CN111607847A - A kind of coupling agent, porous carburized coating fiber and preparation method thereof - Google Patents

Abstract

The invention relates to a coupling agent, a porous carburized coating fiber and a preparation method thereof, belonging to the technical field of carbon fiber material preparation, and solving the inherent low strength problem of the existing activated carbon fibers. The preparation method of the porous carburized coating fiber provided by the present invention includes the following steps: step 1: performing acid-base etching treatment on the surface of the basalt fiber; step 2: using bis(2-furylmethoxy)dimethylsilane The tetrahydrofuran solution and the tetrahydrofuran solution of the furan formaldehyde and furanmethanol condensation resin are coated on the surface-modified basalt fiber, and the coating layer is further polymerized and solidified; step 3: the coated basalt fiber is carbonized and activated to obtain Basalt fiber with porous carburized coating. The invention adopts basalt fiber as matrix fiber, and forms a porous carbon layer through surface carburizing treatment, so that it has the pore characteristics of activated carbon fiber and has good mechanical strength of basalt fiber.

Description

A kind of coupling agent, porous carburized coating fiber and preparation method thereof

technical field

The invention relates to the technical field of new materials, in particular to a coupling agent, a porous carburized coating fiber and a preparation method thereof.

Background technique

The adsorption and separation process is a very common natural process. Through the continuous synthesis and manufacture of various adsorption materials, the adsorption and separation process is widely used in the fields of chemical engineering, biomedicine, analysis and testing, and environmental treatment. With the emergence of a large number of environmental problems such as urban and industrial sewage treatment, heavy metal pollution, organic oil pollutants, clean drinking water, VOCs, waste gas treatment and carbon dioxide capture and recovery, high-efficiency adsorption materials that meet various specific performance requirements are required. In practical applications, activated carbon, resin and activated alumina are mainly used as adsorbent materials in terms of cost and performance. Fibrous activated carbon is a new type of adsorbent material with unique open pore characteristics and excellent weaving and processing properties. It is used in solvent recovery, VOCs removal and water purification equipment. However, its dosage and range are still insignificant compared with ordinary activated carbon.

In terms of physical form, fibrous activated carbon can meet the requirements of the overall component body in various practical applications through the weaving process, and is widely used in industrial pollution control, waste gas, waste liquid, heavy metal pollution, and ecological restoration of polluted soil and water bodies. Activated carbon fiber is chemically stable, acid and alkali resistant, heat resistant, and has good biocompatibility. Because its raw materials and manufacturing process are strictly controllable, its chemical purity is high and its electrical conductivity is good. These determine that it also has great potential in electrochemical processes and related applications of biomaterials. Activated carbon fiber has a relatively special pore structure, the fiber diameter is about 10 microns, the micropores are distributed on the surface of the fiber, and all the pores are in an open state, which is easy to achieve a high specific surface area and improve the adsorption rate at the same time. The adsorption rate of activated carbon fiber is 100-1000 times that of granular activated carbon, and the adsorption capacity is also 1.5-10 times that of granular activated carbon. Activated carbon fiber is easy to manufacture an integral molding structure in practical applications, and the process pressure loss is about 1/3 of that of granular activated carbon. It is suitable for high-velocity airflow and liquid with high viscosity. Environments where granular activated carbon cannot be used.

There are still several problems in the research and development and promotion of activated carbon fibers: 1) It is necessary to optimize the manufacturing cost so that it cannot be too different from granular activated carbon and powder activated carbon; 2) It needs to be realized in terms of surface pore structure and mechanical properties and strength. balance of the two.

SUMMARY OF THE INVENTION

In view of the above analysis, the embodiments of the present invention aim to provide a coupling agent, a porous carburized coated fiber and a preparation method thereof to solve the problem of the inherent low strength of the activated carbon fiber in the prior art.

The object of the present invention is mainly achieved through the following technical solutions:

In one aspect, the present invention provides a coupling agent, wherein the coupling agent is bis(2-furylmethoxy)dimethylsilane; the structural formula of bis(2-furylmethoxy)dimethylsilane is:

On the other hand, the present invention also provides a method for preparing a coupling agent for preparing the above-mentioned coupling agent; bis(2-furylmethoxy)dimethylsilane is composed of dichlorodimethylsilane, furan It is prepared by direct condensation reaction of methanol and sodium hydroxide under solvent-free conditions;

The dosage of furanmethanol is 2.0 to 2.3 times of the molar amount of dichlorodimethylsilane, and the amount of sodium hydroxide is 2.1 to 2.4 times of the molar amount of dichlorodimethylsilane; the temperature of adding dichlorodimethylsilane is -5 ~0°C, the reaction temperature is 20-30°C, and the reaction time is 1.0-2.0 hours.

On the other hand, the present invention also provides a porous carburized coating fiber, the preparation raw material includes the above-mentioned coupling agent, and the porous carburized coating fiber sequentially includes a basalt fiber matrix, a transition layer and a carbonaceous coating from the inside to the outside. ; The transition layer is a Si-C-O transition layer.

