Composite material for optical cable sheath and preparation method of composite material

Abstract

The invention relates to the technical field of optical cables, and discloses a composite material for an optical cable sheath and a preparation method thereof, and the preparation method comprises the following steps: providing a temperature-resistant monomer, a functional monomer and a three-dimensional network structure; carrying out copolymerization reaction on the temperature-resistant monomer and the functional monomer to synthesize a thermoplastic dynamic covalent bond network polymer, and carrying out surface treatment on the three-dimensional network structure reinforcing material; and mixing the thermoplastic dynamic covalent bond network polymer, the surface-treated three-dimensional network structure reinforcing material, the multifunctional nano hybrid filler, the bio-based plasticizer, the antioxidant, the light stabilizer and the flame retardant according to a preset proportion, in the mixing process, the stirring speed is 1000-1500 rpm, the time is 15-20 minutes, the hot pressing temperature is 150-180 DEG C, the pressure is 10-15 MPa, and the time is 5-10 minutes, so as to obtain the composite material. The premix is obtained. According to the composite material for the optical cable sheath and the preparation method thereof, interface bonding between a reinforcing material and a matrix is firm, the composite material can be recycled and repeatedly processed, pollution is effectively reduced, the composite material is more environment-friendly, and the cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical cables, and particularly relates to a composite material for an optical cable sheath and a preparation method thereof. Background Art

[0002] With the continuous advancement of the global informatization process, the demand for communication technologies, especially optical fiber communication, has increased sharply. Due to its high speed and low loss characteristics, optical fibers have been widely used in long-distance communication, data transmission, Internet access and other fields, becoming the core infrastructure of modern communication networks. As an important protective layer for optical fibers, optical cables not only need to ensure the physical protection of optical fibers, but also need to withstand challenges such as temperature changes, humidity, chemical corrosion, etc. in different environments. Therefore, the outer sheath material of optical cables must have excellent mechanical properties, chemical stability, weather resistance and high temperature resistance to ensure the long-term stable operation of optical fibers in complex environments. With the increasing requirements for environmental protection and sustainable development, the development of new environmentally friendly and high-performance composite materials for optical cable sheaths has become the research focus of the optical cable manufacturing industry.

[0003] Currently, most of the materials used for optical cable sheaths are traditional thermoplastic polymer materials, such as polyvinyl chloride, polyethylene or polyurethane, etc. Although these materials have certain temperature resistance, chemical corrosion resistance and mechanical strength, they still have certain deficiencies in some special environments (i.e., high temperature, extreme cold, chemical corrosion, high radiation, marine and high-pressure environments). For example, in the applications of extreme high temperature, low temperature environments or submarine optical cables, traditional materials for optical cable sheaths cannot effectively meet the high-performance requirements, resulting in problems such as aging and cracking of the optical cable protective layer. Although the use of glass fibers or other reinforcing materials can improve the strength of the composite material, the bonding force between them and the matrix is weak, resulting in poor interfacial adhesion between the reinforcing material and the matrix, thus affecting the overall performance of the composite material.

[0004] Therefore, the present solution provides a composite material for an optical cable sheath with strong bonding force and high performance and a preparation method thereof. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the present invention provides a composite material for an optical cable sheath and a preparation method thereof, which enables the interfacial adhesion between the reinforcing material and the matrix to be firm, and ensures that the optical cable can still operate stably in high temperature, high humidity or electromagnetic interference environments, and can be recycled and reprocessed, effectively reducing pollution, being more environmentally friendly and saving costs.

[0006] To achieve the above objectives, the present invention is realized through the following technical solutions: Design a preparation method for a composite material for an optical cable sheath, including the following steps: S1. Provide heat-resistant monomers, functional monomers and three-dimensional network structures; carry out copolymerization reaction on the heat-resistant monomers and functional monomers to synthesize a thermoplastic dynamic covalent bond network polymer, and perform surface treatment on the three-dimensional network structure reinforcing material. The functional monomers include dynamic covalent bond monomers and low-temperature crosslinking monomers; S2. Mix the thermoplastic dynamic covalent bond network polymer, the surface-treated three-dimensional network structure reinforcing material, the multifunctional nano hybrid filler, the bio-based plasticizer, the antioxidant, the light stabilizer and the flame retardant in a preset ratio. During the mixing process, the stirring speed is 1000 - 1500 rpm, the time is 15 - 20 minutes, the hot pressing temperature is 150 - 180 °C, the pressure is 10 - 15 MPa, and it lasts for 5 - 10 minutes to obtain a premix; S3. Introduce temperature-responsive dynamic covalent bonds into the premix to obtain a preform; coat the surface of the preform with a coating material using the sol-gel method; form the preform by an extrusion molding process to obtain a composite material for optical cable jackets. Among them, the coating material includes a coating substrate and a self-healing functionalized molecule, and the thickness is controlled within 5 - 10 μm.

[0007] In some embodiments of the present invention, step S1 specifically includes: S11. Add heat-resistant monomers and dynamic covalent bond monomers into the reaction kettle in a ratio of 1:(1.1 - 1.2), and add a reaction solvent. The reaction solvent includes at least one of xylene and toluene, and then add a crosslinking agent to adjust the crosslinking degree of the thermoplastic dynamic covalent bond network polymer to be between 40% and 70%. React at a temperature of 180 - 220 °C for 4 - 6 hours, and the stirring speed is 200 - 500 rpm. Among them, the heat-resistant monomers include at least one of polyether diol and polyethylene terephthalate, the dynamic covalent bond monomers include at least one of furanized thermoplastic polyurethane and maleimide monomer, and the crosslinking agent includes at least one of disulfide crosslinking agent benzene and benzothiadiazole crosslinking agent; S12. Cool the thermoplastic dynamic covalent bond network polymer to room temperature, then soak it in ethanol for washing, and dry it at 60 °C to control the moisture content to be less than 0.1%; S13. Keep the temperature and stirring speed unchanged, and add low-temperature crosslinking monomers. Among them, the low-temperature crosslinking monomers include at least one of polyvinyl alcohol and amino-functionalized polyurethane to obtain the thermoplastic dynamic covalent bond network polymer; S14. Immerse the three-dimensional network structure reinforcing material in γ-aminopropyltriethoxysilane with a concentration of 0.5 - 2% for silanization treatment, set the temperature at 40 - 60 °C, and the reaction time is 2 - 4 hours; S15. Add a photosensitive crosslinking agent to the three-dimensional network structure reinforcing material, where the photosensitive crosslinking agent includes at least one of styrene-based photocrosslinking agents, benzophenone-based photocrosslinking agents, and benzothiadiazole-based crosslinking agents; S16. Wash the three-dimensional network structure reinforcing material added with the photosensitive crosslinking agent with ethanol to remove excess surface substances, and dry it at 60 °C, controlling the moisture content to be less than 0.1%.

[0008] In some embodiments of the present invention, step S3 specifically includes: S31. Add a temperature-responsive dynamic covalent bond group component to the premix, set the reaction temperature to 180 - 200 °C, the reaction time to 2 - 3 hours, and the added mass of the temperature-responsive dynamic covalent bond group component to account for 5 - 10% of the mass of the premix to obtain a preliminary material, where the temperature-responsive dynamic covalent bond group component includes disulfide bonds; S32. Freeze the preliminary material at -20 - 0 °C for 50 - 60 minutes, and then irradiate it with ultraviolet light, setting the ultraviolet wavelength at 320 - 400 nm, the intensity at 10 - 20 mW / cm², and the irradiation time at 5 - 10 minutes to obtain a prefabricated material.

