FIBER COMPOSITE STRUCTURE AND MANUFACTURING METHOD THEREOF

Abstract

Provided is a fiber composite structure including a plurality of twisted fiber bundles, wherein each of the fiber bundles includes a plurality of fiber strands, an adhesive coated on the fiber strands, and a functional particle interposed between the fiber strands. The functional particle includes a material different from that of the fiber strands. The adhesive includes polydopamine.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. non-provisional patent application claims priority under 35 U.S.C. § 119 of Korean Patent Application No. 10-2023-0103754, filed on Aug. 8, 2023, the entire contents of which are hereby incorporated by reference.

BACKGROUND

The present disclosure herein relates to a fiber composite structure and a manufacturing method thereof.

Compared to a general fiber, a fiber composite structure has advantages such as reduced weight, improved strength, improved processability, and the like. Currently, the most commonly used fiber composite structure is fiber reinforced plastic (FRP), which uses a method of placing a fiber in a polymer matrix to improve the strength. Such a fiber structure composite may be manufactured using only one fiber type, or may be manufactured by using several fiber types in combination. Research has been conducted to improve the physical and chemical properties of a fiber composite structure.

CITATION LIST

Non-Patent Document

• 1. The Chemistry behind Catechol-Based Adhesion J. Saiz-Poseu, J. Mancebo-Aracil, F. Nador, F. Busque, and D. Ruiz-Molina, Angew.Chem.Int.Ed.2019, 58, 696-714, https://onlinelibrary.wiley.com/doi/10.1002/anie.201801063
• 2. Mussel-inspired surface chemistry for multifunctional coatings H Lee, SM Dellatore, WM Miller, PB Messersmith, SCIENCE, 2007, 318, pp. 426-430, DOI: 10.1126/science.1147241

SUMMARY

The present disclosure provides a structure of a fiber composite structure having excellent strength and hydrophilicity, and a manufacturing method thereof.

An embodiment of the inventive concept provides a fiber composite structure including a plurality of fiber bundles, wherein each of the fiber bundles includes a plurality of fiber strands, and including an adhesive coated on the fiber strands, and a functional particle interposed between the fiber strands, wherein the functional particle includes a material different from that of the fiber strands, and the adhesive includes polydopamine.

According to some embodiments, the fiber strands may include a natural fiber or an artificial fiber.

According to some embodiments, the natural fiber may include at least one of a ramie fiber, a linen fiber, a cotton fiber, a jute fiber, a wool fiber, a silk fiber, or a fur fiber.

According to some embodiments, the natural fiber may include a fibrous structure like human hair.

According to some embodiments, the artificial fiber may include at least one of polyethylene terephthalate (PET), polypropylene, polyester, nylon, Kevlar, an acrylic fiber, a metal fiber, a glass fiber, or a carbon fiber.

According to some embodiments, the functional particle may include at least one of a nano-material such as cellulose, graphene, carbon nanotube, and carbon black, or a particulate material having a size of approximately 1 to approximately 100 micrometers, such as a black rayon particle.

According to some embodiments, a first aspect ratio of each of the fiber strands may be greater than a second aspect ratio of the functional particle.

According to some embodiments, the first aspect ratio may be 1 to 1000, and the second aspect ratio may be 1 to 10.

According to some embodiments, a gap between adjacent fiber strands may form a pore, wherein the pore may have a size of approximately 10 nm to approximately 100 μm.

In an embodiment of the inventive concept, a fiber composite structure includes a plurality of collected or twisted fiber bundles, wherein each of the fiber bundles includes a plurality of fiber strands, and includes an adhesive coated on the fiber strands, wherein the adhesive includes protruding first nano-protrusions, and the adhesive includes polydopamine.

In an embodiment of the inventive concept, a method for manufacturing a fiber composite structure includes preparing a plurality of fiber bundles, wetting the fiber bundles in a solution containing an adhesive material, and drying the fiber bundles in the air immediately after taking the fiber bundles wetted in the solution out of the solution.

According to some embodiments, the wetting of the fiber bundles in the solution may be performed within 1 minute.

According to some embodiments, the drying of the fiber bundles may be performed within 1 hour.

According to some embodiments, the solution further may further include a functional particle, wherein the functional particle may include at least one of a nano-material such as cellulose, graphene, carbon nanotube, and carbon black, or a particulate material having a size of approximately 1 to approximately 100 micrometers, such as a black rayon particle.

According to some embodiments, the method may further include performing a plasma treatment on surfaces of the fiber bundles prior to the wetting of the fiber bundles in the solution.