In a fourth aspect, the present invention also provides a method for preparing porous carburized coated fibers, which adopts the above-mentioned bis(2-furylmethoxy)dimethylsilane coupling agent for preparing the above-mentioned porous carburized coating fibers. Carburizing coated fibers; including the following steps:

Step 1. Use sodium hydroxide solution to perform alkali etching treatment on the basalt fiber. After the alkali etching, use deionized water to clean it to neutrality. Use hydrochloric acid solution to perform acid etching treatment on the basalt fiber. After the acid etching treatment, leave it in the air. dry;

Step 2, using the tetrahydrofuran solution of bis(2-furylmethoxy)dimethylsilane to modify the surface of the acid-etched basalt fiber;

Step 3, using the tetrahydrofuran solution of furanformaldehyde and furanmethanol condensation resin to coat the surface-modified basalt fiber, and to polymerize and cure the formed coating layer;

Step 4, carbonizing and activating the basalt fiber after polymerization and curing treatment to prepare porous carburized coating fiber.

Further, in step 1, the mass concentration of the sodium hydroxide solution is 1.0-6.0%, the alkali etching temperature is 20-60° C., and the alkali etching treatment time is 1.0-6.0 h; after the alkali etching, take it out and use deionized water Wash to neutral;

The mass concentration of the hydrochloric acid solution is 1.0-8.0%, the acid etching treatment temperature is 20-60 DEG C, and the acid etching treatment time is 1.0-6.0 h.

Further, in step 2, the acid-etched basalt fiber is loaded with a surface coupling agent by using a tetrahydrofuran solution of bis(2-furylmethoxy)dimethylsilane with a mass concentration of 2.0 to 5.0%. The amount of (2-furylmethoxy)dimethylsilane used is 0.3-2.2% of the mass of the basalt fiber.

Further, in step 3, the mass concentration of the tetrahydrofuran solution of the furanformaldehyde and the furanmethanol condensation resin is 4.0-10%, and the loading of the furanformaldehyde and the furanmethanol condensation resin is 5-25% of the mass of the basalt fiber, and the coating treatment is completed. The basalt fiber was subjected to coating polymerization and curing treatment at 60-90 °C for 1.0-3.0 h.

Further, in step 3, the condensation resin monomer of furancarboxaldehyde-furanmethanol is prepared by heating furancarboxaldehyde, furanmethanol and catalyst maleic anhydride to 60～90℃ under nitrogen protection and reacting for 15～45min;

The usage amount of furanmethanol is 2.2-2.4 times the molar amount of furancarbaldehyde; the usage amount of catalyst maleic anhydride is 1.0-3.0% of the total molar amount of furancarbaldehyde and furanmethanol.

Further, in step 4, the carbonization treatment is heated in a tube furnace, and nitrogen is used as the carrier gas, and the temperature is raised to 550 to 950 °C at a heating rate of 1.0 to 10 °C/min for carbonization treatment, and the carbonization treatment time is 45 to 120min. The flow rate of nitrogen during the treatment is 60-300 ml/min.

Further, in step 4, the activation treatment is to use pulsed air flow to activate the carbonized fiber material to make pores, the temperature is 550-950 ° C, the nitrogen flow is 60-300 ml/min, and dry air is injected into the nitrogen flow. Pulse air flow for 5 to 20s, and pulse air injection operation is repeated 2 to 10 times;

The flow rate of the dry air pulse airflow is 80-200ml/min.

Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

(1) In the prior art, activated carbon fibers need to have a rich pore structure on the surface, which leads to certain problems in their mechanical properties and strength. The invention adopts basalt fiber as the matrix fiber, which ensures the good mechanical properties of the fiber.

(2) The present invention provides a preparation method of porous carburized coating fiber, which uses basalt fiber as matrix fiber, and forms a porous carbon layer through surface carburizing treatment, so that it has the pore characteristics of activated carbon fiber, and has good basalt fiber. The mechanical strength greatly improves the strength, flexibility and weaving properties of the product, thereby solving the problem of low strength inherent in the existing activated carbon fibers.

(3) The present invention provides a bis(2-furylmethoxy)dimethylsilane coupling agent, which can be used as a coupling agent for forming a carburized coating on the surface of basalt fibers, and bis(2- Furylmethoxy) dimethylsilane is an organic molecule with an amphoteric structure. Some groups in its molecular structure can react with the inorganic surface functional groups of basalt fibers to form strong chemical bonds, and another part of the groups can react with organic The polymer undergoes a chemical reaction or physical entanglement, thereby firmly combining two materials with very different properties, forming a molecular bridge with a special function at the interface of the two materials.

(4) The present invention uses basalt fiber as raw material to prepare activated carbon fiber. The continuous basalt fiber has high strength, and also has various excellent properties such as electrical insulation, corrosion resistance and high temperature resistance. The production process of basalt fiber produces less waste and less pollution to the environment. The product can be directly degraded in the environment without any secondary hazards.

(5) The preparation method of the porous carburized coating fiber provided by the present invention forms a porous carbon layer through surface carburizing treatment, so that it has the open pore characteristics of the activated carbon fiber, and the specific surface area of the prepared porous carburizing coating fiber reaches 700 ～1206m ² /g, while the tensile strength of porous carburized coated fibers is 63～127MPa, the elongation at break reaches 0.8～1.6%, and the elastic modulus reaches 1.0～10GPa, which realizes the surface void structure and mechanical properties and strength. balance.

