High-transmission-rate optical cable with low attenuation characteristic and preparation method thereof

Abstract

The invention discloses a high-transmission-rate optical cable with a low attenuation characteristic and a preparation method thereof, belongs to the technical field of optical cable communication, and is used for solving the technical problem that the transmission performance and the mechanical performance of an optical cable in the prior art need to be further improved. According to the optical cable, the polytetrafluoroethylene is filled with the modified graphene and the molybdenum disulfide, so that the mechanical property and the environmental adaptability of the optical cable are effectively improved, and the transmission speed of the optical cable is also effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of optical cable preparation, and in particular to a high transmission rate optical cable with low attenuation characteristics and a preparation method thereof. Background Art

[0002] In today's era of rapid development of digital information, the demand for high-transmission-rate optical cables with low attenuation characteristics is extremely urgent. With the vigorous rise of new infrastructure such as 5G, data centers, computing power networks, and the Internet of Things, the optical fiber communication network, which serves as the "support base" of these facilities, faces higher performance requirements in terms of capacity, distance, and delay. New optical fiber technologies such as ultra-low-loss optical fiber, space-division multiplexing optical fiber, and hollow-core optical fiber are constantly emerging. Among them, ultra-low-loss optical fiber has entered the large-scale commercial stage, helping optical transmission systems develop towards ultra-high speed, large capacity, and long distance.

[0003] In the existing technology, the structure of the optical cable mainly consists of optical fiber, loose tube, insulation layer and sheath layer. Optical cable is usually used in multiple scenarios such as underground pipeline, overhead, and submarine laying. The environment is complex and unpredictable, so strict requirements are placed on the sheath layer of the optical cable. The sheath layer of the optical cable is easily flattened or stretched, and the mechanical properties are not good enough. The optical fiber will be deformed or broken under stress, causing signal transmission attenuation. After the optical cable has been used for a period of time, the sheath will break and the optical fiber will poke out, causing damage to the cable structure and line failures. At the same time, during the construction and line operation process, due to factors such as wind and artificial external forces, the optical cable twists and cracks, causing serious attenuation of the optical cable. Therefore, based on the existing technology, improvements are made to the problems of insufficient transmission rate and mechanical properties of the optical cable. Summary of the Invention

[0004] The object of the present invention is to provide a high transmission rate optical cable with low attenuation characteristics and a preparation method thereof, so as to solve the technical problem in the prior art that the transmission performance and mechanical properties of optical cables need to be further improved.

[0005] The object of the present invention can be achieved by the following technical solution: a high transmission rate optical cable with low attenuation characteristics, the high transmission rate optical cable comprising an optical fiber, a loose tube, an insulation layer and a sheath layer arranged in sequence from the inside to the outside, a gap being left between the optical fiber and the loose tube, and the gap being filled with grease;

[0006] The sheath layer comprises the following components in parts by weight: 60-70 parts of high-pressure low-density polyethylene, 30-40 parts of modified polytetrafluoroethylene, 10-20 parts of random copolymer polypropylene and 3-5 parts of auxiliary additives;

[0007] The preparation method of the modified polytetrafluoroethylene comprises the following steps:

[0008] A1. Modified graphene, molybdenum disulfide, and anhydrous ethanol were mixed and added to a ball mill for dispersion for 8-12 hours. After the ball milling was completed, the milled slurry was transferred to a beaker, polyethylene glycol was added, and stirred for 30-40 minutes to obtain a mixed slurry;

[0009] A2. Add the pretreated polytetrafluoroethylene into the mixer and stir at low speed for 1-2 minutes. Then add the mixed slurry and stir for 10-20 minutes. Then transfer the mixed material to a vacuum drying oven at 60-80°C and dry it to constant weight to obtain modified polytetrafluoroethylene.

[0010] The synthesis mechanism of modified polytetrafluoroethylene is:

[0011] The mechanical force of the ball mill breaks up the agglomerates of modified graphene and molybdenum disulfide. At the same time, anhydrous ethanol acts as a medium to promote the uniform dispersion of the filler in the liquid phase through shear force and impact force. The long-chain molecules of polyethylene glycol are adsorbed on the surface of the filler to form an oleophilic and hydrophobic interface layer, which reduces the van der Waals attraction between the fillers and prevents re-agglomeration. At the same time, the hydroxyl groups of polyethylene glycol can form a weak interaction with the polytetrafluoroethylene molecular chain. After being added to the mixed slurry, the evenly dispersed modified graphene and molybdenum disulfide are embedded in the polytetrafluoroethylene matrix through mechanical stirring force to form a filler-matrix composite system.

[0012] Furthermore, the optical fiber is made of high-purity quartz glass, the loose tube is made of polypropylene or nylon, and the insulation layer is made of poly(p-phenylene terephthalamide); the auxiliary additives are composed of ultraviolet absorber, antioxidant, plasticizer, and lubricant in a weight ratio of 1:0.8:4:0.8.

[0013] Furthermore, in step A1, the modified graphene, molybdenum disulfide, anhydrous ethanol and polyethylene glycol

[0014] The dosage ratio is 1g:3g:40mL:0.01-0.02g, and the polyethylene glycol model is PEG-400.

[0015] Furthermore, in step A2, the weight ratio of the pretreated polytetrafluoroethylene to the mixed slurry is 4:1.