According to some embodiments, the adhesive material may include one among catechol-based adhesive materials such as dopamine, polydopamine, pyrogallol, alpha-methyldopamine, norepinephrine, dihydroxyphenylalanine, alpha-methyldopa, droxdodopa, 5-hydroxydopamine, deacetylated chitosan-catechol, hyaluronic acid-catechol, and alginate-catechol, or chitosan, poly(allylamine), poly(L-lysine), and poly(ethyleneimine).

BRIEF DESCRIPTION OF THE FIGURES

The accompanying drawings are included to provide a further understanding of the inventive concept, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the inventive concept and, together with the description, serve to explain principles of the inventive concept. In the drawings:

FIG. 1 is a diagram schematically showing a fiber composite structure according to some embodiments of the present invention;

FIG. 2 is an enlarged diagram of aa of FIG. 1;

FIG. 3A, FIG. 3B, and FIG. 3C are conceptual diagrams showing a process of manufacturing a fiber composite structure;

FIG. 4A, FIG. 4B, and FIG. 4C are conceptual diagrams showing a process of manufacturing a fiber composite structure;

FIG. 5 is a conceptual diagram showing a process of manufacturing a fiber composite structure according to some embodiments;

FIG. 6 is a stress-strain diagram of Example 1, Comparative Example 1, and Comparative Example 2;

FIG. 7 is a graph showing changes in water contact angle over time in Example 3 and Comparative Example 2; and

FIG. 8 is a graph showing changes in water contact angle according to the number of times of washing in Example 3 and Example 4.

DETAILED DESCRIPTION

In order to facilitate sufficient understanding of the configuration and effects of the inventive concept, preferred embodiments of the inventive concept will be described with reference to the accompanying drawings. However, the inventive concept is not limited to the embodiments set forth below, and may be embodied in various forms and modified in many alternate forms. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art to which the present invention pertains. In the accompanying drawings, elements are illustrated enlarged from the actual size thereof for convenience of description, and the ratio of each element may be exaggerated or reduced.

Unless otherwise defined, terms used in the embodiments of the inventive concept may be interpreted as meanings commonly known to those skilled in the art. Hereinafter, embodiments of the inventive concept will be described with reference to the accompanying drawings to describe the inventive concept in detail.

FIG. 1 is a diagram schematically showing a fiber composite structure according to some embodiments of the present invention. FIG. 2 is an enlarged diagram of aa of FIG. 1.

Referring to FIG. 1, a fiber composite structure 1000 may include a plurality of fiber bundles 100. The fiber bundles 100 may simply be bundled or twisted. The fiber bundles 100 may be entangled with each other.

As shown in FIG. 1 and FIG. 2, each of the fiber bundles 100 may include fiber strands 110 disposed adjacent to each other, and a polydopamine adhesive 300 coated on each of the fiber strands 110.

The fiber strands 110 may include a natural fiber and an artificial fiber. The natural fiber may include at least one of plant-based fibers such as ramie fiber, linen fiber, cotton fiber, or jute fiber. The natural fiber may include animal-based fiber such as wool fiber, silk fiber, and wool (animal hair) fiber. In addition, the natural fiber may include a fibrous structure like human hair.

The artificial fiber may include at least one of rayon, which is a recycled fiber, lyocell fiber, and polyethylene terephthalate (PET), polypropylene, and polyester, which are synthetic fibers, nylon, Kevlar, or an acrylic fiber. In addition, the artificial fiber may include at least one of a metal fiber, a glass fiber, or a carbon fiber, which are inorganic fibers. The fiber strands 110 may be composed of only one fiber, or may be composed by including different types of fibers.

A gap between adjacent fiber strands 110 may form a pore OP. As an example, the pore OP may have a size of approximately 10 nm to approximately 100 μm.

The polydopamine adhesive 300 may contain polydopamine. The polydopamine may be formed from dopamine, a biomaterial. The polydopamine adhesive 300 may bond or fix the fiber strands 110 to each other, and may bond or fix the fiber bundles 100 to each other.

The adhesive may include a molecule that is polymerized by combining oxygen and has increased adhesion on any surface, such as hydrophilic, water-repellent, organic and inorganic surfaces, and may include catechol-based and amine-based molecules. The catechol-based molecule may be dopamine, polydopamine, pyrogallol, alpha-methyldopamine, norepinephrine, dihydroxyphenylalanine, alpha-methyldopa, droxdodopa, 5-hydroxydopamine, deacetylated chitosan-catechol, hyaluronic acid-catechol, or alginate-catechol, and may include one of chitosan, poly(allylamine), poly(L-lysine), and poly(ethyleneimine), which are amine-based molecules.