In the present invention, the above technical solutions can also be combined with each other to achieve more preferred combination solutions. Additional features and advantages of the invention will be set forth in the description which follows, and some of the advantages may become apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention may be realized and attained by the embodiments particularly pointed out in the description and drawings.

Description of drawings

The drawings are for the purpose of illustrating specific embodiments only and are not to be considered limiting of the invention, and like reference numerals refer to like parts throughout the drawings.

Fig. 1 is a schematic diagram of the process of forming a coating by polymerization on the surface of basalt fibers;

Figure 2 is a schematic diagram of the evolution process of the basalt fiber structure during carbonization and activation;

FIG. 3 is a synthesis reaction equation of bis(2-furylmethoxy)dimethylsilane and a reaction equation with the surface of basalt fiber.

Detailed ways

The preferred embodiments of the present invention are specifically described below with reference to the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention, and together with the embodiments of the present invention, are used to explain the principles of the present invention, but not to limit the scope of the present invention.

Basalt fiber According to the national standard of GBT 25045-2010 "Basalt Fiber Roving", the breaking strength of basalt fiber roving should not be less than 0.4N/tex, the moisture content should not be more than 0.2%, and the alkali resistance and temperature resistance should be drawn by monofilament. The retention rate of tensile strength shall not be less than 70%.

Basalt fiber is a continuous fiber drawn at high speed through platinum-rhodium alloy wire drawing bushings after the natural basalt material is melted at 1450℃～1500℃. Basalt fiber is a new type of inorganic environmentally friendly green high-performance fiber material, which is composed of oxides such as silica, alumina, calcium oxide, magnesium oxide, iron oxide and titanium dioxide. The color of pure natural basalt fiber is generally brown with metallic luster. Basalt continuous fiber has high strength, and also has many excellent properties such as electrical insulation, corrosion resistance, and high temperature resistance. The production process of basalt fiber produces less waste and less pollution to the environment. The product can be directly degraded in the environment without any secondary hazards. my country has listed basalt fiber as one of the four major fibers of carbon fiber, aramid fiber, ultra-high molecular weight polyethylene and basalt fiber, which has realized large-scale industrial production. my country has extremely rich volcanic rocks that can produce basalt fiber, which constitutes our unique resource advantage.

The invention adopts the basalt fiber as the matrix fiber, and forms a porous carbon layer through surface carburizing treatment, so that it has the pore characteristics of the activated carbon fiber and the good mechanical properties of the basalt fiber.

The invention provides a coupling agent. The coupling agent is bis(2-furylmethoxy)dimethylsilane; its molecular formula is C ₁₂ H ₁₆ O ₄ Si and the molecular weight is 252.34. The structure is as follows:

The above-mentioned coupling agent is characterized, and its specific characterization results are as follows:

Elemental analysis results are: C, 57.12; H, 6.39; O, 25.36; the mass spectrum peaks obtained by mass spectrometer testing are: m/z: 252.08 (100.0%), 253.09 (13.3%), 253.08 (5.1%), 254.08 (4.0%), 254.09 (1.7%); spectral analysis H-NMR (ppm): 0.14 (6H), 4.90 (4H), 6.39 (2H), 6.47 (2H), 7.67 (2H).

The invention provides a bis(2-furylmethoxy)dimethylsilane coupling agent, which can be used as a surface coupling agent for basalt fibers to form a surface carburized coating (ie, a carbonaceous coating). Di(2-furylmethoxy)dimethylsilane is an organic molecule with an amphoteric structure. Some groups in its molecular structure can react with the inorganic surface functional groups of basalt fibers to form strong chemical bonds. The group can chemically react or physically entangle with the organic polymer, thereby firmly combining two materials with very different properties, forming a molecular bridge with special functions at the interface of the two materials. The synthesis reaction equation of bis(2-furylmethoxy)dimethylsilane is shown in formula (1) in Figure 3. The reaction between bis(2-furylmethoxy)dimethylsilane and the surface of basalt fiber is shown in the formula (1). The equation is shown in equation (2) in FIG. 3 .

The present invention also provides a method for preparing a bis(2-furylmethoxy)dimethylsilane coupling agent, which can be used to modify the surface of basalt fibers. The preparation process of oxy) dimethylsilane is as follows:

Bis(2-furylmethoxy)dimethylsilane is prepared by direct condensation reaction of dichlorodimethylsilane, furanmethanol and sodium hydroxide under solvent-free conditions. Specifically, the furan methanol and sodium hydroxide are mixed, cooled to -5～0°C, dichlorodimethylsilane is added dropwise, the temperature is raised to 20～30°C after the addition is completed, and the reaction is continued for 1.0～2.0 hours, and the solid is removed by filtration salt, the liquid product is bis(2-furylmethoxy)dimethylsilane.

It should be noted that the dosage of furanmethanol is 2.0-2.3 times the molar amount of dichlorodimethylsilane, and the amount of sodium hydroxide is 2.1-2.4 times the molar amount of dichlorodimethylsilane. Strictly controlling the amount of furanmethanol and sodium hydroxide within the corresponding range is beneficial to neutralize the hydrogen chloride produced in the reaction process and avoid side reactions such as polymerization of furanmethanol caused by hydrogen chloride.