[0016] Furthermore, the treatment method for pre-treated polytetrafluoroethylene is as follows: polytetrafluoroethylene and low molecular weight polytetrafluoroethylene are added to a ball mill and ball-milled for 2-4 hours, the ball-milled polytetrafluoroethylene is added to a sodium-naphthalene complex solution protected by nitrogen, the temperature is increased to 35-45°C, the reaction is carried out for 20-30 minutes, and then the polytetrafluoroethylene is washed with deionized water until neutral, and then a KH560 ethanol solution is added, ultrasonicated for 60-80 minutes, and centrifuged to obtain pre-treated polytetrafluoroethylene.

[0017] The synthesis mechanism of pretreated polytetrafluoroethylene is:

[0018] Naphthalene loses electrons under the action of sodium to generate a sodium naphthalene radical anion. The naphthalene ring of sodium naphthalene acts as a nucleophile to attack the C-F bond on the surface of polytetrafluoroethylene, causing the C-F bond to break and generate C-Na + The intermediate combines with the naphthalene ring to form etched polytetrafluoroethylene. The methoxy group of KH560 is hydrolyzed to form a silanol group. The silanol group condenses with the active C site introduced after the sodium-naphthalene treatment on the polytetrafluoroethylene surface to form a silicon-oxygen-carbon covalent bond, fixing KH560 on the polytetrafluoroethylene surface.

[0019] Furthermore, the polytetrafluoroethylene, low molecular weight tetrafluoroethylene, sodium-naphthalene complex solution, and KH560 ethanol solution are used in a ratio of 100 g:0.1-0.5 g:1000 mL:500 mL; the sodium-naphthalene complex solution is composed of naphthalene, sodium, and tetrahydrofuran in a ratio of 0.2 g:0.5 g:50 mL; and the KH560 ethanol solution is composed of γ-glycidyloxypropyltrimethoxysilane, ethanol, and water in a volume ratio of 1:8:1.

[0020] Furthermore, in step A1, the preparation method of modified graphene is:

[0021] B1. Add flake graphite, concentrated sulfuric acid and potassium permanganate into a beaker and mix well. Transfer the beaker to a constant temperature water bath, raise the temperature to 30-40°C, stir and react for 1-2 hours, then raise the temperature to 50-60°C, continue stirring and react for 2-3 hours. After the reaction is completed, filter, wash and dry, and heat to expand to obtain expanded graphite;

[0022] B2. After uniformly mixing concentrated sulfuric acid and sodium nitrate in a beaker, add expanded graphite, stir for 15-20 min, control the temperature to 20-30 ° C, add potassium permanganate, react for 1-2 h, add deionized water, raise the temperature to 40-50 ° C, add 30 wt% hydrogen peroxide solution until the solution color changes from brown to bright yellow, filter, wash and dry to obtain graphite oxide;

[0023] B3. Add graphite oxide and deionized water into a beaker and sonicate at room temperature for 1-2 hours. Adjust the pH to 6.5-7.5 with saturated ammonia water. Add hydrazine hydrate and place the reaction system in a 60-80°C water bath for 2-4 hours. Post-treat to obtain modified graphene.

[0024] The synthesis mechanism of modified graphene is:

[0025] After concentrated sulfuric acid and potassium permanganate come into contact with flake graphite, hydrogen ions and sulfate ions are inserted into the graphite interlayers through ion exchange to form graphite intercalation compounds. At the same time, potassium permanganate releases active oxygen under acidic conditions, oxidizes carbon atoms at the edges and defects of graphite, generates functional groups such as carboxyl and hydroxyl groups, weakens the interlayer van der Waals force, expands the interlayer spacing, and after drying and heating, the interlayer intercalation products are decomposed by heat to form loose and porous expanded graphite; expanded graphite is added to a mixture of concentrated sulfuric acid and sodium nitrate, and sodium nitrate dissociates into nitrate ions in concentrated sulfuric acid, which react with potassium permanganate. Together they constitute a strong oxidation system, further oxidizing the carbon atoms in the graphite layer, introducing a large number of epoxy groups and hydroxyl groups, and forming carboxyl groups on some edges. During the oxidation process, the hydrophilicity of the functional groups causes the graphite layers to adsorb water molecules, resulting in swelling. At the same time, mechanical stirring and the insertion of the oxidant destroy the interlayer bonding force, causing the graphite layer to gradually peel off into a single layer or a few layers of graphite oxide; hydrazine hydrate acts as a reducing agent, reacting with the epoxy, hydroxyl and other functional groups on the surface of the graphite oxide to release nitrogen and generate water molecules, breaking the CO bond and gradually restoring the sp 2 Conjugated structure.

[0026] Furthermore, in step B1, the amount ratio of the flake graphite, concentrated sulfuric acid and potassium permanganate is 2g:10mL:1g; the heating expansion step is: grinding the dried graphite powder and placing it in a muffle furnace, heating it to 800-1000°C at a heating rate of 5-10°C / s, and keeping it warm for 1-2min to obtain expanded graphite; in step B2, the amount ratio of the concentrated sulfuric acid, sodium nitrate, expanded graphite, potassium permanganate and deionized water is 50mL:1g:5g:7.5g:100mL; in step B3, the graphite oxide, deionized water and hydrazine hydrate are 1g:200mL:1-2mL, and the post-treatment step includes: after the reaction is completed, transferring the mixed solution to a centrifuge tube for centrifugation, washing the lower layer of liquid with deionized water 3-5 times, and then transferring it to a 40-60°C vacuum drying oven and drying it to constant weight to obtain modified graphene.

