEBE), 2,2'-[1,1-ethylenebis(4,1-phenyleneoxymethylene)]bisoxirane, bisphenol F diglycidyl ether (DGEBF), poly(bisphenol A-co-epichlorohydrin), or a combination thereof.

[0187] In some embodiments, the epoxy resin is bisphenol A diglycidyl. In some embodiments, the epoxy resin is bisphenol A epoxy resin. In some embodiments, the epoxy resin is bis(4-glycidyloxyphenyl)methane. In some embodiments, the epoxy resin is bisphenol E diglycidyl ether (DGEBE). In some embodiments, the epoxy resin is 2,2'-[1,1-ethylenebis(4,1-phenyleneoxymethylene)]bisoxirane. In some embodiments, the epoxy resin is bisphenol F diglycidyl ether (DGEBF). In some embodiments, the epoxy resin is poly(bisphenol A-co-epichlorohydrin).

[0188] In one aspect, the reactive material separated from the catechol-containing polymer or oligomer is an acrylate monomer or oligomer. In some embodiments, the acrylate monomer or oligomer is an acrylate monomer comprising a vinyl group and at least one of a carboxylate ester and a carboxynitrile; and wherein the acrylate is linear or branched.

[0189] In some embodiments, the acrylate monomer or oligomer is ethyl acrylate, ethylene-methyl acrylate, methyl methacrylate, 2-chloroethyl vinyl ether, 2-hydroxyethyl acrylate, hydroxyethyl methacrylate, butyl acrylate, trimethylolpropane triacrylate (TMPTA), or a combination thereof.

[0190] In some embodiments, the acrylate monomer or oligomer is ethyl acrylate. In some embodiments, the acrylate monomer or oligomer is ethylene-methyl acrylate. In some embodiments, the acrylate monomer or oligomer is methyl methacrylate. In some embodiments, the acrylate monomer or oligomer is 2-chloroethyl vinyl ether. In some embodiments, the acrylate monomer or oligomer is 2-hydroxyethyl acrylate. In some embodiments, the acrylate monomer or oligomer is hydroxyethyl methacrylate. In some embodiments, the acrylate monomer or oligomer is butyl acrylate. In some embodiments, the acrylate monomer or oligomer is trimethylolpropane triacrylate (TMPTA).

[0191] In some embodiments, the reactive material separated from the catechol-containing polymer or oligomer is a silane. In some embodiments, the reactive material separated from the catechol-containing polymer or oligomer is a methacrylate monomer or oligomer. In some embodiments, the reactive material separated from the catechol-containing polymer or oligomer is a methacrylate monomer. In some embodiments, the reactive material separated from the catechol-containing polymer or oligomer is a methacrylate oligomer.

[0192] In one aspect, the catechol-containing material 20 coated on the HPF 10 comprises a catalyst, a cocatalyst, or an accelerator; and the catalyst, the cocatalyst, or the accelerator is a polyurethane catalyst that promotes a polyurethane polymerization reaction, an epoxy resin catalyst that promotes an epoxy resin polymerization reaction, an acrylate catalyst that promotes an acrylate polymerization reaction, or a combination thereof.

[0193] In some embodiments, the catalyst, the cocatalyst, or the accelerator is a polyurethane catalyst that promotes a polyurethane polymerization reaction. In some embodiments, the polyurethane catalyst is an aliphatic amine catalyst, an alicyclic amine catalyst, an alkanolamine catalyst, an aromatic amine catalyst, or an etheramine catalyst.

[0194] In some embodiments, the polyurethane catalyst is an aliphatic amine catalyst. In some embodiments, the aliphatic amine catalyst is N,N-dimethylcyclohexane, triethylenediamine, N,N,N,N-tetramethylalkylenediamine, N,N,N,N-pentamethyldiethylenetriamine, triethylamine, N,N-dimethylbenzylamine, N,N-dimethylhexadecylamine, N,N-dimethylbutylamine, or a combination thereof.

[0195] In some embodiments, the polyurethane catalyst is an alicyclic amine catalyst. In some embodiments, the alicyclic amine catalyst is triethylenediamine, N-ethylmorpholine, N-methylmorpholine, N,N-diethylpiperazine, N,N-bis-(α-hydroxypropyl)-2-methylpiperazine, N-hydroxypropyldimethylmorpholine, or a combination thereof.

[0196] In some embodiments, the polyurethane catalyst is an alkanolamine catalyst. In some embodiments, the alkanolamine catalyst is triethanolamine or N,N-dimethylethanolamine.

[0197] In some embodiments, the polyurethane catalyst is an aromatic amine catalyst. In some embodiments, the aromatic amine catalyst is pyridine or N,N-dimethylpyridine.

[0198] In some embodiments, the polyurethane catalyst is an etheramine catalyst. In some embodiments, the etheramine catalyst is BDMAEE.

[0199] In some embodiments, the polyurethane catalyst is 1,4-diazabicyclo[2.2.2]octane, K-KAT 6212, benzyldimethylamine, or a combination thereof. In some embodiments, the polyurethane catalyst is 1,4-diazabicyclo[2.2.2]octane. In some embodiments, the polyurethane catalyst is K-KAT 6212. In some embodiments, the polyurethane catalyst is benzyldimethylamine.

[0200] In some embodiments, the catalyst, cocatalyst, or accelerator is an epoxy resin catalyst that promotes the polymerization of epoxy resin.

[0201] Suitable catalysts, cocatalysts, or accelerators are substances that accelerate the reaction between amino groups and epoxy groups, such as acids or compounds that can be hydrolyzed into acids. Without limitation, suitable catalysts, cocatalysts, or accelerators are organic carboxylic acids, such as acetic acid, benzoic acid, salicylic acid, 2-nitrobenzoic acid, lactic acid; organic sulfonic acids, such as methanesulfonic acid, p-toluenesulfonic acid, or 4-dodecylbenzenesulfonic acid; sulfonic acid esters; other organic or inorganic acids, such as phosphoric acid or mixtures of the above acids and acid esters; nitrates, especially such as calcium nitrate; or tertiary amines, such as 1,4-diazabicyclo[2.2.2]octane, benzyldimethylamine, α-methylbenzyldimethylamine, triethanolamine, dimethylaminopropylamine.

[0202] In some embodiments, the epoxy resin catalyst is acetic acid, benzoic acid, salicylic acid, 2-nitrobenzoic acid, lactic acid, methanesulfonic acid, p-toluenesulfonic acid, 4-dodecyl-benzenesulfonic acid, sulfonate ester, phosphoric acid, calcium nitrate, 1,4-diazabicyclo-[2.2.2]octane, benzyldimethylamine, α-methylbenzyldimethylamine, triethanolamine, dimethylaminopropylamine, N,N-dimethylpiperidine, triethylenediamine, 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30), benzyldimethylamine (BDMA), 2-(dimethyl-aminomethyl)phenol (DMP-10), N,N-dimethylbenzylamine, (dimethylaminomethyl)phenol, or a combination thereof.

[0203] In some embodiments, the epoxy resin catalyst is 1,4-diazabicyclo[2.2.2]octane.

[0204] In some embodiments, the catalyst, cocatalyst, or accelerator is an acrylate catalyst that promotes acrylate polymerization. In some embodiments, the acrylate catalyst is acrylic acid or a free radical polymerization promoter.

[0205] In some embodiments, the acrylate catalyst is methyl 4-N,N-dimethylamino-phenylacetate (MDMAPA), N,N-dimethylaminoglutethimide (OMAG), N,N-dimethyl-p-toluidine (OMPC), N,N-di-2-hydroxyethyl-p-toluidine (DHEPT), N,N-di-2-hydroxypropyl-p-toluidine (DHPPT), N,N-dimethyl-symxylidine (DMSX), N,N-bis(3-p-tolyloxy-2-hydroxy-propyl)-m-xylidine (BTX), or a combination thereof.

[0206] In one aspect, the catechol-containing polymer or oligomer in the catechol-containing material coated on HPF 20 includes polycatechol styrene (PCS).