[0009] In some embodiments of the present invention, after step S32, it further includes: S33. Dissolve the coating substrate and the self-healing functionalized molecule in ethanol at a mass ratio of 1:1, add γ-aminopropyltriethoxysilane, stir evenly, add a catalyst, and react at 25 - 40 °C for 50 - 60 minutes to obtain a coating material; where the coating substrate includes at least one of nano-silica, nano-titanium dioxide, nano-aluminum oxide, and graphene, the self-healing functionalized molecule includes at least one of self-healing polyurethane and self-healing acrylate, and the catalyst includes one of hydrochloric acid and chlorine water; S34. Immerse the prefabricated material in the coating material for 5 - 10 seconds, then take it out and let it drip dry naturally, and cure it by ultraviolet irradiation, setting the wavelength range at 320 - 400 nm, the irradiation intensity at 10 - 20 mW / cm², and the irradiation time at 5 - 10 minutes.

[0010] In some embodiments of the present invention, after step S34, it further includes: S35. Add the prefabricated material coated with the coating material to a twin-screw extruder. There are at least three temperature zones in the twin-screw extruder, and a plasticized melt is obtained through gradient plasticization. Among them, the temperature zones include the first zone, the second zone, and the third zone. The temperature of the first zone is 120 - 130 °C, the residence time in the first zone is 30 - 40 seconds, and the screw speed in the first zone is 50 - 60 rpm. The temperature of the second zone is 150 - 160 °C, the residence time in the second zone is 20 - 25 seconds, the screw speed in the second zone is 70 - 80 rpm, and the shear rate in the second zone is 100 - 120 s -1 , the temperature of the third zone is 180 - 190 °C, the residence time in the third zone is 15 - 20 seconds, and the shear rate in the third zone is 130 - 150 s -1 ; S36. Inject the plasticized melt into a micro-groove forming die. The groove depth of the micro-groove forming die is 0.2 - 0.5 mm. Press and tilt the micro-groove forming die, and simultaneously apply axial vibration. Cool to room temperature to obtain a composite material for the optical cable sheath. Among them, the tilt angle of the micro-groove forming die is 30 - 45 °, the pressing pressure of the micro-groove forming die is 8 - 12 MPa, the vibration frequency is 10 - 15 Hz, the amplitude is 0.1 - 0.3 mm, and it lasts for 5 - 8 minutes.

[0011] In some embodiments of the present invention, in step S2, calculated by weight percentage, the thermoplastic dynamic covalent bond network polymer accounts for 50 - 60%, the three-dimensional network structure reinforcing material accounts for 15 - 20%, the multifunctional nano hybrid filler accounts for 3 - 5%, the bio-based plasticizer accounts for 8 - 10%, the antioxidant accounts for 0.5 - 1.0%, the light stabilizer accounts for 0.5 - 1.0%, and the flame retardant accounts for 2 - 3%.

[0012] In some embodiments of the present invention, in step S1, in step S1, the three-dimensional network structure reinforcing material includes at least one of a three-dimensional carbon fiber network, a three-dimensional aramid fiber network, an alumina fiber network, and a silicon carbide fiber network.

[0013] In some embodiments of the present invention, in step S2, the multifunctional nano hybrid filler includes at least one of nano-silica@graphene, nano-titanium dioxide@carbon nanotubes, montmorillonite@boron nitride, graphene@silicon carbide, porous carbon@nano-alumina, and iron oxide@nano-silica.

[0014] In some embodiments of the present invention, in step S2, the bio-based plasticizer includes at least one of triethyl citrate, tributyl citrate, epoxidized soybean oil, epoxidized castor oil, polylactic acid plasticizer, or acetylated monoglyceride; The antioxidant includes at least one of octadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,6-di-tert-butyl-4-methylphenol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, or bis(2,4-dicumylphenyl)pentaerythritol diphosphite; The light stabilizer includes at least one of benzotriazole light stabilizer@nano-silica, benzophenone light stabilizer@nano-titanium dioxide, hindered amine light stabilizer@polymethyl methacrylate, zeolitic imidazolate framework material@benzotriazole light stabilizer; The flame retardant includes at least one of ammonium polyphosphate, aluminum hypophosphite, magnesium hydroxide, aluminum hydroxide, melamine polyphosphate, melamine cyanurate, silicone flame retardant, nano-silica, phytic acid, lignin derivative, expanded graphite, ammonium polyphosphate-pentaerythritol-melamine system.

[0015] The present invention provides a composite material for optical cable sheaths, which is prepared by the preparation method of the composite material for optical cable sheaths as described above. The components of the composite material for optical cable sheaths include a thermoplastic dynamic covalent bond network polymer, a three-dimensional network structure reinforcing material, a multifunctional nano hybrid filler, a bio-based plasticizer, an antioxidant, a light stabilizer, and a flame retardant.

[0016] The present invention provides a composite material for optical cable sheaths and a preparation method thereof, having the following beneficial effects: The composite material for optical cable sheaths and its preparation method synthesize a thermoplastic dynamic covalent bond network polymer as the matrix material through the copolymerization reaction of temperature-resistant monomers and functional monomers, effectively improving the adhesion. At the same time, the matrix material has the characteristics of the combination of thermoplasticity and dynamic covalent bond network, and can repair microcracks through the self-healing mechanism under external environmental stimuli such as temperature, ultraviolet rays, and mechanical forces, ensuring the long-term stability of the optical cable sheath. The dynamic covalent bond network enables the matrix material to maintain stable cross-linking strength at low temperatures in the deep sea, and reversibly dissociates at local high temperatures to achieve self-healing, avoiding the failure of the sheath caused by the expansion of microcracks in traditional materials. The surface-treated three-dimensional network reinforcing material forms a strong interfacial bond with the matrix material to form a tough interface, effectively enhancing the tensile strength, as well as enhancing the bonding force and interfacial peel strength with the attached matrix - optical cable. At the same time, the nano-hybrid filler inhibits the crack propagation in the low-temperature and high-pressure environment through the interface slip effect, reducing the elongation at break of the material. The self-healing molecules in the sol-gel coating can trigger the repair reaction, effectively resisting low-temperature and high-pressure erosion. The self-healing molecules in the sol-gel coating can respond to seawater penetration and automatically repair micro-damage, avoiding the corrosion of optical fibers by salt ions and reducing the maintenance cost. The sheath material prepared by this method realizes structural adaptive enhancement in the high-pressure marine environment, and improves the comprehensive performance of pressure resistance, impermeability, and long-term protection, improving the mechanical properties and electromagnetic shielding ability of the composite material, ensuring that the optical cable can still work stably in high-temperature, high-humidity, or electromagnetic interference environments, and can be recycled and reprocessed, effectively reducing pollution, being more environmentally friendly and cost-saving. Brief Description of the Drawings

[0017] Figure 1 It is a schematic exploded view of the micro-groove forming die in the present invention; Figure 2 It is a schematic installation view of the micro-groove forming die in the present invention; Figure 3 It is a schematic three-dimensional view of the micro-groove forming die in the present invention; Figure 4 It is a schematic three-dimensional view of the forming assembly in the present invention; Figure 5 It is a schematic partial side sectional view of the forming assembly in the present invention; Figure 6 It is a schematic front sectional view of the discharge port in the present invention; Figure 7 It is a flowchart for the preparation of the composite material for optical cable sheaths in the present invention.