[0027] The present invention also provides a method for preparing a high transmission rate optical cable, comprising the following steps:

[0028] S1. High-pressure low-density polyethylene, modified polytetrafluoroethylene, and random copolymer polypropylene are mixed in an internal mixer, the temperature is raised to 280-320° C., auxiliary additives are added, and the mixture is uniformly mixed to obtain a premix;

[0029] S2. The premix is ​​placed in a twin-screw extruder and melted and extruded outside the insulating layer. After cooling and forming, a sheath layer is obtained to prepare a high transmission rate optical cable.

[0030] Furthermore, in step S1, the temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end are 80-120°C, 150-200°C, 220-280°C, 280-320°C, 250-300°C, and 280-320°C, respectively.

[0031] The present invention has the following beneficial effects:

[0032] 1. The present invention covers the optical fiber core with a cladding and a buffer layer, which can prevent stress damage to the fiber core during cable laying or bending, and avoid optical signal attenuation due to damage to the fiber core structure. The quartz cladding has excellent chemical and thermal stability, and can maintain a stable refractive index under high and low temperature conditions, avoiding degradation of the cladding performance due to environmental changes, which affects the long-term transmission quality of high-speed signals. The combination of the cladding and the buffer layer ensures uniform adhesion of the coating, forming a compact protective structure, and improving the long-distance and low-latency transmission efficiency of high-speed optical signals.

[0033] 2. The present invention adds polytetrafluoroethylene to the cable material. Polytetrafluoroethylene itself has high heat resistance and weather resistance, which can resist the heat accumulation caused by current or signal loss at high transmission rates of optical cables, avoid softening, deformation or aging of cable materials due to high temperature, ensure the stable operation of optical cables in high temperature environments, and reduce structural damage caused by temperature fluctuations; the modified polytetrafluoroethylene is combined with fillers such as graphene and molybdenum disulfide. The two-dimensional sp² hybridized carbon atoms of graphene form a highly conjugated π electron system. When uniformly dispersed in the polytetrafluoroethylene matrix, the π electron cloud of graphene can shield the electrons through the electron shielding. The effect weakens the dipole orientation polarization of the polytetrafluoroethylene molecular chain, reduces the dielectric constant and dielectric loss, thereby reducing signal attenuation and increasing the transmission rate. At the same time, the d orbital electrons of molybdenum disulfide are delocalized within the layer, but the interlayer electron transmission is limited, forming a dielectric barrier. When dispersed in polytetrafluoroethylene, the layered structure can be oriented along the direction of the electric field to form a dielectric nanolayer, which hinders charge migration and reduces leakage current. At the same time, the interlayer gap can reduce the orientation polarization of the polar CF2 group and further reduce the dielectric loss. That is, the synergistic cooperation of modified graphene and molybdenum disulfide improves the transmission rate of the optical cable.

[0034] 3. The modified graphene of the present invention has a two-dimensional sheet structure and a large specific surface area. The oxygen-containing functional groups on the surface can form hydrogen bonds or van der Waals forces with the polytetrafluoroethylene molecular chains. This strong interfacial bonding can effectively transfer stress and avoid interfacial debonding when the composite material is subjected to external force, thereby improving the overall mechanical strength. The graphene sheets act as heterogeneous nucleation sites, prompting polytetrafluoroethylene to form more and smaller grains, reducing defects in large-sized crystalline regions, thereby improving the elongation at break and tensile strength of the material; the strong interfacial bonding between the graphene sheets and the polytetrafluoroethylene molecular chains can provide a certain buffer space at low temperatures. When the material shrinks due to cooling, the interaction between the sheets and the molecular chains can absorb stress and avoid cracks. In addition, the modified graphene can hinder the orderly arrangement of the molecular chains, reduce the crystallinity, increase the proportion of the amorphous region, and the molecular chains in the amorphous region still maintain a certain flexibility at low temperatures, thereby improving the environmental adaptability of the material. DETAILED DESCRIPTION

[0035] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] In this application, polytetrafluoroethylene was obtained from Shanghai MacLean Biochemical Technology Co., Ltd., with CAS number 9002-84-0 and a refractive index of 1.37 (20°C);

[0037] In this application, KH-560 is γ-glycidyloxypropyltrimethoxysilane, obtained from Shanghai Xinyu Biotechnology Co., Ltd., with a CAS number of 2530-83-8 and a boiling point of 290°C;

[0038] In this application, antioxidant 1010 is from Tianjin Li’anlong New Materials Co., Ltd., with CAS number 6683-19-8 and boiling point 779.1°C;

[0039] In this application, the ultraviolet absorber UV-326 was obtained from Wuhan Xingzhongcheng Technology Co., Ltd., with a CAS number of 3896-11-5;

[0040] In this application, polyethylene glycol was obtained from Nantong Chenrun Chemical Co., Ltd., with a CAS number of 25322-68-3 and a density of 1.27 g / cm³.