[0207] In one aspect, the catechol-containing material (such as 20 PCS) coated on HPF 10 has a thickness of about 5 nanometers to about 100 micrometers. In some embodiments, the catechol-containing material (such as PCS) coated on HPF 20 has a thickness of about 15 nanometers to about 50 micrometers. In some embodiments, the catechol-containing material (such as PCS) coated on HPF 20 has a thickness of about 15 nanometers to about 15 micrometers. In some embodiments, the catechol-containing material (such as PCS) coated on HPF 20 has a thickness of about 100 nanometers to less than about 5 micrometers. In some embodiments, the catechol-containing material (such as PCS) coated on HPF 20 has a thickness of about 150 nanometers to about 1.5 micrometers.

[0208] In some embodiments, the catechol-containing material (such as PCS) coated on the HPF 20 has a thickness of from about 10 nanometers to about 100 micrometers; or from about 10 nanometers to about 100 nanometers; or from about 100 nanometers to about 150 nanometers; or from about 150 nanometers to about 200 nanometers; or from about 200 nanometers to about 250 nanometers; or from about 250 nanometers to about 300 nanometers; or from about 300 nanometers to about 350 nanometers; or from about 350 nanometers to about 400 nanometers; or from about 400 nanometers to about 450 nanometers; or from about 450 nanometers to about 500 nanometers; or from about 500 nanometers to about 550 nanometers; or from about 550 nanometers to about 600 nanometers; or from about 600 nanometers to about 650 nanometers; or from about 650 nanometers to about 700 nanometers; or from about 700 nanometers to about 750 nanometers; or from about 750 nanometers to about 800 nanometers; or from about 800 nanometers to about 850 nanometers; or from about 850 nanometers to about 900 nanometers; or from about 900 nanometers to about 950 nanometers; or from about 950 nanometers to about 1000 nanometers.

[0209] In some embodiments, the catechol-containing material (such as PCS) coated on the HPF 20 has a thickness of from about 1 micrometer to about 1.5 micrometers; or from about 1.5 micrometers to about 5 micrometers; or from about 5 micrometers to about 10 micrometers; or from about 10 micrometers to about 15 micrometers; or from about 15 micrometers to about 20 micrometers; or from about 20 micrometers to about 25 micrometers; or from about 25 micrometers to about 30 micrometers; or from about 30 micrometers to about 35 micrometers; or from about 35 micrometers to about 40 micrometers; or from about 40 micrometers to about 45 micrometers; or from about 45 micrometers to about 50 micrometers; or from about 50 micrometers to about 55 micrometers; or from about 55 micrometers to about 60 micrometers; or from about 60 micrometers to about 65 micrometers; or from about 65 micrometers to about 70 micrometers; or from about 70 micrometers to about 75 micrometers; or from about 75 micrometers to about 80 micrometers; or from about 80 micrometers to about 85 micrometers; or from about 85 micrometers to about 90 micrometers; or from about 90 micrometers to about 95 micrometers; or from about 95 micrometers to about 100 micrometers.

[0210] In some embodiments, the aggregate thickness of the catechol-containing material (such as PCS) coated on the high performance fiber (HPF) is in the range of from about 5 nanometers to about 10 micrometers. In other words, the aggregate thickness is any value selected from the following set of values or within the range defined by any two values, including the endpoints of the range measured in nanometers:

[0211] 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, …… 200, …… 300, …… 400, 500, 600, 700, 800 ……, 900, …… 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000 and 10000.

[0212] In some embodiments, the PCS comprises from about 5% catechol to about 85% catechol. In some embodiments, the PCS comprises from about 10% catechol to 75% catechol, from about 15% catechol to 60% catechol, or from about 20% catechol to about 40% catechol. In some embodiments, the PCS comprises from about 25% catechol to about 35% catechol. In some embodiments, the PCS comprises about 25% catechol. In some embodiments, the PCS comprises about 35% catechol.

[0213] In some embodiments, the PCS comprises from about 20% catechol to about 22% catechol; or from about 22% catechol to about 24% catechol; or from about 24% catechol to about 26% catechol; or from about 26% catechol to about 28% catechol; or from about 28% catechol to about 30% catechol; or from about 30% catechol to about 32% catechol; or from about 32% catechol to about 34% catechol; or from about 34% catechol to about 36% catechol; or from about 36% catechol to about 38% catechol; or from about 38% catechol to about 40% catechol.

[0214] In some embodiments, the PCS comprises from about 5% catechol to about 85% catechol. In other words, the catechol content in the PCS is any value selected from the following set of values or within the range defined by any two values, including the endpoints of the range measured by weight content:

[0215] 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84 and 85.

[0216] In one aspect, the catechol-containing material coated on the HPF 20 is a continuous layer. In one aspect, the catechol-containing material coated on the HPF 20 is a discontinuous layer.

[0217] In some embodiments, the HPF 10 is wet. In some embodiments, the HPF 10 is dry. In some embodiments, the HPF 10 is semi-wet. In some embodiments, the HPF 10 is slightly wet.

[0218] In some embodiments, the surface of the HPF 10 can be treated prior to setting a catechol-containing material coated on the HPF. In some embodiments, the surface of the HPF 10 is anodized. In some embodiments, the surface of the HPF 10 is phosphated.

[0219] Embodiments of the present disclosure have been described in terms of a catechol-containing material coated on the HPF.

[0220] In one aspect, the present disclosure relates to a catechol-containing material 20 coated on the HPF 10, which, as described herein, can also be in contact with another polymer 30.

[0221] In some embodiments, the polymer 30 comprises a polyester. In some embodiments, the polymer 30 comprises a polyurethane. In some embodiments, the polymer 30 comprises a phenol. In some embodiments, the polymer 30 comprises an epoxy resin, an acrylic acid or a silane. In some embodiments, the polymer 30 comprises an epoxy resin. In some embodiments, the polymer 30 comprises an acrylic acid. In some embodiments, the polymer 30 comprises a silane. In some embodiments, the polymer 30 comprises a silicone.

[0222] In some embodiments, the polymer 30 comprises one or more polymers listed in Table 1 below and is selected from the following list:

[0223] Thermoplastics

[0224] Polypropylene, polyethylene (high density and low density), polycarbonate, polyvinyl chloride (PVC), polyetheretherketone (PEEK), polyethersulfone (PES), polyphenylene sulfide (PPS), polyamide (nylon), polymethyl methacrylate (PMMA), polyetherimide (PEI), acetal (POM), sulfone polymers (PPSU, PSU), ethylene-vinyl acetate (EVA), liquid crystal polymer (LCP), polybutylene terephthalate (PBT), acrylonitrile-butadiene-styrene (ABS), fluoropolymer (PTFE, FEP), thermoplastic elastomer (TPE), thermoplastic polyurethane (TPU), polycyclohexanedimethylene terephthalate (PCT).

[0225] Thermosetting Materials

[0226] Epoxy resin, polyester resin, vinyl ester resin, phenolic resin, polyimide, polyurethane, polystyrene, silicone resin, cyanate ester, melamine-formaldehyde resin, poly(dicyclopentadiene) (pDCPD), polyarylate (PAR), polybenzimidazole (PBI), polychlorotrifluoroethylene (PCTFE), methyl methacrylate-butadiene-styrene (MBS).

[0227] Others

[0228] Polyacrylonitrile (PAN), polyhydroxyalkanoates (PHA), biobased polymers (PLA, PHB), polyoxymethylene copolymer (POM-C).

[0229] In some embodiments, polymer 30 is a continuous layer. In some embodiments, polymer 30 is a discontinuous layer.

[0230] In some embodiments, the catechol-containing material 20 and polymer 30 form an interpenetrating polymer network (IPN). As used herein, IPN is considered to refer to at least two polymer networks that are at least partially interpenetrated at the molecular scale but not covalently bonded to each other and cannot be separated unless chemical bonds are broken.

[0231] In some embodiments, the catechol-containing material 20 and polymer 30 form a semi-interpenetrating polymer network (SIPN). As used herein, SIPN is considered to refer to one or more polymer networks and one or more linear or branched polymers, characterized in that at least some of the macromolecules in the linear or branched macromolecules penetrate at least one of the networks at the molecular scale.

[0232] In some embodiments, the catechol-containing material 20 and polymer 30 form a sequential interpenetrating polymer network (SeIPN). As used herein, SeIPN is considered to refer to an interpenetrating polymer network prepared by the following process: wherein a second component network is formed after the formation of the first component network.