Functional particles 400 may be interposed between the fiber strands 110 and/or the fiber bundles 100. The functional particles 400 may include a material different from that of the fiber strands 110. The functional particles 400 may include, for example, at least one of a nano-particle such as cellulose, graphene, carbon nanotube, and carbon black, a micro-particle having a size of approximately 1 to approximately 100 micrometers, such as a black rayon particle, or the like. In the present specification, a particle refers to an object having a shape such as a sphere in zero dimension, a linear shape in one dimension, and a plane in two dimensions. As an example, the functional particle may be a particle fiber such as black rayon.

Each of the fiber strands 110 may have a first aspect ratio, and the functional particles 400 may have a second aspect ratio. The first aspect ratio may be larger than the second aspect ratio. The first aspect ratio may be 1 to 1000, and the second aspect ratio may be 1 to 10. The length of each of the fiber strands 110 may be greater than the length of each of the functional particles 400.

FIG. 3A, FIG. 3B, and FIG. 3C are conceptual diagrams showing a process of manufacturing a fiber composite structure. FIG. 4A, FIG. 4B, and FIG. 4C are conceptual diagrams showing a principle of forming a fiber composite structure. Specifically, FIG. 4A, FIG. 4B, and FIG. 4C are cross-sectional diagrams of fiber strands, and illustrations which describe a process in which the fiber strands are bonded and twisted to each other.

Referring to FIG. 3A, a plurality of fiber strands 110 may be provided in a state of not being bonded or fixed to each other. The fiber strands 110 illustrated in FIG. 3A are designed to have a shape similar to that of a dandelion seed.

Referring to FIG. 3B, a dopamine solution 200 may be coated on the plurality of fiber strands 110. The dopamine solution 200 may contain dopamine. The dopamine solution 200 may further contain a Tris buffer, ethanol, sodium (Na), and water. The dopamine solution 200 may be coated by a method such as dip coating, drip coating, or the like. The coating of the dopamine solution 200 may be performed within 1 second to 1 minute.

As shown in FIG. 3B and FIG. 4A, the dopamine solution between adjacent fiber strands 110 may adhere to the surfaces of the fiber strands 110 by a capillary effect, and may remain in an agglomerated state. According to some embodiments, the dopamine solution 200 may further include the functional particles 400.

For example, as shown in FIG. 4A, the fiber strands 110 may include a first fiber strand F1, a second fiber strand F2, a third fiber strand F3, and a fourth fiber strand F4 which are disposed adjacent to each other. The dopamine solution 200 between the first to fourth fiber strands F1 to F4 may be adhered to the first to fourth fiber strands F1 to F4 by a capillary phenomenon. The functional particle 400 may be disposed between the first to fourth fiber strands F1 to F4.

As shown in FIG. 3B and FIG. 4B, the fiber strands 110 coated with the dopamine solution 200 may be dried naturally in the air atmosphere. Oxygen (O₂) is injected through the interface between air and the dopamine solution 200, and water may evaporate. In the process in which water evaporates, the first to fourth fiber strands F1 to F4 may be brought close to each other, and the first to fourth fiber strands F1 to F4 may receive rotational force. In addition, the first to fourth fiber strands F1 to F4 may become closer to the functional particle 400. In the above process, oxygen diffused in the air and introduced and a dopamine monomolecule combine and are polymerized to form polydopamine.

Referring to FIG. 3C and FIG. 4C, the polydopamine adhesive 300 dopamine may be formed by the polymerization of dopamine. In the evaporation process of water and the formation process of the polydopamine adhesive 300, the first to fourth fiber strands F1 to F4 may bond to each other to form a fiber bundle 100.

FIG. 5 is a conceptual diagram showing a process of manufacturing a fiber composite structure according to some embodiments. Except for those to be described below, the same descriptions as those described above with reference to FIG. 3A to FIG. 3C and FIG. 4A to FIG. 4C are redundant, and thus will be omitted.

Referring to FIG. 5, a surface 100S of the fiber strand 110 may be subjected to plasma treatment to form first nano-protrusions NS1. The plasma treatment may be, for example, oxygen plasma treatment. The oxygen plasma treatment may be performed by creating a vacuum, injecting an oxygen gas, generating plasma, and then reacting the plasma with the surface 110s of the fiber strand 110. The reacting of the plasma with the surface 1105 of the fiber strand 110 may be performed within approximately 1 minute to approximately 1 hour. The plasma processing time may vary depending to the type of a substrate and the conditions of plasma processing. However, the plasma treatment is required to be performed for a predetermined period of time to form each of the first nano-protrusions NS1 with a greater height, and to increase the aspect ratio of the first nano-protrusions NS1. For example, the plasma treatment may be performed for about 30 minutes. The first nano-protrusions NS1 may be arranged along a first direction D1 parallel to the surface 1105 of the fiber strand 110. The first nano-protrusions NS1 may protrude in a second direction D2 perpendicular to the surface 1105 of the fiber strand 110. At least some of the first nano-protrusions NS1 may be bundled and clumped to each other.