[0041] Example 1

[0042] This embodiment provides a method for preparing a sheath layer premix for a high transmission rate optical cable with low attenuation characteristics, comprising the following steps:

[0043] S1. Preparation of modified graphene

[0044] Weigh: 10 g of flake graphite, 50 mL of concentrated sulfuric acid and 4 g of potassium permanganate are added to a beaker and mixed evenly. The beaker is transferred to a constant temperature water bath, the temperature is raised to 30 ° C, and the reaction is stirred for 1 hour. Then the temperature is raised to 50 ° C, and the reaction is continued with stirring for 2 hours. After the reaction is completed, it is cooled to room temperature, 100 mL of deionized water is added to the system, filtered, and the filter cake is washed with deionized water until neutral. It is then transferred to a 60 ° C vacuum drying oven and dried to constant weight. The dried graphite powder is ground and placed in a muffle furnace. It is heated to 800 ° C at a heating rate of 5 ° C / s and kept warm for 1 minute to obtain expanded graphite;

[0045] Weigh: 50 mL of concentrated sulfuric acid and 1 g of sodium nitrate were mixed in a beaker, and then 5 g of expanded graphite was added. The mixture was stirred for 15 min, and the temperature was controlled at 20 ° C. 7.5 g of potassium permanganate was added and the reaction was continued for 1 h. 100 mL of deionized water was added, and the temperature was raised to 40 ° C. 30 wt% hydrogen peroxide solution was added until the color of the solution changed from brown to bright yellow. After the reaction was completed, the mixture was cooled to room temperature and filtered. The filter cake was washed with deionized water until neutral, and then transferred to a vacuum drying oven at 60 ° C and dried to constant weight to obtain graphite oxide.

[0046] Weigh: add 5 g of graphite oxide and 1000 mL of deionized water into a beaker and ultrasonicate at room temperature for 1 hour. Adjust the pH to 7 with saturated ammonia water, add 5 mL of hydrazine hydrate, place the reaction system in a 60°C water bath, and react for 2 hours. After the reaction is completed, transfer the mixed solution to a centrifuge tube and centrifuge. Wash the lower layer of liquid 3 times with deionized water, and then transfer it to a 40°C vacuum drying oven and dry it to constant weight to obtain modified graphene.

[0047] S2. Preparation of modified tetrafluoroethylene

[0048] Weigh: 10g modified graphene, 30g molybdenum disulfide and 400mL anhydrous ethanol, add them to a ball mill and ball mill for 8h. After the ball milling is completed, transfer the ball mill slurry to a beaker, add 0.1g polyethylene glycol, and stir for 30-40min to obtain a mixed slurry;

[0049] Weigh: 40 g of polytetrafluoroethylene and 2 g of low molecular weight polytetrafluoroethylene are added to a ball mill and milled for 2 h. The milled polytetrafluoroethylene is added to 400 mL of a sodium-naphthalene complex solution under nitrogen protection, the temperature is raised to 35°C, and the mixture is reacted for 20 min. The mixture is then washed with deionized water until neutral. 200 mL of KH560 ethanol solution is then added, ultrasonicated for 60 min, centrifuged, and dried in a vacuum drying oven at 60°C to constant weight to obtain pretreated polytetrafluoroethylene.

[0050] Weigh 40 g of pretreated polytetrafluoroethylene and add it into a mixer, stir at low speed for 1 minute, then add the mixed slurry and stir for 10 minutes, then transfer the mixed material to a 60° C. vacuum drying oven and dry it to constant weight to obtain modified polytetrafluoroethylene.

[0051] S3. Preparation of sheath layer premix

[0052] The ultraviolet absorber UV-326, the antioxidant 1010, the dioctyl adipate and the calcium stearate were mixed in a weight ratio of 1:0.8:4:0.8 to obtain an auxiliary additive, which was set aside;

[0053] Weigh 60 parts of high-pressure low-density polyethylene, 30 parts of modified polytetrafluoroethylene, 10 parts of random copolymer polypropylene and auxiliary additives in a mixer and mix them to obtain a sheath layer premix.

[0054] Example 2

[0055] This embodiment provides a method for preparing a sheath layer premix for a high transmission rate optical cable with low attenuation characteristics, comprising the following steps:

[0056] S1. Preparation of modified graphene

[0057] Weigh: 10 g of flake graphite, 50 mL of concentrated sulfuric acid and 4 g of potassium permanganate are added to a beaker and mixed evenly. The beaker is transferred to a constant temperature water bath, the temperature is raised to 35 ° C, and the reaction is stirred for 1.5 hours. Then the temperature is raised to 55 ° C, and the reaction is continued with stirring for 2.5 hours. After the reaction is completed, it is cooled to room temperature, 100 mL of deionized water is added to the system, filtered, and the filter cake is washed with deionized water until neutral, and then transferred to a 70 ° C vacuum drying oven and dried to constant weight. The dried graphite powder is ground and placed in a muffle furnace, and heated to 900 ° C at a heating rate of 8 ° C / s, and kept warm for 1 minute to obtain expanded graphite;

[0058] Weigh: 50 mL of concentrated sulfuric acid and 1 g of sodium nitrate were mixed in a beaker, and then 5 g of expanded graphite was added. The mixture was stirred for 17 min, the temperature was controlled at 25 ° C, 7.5 g of potassium permanganate was added, and the reaction was continued for 1.5 h. 100 mL of deionized water was added, the temperature was raised to 45 ° C, and 30 wt% of hydrogen peroxide solution was added until the color of the solution changed from brown to bright yellow. After the reaction was completed, the mixture was cooled to room temperature and filtered. The filter cake was washed with deionized water until neutral, and then transferred to a vacuum drying oven at 70 ° C and dried to constant weight to obtain graphite oxide.

