CN117263527A

CN117263527A - Method for modifying basalt fiber and improving interface performance of epoxy resin

Info

Publication number: CN117263527A
Application number: CN202311556014.7A
Authority: CN
Inventors: 向东; 邱天; 武元鹏; 刘黎冰; 刘竹溪; 孙浩铭; 张学忠; 李东; 赵春霞; 李辉
Original assignee: Southwest Petroleum University
Current assignee: Southwest Petroleum University
Priority date: 2023-11-21
Filing date: 2023-11-21
Publication date: 2023-12-22
Anticipated expiration: 2043-11-21
Also published as: CN117263527B

Abstract

The invention belongs to the field of continuous basalt fiber surface modification, and particularly relates to a method for modifying basalt fibers and improving the interfacial properties of epoxy resin. The method comprises the following steps: and (3) putting basalt fibers into a mixed solution of acetone and petroleum ether for cleaning, then cleaning under ultrasonic vibration, fixing the basalt fibers on a glass wafer, immersing the basalt fibers in a piranha solution, and drying for later use. The basalt fiber after activation is placed in a straight conduit, ethyl trichlorosilane is added to the left side of the conduit, the humidity is controlled by nitrogen driving moisture, and the basalt fiber is deposited for 4 hours under the condition of 62% relative humidity. Finally immersing the basalt fiber into a water-based polyurethane solution with the mass fraction of 3%, and drying to obtain the modified basalt fiber. The invention utilizes chemical vapor deposition method to successfully graft silicon nanowires and silicon nanotubes on the basalt fiber surface at the same time, and cooperates with a coating method to act on the fiber surface, thereby enhancing the mechanical engagement and chemical bond action between the fiber and the resin, and further increasing the mechanical property combined with the resin.

Description

Method for modifying basalt fiber and improving interface performance of epoxy resin

Technical Field

The invention belongs to the field of continuous basalt fiber surface modification, and particularly relates to a method for modifying basalt fibers and improving the interfacial properties of epoxy resin.

Background

Basalt fiber is prepared by high-speed drawing of molten natural basalt at 1450-1500 ℃, has high length-diameter ratio, is not easy to inhale lung, has no pollution in the preparation process, low cost, excellent mechanical property, high strength, excellent wear resistance and tensile strength, and is 1.4-1.5 times that of E-type glass fiber. The continuous basalt fiber has good chemical stability, has a plurality of unique excellent performances such as heat insulation, moisture resistance, water resistance, acid and alkali resistance, heat preservation, sound absorption, corrosion resistance, no degradation and deterioration after long-term use, and is a low-cost substitute for high-technology fibers such as carbon fibers. The glass fiber is taken from natural ore, has no additive, has the advantages of ultraviolet resistance, wide use temperature range, good insulativity, good high-temperature filterability and the like, and is the only green glass fiber product without environmental pollution and cancerogenic. Can be applied to the fields of heat insulation, protection, shipbuilding, automobiles, high-temperature filter fabrics, fiber reinforced composite materials and the like. But basalt fibers have smooth surfaces, large inertness, poor bundling property and wettability, and poor interfacial properties with epoxy resin (EP) matrixes, so that the mechanical properties are poor, and the application of the fibers in the aspect of composite materials is limited. To improve the interfacial interactions, the fiber surface modification aims to enhance the adhesion between the fiber and the matrix by physical conditioning or by chemical modification of the fiber surface, thereby increasing the contact area of the fiber with the matrix. Chemical (acid or alkali) etching, plasma treatment and other methods can effectively increase the surface roughness, but also damage the internal structure of basalt fibers and cause a certain degree of damage to the fibers themselves. On the other hand, coating surface modification provides weaker physical adhesion without stronger mechanical properties. However, the coupling agent modification bypasses this problem and acts as a "bridge" to improve the interfacial properties of the composite and to increase its mechanical properties.