The surface 1105 of the fiber strand 110 may be coated with the dopamine solution 200, and be dried naturally in the air. The resulting polydopamine adhesive 300 may include second nano-protrusions NS2. Each of the second nano-protrusions NS2 may be formed on the first nano-protrusion NS1 or the bundled first nano-protrusion NS1. The second nano-protrusions NS2 may overlap the first nano-protrusions NS1 in the second direction D2.

Example 1

Ramie fiber strands not bonded to each other with an adhesive or the like, and not twisted were prepared. A tris buffer, ethanol, dopamine, and NaIO₄ were mixed and stirred to prepare a dopamine solution. The ramie fiber strands were immersed in the dopamine solution for no more than 1 minute. Thereafter, the ramie fiber strands were taken out of the dopamine solution, and dried in the air for no more than 1 hour.

Example 2

Black rayon was additionally added to the dopamine solution of Example 1.

Example 3

PET fiber strands not bonded to each other with an adhesive or the like, and not twisted were prepared. Plasma treatment was performed on the PET fiber. The plasma treatment is a process of forming a nano-structure by etching the surface of a fiber using a gas such as oxygen, and imparting hydrophilicity at the same time. By injecting an oxygen (O₂) gas of 40 sccm at a vacuum degree of 40 mTorr, the plasma treatment was performed on the fiber strands under a power of 50 W and a voltage of 400 V. Thereafter, a tris buffer, ethanol, dopamine, and NaIO₄ were mixed and stirred to prepare a dopamine solution. The PET fiber strands were immersed in the dopamine solution for no more than 1 minute. Thereafter, the PET fiber strands were taken out of the dopamine solution, and dried in the air for no more than 1 hour.

Example 4

The same procedure as in Example 3 was performed, except that plasma treatment was not performed in Example 3.

Comparative Example 1

Ramie fiber strands not bonded to each other with an adhesive or the like, and not twisted were prepared.

Comparative Example 2

Ramie fiber strands not bonded to each other with an adhesive or the like, and not twisted were prepared, and a force was applied to one ends and the other ends of the corresponding ramie fiber strands in opposite directions to each other to create a state in which ramie fiber strands were twisted.

Comparative Example 3

The same procedure as in Example 3 was performed, except that the process of coating and drying the dopamine solution was omitted.

FIG. 6 is a stress-strain diagram of Example 1, Comparative Example 1, and Comparative Example 2. Referring to FIG. 6, it has been observed that Example 1 has a stronger strength than Comparative Example 1 and Comparative Example 2.

FIG. 7 is a graph showing changes in water contact angle over time in Example 3 and Comparative Example 2. Referring to FIG. 7, it can be seen that Example 3 has a smaller water contact angle than Comparative Example 2. In addition, during the curing over time, Comparative Example 2 has a sharp increase in the water contact angle, while Example 3 has a small increase in the water contact angle.

FIG. 8 is a graph showing changes in water contact angle according to the number of times of washing in Example 3 and Example 4. Comparing Example 3 with Example 4, it has been observed that Example 3 has a smaller water contact angle than Example 4. In addition, even when the number of times of washing is increased, Example 3 has a smaller water contact angle than Example 4, and thus, maintains durability.

According to one concept of the present invention, a fiber composite structure includes twisted fiber bundles, wherein each of the fiber bundles includes a plurality of fiber strands, and the fiber bundles and the fiber strands may be bonded to each other by a polydopamine adhesive. As a result, the strength of the fiber composite structure may increase (see FIG. 6).

According to another concept of the present invention, a fiber composite structures may include nano-protrusions on surfaces of fiber strands by performing plasma treatment on the fiber strands. By coating a dopamine solution on the plasma-treated fiber strands and drying the same in the air, a polydopamine adhesive may also include nano-protrusions. Polydopamine has hydrophilicity (ex: water contact angle of less than 90 degrees) due to the nature of the material, and the polydopamine adhesive may have superhydrophilicity (ex: water contact angle of less than 10 degrees) due to the inclusion of the nano-protrusions. The superhydrophilicity of the polydopamine adhesive may be maintained despite changes in time and environment compared to a case in which only plasma treatment is performed and polydopamine is not coated (see FIG. 7) or a case in which polydopamine is coated without plasma treatment.