The present invention also provides a porous carburized coating fiber, the preparation raw material includes the above-mentioned coupling agent, that is, the above-mentioned coupling agent is used for preparation, and the porous carburized coating fiber sequentially includes from the inside to the outside: a basalt fiber matrix , transition layer and carbonaceous coating; the transition layer is Si-C-O transition layer.

The present invention also provides a method for preparing porous carburized coating fibers. The coupling agent bis(2-furylmethoxy)dimethylsilane prepared by the above method is used, and basalt fibers are used as matrix fibers. It includes the following steps:

Step 1. Perform surface alkali etching treatment and acid etching treatment on the basalt fiber;

Specifically, in step 1, the present invention uses basalt fiber as the matrix fiber, and its surface needs to be etched to introduce the porous carburized coating. Basalt is a mixture with unique physical and chemical properties formed from the solidification and crystallization of magma, and its chemical composition is complex silicate minerals, such as albite NaAlSi ₃ O ₈ , anorthite CaAl ₂ Si ₂ O ₈ , permeable It exists in the form of pyroxene CaMg[Si ₂ O ₆ ], olivine (Mg, Fe)SiO ₄ , ordinary pyroxene Ca (Mg, Fe)[Si ₂ O ₆ ] and the like.

According to the chemical composition of basalt, alkali and acid etching can be used to treat the fiber surface, among which metal oxides (CaO, MgO, Fe ₂ O ₃ ) can be etched with dilute acid, and silica and alumina can be etched with alkali solution for etching. The etching treatment produces grooves and depressions on the surface of the fiber, thereby effectively increasing the specific surface area of the fiber, making the coating easy to penetrate into the grooves and depressions on the surface, and playing a role in structural anchoring. The increase in the number of clusters improves the wettability and interfacial interaction between the coating and the fiber surface. Basalt fiber is sequentially etched with sodium hydroxide solution with a mass concentration of 1.0-6.0% and hydrochloric acid solution with a mass concentration of 1.0-8.0%.

The specific etching process is as follows: soak the basalt fiber in a sodium hydroxide solution with a mass concentration of 1.0-6.0% at 20-60 ° C for 1.0-6.0 h, take it out and wash it with deionized water until it is neutral; continue to use a mass concentration of 1.0 ～8.0% hydrochloric acid solution is soaked at 20～60℃ for 1.0～6.0h, after the hydrochloric acid treatment, the fibers are washed with deionized water until neutral, and dried in air at 100～120℃.

Controlling the etching conditions within this range is conducive to the formation of grooves and depressions on the fiber surface by etching the fiber surface, thereby effectively increasing the specific surface area of the fiber, making the coating easy to penetrate into the surface grooves and depressions, and play a role in structural anchoring. At the same time, the etching process will increase the number of active groups on the fiber surface, and improve the wettability and interface interaction between the coating and the fiber surface.

It should be emphasized that, due to the complex composition of basalt fibers, alkali etching is mainly aimed at silicon dioxide and alumina components, and acid etching is mainly aimed at metal oxides (CaO, MgO, Fe ₂ O ₃ ). The order of etching and then using acid solution for etching cannot be switched. After the acid solution treatment, the neutralization of the excess alkali adsorbed on the surface can also be achieved at the same time. The surface alkalinity is not conducive to the adhesion of the polymer coating.

Step 2, using the tetrahydrofuran solution of bis(2-furylmethoxy)dimethylsilane to modify the surface of the basalt fiber;

In the above step 2, a tetrahydrofuran solution of bis(2-furylmethoxy)dimethylsilane with a mass concentration of 2.0 to 5.0% is used to load the etched basalt fibers with a surface coupling agent, and bis(2-furan) The amount of dimethyl silane used is 0.3-2.2% of the mass of the basalt fiber.

Step 3. The surface-modified basalt fiber is coated with the tetrahydrofuran solution of the furan-formaldehyde and furan-methanol condensation resin, and the formed coating layer is further polymerized and cured.

In the above-mentioned step 3, the precursor material of the porous carburized coating fiber adopted in the present invention is the condensation resin of furanformaldehyde and furanmethanol, and the monomer of the furanformaldehyde and furanmethanol condensation resin is the catalytic condensation of furanformaldehyde and furanmethanol in maleic anhydride. and made. Furancarboxaldehyde, furanmethanol and catalyst maleic anhydride are heated to 60～90℃ under nitrogen protection and react for 15～45min to obtain dark brown liquid, reaction equation (3) of condensation of furancarboxaldehyde and furanmethanol. Wherein, the usage amount of furanmethanol is 2.2～2.4 times of the molar amount of furanmethanol, and the usage amount of catalyst maleic anhydride is 1.0～3.0% of the total molar amount of furanmethanol and furanmethanol; wherein, the ratio of furanmethanol and furanmethanol is controlled The relationship is favorable for the formation of a trifuran ring condensation structure, and the reaction process thereof is shown in the following reaction formula (3).

The surface-modified basalt fiber is coated with a tetrahydrofuran solution of furanformaldehyde and furanmethanol condensation resin with a mass concentration of 4.0-10%, and the loading amount of furanformaldehyde and furanmethanol condensation resin is 5-25% of the mass of the basalt fiber; The basalt fibers coated with furanformaldehyde and furanmethanol condensation resin are polymerized and cured for 1.0 to 3.0 h at 60 to 90 °C, and the process of polymerizing to form a coating is shown in Figure 1.