[0059] Weigh: add 5g of graphite oxide and 1000mL of deionized water into a beaker and ultrasonicate at room temperature for 1.5h. Adjust the pH to 7 with saturated ammonia water. Add 5-10mL of hydrazine hydrate. Place the reaction system in a 70℃ water bath and react for 3h. After the reaction is completed, transfer the mixed solution to a centrifuge tube and centrifuge. Wash the lower layer of liquid 4 times with deionized water, and then transfer it to a 50℃ vacuum drying oven and dry it to constant weight to obtain modified graphene.

[0060] S2. Preparation of modified tetrafluoroethylene

[0061] Weigh: 10 g of modified graphene, 30 g of molybdenum disulfide, and 400 mL of anhydrous ethanol, mix and add to a ball mill for 10 h. After the ball milling is completed, transfer the ball mill slurry to a beaker, add 0.1 g of polyethylene glycol, and stir for 35 min to obtain a mixed slurry;

[0062] Weigh: 40 g of polytetrafluoroethylene and 2 g of low molecular weight polytetrafluoroethylene are added to a ball mill and milled for 3 h. The milled polytetrafluoroethylene is added to 400 mL of a sodium-naphthalene complex solution under nitrogen protection, the temperature is raised to 40°C, and the mixture is reacted for 25 min. The mixture is then washed with deionized water until neutral. 200 mL of KH560 ethanol solution is then added, ultrasonicated for 7 min, centrifuged, and dried in a vacuum drying oven at 60°C to constant weight to obtain pretreated polytetrafluoroethylene.

[0063] Weigh 40 g of pretreated polytetrafluoroethylene and add it into a mixer, stir at low speed for 2 minutes, then add the mixed slurry and stir for 15 minutes, then transfer the mixed material to a vacuum drying oven at 70° C. and dry it to constant weight to obtain modified polytetrafluoroethylene.

[0064] S3. Preparation of sheath layer premix

[0065] The ultraviolet absorber UV-326, the antioxidant 1010, the dioctyl adipate and the calcium stearate were mixed in a weight ratio of 1:0.8:4:0.8 to obtain an auxiliary additive, which was set aside;

[0066] Weigh 65 parts of high-pressure low-density polyethylene, 35 parts of modified polytetrafluoroethylene, 15 parts of random copolymer polypropylene and auxiliary additives in a mixer and mix them to obtain a sheath layer premix.

[0067] Example 3

[0068] This embodiment provides a method for preparing a sheath layer premix for a high transmission rate optical cable with low attenuation characteristics, comprising the following steps:

[0069] S1. Preparation of modified graphene

[0070] Weigh: 10 g of flake graphite, 50 mL of concentrated sulfuric acid and 4 g of potassium permanganate are added to a beaker and mixed evenly. The beaker is transferred to a constant temperature water bath, the temperature is raised to 40 ° C, and the reaction is stirred for 2 h. Then the temperature is raised to 60 ° C, and the reaction is continued with stirring for 3 h. After the reaction is completed, it is cooled to room temperature, 100 mL of deionized water is added to the system, filtered, and the filter cake is washed with deionized water until neutral. It is then transferred to an 80 ° C vacuum drying oven and dried to constant weight. The dried graphite powder is ground and placed in a muffle furnace. It is heated to 1000 ° C at a heating rate of 10 ° C / s and kept warm for 2 min to obtain expanded graphite;

[0071] Weigh: 50 mL of concentrated sulfuric acid and 1 g of sodium nitrate were mixed in a beaker, and then 5 g of expanded graphite was added. The mixture was stirred for 20 min, and the temperature was controlled at 30 ° C. 7.5 g of potassium permanganate was added and the reaction was carried out for 2 h. 100 mL of deionized water was added, and the temperature was raised to 50 ° C. 30 wt% hydrogen peroxide solution was added until the color of the solution changed from brown to bright yellow. After the reaction was completed, the mixture was cooled to room temperature and filtered. The filter cake was washed with deionized water until neutral, and then transferred to a vacuum drying oven at 60-80 ° C and dried to constant weight to obtain graphite oxide.

[0072] Weigh: add 5g of graphite oxide and 1000mL of deionized water into a beaker and ultrasonicate at room temperature for 2h, adjust the pH to 7 with saturated ammonia water, add 10mL of hydrazine hydrate, place the reaction system in an 80℃ water bath, and react for 4h. After the reaction is completed, transfer the mixed solution to a centrifuge tube and centrifuge, wash the lower layer liquid with deionized water 5 times, and then transfer it to a 60℃ vacuum drying oven and dry it to constant weight to obtain modified graphene.