[0018] In the figure: 11, upper die; 21, lower die; 22, input pipe; 23, telescopic rod; 3, micro-groove; 41, card slot; 42, mandrel; 421, rod shaft; 422, rod head; 5, forming assembly; 51, forming cylinder; 511, feeding port; 512, discharging port; 52, forming shaft core; 53, tooth groove; 531, first inner wall surface; 532, second inner wall surface; 7, support assembly; 71, rotating part; 711, rotating plate; 712, rotating seat; 713, vibration motor; 72, support plate. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] It should be understood that the terms in the present invention are only for describing specific embodiments and are not used to limit the present invention. Additionally, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the range, is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded within the range.

[0021] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art of the present invention. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein can also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0022] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific implementation manners of the specification of the present invention, which are obvious to those skilled in the art. Other implementation manners obtained from the specification of the present invention are obvious to those skilled in the art. The specification and embodiments of this application are only exemplary.

[0023] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0024] Please refer to Figure 7, the present invention provides a method for preparing a composite material, which is applied to the protection of optical cable wrapping, specifically for the composite material of the optical cable sheath, and is applied in the high-pressure environment of the seabed. In this embodiment, the method for preparing the composite material is improved to make it have the advantages of strong adhesion and environmental protection and durability. Specifically, taking the use of the optical cable sheath as an example, it is thus a preferred solution in this embodiment.

[0025] Example 1: The present invention provides a technical solution: a method for preparing a composite material for an optical cable sheath, comprising the following steps: S1. Provide a heat-resistant monomer, a functional monomer, and a three-dimensional network structure; let the heat-resistant monomer and the functional monomer carry out a copolymerization reaction to synthesize a thermoplastic dynamic covalent bond network polymer, and perform surface treatment on the three-dimensional network structure reinforcing material. The functional monomer includes a dynamic covalent bond monomer and a low-temperature cross-linking monomer. First, select a high-temperature-resistant monomer and a functional monomer to carry out a copolymerization reaction to synthesize a thermoplastic dynamic covalent bond network polymer. By selecting a suitable monomer combination, it is possible to ensure that the polymer has excellent heat resistance and controllable structural characteristics. Subsequently, the obtained polymer is combined with the surface treatment of the three-dimensional network structure reinforcing material to improve the interfacial bonding force of the material, laying a foundation for the performance enhancement of the subsequent composite material. Through surface treatment, the dispersibility of the reinforcing material and the compatibility with the matrix material can be effectively improved, thereby enhancing the mechanical properties and thermal stability of the final composite material; S2. Mix the thermoplastic dynamic covalent bond network polymer, the surface-treated three-dimensional network structure reinforcing material, the multifunctional nano hybrid filler, the bio-based plasticizer, the antioxidant, the light stabilizer, and the flame retardant in a preset ratio. During the mixing process, the stirring speed is 1000 - 1500 rpm, the time is 15 - 20 minutes, the hot pressing temperature is 150 - 180 °C, the pressure is 10 - 15 MPa, and it lasts for 5 - 10 minutes to obtain a premix. Mix the synthesized thermoplastic dynamic covalent bond network polymer with the surface-treated three-dimensional network structure reinforcing material. By adding functional additives such as multifunctional nano hybrid fillers, bio-based plasticizers, antioxidants, light stabilizers, and flame retardants, the properties of the composite material can be further improved. For example, the nano hybrid filler can provide enhanced mechanical strength and thermal conductivity, while the plasticizer helps to improve the flexibility of the material, the antioxidants and light stabilizers can enhance the aging resistance of the composite material, and the flame retardant enhances the flame retardant characteristics of the material. During the mixing process, the adopted stirring speed and hot pressing temperature can ensure the full mixing of each component; S3. Introduce temperature-responsive dynamic covalent bonds into the premix to obtain a prefabricated material; coat the prefabricated material surface with a coating material using the sol-gel method; form the prefabricated material through an extrusion molding process to obtain a composite material for the optical cable sheath; wherein, the coating material includes a coating substrate and a self-healing functionalized molecule, and the thickness is controlled within 5 - 10 μm. By introducing temperature-responsive covalent bonds, the material can undergo reversible chemical reactions when subjected to temperature changes, thereby endowing the material with self-healing or other temperature-controllable properties. Then, use the sol-gel method to uniformly coat the coating material on the surface of the prefabricated material, and the thickness of the coating is strictly controlled within 5 - 10 μm to ensure the performance of the coating while not affecting the use effect of the overall material. The coating material contains a coating substrate and a self-healing functionalized molecule, further enhancing the durability and repair ability of the composite material. Finally, through the extrusion molding process, the final composite material for the optical cable sheath is formed, thereby obtaining an optical cable sheath material with excellent performance.

[0026] In this embodiment, as a preferred solution, step S1 specifically includes: S11. Add a temperature-resistant monomer and a dynamic covalent bond monomer to the reaction kettle in a ratio of 1:(1.1 - 1.2), and add a reaction solvent. The reaction solvent includes at least one of xylene and toluene. Then add a crosslinking agent to adjust the crosslinking degree of the thermoplastic dynamic covalent bond network polymer to be between 40% and 70%. React at a temperature of 180 - 220 °C for 4 - 6 hours, and the stirring speed is 200 - 500 rpm. Among them, the temperature-resistant monomer includes at least one of polyether diol and polyethylene terephthalate, the dynamic covalent bond monomer includes at least one of furanized thermoplastic polyurethane and maleimide monomer, and the crosslinking agent includes at least one of disulfide crosslinking agent benzene and benzothiadiazole crosslinking agent. By controlling the molar ratio of the temperature-resistant monomer (such as polyether diol) to the dynamic covalent bond monomer (such as furanized thermoplastic polyurethane) (1:1.1 - 1.2), combined with the sulfur-sulfur dynamic bond of the disulfide crosslinking agent (such as diphenyl disulfide), a controllable range of 40% - 70% crosslinking degree is achieved in the xylene solvent (measured by the swelling method). React at a temperature of 180 - 220 °C (higher than the dynamic bond dissociation temperature) for 4 - 6 hours to ensure the reversible recombination ability of the dynamic covalent bond (such as Diels-Alder bond). At the same time, low-speed stirring at 200 - 500 rpm avoids excessive shearing of the molecular chains, and the resulting polymer dynamic bond density reaches 3.2×10⁻ 4 mol / g (quantitatively analyzed by nuclear magnetic resonance) to improve the self-healing efficiency; S12. Cool the thermoplastic dynamic covalent bond network polymer to room temperature, then soak it in ethanol for washing, and dry it at 60°C, controlling the moisture content to be less than 0.1%. Soaking the thermoplastic dynamic covalent bond network polymer in ethanol can remove unreacted substances or impurities that may exist during the reaction, ensuring the purity and performance of the product. Then, dry the washed polymer at 60°C to remove residual solvent moisture on the surface and inside. By precisely controlling the moisture content to be less than 0.1%, the quality stability of the final product can be ensured, avoiding the influence of excessive moisture on subsequent processing or performance; S13. Keep the temperature and stirring speed unchanged, and add low-temperature crosslinking monomers. The low-temperature crosslinking monomers include at least one of polyvinyl alcohol and amino-functionalized polyurethane, to obtain a thermoplastic dynamic covalent bond network polymer. Crosslinking monomers such as polyvinyl alcohol and amino-functionalized polyurethane can trigger crosslinking reactions under low-temperature conditions, thereby further enhancing the structural stability and thermoplasticity of the polymer. The purpose of this step is to enable the polymer to have better mechanical properties and durability in subsequent applications through the introduction of low-temperature crosslinking monomers, while retaining its thermoplastic characteristics to ensure the reliability of the composite material in different environments; S14. Immerse the three-dimensional network structure reinforcing material in γ-aminopropyltriethoxysilane with a concentration of 0.5 - 2% for silanization treatment, set the temperature at 40 - 60°C, and the reaction time at 2 - 4 hours. Immersing the reinforcing material in a γ-aminopropyltriethoxysilane solution with a concentration of 0.5% - 2% for silanization treatment and reacting at a temperature of 40°C - 60°C for 2 - 4 hours, the silanization process can form silane groups on the surface of the reinforcing material, thereby improving its surface hydrophilicity and chemical bonding force with the polymer matrix. This treatment ensures that the reinforcing material can better combine with the matrix material, enhancing the mechanical properties and structural integrity of the composite material; S15. Add a photosensitive crosslinking agent to the three-dimensional network structure reinforcing material. The photosensitive crosslinking agent includes at least one of styrene-based photo-crosslinking agents, benzophenone-based photo-crosslinking agents, and benzothiadiazole-based crosslinking agents. The photosensitive crosslinking agent has the characteristic of undergoing a crosslinking reaction under ultraviolet light irradiation. By adding the photosensitive crosslinking agent, the reinforcing material can better crosslink with the polymer matrix during subsequent processing, improving important properties such as its tensile strength and heat resistance, and providing a controllable crosslinking network for the material; S16. Wash the three-dimensional network structure reinforcing material added with the photosensitive crosslinking agent with ethanol to remove excess surface substances, and dry it at 60°C, controlling the moisture content to be less than 0.1%. The drying process can ensure that the material will not affect the performance of the final product or the processing process due to residual moisture during subsequent composite processing, ensuring the long-term stability and excellent performance of the material.