Step 4, carbonizing and activating the coated basalt fibers to obtain porous carburized coated fibers.

Specifically, the coated basalt fibers are carbonized, heated in a tube furnace, nitrogen is used as a carrier gas, and the temperature is raised to 550-950 °C at a heating rate of 1.0-10 °C/min for carbonization treatment, and the carbonization treatment time It is 45～120min, and the flow rate of nitrogen in the treatment process is 60～300ml/min. Adopting such carbonization conditions is conducive to the formation of the carbon structure of the coating, and avoids the uneven structure of the microdomain and the decline of the fiber properties caused by the carbonization process.

The carbonized fiber material was activated by pulsed air flow. The activation temperature was the same as the carbonization temperature. Dry air with a flow rate of 80-200ml/min was injected into the nitrogen stream for 5-20s, and the pulsed air injection operation was repeated for 2-10 seconds. Second-rate. The pulsed air treated fibers were cooled to room temperature in the corresponding nitrogen gas. Controlling the carbonization treatment conditions within the corresponding range is beneficial to achieve effective pore making and achieve a balance between higher porosity and fiber strength. The purpose of injecting air into nitrogen is to use the oxygen in the air to oxidatively erode the carbon structure and make holes, and the use of nitrogen to dilute the air is to control the concentration of oxygen to avoid excessive oxidation.

The evolution process of basalt fiber structure during carbonization and activation treatment is shown in Figure 2. The basalt fiber after coating treatment is carbonized. During the carbonization and heat treatment process, the polymer coating gradually transforms to form a carbonaceous coating, and the basalt fiber matrix It can withstand higher temperatures, and its basic performance parameters change less during heat treatment. Due to the existence of surface coupling molecules, the heat treatment process will form a tightly bonded Si-C-O transition layer between the basalt fiber and the carbonaceous coating. In addition, the grooves and depressions formed on the surface of the basalt fiber by etching also become the carbonaceous coating. Structural foundation for impregnation and anchoring.

For the formation of carbonaceous coating, it is necessary to use the method of high temperature activation of pulsed air to make pores. The main principle is to use oxygen in the air to oxidize and erode the carbonaceous coating to form a pore structure. The concentration of oxygen, so as to achieve the purpose of effectively making holes without causing the carbonaceous coating to be damaged by oxidation.

In the prior art, activated carbon fibers are directly prepared from polymer fiber precursors through carbonization and activation, but the mechanical properties of the prepared activated carbon fibers are poor, the tensile strength is lower than 30 MPa, and the elongation ratio and tensile modulus are relatively small. . Compared with the prior art, the present invention uses basalt fiber as the matrix fiber, and forms a porous carbon layer through surface carburizing treatment, so that it has the pore characteristics of activated carbon fiber and good mechanical strength of basalt fiber. The prepared porous carburized coated fibers have a specific surface area of 700 to 1206 m ² /g, and at the same time the porous carburized coated fibers have a tensile strength of 63 to 127 MPa, an elongation at break of 0.8 to 1.5%, and a tensile modulus as high as 63 to 127 MPa. 1.0～7.4GPa, realizing the balance between surface void structure and mechanical properties and strength.

The method of the invention has the advantages of high efficiency and conciseness, reasonable economic cost and wide application prospect.

1) The method of the present invention uses basalt fiber as matrix fiber, and forms a porous carbon layer through surface carburizing treatment, so that it has the pore characteristics of activated carbon fiber, and at the same time has good mechanical strength of basalt fiber, which greatly improves the strength, flexibility and durability of the product. Weaving performance, so as to solve the problem of low strength inherent in the prior art activated carbon fiber itself.

2) The manufacturing cost of activated carbon fiber is mainly concentrated in the two main processes of spinning, forming and heat treatment carbonization. In terms of cost distribution, the cost of carbonization and activation process is mainly energy consumption and equipment depreciation, which is not related to raw materials and the corresponding molding process. , is relatively fixed, generally accounting for 15 to 20% of the total manufacturing cost. The manufacturing cost of activated carbon fiber is mainly concentrated in the precursor fiber forming process, in which the cost of raw materials accounts for more than 30%, the cost of raw material processing and spinning accounts for about 40%, and the cost of spinning and forming stabilization process accounts for about 15%.

The invention directly prepares the activated carbon fiber by coating the basalt fiber, avoids the spinning and forming process, can save at least about 40% of the cost, that is, the spinning cost, and can greatly reduce the manufacturing cost. In addition, basalt continuous fibers have high strength, and also have many excellent properties such as electrical insulation, corrosion resistance, and high temperature resistance. The production process of basalt fiber produces less waste and less pollution to the environment. The product can be directly degraded in the environment without any secondary hazards.

Example 1

The present embodiment provides a method for preparing porous carburized coated fibers, which specifically includes the following steps:

Step 1. 50g basalt fiber is etched with sodium hydroxide solution and hydrochloric acid solution (treatment conditions are listed in Table 1). After the treatment, the fiber is washed with deionized water until neutral, and dried in air at 110°C.

Synthesis of bis(2-furylmethoxy)dimethylsilane: 4.32g of furanmethanol was mixed with 1.84g of sodium hydroxide, cooled to -5°C, 2.58g of dichlorodimethylsilane was added dropwise, and the addition was completed After that, the temperature was raised to 25° C. and the reaction was continued for 1.5 hours, and the solid salt was removed by filtration. The liquid product was bis(2-furylmethoxy)dimethylsilane.