Silicon nanowires are a one-dimensional nanomaterial which has been developed recently, and have attracted considerable attention from researchers due to their own unique optical properties such as fluorescent ultraviolet and thermal conduction. Some researchers have been able to successfully grow one-dimensional silicon nanomaterials on glass slides, cotton fabrics. The surface of the silicon nanowire contains abundant active groups, one end can react with chemical groups on the surface of the basalt fiber, and the other end can be physically entangled or chemically reacted with the polymer, so that the adhesion between the resin matrix and the basalt fiber is enhanced. At present, no research report is reported on modifying the silicon nanowires to the surface of basalt fibers.

Aiming at the advantages of the one-dimensional silicon nanowire, the chemical vapor deposition method is adopted to grow the silicon nanowire on the surface of basalt fiber, and the chemical vapor deposition method and the coating method act on the fiber surface cooperatively, so that the mechanical property of the basalt fiber with epoxy resin is enhanced.

Disclosure of Invention

The invention aims to solve the problem of weak adhesion between basalt fiber and epoxy resin matrix and the like in the prior art, and provides a method for modifying basalt fiber and improving the interface performance of epoxy resin, so that the interface strength between basalt fiber and epoxy resin is improved.

The method for enhancing the interfacial properties of the epoxy resin by basalt provided by the invention comprises the following steps:

s1, adopting an organic mixed solvent for reflux cleaning, and cleaning the surface of basalt fiber in an ultrasonic cleaning tank.

S2, fixing basalt fibers on a glass wafer which is cleaned and dried by ultrasonic vibration, immersing the glass wafer in a piranha solution at the temperature of 100 ℃, immersing the glass wafer at the constant temperature for 20 minutes, cleaning the glass wafer with deionized water for 4 times, and drying the glass wafer in an oven to obtain the basalt fibers with activated surfaces.

And S3, growing polysiloxane by adopting a chemical vapor deposition method, adding 1.2ml of ethyl trichlorosilane into 3g of activated basalt fiber, controlling the humidity by using nitrogen to drive water, taking out the basalt fiber after reacting for a period of time under the condition of the relative humidity of 62%, and respectively washing and drying the basalt fiber by using acetone, absolute ethyl alcohol and deionized water to obtain the basalt fiber with the surface of which the silicon nanowires and the silicon nanotubes are grown.

S4, preparing aqueous polyurethane slurry with the mass fraction of 3%, immersing basalt fibers in the solution, and drying the solution in an oven at 80 ℃ for 10 hours to obtain basalt fibers with a layer of adhesive film on the surface.

Optionally, in step S1, the organic mixed solvent is acetone and petroleum ether, and is configured according to a volume ratio of 3:1, the basalt fiber is placed in a flask, heated to 80 ℃ by using a heating jacket, heated, reflowed and washed for 6 hours, reacted for 10 minutes under ultrasonic oscillation, and then the basalt fiber is placed in an oven at 80 ℃ to be dried for 24 hours, so as to obtain the basalt fiber with the surface desized.

Optionally, in step S2, the cleaning solution used in the ultrasonic vibration cleaning is absolute ethanol and deionized water, the glass wafer serving as the substrate is subjected to ultrasonic vibration cleaning for 15min, and dried under a nitrogen stream, the basalt fiber is uniformly wound and fixed on the glass wafer, after the upper surface and the lower surface of the wafer are tightly adhered to a layer of fiber, the node is tied on the wafer by a wire, the wafer is soaked for 20min at a constant temperature in a piranha solution of 100 ℃, and the piranha solution is dried in an oven of 60 ℃, wherein the piranha solution is concentrated sulfuric acid and hydrogen peroxide with a mass fraction of 30%, and the volume ratio is 7:3, the hydrogen peroxide is added into concentrated sulfuric acid during preparation.

Optionally, in step S3, the apparatus used for growing polysiloxane by chemical vapor deposition method is composed of a mixing chamber, a humidity regulator, and a reaction chamber, wherein one end of the humidity regulator is connected to the mixing chamber with dry and humidified nitrogen, and one end is connected to the reaction chamber with a straight conduit, and the humidified nitrogen is generated by flushing dry nitrogen with a gas washing bottle filled with water.

Optionally, in step S3, the humidity regulator is composed of a three-necked flask, a hygrometer and a sealant, and the apparatus is in a sealed state.