[0027] In this embodiment, as a preferred solution, step S3 specifically includes: S31. Add a temperature-responsive dynamic covalent bond group component to the premix. Set the reaction temperature at 180 - 200 °C and the reaction time at 2 - 3 hours. The added mass of the temperature-responsive dynamic covalent bond group component accounts for 5 - 10% of the mass of the premix to obtain a preparatory material. Among them, the temperature-responsive dynamic covalent bond group component includes disulfide bonds. Through the temperature-responsive dynamic covalent bonds, changes in crosslinking or breaking can be achieved under different temperature conditions, enabling the composite material to achieve self-repair or other adjustable functions when subjected to thermal stimulation. This reaction is carried out within the temperature range of 180 °C - 200 °C, and the reaction time is set at 2 - 3 hours. By ensuring high temperature, temperature-responsive dynamic covalent bonds are formed in the polymer, thereby improving the functionality and controllability of the material; S32. Freeze the preparatory material at -20 - 0 °C for 50 - 60 minutes, and then irradiate it with ultraviolet light. The wavelength of the ultraviolet light is set at 320 - 400 nm, the intensity is 10 - 20 mW / cm², and the irradiation time is 5 - 10 minutes to obtain a prefabricated material. After freezing, the material is irradiated with ultraviolet light for further crosslinking or curing. This process helps to make the structure of the material more stable through ultraviolet curing, preparing for subsequent processing.

[0028] In this embodiment, as a preferred solution, step S3 further includes after step S32: S33. Dissolve the coating substrate and the self-healing functionalized molecule in ethanol at a mass ratio of 1:1, add γ-aminopropyltriethoxysilane, stir evenly, then add a catalyst, and react at 25 - 40 °C for 50 - 60 minutes to obtain a coating material. Among them, the coating substrate includes at least one of nano-silica, nano-titanium dioxide, nano-aluminum oxide, and graphene, the self-healing functionalized molecule includes at least one of self-healing polyurethane and self-healing acrylate, and the catalyst includes one of hydrochloric acid and chlorine water. Adding γ-aminopropyltriethoxysilane for silanization treatment further enhances the binding force between the coating and the material surface. The reaction temperature is set at 25 °C - 40 °C, and the reaction time is 50 - 60 minutes to ensure that the chemical reaction between the coating substrate and the self-healing molecule occurs sufficiently to form a uniform and stable coating material. The coating substrate can include nano-silica, nano-titanium dioxide, graphene, etc., which can enhance the strength and wear resistance of the coating; self-healing functionalized molecules such as self-healing polyurethane or acrylate can endow the coating with self-healing properties, improving the durability of the optical cable sheath; S34. Immerse the prefabricated material in the coating material for 5 - 10 seconds, then take it out and let it drain naturally. Cure it by ultraviolet irradiation with the wavelength range set at 320 - 400 nm, the irradiation intensity at 10 - 20 mW / cm², and the irradiation time at 5 - 10 minutes. Ultraviolet curing can accelerate the crosslinking process of the coating, making the coating harden in a short time and enhancing its weather resistance, anti-pollution property, and wear resistance, thereby improving the overall performance of the composite material.

[0029] In this embodiment, as a preferred solution, after step S34, step S3 further includes: S35. Add the prefabricated material coated with the coating material into a twin-screw extruder. There are at least three temperature zones in the twin-screw extruder, and a plasticized melt is obtained through gradient plasticization. Among them, the temperature zones include the first zone, the second zone, and the third zone. The temperature of the first zone is 120 - 130 °C, the residence time in the first zone is 30 - 40 seconds, and the screw speed in the first zone is 50 - 60 rpm. The temperature of the second zone is 150 - 160 °C, the residence time in the second zone is 20 - 25 seconds, the screw speed in the second zone is 70 - 80 rpm, and the shear rate in the second zone is 100 - 120 s -1 , the temperature of the third zone is 180 - 190 °C, the residence time in the third zone is 15 - 20 seconds, and the shear rate in the third zone is 130 - 150 s -1 . Through the gradient plasticization process, the prefabricated material is transformed into a plasticized melt. Each temperature zone has different temperatures and residence times to ensure that the material can be fully plasticized when passing through each stage and has appropriate viscosity and fluidity. The shear rates in different temperature zones are also different. Through this process, the material is gradually heated and plasticized, and finally an ideal melt is formed, which is suitable for subsequent molding; S36. Inject the plasticized melt into a micro-groove forming mold. The groove depth of the micro-groove forming mold is 0.2 - 0.5 mm. Press and tilt the micro-groove forming mold, and simultaneously apply axial vibration. Cool it to room temperature to obtain the composite material for the optical cable sheath. Among them, the tilt angle of the micro-groove forming mold is 30 - 45 °, the pressing pressure of the micro-groove forming mold is 8 - 12 MPa, the vibration frequency is 10 - 15 Hz, the amplitude is 0.1 - 0.3 mm, and it lasts for 5 - 8 minutes. The groove depth of the mold is 0.2 - 0.5 mm, which is used to manufacture microstructural details. During the molding process, the micro-groove mold will be pressed and tilted, and axial vibration is applied simultaneously. This process helps the melt better fill the mold and ensures the uniformity of the micro-structure. The pressure of the mold and the vibration frequency help ensure that the molded material has excellent surface quality and micro-structure stability, meeting the requirements of the optical cable sheath; Please refer to Figures 1-3, the micro-groove forming die includes an upper die 11 and a lower die 21. A cavity is formed between the upper die 11 and the lower die 21. Micro-grooves 3 are provided on the inner wall surfaces of both the upper die 11 and the lower die 21, and mandrels 42 are detachably connected through the provided clamping grooves 41. The mandrel 42 includes a rod shaft 421 and a rod head 422. One end of the rod head 422 is threadedly connected to the rod shaft 421 through a threaded hole. The outer circular surface of the lower die 2 is fixedly connected with an input pipe 22 for connecting to the output end of a screw injection molding machine. The input pipe 22 communicates with the cavity. The output end of the screw injection molding machine transports the plasticized melt through the input pipe 22 into the cavity. The outer circular surface of the lower die 2 is fixedly connected with a telescopic rod 23. The telescopic end of the telescopic rod 23 is fixedly connected with a fixed rod 24. One end of the fixed rod 24 away from the telescopic rod 23 is fixedly connected with the outer circular surface of the upper die 11; The lower die 21 is provided with a support assembly 7. The support assembly 7 includes a rotating member 71 and a support plate 72. The rotating member 71 includes a rotating plate 711, a rotating seat 712, and a vibration motor 713. The rotating plate 711 is fixedly connected to the bottom of the lower die 21, and the rotating plate 711 is rotatably connected to the rotating seat 712. A locking member is provided between the rotating plate 711 and the rotating seat 712. The locking member can be a bolt that penetrates the rotating seat 712 and then presses against the rotating plate 711, or directly penetrates the rotating seat 712 and the rotating plate 711 for limiting. In this case, the number of screw holes is multiple and evenly distributed around the rotation center of the rotating plate 711. The vibration motor 713 is provided on the rotating plate 711 for generating vibration and transmitting it to the lower die 21. The rotating seat 712 is fixedly connected to the support plate 72. During use, the upper die 11 and the lower die 21 are closed through the telescopic rod 23. The inclination angle of the lower die 21 is adjusted through the connection between the rotating seat 712 and the rotating plate 711. Then the vibration motor 713 is turned on to generate vibration. The output end of the screw injection molding machine transports the plasticized melt through the input pipe 22 into the cavity. After injection molding, the upper die 11 and the lower die 21 are opened through the telescopic rod 23. The mandrel 42 is removed from the lower die 21, and then the rod head 422 is removed. The formed sheath on the rod shaft 421 is taken out.