[0233] In some embodiments, the catechol-containing material 20 and polymer 30 form a sequential semi-interpenetrating polymer network (SSeIPN). As used herein, SSeIPN is considered to refer to a polymer network prepared by the following process: wherein the reaction leading to the formation of the network is completed after the formation of the linear or branched component, or vice versa.

[0234] In some embodiments, the second polymer 50 is disposed on polymer 30. In some embodiments, the second polymer 50 is disposed on and in contact with polymer 30. In some embodiments, the second catechol-containing material 20 is disposed between the polymer matrix 30 and the second polymer 50.

[0235] V. Method for Preparing HPF with a Coating of Catechol-Containing Material

[0236] In one aspect, the present disclosure relates to a method for preparing a HPF coated with a catechol-containing material (such as PCS), the method comprising: disposing the catechol-containing material 20 described herein on the surface of the HPF 10. The method of disposing the catechol-containing material 20 described herein is not particularly limited and will be recognized by those skilled in the art.

[0237] In some embodiments, the method for preparing the coated HPF comprises: disposing the catechol-containing material 20 (e.g., in batches) on the HPF 10 by spin coating, dip coating, spray coating, inkjet printing, flow coating, brush coating, wiping, etc. In some embodiments, the method comprises: disposing the catechol-containing material 20 on the high-performance fiber 10 by spin coating. In some embodiments, the method comprises: disposing the catechol-containing material 20 on the high-performance fiber 10 by dip coating. In some embodiments, the method comprises: disposing the polymer layer 20 on the high-performance fiber 10 by spray coating. In some embodiments, the method comprises: disposing the catechol-containing material 20 on the high-performance fiber 10 by inkjet printing. In some embodiments, the method comprises: disposing the catechol-containing material 20 on the high-performance fiber 10 by flow coating. In some embodiments, the method comprises: disposing the catechol-containing material 20 on the high-performance fiber 10 by brush coating. In some embodiments, the method comprises: disposing the catechol-containing material 20 on the high-performance fiber 10 by wiping.

[0238] In some embodiments, the method for preparing the high-performance fiber comprises: disposing the catechol-containing material 20 on the high-performance fiber 10, wherein the catechol-containing material 20 is applied to the high-performance fiber 10 as a solution. In some embodiments, the solution comprises from about 0.001 wt% to about 10 wt% of a catechol-containing polymer or oligomer. In some embodiments, the solution comprises from about 0.01 wt% to about 5 wt% of a catechol-containing polymer or oligomer. In some embodiments, the solution comprises from about 0.01 wt% to about 1 wt% of a catechol-containing polymer or oligomer. In some embodiments, the solution comprises from about 0.1 wt% to about 1 wt% of a catechol-containing polymer or oligomer.

[0239] In some embodiments, the solution comprises: from about 0.001 wt% to about 0.005 wt% of a catechol-containing polymer or oligomer; or from about 0.005 wt% to about 0.01 wt% of a catechol-containing polymer or oligomer; or from about 0.01 wt% to about 0.02 wt% of a catechol-containing polymer or oligomer; or from about 0.02 wt% to about 0.03 wt% of a catechol-containing polymer or oligomer; or from about 0.03 wt% to about 0.04 wt% of a catechol-containing polymer or oligomer; or from about 0.04 wt% to about 0.05 wt% of a catechol-containing polymer or oligomer; or from about 0.05 wt% to about 0.06 wt% of a catechol-containing polymer or oligomer; or from about 0.06 wt% to about 0.07 wt% of a catechol-containing polymer or oligomer; or from about 0.07 wt% to about 0.08 wt% of a catechol-containing polymer or oligomer; or from about 0.08 wt% to about 0.09 wt% of a catechol-containing polymer or oligomer; or from about 0.09 wt% to about 0.1 wt% of a catechol-containing polymer or oligomer; or from about 0.1 wt% to about 0.11 wt% of a catechol-containing polymer or oligomer; or from about 0.11 wt% to about 0.12 wt% of a catechol-containing polymer or oligomer; or from about 0.12 wt% to about 0.13 wt% of a catechol-containing polymer or oligomer; or from about 0.13 wt% to about 0.14 wt% of a catechol-containing polymer or oligomer; or from about 0.14 wt% to about 0.15 wt% of a catechol-containing polymer or oligomer; or from about 0.15 wt% to about 0.2 wt% of a catechol-containing polymer or oligomer; or from about 0.2 wt% to about 0.25 wt% of a catechol-containing polymer or oligomer; or from about 0.25 wt% to about 0.3 wt% of a catechol-containing polymer or oligomer; or from about 0.3 wt% to about 0.35 wt% of a catechol-containing polymer or oligomer; or from about 0.35 wt% to about 0.4 wt% of a catechol-containing polymer or oligomer; or from about 0.4 wt% to about 0.45 wt% of a catechol-containing polymer or oligomer; or from about 0.45 wt% to about 0.5 wt% of a catechol-containing polymer or oligomer; or from about 0.5 wt% to about 0.75 wt% of a catechol-containing polymer or oligomer; or from about 0.75 wt% to about 1 wt% of a catechol-containing polymer or oligomer; or from about 1.25 wt% to about 1.5 wt% of a catechol-containing polymer or oligomer; or from about 1.5 wt% to about 1.75 wt% of a catechol-containing polymer or oligomer; or from about 1.75 wt% to about 2 wt% of a catechol-containing polymer or oligomer.

[0240] In some embodiments, the catechol-containing polymer or oligomer used in the solution is polycatechol styrene (PCS). In some embodiments, the solution comprises from about 0.001 wt% to about 10 wt% of PCS. In some embodiments, the solution comprises from about 0.01 wt% to about 5 wt% of PCS. In some embodiments, the solution comprises from about 0.01 wt% to about 1 wt% of PCS. In some embodiments, the solution comprises from about 0.1 wt% to about 1 wt% of PCS.

[0241] In some embodiments, the solution comprises from about 0.001 wt% to about 0.005 wt% of PCS; or from about 0.005 wt% to about 0.01 wt% of PCS; or from about 0.01 wt% to about 0.02 wt% of PCS; or from about 0.02 wt% to about 0.03 wt% of PCS; or from about 0.03 wt% to about 0.04 wt% of PCS; or from about 0.04 wt% to about 0.05 wt% of PCS; or from about 0.05 wt% to about 0.06 wt% of PCS; or from about 0.06 wt% to about 0.07 wt% of PCS; or from about 0.07 wt% to about 0.08 wt% of PCS; or from about 0.08 wt% to about 0.09 wt% of PCS; or from about 0.09 wt% to about 0.1 wt% of PCS; or from about 0.1 wt% to about 0.11 wt% of PCS; or from about 0.11 wt% to about 0.12 wt% of PCS; or from about 0.12 wt% to about 0.13 wt% of PCS; or from about 0.13 wt% to about 0.14 wt% of PCS; or from about 0.14 wt% to about 0.15 wt% of PCS; or from about 0.15 wt% to about 0.2 wt% of PCS; or from about 0.2 wt% to about 0.25 wt% of PCS; or from about 0.25 wt% to about 0.3 wt% of PCS; or from about 0.3 wt% to about 0.35 wt% of PCS; or from about 0.35 wt% to about 0.4 wt% of PCS; or from about 0.4 wt% to about 0.45 wt% of PCS; or from about 0.45 wt% to about 0.5 wt% of PCS; or from about 0.5 wt% to about 0.75 wt% of PCS; or from about 0.75 wt% to about 1 wt% of PCS; or from about 1.25 wt% to about 1.5 wt% of PCS; or from about 1.5 wt% to about 1.75 wt% of PCS; or from about 1.75 wt% to about 2 wt% of PCS.

[0242] In some embodiments, the solution comprises a catechol-containing polymer or oligomer (such as PCS) in an amount that is a value listed below or within any range defined by any two of the following values, including the endpoints of the range:

[0243] 0.001, 0.002, 0.003, 0.004, 0.005, 0.006, 0.007, 0.008, 0.009, 0.010, ……, 0.020, 0.030, 0.040, 0.050, 0.060, 0.070, 0.080, 0.090, 0.100, ……, 0.200, 0.300, 0.400, 0.500, 0.600, 0.700, 0.800, 0.900, 1.000, ……, 2.000, 3.000, 4.000, 5.000, 6.000, 7.000, 8.000, 9.000, and 10.000.