Preparation of the condensation resin monomer of furancarboxaldehyde and furanmethanol: 9.6g furancarboxaldehyde, 22.56g furanmethanol and 0.65g catalyst maleic anhydride were heated to 85°C under nitrogen protection and reacted for 30min to obtain a dark brown liquid.

Step 2, using a tetrahydrofuran solution of bis(2-furylmethoxy)dimethylsilane with a mass concentration of 3.6% to load the etched basalt fiber with a surface coupling agent, bis(2-furylmethoxy) ) The usage amount of dimethylsilane is 1.8% of the quality of basalt fiber;

Step 3. The surface-modified basalt fiber is coated with a tetrahydrofuran solution of furanformaldehyde and furanmethanol condensation resin with a mass concentration of 8%, and the loading amount of furanformaldehyde and furanmethanol condensation resin is 18% of the mass of the basalt fiber. The coated fibers were subjected to coating polymerization and curing treatment at 85 °C for 2.0 h.

Step 4. The coated basalt fiber is carbonized, heated in a tube furnace, nitrogen is used as a carrier gas, and the temperature is raised to 700 °C at a heating rate of 5 °C/min for carbonization treatment. The carbonization treatment time is 90min. The treatment process The flow rate of nitrogen in the medium was 180ml/min. The carbonized fiber material was activated by pulsed air flow, and the activation temperature was the same as the carbonization temperature. Dry air with a flow rate of 140ml/min was injected into the nitrogen flow for 8s, and the pulsed air injection operation was repeated 5 times. The pulsed air treated fibers were cooled to room temperature in the corresponding nitrogen gas.

Table 1 Effects of surface etching basalt fibers on the properties of porous carburized coating fibers under different conditions

In this embodiment, the basalt fiber is used as the matrix fiber, and the porous carbon layer is formed by surface carburizing treatment, so that it has the pore characteristics of the activated carbon fiber, and at the same time has the good mechanical strength of the basalt fiber. The strength, flexibility and weaving properties of the product are greatly improved, thereby solving the inherent low strength of the activated carbon fibers in the prior art. The tensile strength of the porous carburized coating fiber is 20-110MPa, the elongation at break is 0.5-1.3%, and the tensile modulus is 1.0-6.0GPa.

Example 2

Step 1. Soak 50 g of basalt fiber in sodium hydroxide solution with a mass concentration of 3.5% at 40 °C for 3 hours, then take it out and wash it with deionized water until it becomes neutral; continue to soak in hydrochloric acid solution with a mass concentration of 5% at 35 °C for 3 hours, hydrochloric acid After the treatment, the fibers were washed with deionized water until neutral, and dried in air at 110°C.

Synthesis of bis(2-furylmethoxy)dimethylsilane: 4.32g of furanmethanol was mixed with 1.84g of sodium hydroxide, cooled to -5°C, 2.58g of dichlorodimethylsilane was added dropwise, and the addition was completed After that, the temperature was raised to 25° C. and the reaction was continued for 1.5 hours, and the solid salt was removed by filtration. The liquid product was bis(2-furylmethoxy)dimethylsilane.

Preparation of the condensation resin monomer of furancarboxaldehyde and furanmethanol: 9.6g furancarboxaldehyde, 22.56g furanmethanol and 0.65g catalyst maleic anhydride were heated to 85°C under nitrogen protection and reacted for 30min to obtain a dark brown liquid.

Step 2, using a tetrahydrofuran solution of bis(2-furylmethoxy)dimethylsilane with a mass concentration of 3.6% to load the etched basalt fiber with a surface coupling agent;

Step 3, using the tetrahydrofuran solution of furan formaldehyde and furan methanol condensation resin with a mass concentration of 8% to coat the surface-modified basalt fiber. The usage amounts of bis(2-furylmethoxy)dimethylsilane and furanformaldehyde and furanmethanol condensation resin are listed in Table 2, and the coated fibers are polymerized and cured for 2.0h at 85°C.

Step 4. The coated basalt fiber is carbonized, heated in a tube furnace, nitrogen is used as a carrier gas, and the temperature is raised to 700 °C at a heating rate of 5 °C/min for carbonization treatment. The carbonization treatment time is 90min. The treatment process The flow rate of nitrogen in the medium was 180ml/min. The carbonized fiber material was activated by pulsed air flow, and the activation temperature was the same as the carbonization temperature. Dry air with a flow rate of 140ml/min was injected into the nitrogen flow for 8s, and the pulsed air injection operation was repeated 5 times. The pulsed air treated fibers were cooled to room temperature in the corresponding nitrogen gas.

Table 2 Influence of the amount of coupling agent and resin precursor on material properties

Example 3

Step 1. Soak 50 g of basalt fiber in sodium hydroxide solution with a mass concentration of 3.5% at 40 °C for 3 hours, then take it out and wash it with deionized water until it becomes neutral; continue to soak in hydrochloric acid solution with a mass concentration of 5% at 35 °C for 3 hours, hydrochloric acid After the treatment, the fibers are washed with deionized water until neutral, and dried in the air at 110 °C;

Synthesis of bis(2-furylmethoxy)dimethylsilane: 4.32g of furanmethanol was mixed with 1.84g of sodium hydroxide, cooled to -5°C, 2.58g of dichlorodimethylsilane was added dropwise, and the addition was completed After that, the temperature was raised to 25° C. and the reaction was continued for 1.5 hours, and the solid salt was removed by filtration. The liquid product was bis(2-furylmethoxy)dimethylsilane.