[0030] The plasticized melt is injected into the cavity of the micro-groove forming die at a injection speed of 200-300mm / s by a screw injection molding machine. In a twin-screw extruder, the optical cable sheath composite material is heated, sheared and kneaded to form a uniform plasticized melt. The fluidity of the plasticized melt is sufficient to fill the micro-groove die. The inside of the micro-groove forming die contains a plurality of tiny grooves, the depth of these grooves is 0.2-0.5mm, the width is 0.3-0.4mm, and the arrangement is linear or grid-like. The micro-grooves can also extend in a spiral along the circumference of the cavity of the die (spiral angle 15°-30°). When the die is closed, the spiral directions of the grooves on the upper and lower dies are mirror-symmetrical, and a continuous groove texture surrounding the outer circumference of the sheath is naturally formed after closing. Between the circumferential spiral main grooves, auxiliary micro-grooves (depth 0.1-0.2mm) along the length direction of the micro-groove forming die (i.e., the axial direction of the optical cable sheath) are added to form a "main spiral + auxiliary axial" composite structure. And the micro-groove forming die is inclined during use, and the inclination angle of the micro-groove forming die is 30°-45°, which helps the melt to fill the micro-grooves more evenly under the action of gravity and pressure, so that the plasticized melt can be quickly and evenly distributed. After the plasticized melt is injected into the die, due to its fluidity, it will first fill along the grooves inside the micro-groove forming die. The flow of the melt is affected by the surface of the micro-groove forming die, especially the inclination angle and the arrangement of the grooves. When the plasticized melt flows into the micro-groove forming die, due to the inclination angle of the micro-groove forming die, the plasticized melt will be affected by the combined action of gravity and pressure and flow evenly along the groove depth. By synchronously applying axial vibration, the plasticized melt can be more evenly distributed in each groove, avoiding the appearance of voids or unevenness. Through the inclination angle of the micro-groove forming die and axial vibration, it can be ensured that the plasticized melt evenly fills the entire die, improving the density of the optical cable sheath, reducing the generation of bubbles, and enhancing its compressive resistance, corrosion resistance and durability; The micro-groove texture on the surface of the optical cable sheath can significantly improve its anti-slip performance. Especially during the installation and operation of the optical cable, the friction between the optical cable sheath and other surfaces is enhanced. Through the arrangement of the groove texture, the optical cable sheath can generate stronger friction with the support structure or the contact surface, preventing the optical cable from sliding or shifting in position due to external force or vibration, and can be well applied in occasions where precise positioning is required; Meanwhile, the groove patterns on the surface can effectively disperse the externally applied pressure. Under the action of external forces, the grooves can help evenly distribute the force transmission, reduce the pressure concentration in local areas, thereby improving the compressive performance of the optical cable sheath. This design makes the optical cable less likely to deform under external pressure, effectively protecting the internal optical fibers from damage. At the same time, the grooves can also enhance the wear resistance of the sheath because its surface is not smooth and is less affected by scratching and abrasion, thus extending the service life of the optical cable. The design of the groove patterns also has a positive effect on the surface anti-pollution performance of the optical cable sheath. Due to the uneven surface, it is difficult for external dust, dirt, oil, etc. to stay or adhere to the surface, thereby reducing the frequency of cleaning and maintenance and lowering the decline in material performance caused by pollution; Since the optical cable sheath material has a self-healing function, the surface groove patterns contribute to the occurrence of the self-healing process. When external forces or environmental factors cause minor damage to the surface of the optical cable sheath, the groove patterns help the self-healing process of the repair material. The groove patterns provide more contact surfaces for the self-healing molecules, promoting the repair effect of the material and enabling the optical cable sheath to restore its original function.

[0031] Please refer to Figures 4-6 , or the direct extrusion method can also be used for the production of the optical cable sheath. Specifically, the plasticized melt is directly extruded through a twin-screw extruder and then naturally cooled to form the optical cable sheath. This is a well-known existing technology and is only cited here. More specifically, a forming component 5 is provided at the output end of the twin-screw extruder. The forming component 5 includes a forming cylinder 51 and a forming core 52. The forming cylinder 51 is provided with a feed inlet 511 and a discharge outlet 512. Both the forming core 52 and the forming cylinder 51 are arranged at the output end of the twin-screw extruder, specifically, they can be welded to the output end of the twin-screw extruder or connected to the output end of the twin-screw extruder by threads. At least part of the forming core 52 is located inside the discharge outlet 512, and the outer surface of the forming core 52 is spaced from the inner wall surface of the discharge outlet 512. A plurality of tooth grooves 53 are circumferentially formed on the inner wall of the discharge outlet 512. The tooth grooves 53 have a first inner wall surface 531 and a second inner wall surface 532. Both the first inner wall surface 521 and the second inner wall surface 522 are arc-shaped. After the plasticized melt output by the twin-screw extruder enters the feed inlet 511 of the forming cylinder 51, it flows towards the discharge outlet 512, simultaneously wrapping around the outer surface of the forming core 52, and then enters the discharge outlet 512 and is discharged. By the formation of the tooth grooves 53, the surface of the extruded optical cable sheath has linear groove patterns extending along the axial direction, so that the surface groove patterns contribute to the occurrence of the self-healing process. When external forces or environmental factors cause minor damage to the surface of the optical cable sheath, the groove patterns help the self-healing process of the repair material. The groove patterns provide more contact surfaces for the self-healing molecules, promoting the repair effect of the material and enabling the optical cable sheath to restore its original function.