Optionally, in step S3, 3g basalt fiber was fixed on a glass wafer, placed in a straight catheter, and 1.2ml ethyl trichlorosilane was added to the left side thereof, keeping the fiber at a horizontal distance of 1-3cm from the liquid.

Optionally, in step S3, the relative humidity is controlled to be 62%, the reaction time is 4 hours, the dynamic balance of the reaction is required to be maintained, and the basalt fiber after the reaction is washed with acetone, absolute ethanol and deionized water for 3 times in sequence.

Optionally, in the step S3, the length of the silicon nanowire and the silicon nanotube on the surface of the obtained modified basalt fiber is 4-8 mu m, and the diameter is 200-600 nm.

Optionally, in step S4, an aqueous polyurethane slurry containing 3% of mass fraction is prepared, basalt fibers are tensioned and kept in a straightened state, after being immersed in the solution for 15min, excess liquid is extruded in one direction by a stick, and then the solution is put into an oven at 80 ℃ for drying for 10h, so that the basalt fibers with surface growing silicon nanowires and silicon nanotubes and a layer of adhesive film are obtained.

Compared with the prior art, the invention has the following advantages:

firstly, ethyl trichlorosilane is used as a precursor, basalt fiber is used as a matrix, and piranha solution is used as an activation solution; the surface of basalt fiber after being activated by the activating solution contains a large number of active groups, silicon nanowires can be self-assembled and grown on the surface of basalt fiber by controlling the specific parameter conditions (parameters such as nitrogen flow rate, relative humidity, silane content, reaction time and the like) of the modification reaction in the step S3, the control of the moisture content is extremely important for the hydrolysis of the ethyl trichlorosilane, the fiber is deactivated due to excessive moisture, and the effect of catalyzing the hydrolysis cannot be achieved due to too little moisture. By controlling the reaction time, the diameters and the lengths of the silicon nanowires and the silicon nanotubes grown by the silicon can be controlled, the optimal reaction time is controlled to be 4 hours, and the silicon nanowires with the lengths of 4-8 mu m and the diameters of 200-600 nm are grown.

Secondly, the preparation method has the advantages of small reagent consumption and small pollution, and the silicon nanowires can be grown on the basalt fiber surface in situ by utilizing a chemical vapor deposition method. The silicon nanowire is a one-dimensional nano material, has the excellent performance of an inorganic material, has the advantages of extremely high thermal stability, chemical stability and the like, and can improve the chemical stability and the thermal stability of the fiber by successfully modifying the silicon nanowire to the surface of the fiber. A large number of silicon nanowires are generated and uniformly distributed on the surface of basalt fiber, because ethyl trichlorosilane is completely hydrolyzed to obtain enough silanol which is dehydrated and condensed with hydroxyl groups activated by the piranha solution, the silanol is dehydrated and condensed as well, and the silanol is repeatedly crosslinked to form a three-dimensional network structure. And the hydroxyl of the ethyl trichlorosilane and the hydroxyl of the epoxy resin are subjected to dealcoholization and dehydration reaction, so that the mechanical engagement and chemical bond action between the fiber and the resin are enhanced, and the mechanical property combined with the resin is improved.

Thirdly, the aqueous polyurethane solution is a solvent which is green, environment-friendly, light-resistant, corrosion-resistant and convenient to construct, hydroxyl, epoxy and amino contained in the aqueous polyurethane solution can be crosslinked with resin, so that the wettability between basalt fiber and epoxy resin is effectively improved, covalent bonds can be formed through chemical reaction, and the interface bonding performance between resin matrix and basalt fiber is improved. The tensile strength, the interfacial shear strength and the contact angle of the single fiber are tested, and the result proves that the tensile strength of the single fiber grown on the basalt fiber by the silicon nanowire is improved by 41.4 percent, the interfacial shear strength is improved by 64.3 percent, and the contact angle with the epoxy resin is reduced.