[0073] S2. Preparation of modified polytetrafluoroethylene

[0074] Weigh: 10 g of modified graphene, 30 g of molybdenum disulfide, and 400 mL of anhydrous ethanol, mix and add to a ball mill for 12 h. After the ball milling is completed, transfer the ball-milled slurry to a beaker, add 0.1 g of polyethylene glycol, and stir for 40 min to obtain a mixed slurry;

[0075] Weigh: 40 g of polytetrafluoroethylene and 2 g of low molecular weight polytetrafluoroethylene are added to a ball mill and milled for 4 h. The milled polytetrafluoroethylene is added to 400 mL of a sodium-naphthalene complex solution under nitrogen protection, the temperature is raised to 45°C, and the mixture is reacted for 30 min. The mixture is then washed with deionized water until neutral. 200 mL of KH560 ethanol solution is then added, ultrasonicated for 80 min, centrifuged, and dried in a vacuum drying oven at 60°C to constant weight to obtain pretreated polytetrafluoroethylene.

[0076] Weigh 40 g of pretreated polytetrafluoroethylene and add it into a mixer, stir at low speed for 2 minutes, then add the mixed slurry and stir for 20 minutes, then transfer the mixed material to an 80° C. vacuum drying oven and dry it to constant weight to obtain modified polytetrafluoroethylene.

[0077] S3. Preparation of sheath layer premix

[0078] The ultraviolet absorber UV-326, the antioxidant 1010, the dioctyl adipate and the calcium stearate were mixed in a weight ratio of 1:0.8:4:0.8 to obtain an auxiliary additive, which was set aside;

[0079] Weigh 70 parts of high-pressure low-density polyethylene, 40 parts of modified polytetrafluoroethylene, 20 parts of random copolymer polypropylene and auxiliary additives in a mixer and mix them to obtain a sheath layer premix.

[0080] Example 4

[0081] This embodiment provides a method for preparing a high-transmission-rate optical cable with low attenuation characteristics, comprising the following steps:

[0082] Step 1: Wrapping

[0083] Several optical fibers are arranged in parallel, loose tubes are wrapped around the outer periphery of the optical fibers, the gap between the optical fibers and the loose tubes is filled with grease, and a tape is wrapped around the outside of the loose tubes to form an insulation layer.

[0084] Step 2: Extrusion molding

[0085] The sheath layer premix prepared in Example 1 was added to a twin-screw extruder. The temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end were 80°C, 150°C, 220°C, 280°C, 250°C, and 280°C, respectively. The main shaft speed of the twin-screw extruder was adjusted and melt mixing was maintained for 10 minutes. The premix was extruded and coated on the outside of the insulation layer. After cooling and molding, a sheath layer was obtained to prepare a high transmission rate optical cable.

[0086] Example 5

[0087] This embodiment provides a method for preparing a high-transmission-rate optical cable with low attenuation characteristics, comprising the following steps:

[0088] Step 1: Wrapping

[0089] Several optical fibers are arranged in parallel, loose tubes are wrapped around the outer periphery of the optical fibers, the gap between the optical fibers and the loose tubes is filled with grease, and a tape is wrapped around the outside of the loose tubes to form an insulation layer.

[0090] Step 2: Extrusion molding

[0091] The sheath layer premix prepared in Example 2 was added to a twin-screw extruder. The temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end were 100°C, 175°C, 260°C, 300°C, 275°C, and 300°C, respectively. The main shaft speed of the twin-screw extruder was adjusted to maintain melt mixing for 13 minutes. The premix was extruded and coated on the outside of the insulation layer. After cooling and molding, a sheath layer was obtained to prepare a high transmission rate optical cable.

[0092] Example 6

[0093] This embodiment provides a method for preparing a high-transmission-rate optical cable with low attenuation characteristics, comprising the following steps:

[0094] Step 1: Wrapping

[0095] Several optical fibers are arranged in parallel, loose tubes are wrapped around the outer periphery of the optical fibers, the gap between the optical fibers and the loose tubes is filled with grease, and a tape is wrapped around the outside of the loose tubes to form an insulation layer.

[0096] Step 2: Extrusion molding

[0097] The cable material prepared in Example 3 was added to a twin-screw extruder. The temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end were 120°C, 200°C, 280°C, 320°C, 300°C, and 320°C, respectively. The main shaft speed of the twin-screw extruder was adjusted to maintain melt mixing for 15 minutes. The material was extruded and coated on the outside of the insulation layer. After cooling and molding, a sheath layer was obtained to prepare a high transmission rate optical cable.

[0098] Comparative Example 1

[0099] The difference between this comparative example and Example 6 is that when the sheath layer premix prepared in Example 3 is used, modified graphene is not added when preparing modified polytetrafluoroethylene in step S2.

[0100] Comparative Example 2

[0101] The difference between this comparative example and Example 6 is that when the sheath layer premix prepared in Example 3 is used, molybdenum disulfide is not added when preparing the modified polytetrafluoroethylene in step S2.

[0102] Comparative Example 3

[0103] The difference between this comparative example and Example 6 is that when the sheath layer premix prepared in Example 3 is used, in step S3, the modified polytetrafluoroethylene in step S2 is replaced by polytetrafluoroethylene.

