CN111690158A

CN111690158A - Method for optimizing interface of basalt reinforced resin matrix composite material

Info

Publication number: CN111690158A
Application number: CN202010545209.1A
Authority: CN
Inventors: 向东; 李鹏飞; 赵春霞; 王斌; 李云涛; 张�杰
Original assignee: Southwest Petroleum University
Current assignee: Southwest Petroleum University
Priority date: 2020-06-16
Filing date: 2020-06-16
Publication date: 2020-09-22
Anticipated expiration: 2040-06-16
Also published as: CN111690158B

Abstract

The invention discloses a method for optimizing an interface of a basalt reinforced resin matrix composite material, which mainly comprises the steps of immersing basalt fibers in a piranha solution for soaking and activation to obtain basalt fibers with activated surfaces; putting the activated basalt fiber into dehydrated and deoxygenated toluene, adding methyl triethoxysilane, adding hydrochloric acid to keep the solution acidic, reacting for 6-10 h, cleaning, and drying to obtain a modified basalt fiber; fixing the modified basalt fiber on a mould, wherein the length of the fiber is equivalent to that of the mould, and then pouring the mixed liquid of the resin and the curing agent into the mould for mould pressing to obtain the composite material. According to the invention, the silicon nanowires are grown on the surface of the basalt fiber, so that the surface roughness of the fiber is improved, and meanwhile, a large number of active groups such as hydroxyl groups exist on the silicon nanowires, so that the mechanical engagement and chemical bonding effects between the fiber and resin are enhanced, and the interface performance of the basalt reinforced resin matrix composite material is effectively optimized.

Description

Method for optimizing interface of basalt reinforced resin matrix composite material

Technical Field

The invention belongs to the field of basalt fiber composite materials, and particularly relates to an interface optimization method of a modified basalt fiber reinforced resin matrix composite material.

Background

The basalt fiber is a high-technology fiber following carbon fiber, aramid fiber and ultra-high molecular weight polyethylene fiber, is a high-performance inorganic fiber which is made of natural basalt and is called as a green industrial material, and is commonly called as a pollution-free green material in twenty-first century. The increasing environmental awareness worldwide has led to a shift to the mode of designing environmentally friendly materials, and basalt fiber can be classified as a sustainable material because basalt fiber is made of natural materials and does not add chemical additives as well as any solvents, pigments or other harmful substances during its production. When the basalt fiber is recycled from the resin, because the melting point of the basalt fiber is 1400 ℃ which is very high, the only residue of the composite material containing the basalt fiber is the basalt after being burnt, and therefore, the basalt fiber can be recycled as a wire drawing raw material. In addition, the basalt fiber has similar components with soil, and can directly return to the natural world without special treatment after use, thereby being a genuine green and environment-friendly material. The basalt fiber is 100% natural inorganic fiber and inert, and the basalt fiber product has no harmful reaction with air or water, is not flammable and is not explosive. Basalt fiber has many raw material sources, is low in price, not only has high strength, but also has a plurality of excellent properties such as electrical insulation, corrosion resistance, high temperature resistance, low hygroscopicity and sound absorption, and is widely used for road construction, buildings and other applications needing reinforcement. In addition, the composite material prepared from the basalt fiber can be widely applied to the military and civil fields of aerospace, construction, chemical engineering, medicine, electronics, agriculture and the like, so the basalt fiber is known as a new material in the 2l century.

The resin-based composite material is widely applied to the fields of machinery manufacturing, aerospace, ship manufacturing, chemical industry, building, automobile manufacturing, military industry and the like of national economy by the unique advantages of high specific strength and specific stiffness, strong designability, good fatigue fracture resistance, corrosion resistance, good structural dimensional stability and convenience for large-area integral forming, is particularly applied to airplanes in large quantities, and can realize the corresponding weight reduction of 25-30 percent of the airplane structure. In addition, the structure and the functional designability potential of the composite material are deeply developed through the comprehensive research of the structure/material/process of the composite material and the interdisciplinary subjects of the material/process/design/electronics/pneumatics, and the application prospect of the resin-based composite material can be further improved. Through extensive and intensive research, the basalt fiber becomes an ideal reinforcement of the resin-based composite material by virtue of good comprehensive performance of the basalt fiber.