[0244] In some embodiments, the concentration of the PCS-type catechol-containing material can be as high as 20%.

[0245] In some embodiments, the solution further comprises an aqueous or organic solvent for dissolving the catechol-containing polymer or oligomer. In some embodiments, the organic solvent is acetone, toluene, chloroform, dichloromethane (DCM), ethyl acetate, methyl ethyl ketone (MEK), or a combination thereof.

[0246] In some embodiments, the organic solvent is acetone. In some embodiments, the organic solvent is toluene. In some embodiments, the organic solvent is chloroform. In some embodiments, the organic solvent is dichloromethane (DCM). In some embodiments, the organic solvent is ethyl acetate. In some embodiments, the organic solvent is methyl ethyl ketone (MEK). In some embodiments, the organic solvent is a combination of acetone and toluene. In some embodiments, the organic solvent is acetone and the catechol-containing polymer or oligomer is PCS. In some embodiments, the organic solvent is toluene and the catechol-containing polymer or oligomer is PCS. In some embodiments, the organic solvent is a combination of acetone and toluene and the catechol-containing polymer or oligomer is PCS.

[0247] The pH of the solution is not particularly limited. In some embodiments, the pH of the solution is about 3; or about 3.5; or about 4; or about 4.5; or about 5; or about 5.5; or about 6; or about 6.5; or about 7; or about 7.5; or about 8; or about 8.5; or about 9; or about 9.5; or about 10; or about 10.5; or about 11.

[0248] In some embodiments, the pH of the solution is about 3 - 3.5; or about 3.5 - 4; or about 4 - 4.5; or about 4.5 - 5; or about 5 - 5.5; or about 5.5 - 6; or about 6 - 6.5; or about 6.5 - 7; or about 7 - 7.5; or about 7.5 - 8; or about 8 - 8.5; or about 8.5 - 9; or about 9 - 9.5; or about 9.5 - 10; or about 10 - 10.5; or about 10.5 - 11.

[0249] In one embodiment, the molecular weight range of the PCS monomer / oligomer / polymer is as low as 4000 Da to as high as 1,000,000. This does not exclude that lower molecular weight oligomers or higher molecular weight polymers are suitable for the present disclosure.

[0250] In one embodiment, the molecular weight of the PCS material is any one of the values given in kilodaltons below and any value within the range defined by any two of the following values, including their endpoints:

[0251] 0.2, 0.4, 0.6, 0.8, 1, 2, 3, 4, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210, 220, 230, 240, 250, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 610, 620, 630, 640, 650, 660, 670, 680, 690, 700, 710, 720, 730, 740, 750, 760, 770, 780, 790, 800, 810, 820, 830, 840, 850, 860, 870, 880, 890, 900, 910, 920, 930, 940, 950, 960, 970, 980, 990 and 1000.

[0252] Obviously, the above ranges include the monomeric, oligomeric, and polymeric portions of catechol - styrene.

[0253] VI. High-Performance Fiber-Reinformed Composite Polymer Structures

[0254] In one embodiment, the HPF coated with a catechol-containing sizing agent (such as PCS) of the present disclosure is used to prepare FRCP polymer structures and articles. Thermosetting and thermoplastic polymers are used as matrix materials, as described below. Then, carbon fibers coated with a catechol-containing material (such as PCS) are used in the following matrices to prepare fiber-reinforced composites.

[0255] Table 1

[0256]

[0257] Examples of suitable plastic materials include thermoplastic polymers, thermosetting polymers, resins, and crosslinked resins, including, for example, polyphenylene sulfide (PPS) and polyether ketone ketone (PEKK). The thermoplastic polymer matrix material can include any one of a variety of suitable thermoplastic polymers, such as polypropylene (PP), polyethylene (PE), and polyvinyl chloride (PVC).

[0258] Some matrix resins that can be used as matrices to prepare fiber-reinforced composites from the HPF of the present disclosure are as follows:

[0259] Thermoplastics

[0260] Polypropylene, polyethylene (high density and low density), polycarbonate, polyvinyl chloride (PVC), polyether ether ketone (PEEK), polyether sulfone (PES), polyphenylene sulfide (PPS), polyamide (nylon), polymethyl methacrylate (PMMA), polyetherimide (PEI), acetal (POM), sulfone polymers (PPSU, PSU), ethylene-vinyl acetate (EVA), liquid crystal polymer (LCP), polybutylene terephthalate (PBT), acrylonitrile-butadiene-styrene (ABS), fluoropolymer (PTFE, FEP), thermoplastic elastomer (TPE), thermoplastic polyurethane (TPU), polycyclohexanedimethylene terephthalate (PCT).

[0261] Thermosetting Materials

[0262] Epoxy resin, polyester resin, vinyl ester resin, phenolic resin, polyimide, polyurethane, polystyrene, silicone resin, cyanate ester, melamine-formaldehyde resin, poly(dicyclopentadiene) (pDCPD), polyarylate (PAR), polybenzimidazole (PBI), polychlorotrifluoroethylene (PCTFE), methyl methacrylate-butadiene-styrene (MBS).

[0263] Others

[0264] Polyacrylonitrile (PAN), polyhydroxyalkanoates (PHA), biobased polymers (PLA, PHB), polyoxymethylene copolymer (POM-C).

[0265] VII. Articles Made from Fiber Reinforced Composites (FRC)

[0266] In one aspect of the present disclosure, an article is prepared from the aforementioned FRCs.

[0267] In addition to coating individual carbon fibers, the PCS-type material can also be used as a thin film primer for HPF fiber components. In one embodiment, the component is immersed in a self-polymerizing container of an oligomeric catechol-containing material (such as an oligomer of PCS), and the component is polymerized to produce a PCS layer on the carbon fiber surface. Alternatively, the polymeric PCS in solution form as described in the present disclosure can be used for dip coating or spraying on components or articles formed from the HPFs of the present disclosure. In other words, in one embodiment, the present disclosure relates to preparing a component from the HPF fibers described herein and coating the component with a PCS-type material in solution (dissolved in a solvent such as acetone).

[0268] In one embodiment of the present disclosure, a fiber-reinforced composite polymer is prepared using one or more HPF fibers as described herein, and the fiber-reinforced composite polymer is coated or uncoated with a PCS-type coating material, wherein the matrix is one or more matrix polymers and resins as described herein. An article is made from such a fiber-reinforced composite polymer.

[0269] In one embodiment, the present disclosure provides a method for applying a coating to at least one surface of a substrate made from a fiber-reinforced thermoplastic composite as described herein (sized with and without a PCS-type material), wherein the method comprises: a first step of applying a PCS-type layer optionally filled with graphene particles or zinc particles as a primer to the surface of the substrate, and then a second step of applying the coating to the tacky PCS-type layer filled with zinc particles or graphene particles.

[0270] Despite the low surface energy of the fiber-reinforced thermoplastic composite substrate, a high level of adhesion is generated between the substrate and the coating using the PCS-type layer.

[0271] The tacky PCS-type layer has a thickness of 100 nm to 100 µm; the tacky PCS-type layer is filled with graphene and contains 0.5 wt% to 2 wt% of graphene.

[0272] The present disclosure also provides a substrate (such as an aircraft component) comprising a coating on at least one surface, wherein the substrate comprises a tacky PCS-type layer filled with zinc particles or graphene particles inserted between the surface of the substrate and the coating as a primer.

[0273] According to one embodiment, the panel is made of an FRC material. For example, the panel comprises carbon fibers embedded in a thermoplastic resin matrix, which thermoplastic resin matrix is of the PEEK type, PEKK type, PAEK type or PPS type, for example.

[0274] The coating comprises at least one paint layer or protective layer. According to one embodiment, the coating includes at least one anti-corrosion layer, at least one paint layer, and at least one varnish layer. These different layers are applied in the same manner as in the prior art.