[0032] In this embodiment, as a preferred solution, in step S2, calculated by weight percentage, the thermoplastic dynamic covalent bond network polymer accounts for 50-60%, the three-dimensional network structure reinforcing material accounts for 15-20%, the multifunctional nano hybrid filler accounts for 3-5%, the bio-based plasticizer accounts for 8-10%, the antioxidant accounts for 0.5-1.0%, the light stabilizer accounts for 0.5-1.0%, and the flame retardant accounts for 2-3%.

[0033] In this embodiment, as a preferred solution, in step S1, the three-dimensional network structure reinforcing material includes at least one of three-dimensional graphene aerogel, three-dimensional carbon fiber network, three-dimensional aramid fiber network, zeolitic imidazolate framework material, copper-based metal-organic framework, alumina fiber network, silicon carbide fiber network, three-dimensional polyurethane foam or three-dimensional polyimide foam.

[0034] In this embodiment, as a preferred solution, in step S2, the multifunctional nano hybrid filler includes at least one of nano-silica@ graphene, nano-titanium dioxide@ carbon nanotube, montmorillonite@ boron nitride, graphene@ silicon carbide, porous carbon@ nano-alumina, iron oxide@ nano-silica. These fillers can significantly improve the mechanical properties, thermal conductivity, electrical conductivity and flame retardancy of the material.

[0035] In this embodiment, as a preferred solution, in step S2, the bio-based plasticizer includes at least one of triethyl citrate, tributyl citrate, epoxidized soybean oil, epoxidized castor oil, polylactic acid plasticizer or acetylated monoglyceride; the antioxidant includes at least one of octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, pentaerythritol tetrakis [3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,6-di-tert-butyl-4-methylphenol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite or bis(2,4-dicumylphenyl)pentaerythritol diphosphite; the light stabilizer includes at least one of benzotriazole light stabilizer@ nano-silica, benzophenone light stabilizer@ nano-titanium dioxide, hindered amine light stabilizer@ polymethyl methacrylate, zeolitic imidazolate framework material@ benzotriazole light stabilizer; the flame retardant includes at least one of ammonium polyphosphate, aluminum hypophosphite, magnesium hydroxide, aluminum hydroxide, melamine polyphosphate, melamine cyanurate, silicone flame retardant, nano-silica, phytic acid, lignin derivative, expanded graphite, ammonium polyphosphate-pentaerythritol-melamine system.

[0036] Synthetic thermoplastic dynamic covalent bond network polymers are used as matrix materials to ensure that the matrix materials have the characteristics of the combination of thermoplasticity and dynamic covalent bond networks, and can repair microcracks through a self-healing mechanism under external environmental stimuli such as temperature, ultraviolet light, and mechanical force, ensuring the long-term stability of the optical cable sheath; the thermoplastic dynamic covalent bond network polymers are mixed with reinforcing materials through processes such as high-speed stirring and hot pressing to ensure the uniform dispersion of the reinforcing materials, the high uniformity of the composite materials, and good interfacial bonding force. The cross-linking treatment during the preparation of the matrix materials can enhance the mechanical properties, thermal stability, and efficiency of the self-healing function of the materials. The self-healing function can be adjusted by the cross-linking degree to still have a certain flexibility and self-healing ability at low temperatures, while maintaining high mechanical strength at high temperatures; the main purpose of the drying process is to remove solvents and moisture in the raw materials, prevent the negative impact of residual solvents on the material properties, and ensure the uniformity and stability of the materials; the three-dimensional reinforcing materials are introduced with siloxane groups through the silanization treatment of γ-aminopropyltriethoxysilane, improving the bonding force with the matrix, and the interfacial peel strength is increased by ≥20%. The reinforcing materials improve the tensile resistance, impact resistance, electromagnetic interference resistance, and thermal stability of the optical cable sheath, enabling the composite materials to maintain excellent performance in various extreme environments, improving the mechanical properties and electromagnetic shielding ability of the composite materials, and ensuring that the optical cable can still work stably in high-temperature, high-humidity, or electromagnetic interference environments. The reinforcing materials can not only improve the mechanical properties and electromagnetic shielding ability of the composite materials, but also improve the thermal stability through thermal conductivity, preventing heat accumulation, especially having a better effect at extreme temperatures. They can also promote the expansion of the self-healing reaction when combined with the polymer cross-linking structure, thereby improving the repair efficiency of the materials. The multifunctional nano-hybrid fillers can not only increase the hardness, ultraviolet resistance, and anti-aging ability of the composite materials, but also enhance the water resistance, corrosion resistance, self-cleaning, and other properties. The bio-based plasticizers can not only improve the flexibility and processability of the materials, but also improve the low-temperature performance and enhance the anti-aging property. The light stabilizers can not only improve the ultraviolet resistance, but also cooperate with the antioxidants to extend the service life and cooperate with the surface functionalized coating to improve the stability; the flame retardants can not only improve the flame retardant performance of the composite materials, but also cooperate to enhance the high-temperature resistance of the materials and inhibit the release of harmful gases; The self-healing ability is optimized by introducing temperature-responsive dynamic covalent bonds to ensure the best performance in high-pressure low-temperature or extremely high-temperature environments. After synthesizing the thermoplastic dynamic covalent bond network polymers, they are first fully mixed with other additives, reinforcing materials, and fillers, and then optimized and activated, which can ensure the uniform dispersion of all components and their interaction in the same reaction process, and can promote each other with other functional components to improve the comprehensive performance of the materials and play a synergistic role. The combination of low-temperature activation and ultraviolet irradiation activation ensures that the materials can still maintain the self-healing function in extremely low-temperature environments or when exposed to ultraviolet light; The surface-functionalized coating combines the nano-coating with self-healing functional molecules to form a coating with stronger adhesion and weather resistance. It not only has anti-ultraviolet, water resistance and self-cleaning properties, but also can improve the bonding force between the surface and the substrate, and endows the coating with self-healing properties. The thickness of the coating avoids the problems that being too thick may cause the material to become brittle, crack, and being too thin cannot provide sufficient protection. Photosensitive materials are added to the composite material, and ultraviolet irradiation is used to accelerate the curing process, shortening the curing time and improving the coating quality; In the forming process, through the synergistic regulation of temperature and shear, not only the responsiveness of the dynamic covalent bond is retained, but also the orderly arrangement of the reinforcing phase is realized, solving the contradiction between the fluidity and mechanical properties of the material, and improving the fracture toughness of the material. The multi-stage pressure gradient cooling actively regulates the phase evolution of the material during the curing stage through physical field coupling intervention, and synergistically optimizes the dimensional stability and fatigue resistance; Through the full-chain optimization of directional plasticization-interface interlocking-stress coordination, the optical cable sheath has both high mechanical strength, self-healing efficiency and dimensional stability; By precisely regulating the ratio of each component, a quadruple performance breakthrough of high strength, self-healing, weather resistance and environmental friendliness of the optical cable sheath material is achieved, and at the same time, a closed-loop matching with the forming process is formed.

[0037] The present invention provides a composite material for optical cable sheaths, which is prepared by the preparation method of the composite material for optical cable sheaths as above. The components of the composite material for optical cable sheaths include thermoplastic dynamic covalent bond network polymers, three-dimensional network structure reinforcing materials, multifunctional nano hybrid fillers, bio-based plasticizers, antioxidants, light stabilizers and flame retardants.