Preparation of the condensation resin monomer of furancarboxaldehyde and furanmethanol: 9.6g furancarboxaldehyde, 22.56g furanmethanol and 0.65g catalyst maleic anhydride were heated to 85°C under nitrogen protection and reacted for 30min to obtain a dark brown liquid.

Step 2, using a tetrahydrofuran solution of bis(2-furylmethoxy)dimethylsilane with a mass concentration of 3.6% to load the etched basalt fiber with a surface coupling agent, bis(2-furylmethoxy) ) The usage amount of dimethylsilane is 1.8% of the quality of basalt fiber;

Step 3. The surface-modified basalt fiber is coated with a tetrahydrofuran solution of furanformaldehyde and furanmethanol condensation resin with a mass concentration of 8%, and the loading amount of furanformaldehyde and furanmethanol condensation resin is 18% of the mass of the basalt fiber. The coated fibers were polymerized and cured at 85°C for 2.0 h.

Step 4. The basalt fiber after the coating treatment is carbonized and heated by a tube furnace, and the carbonization treatment is heated by a tube furnace. The corundum tube is used as the heating chamber, and the heat treatment is heated at the set heating rate to the processing temperature, and the processing time is: 90min, and the flow rate of nitrogen during the treatment was 180ml/min. The carbonized fiber material was activated by pulsed air flow, and the activation temperature was the same as the carbonization temperature. The process parameters are shown in Table 3. The pulsed air treated fibers were cooled to room temperature in the corresponding nitrogen gas.

Table 3 carbonization and activation treatment reaction conditions

Comparative Example 1

In this comparative example, regenerated cellulose viscose staple fibers and polyacrylonitrile (PAN) fiber raw materials (as shown in Table 4) are directly carbonized. The carbonization treatment is heated by a tube furnace, and nitrogen is used as the carrier gas. The rate was 5°C/min, the temperature range of the heat treatment was 700°C, the treatment time was 90 min, and the flow rate of nitrogen during the treatment was 180 ml/min. The carbonized fiber material was activated by pulsed air flow, and the activation temperature was the same as the carbonization temperature. Dry air with a flow rate of 140ml/min was injected into the nitrogen flow for 8s, and the pulsed air injection operation was repeated 5 times. The pulsed air treated fibers were cooled to room temperature in the corresponding nitrogen gas.

Table 4 Performance comparison of activated carbon fibers prepared from different precursors

Comparative Example 1 The activated carbon fiber is directly prepared from the polymer fiber precursor through carbonization and activation, but the mechanical properties of the obtained activated carbon fiber are poor, and the tensile strength is lower than 30MPa. Modulus cannot be measured.

The invention uses basalt fiber as matrix fiber, and forms a porous carbon layer through surface carburizing treatment, so that it has the pore characteristics of activated carbon fiber and has good mechanical strength of basalt fiber. The strength, flexibility and weaving properties of the product are greatly improved (mainly referring to the two parameters of elongation ratio and tensile modulus), thereby solving the problem of low inherent strength of activated carbon fibers in the prior art. The tensile strength of the porous carburized coating fiber is 20-110MPa, the elongation at break is 0.8-1.2%, and the tensile modulus is 1.0-6.0GPa. The invention adopts the basalt fiber as the matrix fiber, which ensures the good mechanical properties of the fiber, and simultaneously forms a porous carbon layer through surface carburizing treatment, so that it has the open pore characteristics of the activated carbon fiber. The specific surface area of the porous carburized coating fiber reaches 700～1206m ² /g.

The performance advantages of the present invention relative to Comparative Example 1 are as follows:

1) The tensile strength of activated carbon fibers based on regenerated fiber fibers (viscose staple fibers) is less than 10 MPa, and the tensile strength of activated carbon fibers based on PAN is less than 30 MPa, while the porous carburized coating fibers based on basalt fibers of the present invention have a tensile strength. The tensile strength can reach 110MPa. The method of the invention uses the basalt fiber as the matrix fiber, and forms a porous carbon layer through surface carburizing treatment, so that the pore characteristics of the activated carbon fiber and the good mechanical strength of the basalt fiber are matched with each other, and the strength, flexibility and weaving performance of the product are greatly improved, so as to solve the problem of The problem of low strength inherent in the prior art activated carbon fiber itself.

2) The present invention directly prepares the activated carbon fiber by coating the basalt fiber, avoids the spinning and forming process, and can greatly reduce the manufacturing cost. In addition, basalt continuous fibers have high strength, and also have many excellent properties such as electrical insulation, corrosion resistance, and high temperature resistance. The production process of basalt fiber produces less waste and less pollution to the environment. The product can be directly degraded in the environment without any secondary hazards. The manufacturing cost of activated carbon fiber is mainly concentrated in the two main processes of spinning forming and heat treatment carbonization. In terms of cost distribution, the cost of carbonization activation process is mainly energy consumption and equipment depreciation, which is not related to raw materials and corresponding forming processes. Relatively It is relatively fixed, generally accounting for 15 to 20% of the total manufacturing cost. The manufacturing cost of activated carbon fiber is mainly concentrated in the precursor fiber forming process, of which the cost of raw materials accounts for more than 30%, the cost of raw material processing and spinning accounts for about 40%, and the cost of spinning and forming stabilization process accounts for about 15%.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. Substitutions should be covered within the protection scope of the present invention.