[0104] Comparative Example 4

[0105] The difference between this comparative example and Example 6 is that when the sheath layer premix prepared in Example 3 is used, step S2 is omitted, and no modified polytetrafluoroethylene is added to the prepared cable material.

[0106] Performance testing:

[0107] The tensile strength and elongation at break of the cable samples prepared in Examples 4-6 and Comparative Examples 1-4 were measured with reference to Standard XF 306.1-2007 "Classification and requirements for flame retardant and fire resistant cables with plastic insulation Part 1: Flame retardant cables";

[0108] The attenuation characteristics of the cable samples prepared in Examples 4-6 and Comparative Examples 1-4 were measured with reference to the standard GB / T 17737.113-2024 "Coaxial communication cables Part 1-113: Electrical test methods - Attenuation constant test";

[0109] The environmental adaptability of the cable samples prepared in Examples 4-6 and Comparative Examples 1-4 was determined with reference to the standard GB / Z 41287.1-2022 “Building drop cables for communications, Part 1: Drop cables for ducts and direct burial”. The specific test results are shown in Table 1.

[0110] Table 1 - Performance test data of the sample

[0111] Group Project Tensile strength / MPa Elongation at break / % <![CDATA[Attenuation constant / dB·km -1 > Temperature derating / grade Example 4 16.8 208.6 0.15 Level 1 Example 5 17.2 209.7 0.14 Level 1 Example 6 16.9 207.8 0.16 Level 1 Comparative Example 1 14.3 168.5 0.17 Level 2 Comparative Example 2 14.6 169.5 0.18 Level 2 Comparative Example 3 14.1 164.3 0.20 Level 2 Comparative Example 4 13.8 163.2 0.21 Level 2

[0112] Data Analysis:

[0113] Comparing and analyzing the data in the above table, the cable prepared by the present invention has a sheath layer tensile strength of 17.2 MPa, a breaking elongation of 209.7%, and an attenuation constant of 0.14 dB·km. -1 The temperature attenuation level is all level 1, and all performance parameters are better than those of the comparative example, indicating that the present invention fills polytetrafluoroethylene with modified graphene and molybdenum disulfide, which not only effectively improves the mechanical properties and environmental adaptability of the optical cable, but also effectively improves the transmission rate of the optical cable.

[0114] Comparative Example 1 Compared with the embodiment, the two-dimensional sp² hybridized carbon atoms of graphene form a highly conjugated π electron system. When uniformly dispersed in the polytetrafluoroethylene matrix, the π electron cloud of graphene can weaken the dipole orientation polarization of the polytetrafluoroethylene molecular chain through the electron shielding effect, thereby reducing the dielectric constant and dielectric loss, thereby reducing signal attenuation and increasing the transmission rate. At the same time, the mechanical properties of the cable are improved due to the influence of the lamellar structure of the modified graphene;

[0115] Comparative Example 2 Compared with the embodiment, the d-orbital electrons of molybdenum disulfide are delocalized within the layer, but the interlayer electron transmission is limited, forming a dielectric barrier. When dispersed in polytetrafluoroethylene, the layered structure can be oriented along the direction of the electric field to form a dielectric nanolayer, which hinders charge migration and reduces leakage current. At the same time, the interlayer gaps can reduce the orientation polarization of the polar CF2 group, further reducing the dielectric loss and improving the transmission rate of the optical cable.

[0116] Compared with the embodiment, the modified polytetrafluoroethylene is combined with fillers such as graphene and molybdenum disulfide. With the assistance of graphene and molybdenum disulfide, local overheating at high transmission rates is reduced, friction is further reduced, and the flexibility of the optical cable during laying is improved. It cooperates with the matrix resin to form multi-layer insulation protection, thereby enhancing the stability of signal transmission.

[0117] Comparative Example 4 Compared with the embodiment, polytetrafluoroethylene has high heat resistance and weather resistance, which can resist the heat accumulation caused by current or signal loss at high transmission rates in optical cables, avoid softening, deformation or aging of cable materials due to high temperature, ensure stable operation of optical cables in high temperature environments, and reduce structural damage caused by temperature fluctuations.

[0118] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to specific embodiments. Obviously, many modifications and variations are possible based on the contents of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A high transmission rate optical cable with low attenuation characteristics, characterized in that: The high transmission rate optical cable comprises an optical fiber, a loose tube, an insulation layer and a sheath layer arranged in sequence from the inside out, a gap is left between the optical fiber and the loose tube, and the gap is filled with grease; The sheath layer comprises the following components in parts by weight: 60-70 parts of high-pressure low-density polyethylene, 30-40 parts of modified polytetrafluoroethylene, 10-20 parts of random copolymer polypropylene and 3-5 parts of auxiliary additives; The preparation method of the modified polytetrafluoroethylene comprises the following steps: A1. Modified graphene, molybdenum disulfide, and anhydrous ethanol were mixed and added to a ball mill for dispersion for 8-12 hours. After the ball milling was completed, the milled slurry was transferred to a beaker, polyethylene glycol was added, and stirred for 30-40 minutes to obtain a mixed slurry; A2. Add the pretreated polytetrafluoroethylene into the mixer and stir at low speed for 1-2 minutes. Then add the mixed slurry and stir for 10-20 minutes. Then transfer the mixed material to a vacuum drying oven at 60-80°C and dry it to constant weight to obtain modified polytetrafluoroethylene.