In a continuous basalt fiber reinforced resin matrix composite system, basalt fibers play a role of a reinforcement, a resin matrix plays a role of connecting the reinforcement and transferring load, and an interface layer between the basalt fibers and the resin matrix plays a role of a ligament, which is a bridge for the fiber reinforcement to play an effective role. When the composite material is under the action of external load, the matrix transfers the load to the fiber reinforcement body through the interface, so that the basalt fiber and the matrix form a whole which effectively exerts the comprehensive performance. Thus, if the adhesion of the fibers to the resin matrix is poor, the resin cannot transfer the stresses it is subjected to the fiber reinforcement, and can also cause cracks to initiate within the composite material, resulting in poor material properties. Similar to other high-performance fibers, the basalt fibers have high density, are chemically inert on the surface, have poor interface compatibility with resin, have an unsatisfactory bonding effect, and greatly influence the exertion of excellent performance of the material. Therefore, it is necessary to improve the interfacial strength of the basalt fiber resin matrix composite material.

Disclosure of Invention

The invention aims to provide a method for optimizing an interface of a basalt reinforced resin matrix composite material, aiming at the problems of poor interface compatibility and poor bonding effect between basalt fibers and resin in the prior art, and improving the interface strength of the basalt fiber resin matrix composite material.

The method for optimizing the interface of the basalt reinforced resin matrix composite material provided by the invention comprises the following steps:

s1, heating, refluxing and cleaning the basalt fiber in a mixed solution of acetone and petroleum ether at 60 ℃ for 4-8 h, cleaning with plasma water for 3-4 times, and drying the basalt fiber in a vacuum oven at 80 ℃ for 12h to obtain the basalt fiber with the surface being desized.

And S2, immersing the cleaned basalt fiber into a piranha solution, heating to 90 ℃, soaking for 10-40 min at a constant temperature, cleaning for 2-3 times by using plasma water, and drying in a 60 ℃ drying oven to obtain the basalt fiber with the activated surface. The piranha solution is a mixed solution of analytically pure hydrogen peroxide with the mass percentage concentration of 30% and concentrated sulfuric acid according to the volume ratio of 7:3, and the hydrogen peroxide is added into the concentrated sulfuric acid during preparation.

S3, carrying out dehydration and deoxidization treatment on toluene, putting activated basalt fibers wound and fixed on a glass sheet carrier into the dehydrated and deoxidized toluene under the condition of continuously introducing nitrogen for protection, then adding methyltriethoxysilane into the toluene, then adding hydrochloric acid to keep the solution acidic, stirring and reacting at the rotating speed of 30-40 rpm for 6-10 h, then taking out the basalt fibers, cleaning and drying in an oven at the temperature of 60 ℃ to obtain modified basalt fibers; the hydrochloric acid is a hydrochloric acid solution with the volume fraction of 32%, and the volume ratio of the hydrochloric acid solution to the dehydrated and deoxygenated toluene is 1: 1500.

S4, fixing the modified basalt fiber on a mold, wherein the length of the fiber is equivalent to that of the mold, and then pouring the mixed liquid of the resin and the curing agent into the mold for mold pressing to obtain the composite material.

Preferably, in step S1, the basalt fiber is heated and refluxed for 6 hours at 60 ℃ in a mixed solution of acetone and petroleum ether in a volume ratio of 2:1, then washed with a large amount of plasma water for 3-4 times, and then the fiber is placed in a vacuum oven to be dried for 12 hours at 80 ℃.