[0275] According to a process, the application method comprises: preparatory steps, such as degreasing, carried out on the face of the substrate, for example, before the step of applying the viscous PCS-type layer. This latter layer can be applied to the face of the substrate in a non-aqueous solution, for example, by spraying or dipping.

[0276] According to one embodiment, the viscous PCS-type layer is filled with graphene particles. The viscous PCS-type layer contains 0.5 wt% to 2 wt% of graphene. In one configuration, the graphene particles are present in flake form. Due to the presence of graphene, the viscous PCS-type layer is electrically and thermally conductive. The graphene present also imparts anti-corrosion properties to the layer.

[0277] According to one embodiment, the viscous PCS-type layer is filled with zinc particles to impart anti-corrosion properties to the layer and to obtain an anti-corrosion barrier free of chromium or cadmium. In this embodiment, the viscous PCS layer contains 0.5 wt% to 2 wt% of zinc.

[0278] Despite the low surface energy of the thermoplastic composite substrate, the use of the viscous PCS-type layer creates a high level of adhesion between the substrate and the coating, without the need for any surface treatment, such as plasma treatment.

[0279] When the viscous PCS-type layer is filled with graphene, it forms a lightning protection layer, which can assist or replace another lightning protection layer, such as a metal mesh. To obtain a lightning protection layer, adding graphene to the viscous PCS-type layer is more effective than adding the same amount of graphene to PCS, because the thickness of the viscous PCS-type layer is significantly less than the thickness of the coating and allows for a greater concentration of graphene to be obtained.

[0280] According to one embodiment, a prior art composite panel covered with a first coating includes a metal mesh inserted between the panel and the first coating, thus forming a lightning protection layer. Such a panel may have a damaged area on its surface where the metal mesh and the first coating are no longer present. According to another advantage of the present disclosure, this type of panel can be repaired by first covering the damaged area with a viscous PCS-type layer filled with graphene particles and then covering the damaged area with a second coating. After repair, the viscous PCS-type layer in contact with the metal mesh ensures the continuity of the lightning protection layer, while the second coating ensures the continuity of the first coating.

[0281] Experiments

[0282] Example 1: Aromatic Polyamide Fibers as High-Performance Fibers

[0283] As described above, the present disclosure relates to high-performance fibers (HPF), such as HPP (high-performance polymer) fibers coated with polycatechol styrene (PCS). In this experiment, raw aramid fibers (AF; 25 g) were placed in a glass reaction vessel. 1 L of acetone was added to the vessel and stirred for 1 hour to clean the aramid fibers.

[0284] A portion of the fibers was separated and dried, and the remaining portion was placed in 1 L of acetone with 60 g of ZnCl2 solution and stirred for 6 hours to break the hydrogen bonds of the fibers (without wishing to be bound by this theory) to functionalize them. A portion of the fibers was separated and dried, and the remaining portion was placed in 1 L of acetone with 5 g of PCS and stirred for 1 hour.

[0285] The fibers were filtered from each solution using vacuum filtration. The filtered fibers were rinsed with 1x phosphate-buffered saline (PBS) and isopropanol to remove any residues, unbound PCS, and debris that did not adhere to the fibers.

[0286] After drying in a vacuum chamber at 25 °C, the fibers were analyzed using SEM. Through visual inspection under magnification, it was observed that the fibers had a thin film coating. The resulting SEM images are as follows: Figure 2A to Figure 2C; Figure 2D to Figure 2F ; and Figure 2G to Figure 2I . Figure 2A to Figure 2C shows a lower magnification, Figure 2D to Figure 2F shows a higher magnification; and Figures G to Figure 2I show the highest magnification used as shown in the SEM. Figures 2A, Figure 2D and Figure 2G show the clean aramid fibers; Figure 2B , Figure 2E and Figure 2H show the ZnCl2-treated clean aramid fibers; and Figures 2C, Figure 2F and Figure 2I show the aramid fibers subsequently coated with ZnCl2 + PCS.

[0287] The present disclosure relates to individual aromatic polyamide fibers coated with a thin poly(catechol-styrene) (PCS) film. The thin polymer film functionalizes the surface of the previously inert aromatic polyamide fibers with catechol moieties, which can contribute to adhesion to the matrix of various thermosetting and thermoplastic composites. In one embodiment, the coating method includes simply stirring the raw aromatic polyamide fibers in an organic solvent containing dissolved PCS. The PCS in the solution forms bonds with the surface of the aromatic polyamide fibers, leaving a deposited thin film. After the coating reaction, the fibers are filtered, rinsed with isopropanol and DI water, and dried in a vacuum chamber to remove any residual solvent.

[0288] This one-step coating process has several advantages over many other coating processes. Previous AF coatings using mussel-inspired materials, specifically polydopamine, required a self-polymerization reaction to occur. This reaction was difficult to manage and control and was not easily scalable. The advantage of PCS is that it is pre-polymerized, so the coating process simply involves allowing the pre-formed catechol-containing polymer to interact with the surface of the aromatic polyamide fibers. Current experiments have been conducted at room temperature in an acetone bath with a 5:1 weight ratio of AF:PCS.

[0289] In one embodiment, the present disclosure relates to individual and multiple HPP fibers coated with a thin poly(catechol-styrene) (PCS) film. The thin polymer film functionalizes the surface of the previously inert carbon fiber with catechol moieties, which can contribute to adhesion to the matrix of various thermosetting and thermoplastic composites. The coating method includes stirring the raw carbon fibers in an organic solvent containing dissolved PCS. The PCS in the solution forms bonds with the surface of the carbon fibers, leaving a deposited thin film. After the coating reaction, the fibers are filtered, rinsed with isopropanol and DI water, and dried, preferably in a vacuum chamber to remove any residual solvent.

[0290] This one-step coating process has several advantages over many other coating processes. The advantage of PCS is that it is pre-polymerized, so in one embodiment of the coating process, the pre-formed catechol-containing polymer interacts with the surface of the carbon fibers.

[0291] Current experiments have been conducted at room temperature in an acetone bath with a 5:1 weight ratio of HPP fibers:PCS. Coating process variables, such as temperature, inert atmosphere, addition of oxidants, varying material ratios, etc., can be adjusted to provide a more optimized fiber coating.

[0292] These coated fibers are incorporated into a composite matrix to produce a fiber-reinforced material.

[0293] Coating Process

[0294] ● In the first step, 25 g of raw material short-cut aromatic polyamide fibers were added to a 4-liter reaction flask.

[0295] ● 1 liter of acetone was added to the reaction flask.

[0296] ● AF and acetone were stirred in the sealed reaction flask at room temperature for 1 hour.

[0297] ● A part of the fibers was separated and dried, and the other part was put into a reaction flask containing 1 liter of acetone and 60 g of ZnCl2.

[0298] ● AF was stirred in the sealed reaction flask at room temperature in a 6% ZnCl2 bath for 6 hours.

[0299] ● A part of the fibers was separated and dried, and the other part was put into a reaction flask containing 1 liter of acetone and 5 g of PCS. PCS was dissolved in an organic solvent.

[0300] ● AF was stirred in the sealed reaction flask at room temperature in a 0.5% PCS bath for 1 hour.

[0301] ● The fibers were filtered from the liquid medium, rinsed with 1x phosphate-buffered saline, and then rinsed with isopropanol to remove any loose PCS and other debris.

[0302] ● The fibers were analyzed under SEM, and Images 2A to 2I were taken.