2. The optical cable with low attenuation and high transmission rate according to claim 1, characterized in that: The optical fiber is made of quartz glass with a purity of 99.99%, the loose tube is made of polypropylene material or nylon material, and the insulation layer is made of poly(p-phenylene terephthalamide); the auxiliary additives are composed of ultraviolet absorber, antioxidant, plasticizer, and lubricant in a weight ratio of 1:0.8:4:0.

8.

3. The optical cable with low attenuation and high transmission rate according to claim 1, characterized in that: In step A1, the usage ratio of the modified graphene, molybdenum disulfide, anhydrous ethanol and polyethylene glycol is 1 g:3 g:40 mL:0.01-0.02 g, and the polyethylene glycol model is PEG-400.

4. The optical cable with low attenuation and high transmission rate according to claim 3, characterized in that: In step A2, the weight ratio of the pretreated polytetrafluoroethylene to the mixed slurry is 4:

1.

5. The optical cable with low attenuation and high transmission rate according to claim 4, characterized in that: The method for pre-treating polytetrafluoroethylene is as follows: adding polytetrafluoroethylene and low molecular weight polytetrafluoroethylene into a ball mill and ball milling for 2-4 hours, adding the ball-milled polytetrafluoroethylene into a sodium-naphthalene complex solution protected by nitrogen, raising the temperature to 35-45° C., reacting for 20-30 minutes, washing with deionized water to neutrality, then adding KH560 ethanol solution, ultrasonicating for 60-80 minutes, and centrifuging and drying to obtain pre-treated polytetrafluoroethylene.

6. The optical cable with low attenuation and high transmission rate according to claim 5, characterized in that: The polytetrafluoroethylene, low molecular weight tetrafluoroethylene, sodium-naphthalene complex solution, and KH560 ethanol solution are used in a ratio of 20 g:1 g:200 mL:100 mL; the sodium-naphthalene complex solution is composed of naphthalene, sodium, and tetrahydrofuran in a ratio of 0.2 g:0.5 g:50 mL; and the KH560 ethanol solution is composed of γ-glycidyloxypropyltrimethoxysilane, ethanol, and water in a volume ratio of 1:8:

1.

7. The optical cable with low attenuation and high transmission rate according to claim 1, characterized in that: In step A1, the preparation method of modified graphene is: B1. Add flake graphite, concentrated sulfuric acid and potassium permanganate into a beaker and mix well. Transfer the beaker to a constant temperature water bath, raise the temperature to 30-40°C, stir and react for 1-2 hours, then raise the temperature to 50-60°C, continue stirring and react for 2-3 hours. After the reaction is completed, filter, wash and dry, and heat to expand to obtain expanded graphite; B2. After uniformly mixing concentrated sulfuric acid and sodium nitrate in a beaker, add expanded graphite, stir for 15-20 min, control the temperature to 20-30 ° C, add potassium permanganate, react for 1-2 h, add deionized water, raise the temperature to 40-50 ° C, add 30 wt% hydrogen peroxide solution until the solution color changes from brown to bright yellow, filter, wash and dry to obtain graphite oxide; B3. Add graphite oxide and deionized water into a beaker and sonicate at room temperature for 1-2 hours. Adjust the pH to 6.5-7.5 with saturated ammonia water. Add hydrazine hydrate and place the reaction system in a 60-80°C water bath for 2-4 hours. Post-treat to obtain modified graphene.

8. The optical cable with low attenuation and high transmission rate according to claim 7, characterized in that: In step B1, the ratio of the flake graphite, concentrated sulfuric acid and potassium permanganate is 2g:10mL:1g; The heating expansion step comprises: grinding the dried graphite powder and placing it in a muffle furnace, heating it to 800-1000° C. at a heating rate of 5-10° C. / s, and keeping it warm for 1-2 minutes to obtain expanded graphite; in step B2, the amount ratio of concentrated sulfuric acid, sodium nitrate, expanded graphite, potassium permanganate and deionized water is 50 mL:1 g:5 g:7.5 g:100 mL; in step B3, the amount ratio of graphite oxide, deionized water and hydrazine hydrate is 1 g:200 mL:1-2 mL, and the post-processing step comprises: after the reaction is completed, transferring the mixed solution to a centrifuge tube and centrifuging it, washing the lower layer liquid with deionized water 3-5 times, and then transferring it to a vacuum drying oven at 40-60° C. and drying it to constant weight to obtain modified graphene.

9. A method for preparing a high transmission rate optical cable according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1. High-pressure low-density polyethylene, modified polytetrafluoroethylene, and random copolymer polypropylene are mixed in an internal mixer, the temperature is raised to 280-320° C., auxiliary additives are added, and the mixture is uniformly mixed to obtain a premix; S2. The premix is ​​placed in a twin-screw extruder and melted and extruded outside the insulation layer. After cooling and forming, a sheath layer is obtained to prepare a high transmission rate optical cable.

10. The method for preparing a high transmission rate optical cable with low attenuation characteristics according to claim 9, characterized in that: In step S1, the temperatures of the six temperature zones of the twin-screw extruder from the feed end to the discharge end are 80-120°C, 150-200°C, 220-280°C, 280-320°C, 250-300°C, and 280-320°C, respectively.