In step S3, if the fiber is directly added to toluene without being fixed, the fiber is stirred into a mass with the rotation of the magnet, and the silicon nanowire cannot be formed, so that the fiber needs to be fixed on the carrier. The operation of winding the basalt fiber around the solid on the carrier may be performed in step S2, or may be performed in step S3. In the first case, in step S2, the cleaned basalt fiber may be wound around and fixed on a glass plate or a glass rod carrier, and then immersed in a piranha solution for 30min at 90 ℃. Then, in step S3, the activated fiber wound on the carrier obtained in step S2 is directly added to dehydrated oxygen-removed toluene. In the second case, in step S2, the fibers are not immobilized, but in step S3, the fibers are immobilized on a support and then added to toluene to carry out a subsequent reaction.

Preferably, in step S3, the dosage volume ratio of the hydrochloric acid solution, the dehydrated deoxygenated toluene and the methyltriethoxysilane is 1:1500:20, the reaction time is 8 hours, and the basalt fiber after the reaction is washed by acetone, absolute ethyl alcohol and plasma water in sequence.

In the step S3, by strictly controlling experimental conditions and environment, silicon nanowires grow on the surface of the obtained modified basalt fiber, wherein the diameter of each silicon nanowire is 100-600 nm, and the length of each silicon nanowire is 10-15 microns.

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

the invention uses methyl triethoxysilane as a precursor, basalt fiber as a matrix and piranha solution as an activation solution; after the basalt fiber is activated by the activation solution, the surface of the basalt fiber contains a large number of active groups, and by controlling the specific parameter conditions (parameters such as dehydration, oxygen removal, nitrogen protection, solution acidity, solvent water content, reaction time and the like) of the modification reaction in the step S3, the silicon nanowires are grown on the surface of the basalt fiber in a self-assembly manner by hydrolyzing methyltriethoxysilane under the acidic condition. Particularly, the diameter and the length of the silicon nanowire grown from the silicon can be controlled by controlling the reaction time, the optimal reaction time is controlled to be 8 hours, and the silicon nanowire with the diameter of 100 nm-600 nm and the length of 10-15 mu m is grown.

Secondly, the preparation method solves the problem of poor interface performance between the basalt fiber and the resin matrix, and the silicon nanowire can be grown on the surface of the basalt fiber in situ by using a solution method. As a one-dimensional material, the silicon nanowire belongs to an inorganic nano material, so that the silicon nanowire has the excellent performance of the inorganic material, extremely high thermal stability, chemical stability, low thermal conductivity and the like, and the chemical stability and the thermal stability of the fiber can be improved by successfully modifying the silicon nanowire on the surface of the fiber. The silicon nanowires are coated on the surface of the basalt fiber, so that the roughness of the surface of the basalt fiber is improved. Meanwhile, because a large number of active groups such as hydroxyl groups exist on the silicon nanowire, the mechanical engagement and chemical bonding effects between the basalt fiber and the resin are enhanced, and the interface performance of the basalt reinforced resin matrix composite material is optimized.

The method effectively optimizes the interface performance of the basalt fiber reinforced resin matrix composite material, so that the resin matrix and the basalt fiber are bonded more firmly, and the tensile property, the impact property and the interlaminar shear property of the basalt fiber reinforced resin matrix composite material are obviously improved. Test results show that the tensile strength of the basalt fiber reinforced epoxy resin matrix composite material can be improved by nearly 80%, the impact strength can be improved by nearly 54%, and the interlaminar shear strength can be improved by nearly 50%.

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.

Drawings

FIG. 1 is a schematic diagram of the growth mechanism of the self-assembled nano-wire of the silicon on the surface of the basalt fiber.

FIG. 2 is an SEM image of silicon nanowires on the surface of the modified basalt fiber.

Detailed Description

The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.