[0303] In Figure 2, SEM micrographs of aromatic polyamide fibers (2A, 2D, 2G) without any coating treatment; fibers in a 6% ZnCl2 bath (2B, 2E, 2H); and fibers treated in a ZnCl2 bath and a PCS coating (2C, 2F, 2I) are shown. The (2A, 2D, 2G) aromatic polyamide fibers are those that have been cleaned with an acetone bath for one hour. The (2B, 2E, 2H) are part of the cleaned aromatic polyamide fibers stirred in a 6% ZnCl2 bath for 6 hours. The (2C, 2F, 2I) aromatic polyamide fibers are part of the ZnCl2 - treated fibers stirred in a 0.5% PCS bath for 1 hour. The PCS - coated fibers are then washed with 1x phosphate - buffered saline and then with isopropanol to remove any unbound PCS from the fibers. (I) It can be seen that PCS adheres to and coats the individual aromatic polyamide fibers. The ZnCl2 bath is necessary to break the hydrogen bonds formed between the aromatic polyamide fibers themselves, thus improving the surface modification ability of the fibers and allowing new hydrogen bonds to form at this site. The extensive coating on the aromatic polyamide fibers is most likely the result of hydrogen bonds formed between the aromatic polyamide fibers and the functional catechol groups of PCS. Panel 2D and panel 2G are magnified views of panel 2A at 250x and 2Kx respectively at 50x. Panel 2E and panel 2H are magnified views of panel 2B at 250x and 2Kx respectively at 60x. Panel 2F and panel 2I are magnified views of panel 2C at 250x and 2Kx respectively at 60x. The scale bar for panel 2A, panel 2B, and panel 2C is 200 microns, for panel 2D, panel 2E, and panel 2F is 100 microns, and for panel 2G, panel 2H, and panel 2I is 10 microns.

[0304] Surprisingly, simply stirring the dissolved PCS in an organic solvent with the raw aromatic polyamide fibers produces a polymer coating. The fact that no heat or other reactants are required to stimulate the reaction between the materials seems to indicate that PCS has a strong affinity for the surface of the aromatic polyamide fibers.

[0305] The HPP fibers can be staple filaments and can be any of the following polymer types: polyaramide, polyester, and UHMWPE. The length of the HPP fiber staple filaments is not critical, but in one embodiment, it is from 5 microns to 50 mm. The diameter and number of filaments making up the HPP fiber staple filaments are also not critical, but in one embodiment, the diameter is typically from 500 nm to 50 microns and the number of filaments is typically from 100 to 100,000. The HPP fiber staple filaments can be pre - sized.

[0306] Example 2: Carbon Fibers as High-Performance Fibers

[0307] As previously mentioned, the present disclosure relates to carbon fibers (CFs) coated with polycatechol styrene (PCS). In this experiment, raw carbon fibers (25 g) were placed in a glass reaction vessel. 1 L of acetone and 4 g of poly(catechol-styrene) were added to the vessel. Using a overhead stirrer, the mixture was stirred at room temperature for 24 hours. The fibers were filtered out of the solution using vacuum filtration. The filtered fibers were rinsed with isopropanol and deionized water to remove any residues and debris that did not adhere to the fibers.

[0308] After drying in a vacuum chamber at 25 °C, the fibers were analyzed using SEM. Through visual inspection under magnification, it was observed that the fibers had a thin film coating on the carbon fibers. The resulting SEM images are provided in Figure 3A , Figure 3B and Figure 3C , which correspond to magnifications of 7Kx, 2x, and 700x, respectively. Figure 4 shows SEM images of both untreated Teijin Tenax short fibers and PCS-coated short fibers.

[0309] Coating Process

[0310] The current experiment was conducted in an acetone bath at room temperature with a CF:PCS weight ratio of 5:1. The coating process variables, such as temperature, inert atmosphere, addition of oxidizing agent, varying material ratios, etc., can be adjusted to provide a more optimized fiber coating. These coated fibers were incorporated into a composite matrix to produce a fiber-reinforced material.

[0311] The coating process is described in the following steps:

[0312] ● In the first step, 25 grams of raw chopped carbon fibers were added to a 4-liter reaction flask.

[0313] ● Then 1 liter of acetone was added to the reaction flask.

[0314] ● In the next step, 5 grams of PCS were added to the acetone / carbon fiber mixture. The PCS dissolves in the organic solvent.

[0315] ● The mixed contents in the reaction flask were stirred at room temperature for 24 hours in a sealed reaction flask.

[0316] ● The fibers were filtered from the liquid medium and rinsed with isopropanol, followed by rinsing with deionized water to remove any loose PCS and other debris.

[0317] ● The fibers were analyzed under SEM, and the images shown in Figure 3A , Figure 3B and Figure 3C were taken.

[0318] Surprisingly, simply stirring the dissolved PCS in an organic solvent with the raw carbon fibers produces a polymer coating. The fact that no heat or other reactants are needed to stimulate the reaction between the materials seems to indicate that PCS has a strong affinity for the carbon fiber surface.

[0319] Example 3: Carbon Fibers as High-Performance Fibers

[0320] The purpose of this experiment was to test the efficacy / performance of poly(catechol-styrene) (PCS)-coated carbon fibers. A very thin PCS coating (or sizing) on the carbon fibers enhanced the interfacial adhesion between the fibers and the resin in fiber-reinforced plastic composites and increased the interfacial shear strength (IFSS). This was true for both thermosetting and thermoplastic resin systems. In addition, the improvement in fiber / resin interfacial adhesion led to improved material properties of the resulting composites, such as increased flexural strength / modulus and increased compressive strength / modulus.

[0321]

[0322] Then, carbon fibers coated with a catechol-containing material such as PCS were used in the following matrices to prepare fiber-reinforced composites.

[0323] Table 2

[0324]

[0325]

[0326] The Ecodyst system was used for the large-scale coating of carbon fibers. The first fibers to be coated were recycled short carbon fibers from R&M. Approximately 18 liters of acetone were added to the Ecodyst together with 90 g of PCS. For this coating, PCS32 with an Mw of 150,000 g / mol was used. The PCS was completely dissolved in the acetone before adding 250 g of carbon fibers. The carbon fibers were then stirred for 1 hour, after which the PCS solution was drained and collected for subsequent batches. The carbon fibers were then spread out on large cookie sheets and placed under a fume hood overnight to dry and remove any excess acetone. This process was repeated until 2 kg of carbon fibers were coated, and the PCS solution was completely replaced after coating 1 kg of carbon fibers.

[0327] In Figure 4, carbon fibers coated with PCS are shown. SEM micrographs of carbon fibers without any coating treatment (Figure 4A, Figure 4C, Figure 4E) or with a PCS coating ( Figure 4B , Figure 4D , Figure 4F ) are presented. In Figure 4A, Figure 4C, and Figure 4E, the carbon fibers have been cleaned with a one-hour acetone bath. Figure 4B , Figure 4D and Figure 4FA portion of the cleaned carbon fibers stirred in a 0.5% PCS bath for one hour is shown. The PCS-coated fibers were then washed with 1x phosphate buffered saline and then with isopropyl alcohol to remove any unbound PCS from the fibers. In Figure 4F it can be seen that PCS adheres to and coats the individual carbon fibers. Figures 4C and 4E are magnified views of Figure 4A at 800x and 2Kx respectively, at 50x. Figure 4D and Figure 4F are magnified views of Figure 4B at 800x and 2Kx respectively, at 60x. The scale bar for Figure 4A and Figure 4B is 200 microns, for Figure 4C, Figure 4D is 20 microns, and for Figure 4E, Figure 4F is 10 microns.

[0328] Example 4: Recycled Carbon Fibers as High-Performance Fibers

[0329] Recycled carbon fibers are coated with PCS. SEM micrographs of the recycled carbon fibers are provided in Figure 5. (Figures 5A, 5C) are recycled carbon fibers that have been cleaned with acetone; there appears to be a residual coating on the fibers that may be epoxy resin. Figures 5B and Figure 5D show recycled carbon fibers that have been treated with a poly(catechol-styrene) (PCS) coating. The PCS-coated fibers appear to have a thicker and more prominent coating than the residual coating on the recycled carbon fibers. The fibers were cleaned in an acetone bath, stirred in a 0.5% PCS solution for 1 hour, and then rinsed in an isopropyl alcohol bath to remove any unbound PCS. Figures 5C and Figure 5D are magnified views of Figures 5A and 5B at 3Kx respectively, at 250x. The scale bar for Figures 5A and 5B is 200 microns, and for Figures 5C and Figure 5D is 10 microns.

[0330] In addition, it has been shown that the fiber coating thickness can be adjusted by varying the concentration of PCS in the coating bath. However, the optimal coating thickness for improving IFSS and improved composite properties has not yet been determined. Figure 2 shows the effect of varying the concentration of PCS in the coating bath.