Claims (10)

1. a coupling agent, is characterized in that, described coupling agent is two (2-furylmethoxy) dimethylsilane; The structural formula is:

2. the preparation method of a coupling agent, it is characterised in that, for the preparation of the coupling agent in claim 1, the two (2-furylmethoxy) dimethylsilane is composed of dichlorodimethylsilane , furan methanol and sodium hydroxide are prepared by direct condensation reaction under solvent-free conditions; The amount of the furanmethanol is 2.0-2.3 times the molar amount of dichlorodimethylsilane, and the amount of the sodium hydroxide is 2.1-2.4 times the molar amount of dichlorodimethylsilane; dichlorodimethylsilane is added The temperature is -5 to 0°C, the reaction temperature is 20 to 30°C, and the reaction time is 1.0 to 2.0 hours. 3. A porous carburized coating fiber is characterized in that, preparation raw material comprises the coupling agent described in claim 1 and 2, and described porous carburizing coating fiber sequentially comprises basalt fiber matrix, transition layer from inside to outside. and carbonaceous coating; the transition layer is a Si-C-O transition layer. 4. a preparation method of porous carburizing coating fiber, is characterized in that, for preparing the porous carburizing coating fiber in claim 3; Comprise the steps: Step 1. Use sodium hydroxide solution to perform alkali etching treatment on the basalt fiber. After the alkali etching, use deionized water to clean it to neutrality. Use hydrochloric acid solution to perform acid etching treatment on the basalt fiber. After the acid etching treatment, leave it in the air. dry; Step 2, using the tetrahydrofuran solution of bis(2-furylmethoxy)dimethylsilane to modify the surface of the acid-etched basalt fiber; Step 3, using the tetrahydrofuran solution of furanformaldehyde and furanmethanol condensation resin to coat the surface-modified basalt fiber, and to polymerize and cure the formed coating layer; Step 4, carbonizing and activating the basalt fiber after polymerization and curing treatment to prepare porous carburized coating fiber. 5 . The method for preparing porous carburized coated fibers according to claim 4 , wherein, in the step 1, the mass concentration of the sodium hydroxide solution is 1.0-6.0%, and the alkali etching temperature is 20 . ～60℃, the alkali etching treatment time is 1.0～6.0h; after alkali etching, take out and wash with deionized water until neutral; The mass concentration of the hydrochloric acid solution is 1.0-8.0%, the acid etching treatment temperature is 20-60° C., and the acid etching treatment time is 1.0-6.0 h. 6 . The method for preparing porous carburized coated fibers according to claim 4 , wherein in the step 2, bis(2-furanylmethoxy)bis(2-furylmethoxy)di having a mass concentration of 2.0-5.0% is used. 7 . The tetrahydrofuran solution of methylsilane is used to load the surface coupling agent on the acid-etched basalt fibers, and the amount of bis(2-furylmethoxy)dimethylsilane used is 0.3-2.2% of the mass of the basalt fibers. 7 . The method for preparing porous carburized coated fibers according to claim 4 , wherein, in the step 3, the mass concentration of the tetrahydrofuran solution of furanformaldehyde and furanmethanol condensation resin is 4.0 to 10%, and the furan The loading of formaldehyde and furanmethanol condensation resin is 5-25% of the mass of the basalt fiber, and the coated basalt fiber is subjected to coating polymerization and curing treatment at 60-90° C. for 1.0-3.0 hours. 8. The preparation method of porous carburized coated fiber according to claim 4, characterized in that, in the step 3, the condensation resin monomer of the furanformaldehyde-furanmethanol is composed of furanformaldehyde, furanmethanol and a catalyst Maleic anhydride is prepared by heating to 60～90℃ for 15～45min under nitrogen protection; The usage amount of the furanmethanol is 2.2-2.4 times the molar amount of the furancarbaldehyde; the usage amount of the catalyst maleic anhydride is 1.0-3.0% of the total molar amount of the furancarbaldehyde and the furanmethanol. 9 . The method for preparing porous carburized coated fibers according to claim 4 , wherein, in the step 4, the carbonization treatment is heated by a tube furnace, nitrogen is used as a carrier gas, and 1.0-10 The heating rate of ℃/min is increased to 550-950 ℃ to carry out carbonization treatment, the carbonization treatment time is 45-120min, and the flow rate of nitrogen in the treatment process is 60-300ml/min. 10. The preparation method of porous carburized coated fiber according to claim 9, characterized in that, in the step 4, the activation treatment is to use pulsed air flow to activate the carbonized fiber material to make pores, and the temperature The temperature is 550～950℃, the nitrogen flow rate is 60～300ml/min, the dry air pulse airflow is injected into the nitrogen flow for 5～20s, and the pulse air injection operation is repeated 2～10 times; The flow rate of the dry air pulse airflow is 80-200ml/min.

Images