Drawings

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

FIG. 1 is a flow chart of the preparation of the present invention;

FIG. 2 is a reaction mechanism diagram of the present invention;

FIG. 3 is a scanning electron microscope image of untreated basalt fibers;

FIG. 4 is a scanning electron microscope image of a silicon nanowire modified basalt fiber;

FIG. 5 is a graph of basalt fiber monofilament tensile strength under different moisture modification processes;

FIG. 6 is a graph of basalt fiber monofilament tensile strength under different time modification processes;

FIG. 7 is a graph of basalt fiber monofilament tensile strength before and after modification;

FIG. 8 is a graph of basalt fiber interfacial shear strength before and after modification.

Detailed Description

The invention will be further described with reference to examples and figures.

Example 1

As shown in FIG. 1, the method for modifying basalt fiber and improving the interfacial property of epoxy resin provided by the invention is prepared by the following steps:

s1, preparing acetone and petroleum ether according to the volume ratio of 3:1, placing the basalt fiber into a flask, heating the basalt fiber to 80 ℃ by using a heating sleeve, heating, refluxing and cleaning for 6 hours, reacting for 10 minutes under ultrasonic vibration, and then placing the basalt fiber into an oven at 80 ℃ for drying for 24 hours to obtain the basalt fiber with the surface desized.

S2, the piranha solution is concentrated sulfuric acid and hydrogen peroxide with the mass fraction of 30%, and the volume ratio is 7:3, configuring in proportion for standby. The cleaning solution used for ultrasonic vibration cleaning is absolute ethyl alcohol and deionized water, ultrasonic vibration cleaning is carried out on a glass wafer serving as a substrate for 15min, drying is carried out under nitrogen flow, basalt fibers are uniformly wound and fixed on the glass wafer, after the upper surface and the lower surface of the wafer are tightly adhered to a layer of fibers, a wire is used for fastening a node on the wafer, the temperature of the wafer is kept constant for 20min under 100 ℃ for piranha solution, and the wafer is put into a 60 ℃ oven for drying, so that the basalt fibers with activated surfaces are obtained.

S3, firstly building equipment for growing polysiloxane by a chemical vapor deposition method, wherein the equipment consists of a mixing chamber, a humidity regulator and a reaction chamber, one end of the humidity regulator is connected with the mixing chamber with dry and humidified nitrogen, and the other end of the humidity regulator is connected with the reaction chamber with a straight conduit, wherein the humidified nitrogen is generated by flushing the dry nitrogen through a water-filled gas washing bottle, and the humidity regulator consists of a three-neck flask, a hygrometer and sealant, and is in a sealing state. 3g basalt fiber was fixed on a glass wafer and placed in a straight catheter, and 1.2ml ethyl trichlorosilane was added to the left side of the catheter, keeping the fiber and liquid level at a distance of 1-3cm. Controlling the relative humidity at 62% and the reaction time at 4h, wherein the reaction needs to keep dynamic balance, and cleaning the basalt fiber after the reaction with acetone, absolute ethyl alcohol and deionized water for 3 times in sequence.

S4, preparing aqueous polyurethane slurry with the mass fraction of 3%, tensioning basalt fibers, keeping the basalt fibers in a straight state, immersing the basalt fibers in the solution for 15min, extruding redundant liquid in one direction by using a stick, and drying the extruded redundant liquid in an oven at 80 ℃ for 10h to obtain basalt fibers with surface-grown silicon nanowires and silicon nanotubes and a layer of adhesive film.

The growth mechanism of the basalt fiber surface self-assembled silicon nanowire is shown in figure 2. A large number of silicon nanowires are generated and uniformly distributed on the surface of basalt fiber, because ethyl trichlorosilane is completely hydrolyzed to obtain enough silanol which is dehydrated and condensed with hydroxyl groups activated by the piranha solution, the silanol is dehydrated and condensed, and the silanol is repeatedly crosslinked to form a three-dimensional network structure. The untreated basalt fiber is named as BF, the basalt fiber modified by the piranha solution is named as BF-OH, and the basalt fiber modified under different relative humidity and different reaction time is named as BF-OH(for example, basalt fiber is modified at the relative humidity of 62 percent and the deposition time of 4 hours, and is named as BF-H62-T4), and basalt fiber of waterborne polyurethane is named as BF-H62-T4-WPU.