[0331] Example 5: PCS Coating Thickness Can Be Controlled by Polymer Concentration

[0332] SEM micrographs of poly(catechol-styrene) (PCS)-coated recycled carbon fibers are shown in Figure 6A to Figure 6D For Figures 6A and 6C, the fibers were coated with a 0.5% PCS solution, which provided good coverage of the fibers. For Figures 5B and Figure 5D, the fibers were coated with a 3% PCS solution, which recoated the fibers with a thick PCS coating. These data indicate that the PCS coating thickness is controllable based on the concentration of the polymer solution. The fibers were cleaned in an acetone bath, stirred in a 0.5% PCS solution or a 3% PCS solution for 1 hour, and then rinsed in an isopropyl alcohol bath to remove any unbound PCS. Figures 6C and Figure 6D are magnified views of Figures 6A and 6B at 250x and 3Kx, respectively. The scale bars for Figures 6A and 6B are 200 microns, and the scale bars for Figures 6C and Figure 6D are 10 microns.

[0333] The fibers used here are recycled carbon fibers containing a large amount (5% to 14%) of residual resin (thought to be epoxy resin). However, it is clear that the thickness of the PCS coating varies with the concentration of the polymer in the coating bath. It must also be noted that the PCS concentration numbers (0.5% and 3%) are the weight percentages of PCS in the acetone bath, not the resulting weight percentages of the coating added to the carbon fibers.

[0334] Example 6: Poly(catechol-styrene) as a Sizing Agent for Carbon Fiber Reinforced Composites

[0335] In this example, PCS was used as a carbon fiber sizing agent to achieve composite material properties. The performance of the PCS sizing agent varies with the resin system. An epoxy resin system was used for this test. Dip coating was used to coat carbon fiber tows and fabrics with PCS. The PCS sizing thickness and its weight concentration relative to the carbon fiber material (while varying the dip bath concentration) were quantified. The laminates were composed of PCS-sized tows and / or fabrics. The effect of PCS sizing on composite material properties was evaluated: tensile strength / modulus; flexural strength / modulus; and compressive strength / modulus. The properties of the composites constructed with PCS sizing were compared with those of composites constructed using as-received fabric (with standard sizing) and desized fabric. This allowed for a clear evaluation of the effect of PCS sizing on composite material properties. Dip coating was used to prepare PCS-sized carbon fiber fabrics and tows. Since PCS is not water-soluble, a suitable solvent was selected for the coating process. For example, acetone was used for coating applications. The dip coating process was optimized to control the PCS sizing addition, which was controlled by the PCS concentration in the coating bath and the residence time of the fibers in the coating solution.

[0336] Three different "levels" of PCS sizing addition were selected (e.g., adding 0.5 mass%, 1 mass%, and 1.5 mass% of PCS to the fiber material). Using various sized carbon fiber fabrics, multi-layer laminates were fabricated for the purpose of material property testing. For the purpose of experimental control, laminates were also fabricated using as-received fabric (with standard sizing) and unsized fabric. A suitable epoxy resin was used for all composite samples. After fabrication, panels were cut to produce test samples for testing.

[0337] For the test samples, the following material properties are evaluated:

[0338] ● Tensile strength and modulus

[0339] ● Flexural strength and modulus

[0340] ● Compressive strength and modulus

[0341] The material property data from the samples with PCS sizing are compared with the control samples to evaluate the impact on the overall material properties.

[0342] To test the increased laminate bond strength, lap shear tests are performed on composite laminates bonded with an epoxy 250°F cured adhesive. Baseline samples without surface preparation and samples with surface preparation are tested. Samples are also prepared with a 1% additive brushed onto the unprepared and prepared surfaces. In one test, rubber sheets are bonded to a bismaleimide laminate surface with various adhesives at elevated temperatures and room temperature. The peel strength is measured. In one evaluation, a paint adhesion test of polyetheretherketone (PEEK) laminates is performed.

[0343] Two samples of polycatechol styrene are used for the sizing of carbon fibers. The molecular weight of the first sample is 240K daltons, and the molecular weight of the second sample is 110K daltons. The carbon fibers used are laid in a 0° / 90° biaxial orientation. Sized and unsized fibers are preformed. Dip coating solutions of PCS are prepared in acetone at concentrations of 0.5 wt%, 1.0 wt%, 1.5 wt%, and 2 wt%. Composite plates are made from sized and unsized fibers. Chomarat ® carbon fiber (0 / 90) (Chomarat North America, SC) is used. The carbon fibers ( Figure 7A ) are immersed in the solution ( Figure 7B and Figure 7C ), for example, 0.5 g of the polymer is immersed in 99.5 g of acetone for 5 minutes, 15 minutes, and 30 minutes. The samples are air dried for 24 hours ( Figure 7D ).

[0344] The MP peak is observed after a 30-minute dip coating treatment. No OH stretch is detected near the wavenumber of 3300 - 3400 cm -1 . See Table 3 below and Figure 7.1 :

[0345]

[0346] Figure 7E 、 Figure 7F and Figure 7G show the two-layer ready-to-use Chomarat at three different magnifications® Carbon fiber (0 / 90). These fibers are untreated and some sizing agent was seen in the SEM before burnout. To remove the sizing already present in the ready-to-use carbon fibers, they were burned out in a furnace at 400 °C for one hour. Figure 7H The carbon fibers before burnout are shown, and Figure 7I and Figure 7J the carbon fibers after burnout are shown. Figure 7K 、 Figure 7L and Figure 7M are SEM micrographs of the carbon fibers after furnace burnout. It can be seen that the carbon fibers are now unsized.

[0347] FTIR was performed on carbon fibers, on 240K polymer samples, and on carbon fibers with 240K polymer sized on them using a Thermo Scientific Nicolet iS50 FT-IR spectrometer (which measures the absorption spectrum in the mid-IR region (5000 - 400 cm -1 ). The infrared spectral region was 4000 - 400 cm -1 , and the number of scans was 64.

[0348] Figure 8 FTIR scans of the ready-to-use and burned-out carbon fibers are shown. Both the ready-to-use and unsized carbon fibers were dip-coated with an acetone solution of 240K PCS.

[0349] Figure 9A 、 Figure 9B and Figure 9C are SEMs of the ready-to-use carbon fibers coated with a 0.5% PCS polymer acetone solution and dip-coated for 30 minutes.

[0350] Figure 10A 、 Figure 10B and Figure 10C are SEMs of the ready-to-use carbon fibers coated with a 1.0% PCS polymer acetone solution and dip-coated for 30 minutes.

[0351] Figure 11 FTIR scans of the ready-to-use carbon fibers coated with 1% PCS in acetone solvent with dip-coating for 5 minutes, 15 minutes, and 30 minutes are shown. The PCS used was 240K Dalton molecular weight material.

[0352] Figure 12A 、 Figure 12B and Figure 12C are SEMs of the ready-to-use carbon fibers coated with a 1.5% PCS polymer acetone solution and dip-coated for 5 minutes.

[0353] Figure 13A , Figure 13B and Figure 13C are SEMs of as - received carbon fibers coated with a 1.5% PCS polymer acetone solution and dip - coated for 15 minutes.

[0354] Figure 14A , Figure 14B and Figure 14C are SEMs of as - received carbon fibers coated with a 1.5% PCS polymer acetone solution and dip - coated for 30 minutes.

[0355] Figure 15 show FTIR scans of as - received carbon fibers coated with 1.5% PCS in acetone solvent with dip - coating times of 5 minutes, 15 minutes, and 30 minutes. The PCS used is a 240K Dalton molecular weight material.

[0356] Figure 16A , Figure 16B and Figure 16C are SEMs of as - received carbon fibers coated with a 2.0% PCS polymer acetone solution and dip - coated for 5 minutes.

[0357] Figure 17A , Figure 17B and Figure 17C are SEMs of as - received carbon fibers coated with a 2.0% PCS polymer acetone solution and dip - coated for 15 minutes.

[0358] Figure 18A , Figure 18B and Figure 18C are SEMs of as - received carbon fibers coated with a 2.0% PCS polymer acetone solution and dip - coated for 30 minutes.

[0359] Figure 19 show FTIR scans of as - received carbon fibers coated with 2.0% PCS in acetone solvent with dip - coating times of 5 minutes, 15 minutes, and 30 minutes. The PCS used is a 240K Dalton molecular weight material.