A fiber composite structure according to the inventive concept includes twisted fiber bundles, wherein each of the fiber bundles includes a plurality of fiber strands, and the fiber bundles and the fiber strands may be bonded to each other by a polydopamine adhesive. The polydopamine adhesive may twist and strongly bond the fiber bundles and the fiber strands during a curing process. As a result, the strength of the fiber composite structure may increase. The polydopamine adhesive according to some embodiments may include nano-protrusions on the surface thereof. As a result, the fiber composite structure may be superhydrophilic.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, it will be understood by those who have ordinary skills in the art to which the present invention pertains that the present invention may be embodied in other specific forms without changing the technical spirit or essential features thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims

1. A fiber composite structure comprising: a plurality of fiber bundles, wherein each of the fiber bundles includes a plurality of fiber strands;an adhesive coated on the fiber strands; anda functional particle interposed between the fiber strands,wherein: the functional particle includes a material different from that of the fiber strands; andthe adhesive includes polydopamine.

2. The fiber composite structure of claim 1, wherein the fiber strands comprise a natural fiber or an artificial fiber.

3. The fiber composite structure of claim 2, wherein the natural fiber comprises at least one of a ramie fiber, a linen fiber, a cotton fiber, a jute fiber, a wool fiber, a silk fiber, or a fur fiber.

4. The fiber composite structure of claim 2, wherein the natural fiber comprises a fibrous structure like human hair.

5. The fiber composite structure of claim 2, wherein the artificial fiber comprises at least one of polyethylene terephthalate (PET), polypropylene, polyester, nylon, Kevlar, an acrylic fiber, a metal fiber, a glass fiber, or a carbon fiber.

6. The fiber composite structure of claim 1, wherein the functional particle comprises at least one of a nano-material such as cellulose, graphene, carbon nanotube, and carbon black, or a particulate material having a size of approximately 1 to approximately 100 micrometers, such as a black rayon particle.

7. The fiber composite structure of claim 1, wherein a first aspect ratio of each of the fiber strands is greater than a second aspect ratio of the functional particle.

8. The fiber composite structure of claim 7, wherein: the first aspect ratio is 1 to 1000; andthe second aspect ratio is 1 to 10.

9. The fiber composite structure of claim 1, wherein a gap between adjacent fiber strands forms a pore, wherein the pore has a size of approximately 10 nm to approximately 100 μm.

10. A fiber composite structure comprising: a plurality of collected or twisted fiber bundles, wherein each of the fiber bundles includes a plurality of fiber strands; andan adhesive coated on the fiber strands,wherein: the adhesive includes protruding first nano-protrusions; andthe adhesive includes polydopamine.

11. The fiber composite structure of claim 10, wherein the first nano-protrusion has the shape of a nano-fiber, a nano-pillar, or a combination thereof.

12. The fiber composite structure of claim 10, wherein each of the fiber bundles comprises second nano-protrusions on the surface thereof, wherein: the first nano-protrusions are disposed on the second nano-protrusions; andthe first nano-protrusions vertically overlap the second nano-protrusions corresponding thereto, respectively.

13. A method for manufacturing a fiber composite structure, the method comprising: preparing a plurality of fiber bundles;wetting the fiber bundles in a solution containing an adhesive material; anddrying the fiber bundles in the air immediately after taking the fiber bundles wetted in the solution out of the solution.

14. The method of claim 13, wherein the wetting of the fiber bundles in the solution is performed within 1 minute.

15. The method of claim 13, wherein the drying of the fiber bundles is performed within 1 hour.

16. The method of claim 13, wherein the solution further comprises a functional particle, wherein the functional particle includes at least one of a nano-material such as cellulose, graphene, carbon nanotube, and carbon black, or a particulate material having a size of approximately 1 to approximately 100 micrometers, such as a black rayon particle.

17. The method of claim 13, further comprising performing a plasma treatment on surfaces of the fiber bundles prior to the wetting of the fiber bundles in the solution.

18. The method of claim 17, wherein the adhesive material comprises one among catechol-based adhesive materials such as dopamine, polydopamine, pyrogallol, alpha-methyldopamine, norepinephrine, dihydroxyphenylalanine, alpha-methyldopa, droxdodopa, 5-hydroxydopamine, deacetylated chitosan-catechol, hyaluronic acid-catechol, and alginate-catechol, or chitosan, poly(allylamine), poly(L-lysine), and poly(ethyleneimine).