Comparative example 1

The basalt fiber is not subjected to any modification treatment, as shown in fig. 3. The basalt fiber is modified by the silicon nanowire as shown in fig. 4.

Comparative example 2

In comparison with example 1, the relative humidity was changed to 58% and 64% in S3, and the mechanical properties of basalt fibers before and after modification were investigated, and the tensile strength of monofilaments was tested. The test results are shown in fig. 5. Fig. 5 illustrates that unmodified basalt fiber monofilaments have lower breaking strength, the breaking strength of the piranha solution after treatment is reduced, and the loss of the fiber itself is smaller. After modification under different relative humidities, the breaking strength and the tensile strength with the humidity of 62% are the highest, and Si-O-Si chemical bonds exist in the silicon nanowires, so that the silicon nanowires have higher bond energy and can exist stably. However, when the humidity is too high, no redundant gaps are used for growing the silicon nanowires, and the silicon nanowires compete with the original silicon nanowires, so that some lodging phenomena are caused, and the silicon nanowires fall off.

Comparative example 3

In comparison with example 1, the test results of the change in S3, the reaction times were 1h, 3h, and 5h, respectively, were shown in FIG. 6. Fig. 6 illustrates that the tensile strength after 4 hours of deposition is highest, the silicon nanowires grown in too short time cannot uniformly cover the surface of the fiber, even fall off is caused, interfacial stress is generated when the time is too long, the fiber is more easily embrittled, and the surface roughness and mechanical bonding effect can be enhanced to the greatest extent by a proper amount of grafted silicon nanowires, so that the mechanical property is increased.

Comparative example 4

In comparison with example 1, after the aqueous polyurethane solution in S4 was added, the monofilament tensile strength was tested, and the test results are shown in fig. 7. Fig. 7 illustrates that the aqueous polyurethane not only can improve the wettability between the fiber surface and the resin, but also can form covalent bonds through chemical reaction, and hydroxyl groups, epoxy groups and amino groups contained in the aqueous polyurethane can be crosslinked with the resin, so that the tensile strength can be greatly improved.

To verify interfacial adhesion between basalt fibers and epoxy matrix, a droplet debonding test was performed, the test results are shown in fig. 8. FIG. 8 illustrates that the unmodified basalt fiber has a smooth surface, poor interfacial interaction with the epoxy matrix, roughened graft-active-group surface, and a surface-residual portion of epoxy. After the silicon nanowires are grafted, more resin remains on the surface, so that the surface roughness is improved. After the aqueous polyurethane is coated, some grooves on the outer part are filled, so that a wet adhesive film is formed, and a large amount of resin remains. The main reason is that the wedge effect causes the resin to be better embedded with the surface of the fiber, because the surface bonding of the silicon nanowire and the fiber is mainly performed by covalent bonds generated by chemical grafting, when the fiber is pulled out from the resin substrate, the interface damage form is converted into the damage of the covalent bonds, namely not only the separation between the fiber and the epoxy resin, but also the new combined layer of the silicon nanowire and the resin is damaged, so that the interface shearing strength of the basalt fiber and the resin substrate is greatly improved, and the method is described for modifying the fiber, so that the interface interaction with the resin substrate can be effectively enhanced.

The present invention is not limited to the above-mentioned embodiments, but is not limited to the above-mentioned embodiments, and any person skilled in the art can make some changes or modifications to the equivalent embodiments without departing from the scope of the technical solution of the present invention, but any simple modification, equivalent changes and modifications to the above-mentioned embodiments according to the technical substance of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for modifying basalt fiber and improving interface performance of epoxy resin is characterized by comprising the following steps:

s1, adopting an organic mixed solvent for reflux cleaning, and cleaning the surface of basalt fiber in an ultrasonic cleaning tank;

s2, fixing basalt fibers on a glass wafer which is cleaned and dried by ultrasonic vibration, immersing the glass wafer in a piranha solution at 100 ℃, soaking the glass wafer at a constant temperature for 20 minutes, cleaning the glass wafer with deionized water for 4 times, and drying the glass wafer in an oven to obtain the basalt fibers with activated surfaces;

s3, growing polysiloxane by adopting a chemical vapor deposition method, adding 1.2ml of ethyl trichlorosilane into 3g of activated basalt fiber, controlling humidity by using nitrogen to drive water, taking out the basalt fiber after reacting for a period of time under the condition of 62% of relative humidity, and respectively washing and drying the basalt fiber by using acetone, absolute ethyl alcohol and deionized water to obtain basalt fiber with surface grown silicon nanowires and silicon nanotubes;