[0038] Example two: In a reaction kettle, polyether diol and furanized polyurethane are mixed in a ratio of 1:1.2, xylene is used as a solvent, 1.5% disulfide cross-linking agent is added, and the reaction is carried out at 200 °C for 5 hours with a stirring speed of 300 rpm to obtain a thermoplastic dynamic covalent bond network polymer with a cross-linking degree of 60%. The thermoplastic dynamic covalent bond network polymer is cooled to room temperature, washed with ethanol and dried at 60 °C, and the water content is <0.1%. The three-dimensional aramid fiber network is immersed in a 1.5% γ-aminopropyltriethoxysilane solution and treated at 50 °C for 3 hours, loaded with 1% benzothiadiazole photo-cross-linking agent, and washed with ethanol and dried at 60 °C.

[0039] Mix 55% of thermoplastic dynamic covalent bond network polymer, 18% of three-dimensional aramid fiber network, 4% of iron oxide@nano-silica, 9% of bio-based plasticizer, 0.8% of antioxidant, 0.7% of light stabilizer, and 2.5% of flame retardant by weight percentage, stir at 1500 rpm for 18 minutes, and hot press at 160 °C for 8 minutes under a pressure of 12 MPa to obtain a premix.

[0040] Add 8% disulfide monomer to the premix, react at 190 °C for 2.5 hours, then freeze at -10 °C for 55 minutes. The ultraviolet irradiation is carried out at 365 nm and 15 mW / cm² for 8 minutes to activate the dynamic bond self-healing function; Dissolve 10% nano-SiO₂ and self-healing polyurethane in ethanol at a ratio of 1:1, add 1% γ-aminopropyltriethoxysilane linker, stir evenly, then add 0.1% hydrochloric acid catalyst, and react at 30 °C for 1 hour to form a sol. Immerse the substrate material in the sol for 5 seconds, take it out and let it drain naturally. The ultraviolet curing is carried out at 320 nm and 15 mW / cm² for 7 minutes, and the coating thickness is 8 μm.

[0041] Add the premix to a twin-screw extruder, with the first zone at 130 °C / 40 s, the second zone at 160 °C / 25 s, the third zone at 185 °C / 20 s, and the screw speed at 70 rpm.

[0042] Inject the plasticized melt into a grooved mold, set the depth at 0.3 mm, the inclination angle at 30°, apply axial vibration synchronously, with a frequency of 12 Hz, an amplitude of 0.2 mm and a radial pressure of 10 MPa, for 6 minutes.

[0043] Cool by high-pressure aerosol (0.4 MPa nitrogen, atomized water droplets ≤ 10 μm) to 80 °C, cool by magnetic field assistance to 60 °C, and cool slowly under constant humidity (50% humidity) to 25 °C.

[0044] Polish the surface of the formed material, and then adjust it in an environment of 50 °C / 60% humidity for 24 hours to enhance the environmental adaptability.

[0045] By copolymerizing a low glass transition temperature monomer (i.e., polyether diol) with a dynamic bond monomer (i.e., furanized polyurethane), and regulating the crosslinking degree (i.e., 60%) with a crosslinking agent, the polymer has both fluidity and network integrity; after the aramid fiber is silanized, siloxane groups (Si-O-C bonds) are introduced on the surface to enhance the interfacial bonding strength with the matrix; control the water content < 0.1% to avoid the generation of bubbles or degradation of dynamic bonds during high-temperature processing; make each component evenly dispersed by stirring at 1500 rpm and hot pressing to form a dense premix; through freeze-ultraviolet activation, the dynamic bond achieves a 98% crack healing rate at 80 °C for 10 minutes; the nano-SiO₂ coating prepared by the sol-gel method endows the surface with hydrophobicity and wear resistance; gradient plasticization and dynamic shear field forming eliminate weld lines, and the forming shrinkage rate ≤ 0.08%.

[0046] The optical cable sheath material prepared in this example has high-efficiency self-healing ability (repair 50 μm cracks at 80 °C for 10 minutes), superhydrophobic surface (contact angle 155°), salt spray corrosion resistance, and is suitable for the protection of communication optical cables in areas with drastic temperature differences.

[0047] Example Three: Polyethylene terephthalate was mixed with maleimide monomer (1:1.1), 2% thiadiazole crosslinking agent was added, and the reaction was carried out at 220 °C for 4 hours to obtain a thermoplastic dynamic covalent bond polymer with a crosslinking degree of 65%. The three-dimensional carbon fiber grid was treated with 2% silane, loaded with 1.5% benzophenone photo-crosslinking agent, washed with ethanol and dried at 60 °C.

[0048] Dynamic covalent bond network polymer 58% + carbon fiber 20% + montmorillonite@boron nitride 3% + plasticizer 8% + flame retardant 3%, mixed at 1600 rpm for 20 minutes and hot-pressed at 180 °C for 10 minutes.

[0049] 10% mercaptan-peroxide dynamic bond was added to the premix, reacted at 200 °C for 2 hours, frozen-ultraviolet activated, nano-TiO2 coating (7% solid content) was coated on the preform, ultraviolet cured, high-pressure aerosol cooled (0.5 MPa), magnetic field 1.0 T was used to orient the filler, and vacuum packaged + covered with antioxidant film to obtain the preform.

[0050] Silanization treatment improves the interfacial bonding strength between carbon fiber and matrix. Stirring and hot pressing (180 °C / 10 MPa) at a speed of 1600 rpm make boron nitride#montmorillonite nanosheets evenly dispersed. Mercaptan-peroxide dynamic bond is activated at 200 °C to improve the impact resistance of the material. Nano-TiO2 coating improves wear resistance. High-pressure aerosol cooling and magnetic field orientation optimize the stress distribution.

[0051] The optical cable sheath material prepared in this example has excellent mechanical strength, excellent flame retardant performance, and strong deep-sea compressive capacity, and is suitable for high-strength demand scenarios such as submarine optical cables.

[0052] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a composite material for an optical cable sheath, characterized in that: The following steps are involved: S1. Provide heat-resistant monomers, functional monomers and three-dimensional network structures; Allowing a heat-resistant monomer and a functional monomer to copolymerize to synthesize a thermoplastic dynamic covalent bond network polymer, and performing surface treatment on the three-dimensional network structure reinforcement material, wherein the functional monomer includes a dynamic covalent bond monomer and a low-temperature cross-linking monomer; S2, mixing the thermoplastic dynamic covalent bond network polymer, the surface treated three-dimensional mesh structure reinforcement material, the multifunctional nano hybrid filler, the bio-based plasticizer, the antioxidant, the light stabilizer and the flame retardant according to a preset ratio, during the mixing process, the stirring speed is 1000-1500rpm, the time is 15-20 minutes, the hot pressing temperature is 150-180°C, the pressure is 10-15MPa, and the duration is 5-10 minutes to obtain a premix; S3. Introducing temperature-responsive dynamic covalent bonds into the premix to obtain a prefabricated material; applying a coating material to the surface of the prefabricated material using a sol-gel method; molding the prefabricated material through an extrusion molding process to obtain a composite material for an optical cable sheath; wherein the coating material includes a coating substrate and self-healing functional molecules, and the thickness is controlled at 5-10 μm.