[0360] Figure 20A shows the upper surface of the carbon fiber after dip - coating for 5 minutes, 15 minutes, and 30 minutes. Figure 20B shows the bottom surface of the carbon fiber after dip - coating for 5 minutes, 15 minutes, and 30 minutes.

[0361] Figure 21 shows carbon fibers sized with PCS via dip - coating and then used to prepare a laminate with a PEEK matrix.

[0362] It can be seen that for 1.5 wt% and 2 wt% dip coating with 240 kDa PCS in acetone, distinct peaks and sizing were observed on CF (ready-to-use).

[0363] In a similar manner, unsized carbon fibers (burned ready-to-use) were also coated with 0.5%, 1.0%, 1.5% and 2.0% PCS acetone solutions. Two molecular weights of PCS were used to form the dip coating solutions.

Claims

1. A coated high performance fiber (HPF), wherein the HPF is coated with a catechol-containing material, and the catechol-containing material comprises a polymer containing catechol, semiquinone or quinone.

2. The coated HPF according to claim 1, wherein the catechol-containing material coated on the HPF comprises a monomer, oligomer or polymer catechol or catechol-containing material, wherein the catechol is present as catechol and / or as semiquinone and / or as quinone, but no amine is present; and wherein the polymer layer optionally comprises at least one of the following: a) a reactive substance separated from the catechol or catechol-containing material; and b) a catalyst, cocatalyst or accelerator.

3. The coated HPF according to claim 1, wherein the polymeric material comprises a reactive substance separated from the catechol-containing polymer or oligomer; and the reactive substance is a polyurethane component, an epoxy resin, an acrylate monomer or oligomer, a methacrylate monomer or oligomer, a silane or a combination thereof.

4. The coated HPF according to claim 3, wherein the reactive substance is: (i) a polyurethane component; (ii) a polyurethane component, which is a polyol or an organic compound containing multiple hydroxyl groups, and wherein the polyurethane is linear or branched; (iii) Polyurethane component, said polyurethane component being 1,6 - hexanediol, glycerol, Stepanpol PDC - 279 ® or polycaprolactone triol; (iv) an epoxy resin; (v) an epoxy resin, which is an epoxy monomer, epoxy oligomer, polyepoxide or a combination thereof; and wherein the epoxy resin is linear or branched; (vi) an epoxy resin, which is bisphenol A diglycidyl ether, bisphenol A epoxy resin, bis(4-glycidyloxyphenyl)methane, bisphenol E diglycidyl ether (DGEBE), 2,2'-[l,l-ethylenediylbis(4,1-phenyleneoxymethylene)] bisoxirane, bisphenol F diglycidyl ether (DGEBF), poly(bisphenol A-co-epichlorohydrin) or a combination thereof; (vii) an acrylate monomer or oligomer; (viii) an acrylate monomer or oligomer, which is an acrylate monomer containing at least one of a carboxylate and a carbonitrile and a vinyl group; and wherein the acrylate is linear or branched; or (ix) an acrylate monomer or oligomer, which is ethyl acrylate, ethylene-methyl acrylate, methyl methacrylate, 2-chloroethyl vinyl ether, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, butyl acrylate, trimethylolpropane triacrylate (TMPTA) or a combination thereof.

5. The coated HPF according to any one of the preceding claims, wherein the polymer layer comprises the catalyst, the cocatalyst or the accelerator; and the catalyst, the cocatalyst or the accelerator is a polyurethane catalyst for promoting polyurethane polymerization reaction, an epoxy resin catalyst for promoting epoxy resin polymerization reaction, an acrylate catalyst for promoting acrylate polymerization reaction or a combination thereof.

6. The coated HPF according to claim 5, wherein the catalyst, the cocatalyst or the accelerator is: (i) A polyurethane catalyst that promotes polyurethane polymerization; (ii) A polyurethane catalyst that promotes polyurethane polymerization, and the polyurethane catalyst is 1,4-diazabicyclo[2.2.2]octane, K-KAT 6212, benzyldimethylamine, or a combination thereof; (iii) An epoxy resin catalyst that promotes epoxy resin polymerization; (iv) An epoxy resin catalyst that is 1,4-diazabicyclo[2.2.2]octane; (v) An acrylate catalyst that promotes acrylate polymerization; or (vi) An acrylate catalyst that is acrylic acid or a free radical polymerization promoter.

7. The coated HPF according to any one of the preceding claims, wherein the coating of the polymeric material has a thickness of: (i) From about 5 nanometers to about 100 micrometers; (ii) From about 15 nanometers to about 50 micrometers; (iii) From about 15 nanometers to about 15 micrometers; (iv) From about 50 nanometers to less than about 15 micrometers; or (v) From about 50 nanometers to about 1.5 micrometers.

8. The coated HPF according to any one of the preceding claims, wherein the catechol-containing polymer or oligomer comprises polycatechol styrene (PCS).

9. The coated HPF according to any one of the preceding claims, wherein the molecular weight is in the range of 100 to 1,000,000.

10. The coated HPF according to claim 8, wherein the PCS comprises from about 15% to about 85% catechol.

11. The coated HPF according to claim 10, wherein the PCS comprises about 25% catechol or about 35% catechol.

12. The coated HPF according to any one of the preceding claims, wherein the HPF is a polymer.

13. The coated HPF according to any one of the preceding claims, wherein the HPF is an aromatic polyamide, a super aromatic polyamide, an aromatic polyamide copolymer, a meta-aramid, an LCP, a UHMWPE polymer, a polyamide, a polyester, a polyolefin, or a combination thereof.

14. A fiber-reinforced composite comprising one or more HPFs according to claim 13.

15. A coated high-performance fiber (HPF) according to claims 1 to 11, wherein the HPF is a carbon fiber.

16. A fiber-reinforced composite comprising the HPF fiber according to claim 15.

17. A fiber-reinforced composite according to claim 14 or 16, wherein the matrix polymer is selected from: Polypropylene, polyethylene, polycarbonate, polyvinyl chloride, polyetheretherketone, polyethersulfone, polyphenylene sulfide, polyamide, polymethyl methacrylate, polyetherimide, acetal resin, sulfone polymer, ethylene-vinyl acetate, liquid crystal polymer, polybutylene terephthalate, acrylonitrile-butadiene-styrene, fluoropolymer, thermoplastic elastomer, thermoplastic polyurethane, cyclohexanedimethanol terephthalate, epoxy resin, polyester resin, vinyl ester resin, phenolic resin, polyimide, polyurethane, polystyrene, silicone resin, cyanate ester, melamine-formaldehyde resin, poly(dicyclopentadiene), polyarylate, polybenzimidazole, polychlorotrifluoroethylene, methyl methacrylate-butadiene-styrene, polyacrylonitrile, polyhydroxyalkanoate, polylactic acid, polyhydroxybutyrate, polyoxymethylene copolymer.

18. A method for preparing the HPF according to claim 13 or 15, the method comprising: Exposing the HPF to a prepolymerized catechol-containing polymer dissolved in one or more solvents.

19. A method for functionalizing a surface of an HPF surface according to claim 13 or 15, the method comprising: Exposing the said HPF to a prepolymerized catechol-containing polymer dissolved in one or more solvents.

20. The coated HPF according to claim 13 or 15, wherein the HPF is completely or partially covered with a material comprising a PCS polymer.

21. An article comprising the fiber-reinforced composite according to claim 13 or 15.

22. A method for applying a coating to at least one face of a substrate made of the fiber-reinforced composite according to claim 14 or 16, wherein the method comprises: Applying a PCS layer filled with graphene particles or zinc particles as a primer to the at least one face of the substrate, and Applying a coating to the PCS layer filled with zinc particles or graphene particles.

23. The method according to claim 21, wherein: The viscous PCS layer filled with zinc particles or graphene particles has a thickness between 200 nm and 100 µm; and / or The PCS layer is filled with graphene particles and contains 0.5 wt% to 2 wt% of graphene.

24. A substrate comprising a coating applied on at least one face by implementing the method according to claim 21 or 22.

25. An aircraft component comprising the substrate according to claim 23.

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