2. The method for modifying basalt fiber and improving the interfacial property of epoxy resin according to claim 1, wherein in step S1, the organic mixed solvent is acetone and petroleum ether, which are prepared according to the volume ratio of 3:1, the basalt fiber is placed in a flask, heated to 80 ℃ by a heating jacket, heated, reflowed and washed for 6 hours, reacted for 10 minutes under ultrasonic oscillation, and then the basalt fiber is placed in an oven at 80 ℃ for drying for 24 hours, so as to obtain the basalt fiber with the desized surface.

3. The method for modifying basalt fiber and improving the interfacial property of epoxy resin according to claim 1, wherein in the step S2, the cleaning solution used for ultrasonic vibration cleaning is absolute ethyl alcohol and deionized water, the glass wafer serving as a substrate is subjected to ultrasonic vibration cleaning for 15min, and is dried under nitrogen flow, the basalt fiber is uniformly wound and fixed on the glass wafer, after the upper surface and the lower surface of the wafer are tightly adhered to one layer of fiber, the nodes are fastened on the wafer by using wires, the wafer is soaked for 20min at a constant temperature under a temperature of 100 ℃, and the wafer is dried under a temperature of 60 ℃, wherein the piranha solution is concentrated sulfuric acid and hydrogen peroxide with a mass fraction of 30%, and the ratio of 7:3, the hydrogen peroxide is added into concentrated sulfuric acid during preparation.

4. The method for modifying basalt fiber and improving interfacial properties of epoxy resin according to claim 1, wherein in step S3, the equipment used for growing polysiloxane by chemical vapor deposition method is composed of three parts of a mixing chamber, a humidity regulator and a reaction chamber, wherein one end of the humidity regulator is connected with the mixing chamber with dry and humidified nitrogen, and one end is connected with the reaction chamber of a straight conduit, wherein the humidified nitrogen is generated by flushing dry nitrogen through a water-filled gas washing bottle.

5. The method of modifying basalt fiber according to claim 4, wherein in step S3, the humidity regulator is composed of a three-neck flask, a hygrometer and a sealant, and the apparatus is in a sealed state.

6. The method for modifying basalt fiber and improving interfacial properties of epoxy resin according to claim 1, wherein in step S3, 3g basalt fiber is fixed on a glass wafer, placed in a straight pipe, and 1.2ml ethyl trichlorosilane is added to the left side thereof, and the fiber is kept at a horizontal distance of 1-3cm from the liquid.

7. The method for modifying basalt fiber and improving interfacial properties of epoxy resin according to claim 1, wherein in step S3, the relative humidity is controlled to 62%, the reaction time is 4 hours, the reaction is required to maintain dynamic balance, and the basalt fiber after the reaction is washed with acetone, absolute ethanol and deionized water in sequence for 3 times.

8. The method for modifying basalt fiber and improving interfacial properties of epoxy resin according to claim 1, wherein the length of the silicon nanowire and the silicon nanotube on the surface of the modified basalt fiber obtained in the step S3 is 4-8 μm, and the diameter is 200-600 nm.

9. The method for modifying basalt fiber and improving interfacial properties of epoxy resin according to claim 1, wherein in step S4, an aqueous polyurethane slurry containing 3% by mass is prepared, the basalt fiber is tensioned and kept in a straightened state, after immersing in the solution for 15min, excess liquid is squeezed out in one direction by a stick, and then the basalt fiber is dried in an oven at 80 ℃ for 10h, so as to obtain the basalt fiber with surface-grown silicon nanowires and silicon nanotubes and a layer of adhesive film.