2. The method for preparing a composite material for optical cable sheath according to claim 1, characterized in that: Step S1 specifically includes: S11, adding a heat-resistant monomer and a dynamic covalent bond monomer in a ratio of 1: (1.1-1.2) to a reactor, and adding a reaction solvent, wherein the reaction solvent includes at least one of xylene and toluene, and then adding a crosslinking agent, adjusting the crosslinking degree of the thermoplastic dynamic covalent bond network polymer to between 40-70%, reacting at a temperature of 180-220° C. for 4-6 hours, and stirring at a speed of 200-500 rpm, wherein the heat-resistant monomer includes at least one of polyether glycol and polyethylene terephthalate, the dynamic covalent bond monomer includes at least one of furanized thermoplastic polyurethane and maleimide monomer, and the crosslinking agent includes at least one of disulfide crosslinking agent benzene and thiadiazole crosslinking agent; S12, cooling the thermoplastic dynamic covalent bond network polymer to room temperature, then immersing it in ethanol for washing, and drying it at 60° C. to control the moisture content to be less than 0.1%; S13, maintaining the temperature and stirring speed unchanged, adding a low-temperature cross-linking monomer, wherein the low-temperature cross-linking monomer includes at least one of polyvinyl alcohol and amino polyurethane, to obtain the thermoplastic dynamic covalent bond network polymer; S14, immersing the three-dimensional network structure reinforcement material in γ-aminopropyltriethoxysilane with a concentration of 0.5-2% for silanization treatment, setting the temperature to 40-60° C., and the reaction time to 2-4 hours; S15, adding a photosensitive crosslinking agent to the three-dimensional network structure reinforcing material, wherein the photosensitive crosslinking agent includes at least one of a styrene-based photocrosslinking agent, a benzophenone-based photocrosslinking agent, and a benzothiadiazole-based crosslinking agent; S16. The three-dimensional network structure reinforcement material to which the photosensitive crosslinking agent is added is cleaned with ethanol to remove excess surface substances, and dried at 60° C. to control the moisture content to be less than 0.1%.

3. The method for preparing a composite material for optical cable sheath according to claim 1, characterized in that: Step S3 specifically includes: S31, adding a temperature-responsive dynamic covalent bond group component to the premix, setting the reaction temperature to 180-200° C., the reaction time to 2-3 hours, the added mass of the temperature-responsive dynamic covalent bond group component accounting for 5-10% of the mass of the premix, to obtain a preparatory material, wherein the temperature-responsive dynamic covalent bond group component includes a disulfide bond; S32. Freeze the prepared material at -20-0°C for 50-60 minutes, and then irradiate it with ultraviolet light, with the ultraviolet wavelength set at 320-400nm, the intensity at 10-20mW / cm², and the irradiation time at 5-10 minutes to obtain a prefabricated material.

4. The method for preparing a composite material for optical cable sheath according to claim 3, characterized in that: After step S32, the following steps are also included: S33, dissolving the coating substrate and the self-repairing functional molecules in ethanol at a mass ratio of 1:1, adding γ-aminopropyltriethoxysilane, stirring evenly, adding a catalyst, and reacting at 25-40°C for 50-60 minutes to obtain a coating material; wherein the coating substrate comprises at least one of nano-silicon dioxide, nano-titanium dioxide, nano-aluminum oxide, and graphene, the self-repairing functional molecules comprise at least one of self-repairing polyurethane and self-repairing acrylate, and the catalyst comprises one of hydrochloric acid and chlorine water; S34. Immerse the prefabricated material in the coating material for 5-10 seconds, then take it out and let it drip dry naturally, and use ultraviolet radiation to cure it. The wavelength range is set to 320-400nm, the irradiation intensity is 10-20mW / cm², and the irradiation time is 5-10 minutes.

5. The method for preparing a composite material for optical cable sheath according to claim 4, characterized in that: After step S34, the method further includes: S35. Add the prefabricated material coated with the coating material into a twin-screw extruder, wherein at least three temperature zones are provided in the twin-screw extruder, and a plasticized melt is obtained by gradient plasticization, wherein the temperature zones include a first zone, a second zone and a third zone, the temperature of the first zone is 120-130°C, the residence time in the first zone is 30-40 seconds, the screw speed of the first zone is 50-60rpm, the temperature of the second zone is 150-160°C, the residence time in the second zone is 20-25 seconds, the screw speed of the second zone is 70-80rpm, and the shear rate of the second zone is 100-120s -1 The temperature of the third zone is 180-190°C, the residence time in the third zone is 15-20 seconds, and the shear rate in the third zone is 130-150s -1 ; S36, injecting the plasticized melt into a micro-groove forming mold, wherein the groove depth of the micro-groove forming mold is 0.2-0.5mm, pressing and tilting the micro-groove forming mold, and synchronously applying axial vibration, cooling to room temperature to obtain a composite material for an optical cable sheath, wherein the inclination angle of the micro-groove forming mold is 30-45°, the pressing pressure of the micro-groove forming mold is 8-12MPa, the vibration frequency is 10-15Hz, the amplitude is 0.1-0.3mm, and it lasts for 5-8 minutes.

6. The method for preparing a composite material for optical cable sheath according to claim 1, characterized in that: In step S2, calculated by weight percentage, the thermoplastic dynamic covalent bond network polymer accounts for 50-60%, the three-dimensional network structure reinforcement material accounts for 15-20%, the multifunctional nano-hybrid filler accounts for 3-5%, the bio-based plasticizer accounts for 8-10%, the antioxidant accounts for 0.5-1.0%, the light stabilizer accounts for 0.5-1.0%, and the flame retardant accounts for 2-3%.

7. The method for preparing a composite material for optical cable sheath according to claim 1, characterized in that: In step S1, the three-dimensional mesh structure reinforcement material includes at least one of a three-dimensional carbon fiber network, a three-dimensional aramid fiber network, an aluminum oxide fiber network and a silicon carbide fiber network.

8. The method for preparing a composite material for optical cable sheath according to claim 1, characterized in that: In step S2, the multifunctional nano hybrid filler includes at least one of nano silicon dioxide@graphene, nano titanium dioxide@carbon nanotube, montmorillonite@boron nitride, graphene@silicon carbide, porous carbon@nano alumina, and iron oxide@nano silicon dioxide.

9. The method for preparing a composite material for optical cable sheath according to claim 1, characterized in that: In step S2, the bio-based plasticizer includes at least one of triethyl citrate, tributyl citrate, epoxidized soybean oil, epoxidized castor oil, polylactic acid plasticizer or acetylated monoglyceride; The antioxidant comprises at least one of β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2,6-di-tert-butyl-4-methylphenol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol, tris(2,4-di-tert-butylphenyl)phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite or bis(2,4-dicumylphenyl)pentaerythritol diphosphite; The light stabilizer includes at least one of benzotriazole light stabilizer@nano silicon dioxide, benzophenone light stabilizer@nano titanium dioxide, hindered amine light stabilizer@polymethyl methacrylate, and zeolite imidazolate framework material@benzotriazole light stabilizer; The flame retardant comprises at least one of ammonium polyphosphate, aluminum hypophosphite, magnesium hydroxide, aluminum hydroxide, melamine polyphosphate, melamine cyanurate, silicone flame retardant, nano silicon dioxide, phytic acid, lignin derivatives, expanded graphite, and ammonium polyphosphate-pentaerythritol-melamine system.

10. A composite material for optical cable sheath, characterized in that: The composite material for optical cable sheath is prepared by the preparation method of the composite material for optical cable sheath according to any one of claims 1 to 9, and the components of the composite material for optical cable sheath include thermoplastic dynamic covalent bond network polymer, three-dimensional network structure reinforcement material, multifunctional nano hybrid filler, bio-based plasticizer, antioxidant, light stabilizer and flame retardant.

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