Example 1

(1) heating basalt fibers in a mixed solution of acetone and petroleum ether according to the volume ratio of 2:1 at 60 ℃, refluxing and cleaning for 6h, cleaning with plasma water for 3-4 times, and then placing the basalt fibers in a vacuum oven to be dried for 12h at 80 ℃ to obtain the basalt fibers with the surface being desized. (2) Preparing piranha solution (piranha solution) from hydrogen peroxide (30% by mass concentration) and concentrated sulfuric acid according to the volume ratio of 7:3, and adding the hydrogen peroxide into the concentrated sulfuric acid during preparation. And immersing the basalt fiber subjected to surface cleaning and desizing into a prepared activation solution, heating to 90 ℃, soaking for 30min, cleaning for 2-3 times by using a large amount of plasma water, and drying in a 60 ℃ drying oven to obtain the activated basalt fiber. (3) Putting the activated fiber wound on a glass plate into a beaker, adding 90mL of thoroughly dehydrated and deoxygenated ultra-dry toluene solution, 60uL of hydrochloric acid solution with volume fraction of 32% and 1.2mL of methyltriethoxysilane; introducing nitrogen for protection in the experimental process, keeping the low-speed stirring at the rotating speed of 40rpm, reacting for 8 hours, sequentially cleaning with acetone, absolute ethyl alcohol and a large amount of plasma water, and drying in a 60 ℃ drying oven to obtain the modified basalt fiber. (4) Fixing two ends of modified continuous basalt fibers on two ends of a mould, wherein the length of the fibers is equivalent to the length of the mould, controlling the mass fraction of the basalt fibers added in the mould pressing process to be 4%, then mixing E51 epoxy resin and curing agent 2125B according to the mass ratio of 100:50, pouring the mixture into the mould with the fibers, and preparing the basalt fiber reinforced epoxy resin composite material by adopting a unidirectional laying mould pressing method.

In the above method, the basalt fiber winding operation on the glass plate may also be performed at step S2.

The growth mechanism of the self-assembled silicon nanowires on the surfaces of the basalt fibers is shown in figure 1. After the piranha solution is activated, the surface of the basalt fiber contains a large number of active hydroxyl groups, the methyltriethoxysilane is hydrolyzed under an acidic condition, and the silicon nanowires are grown on the surface of the basalt fiber in a self-assembly form.

Example 2

The reaction time in step (3) was changed to 4 hours based on example 1, and the other steps were the same as in example 1.

Comparative example 1

Compared with the example 1, in the experimental process, nitrogen is not introduced into the step (3) for protection.

Comparative example 2

In comparison with example 1, the toluene solution added in the experiment of step (3) was not subjected to dehydration oxygen removal treatment.

Comparative example 3

The basalt fiber is not subjected to any modification treatment.

In order to verify the growth condition of the silicon nanowires on the fiber surfaces in each group, the basalt fiber surfaces in each group were observed, and the test results are shown in table 1.

TABLE 1 silicon nanowire length and diameter in the examples and comparative documents

As can be seen from Table 1, the experimental conditions should be strictly controlled when the silicon nanowires are grown in situ on the surface of the basalt fiber. When nitrogen protection is not introduced and the toluene solvent does not remove water and oxygen, the silicon nanowires cannot grow on the surface of the basalt fiber, the growth of the silicon nanowires can be influenced by the moisture in the toluene solvent, and the growth of the silicon nanowires is favored when the moisture content in the toluene is less. Meanwhile, when the fiber modification time is 4 hours, the diameter of the silicon nanowire is 100-400 nm, and the length of the silicon nanowire reaches 3-6 microns, and when the modification time is 8 hours, the diameter of the silicon nanowire growing on the surface of the fiber reaches 300-600 nm, and the length of the silicon nanowire growing on the surface of the fiber reaches 10-15 microns, as shown in figure 2. At the moment, a large number of silicon nanowires grow on the surface of the basalt fiber, and the fibers can be uniformly coated by the silicon nanowires, which shows that the length and the diameter of the silicon nanowires can be increased along with the prolonging of time.

In order to verify the performance of the basalt fiber reinforced epoxy resin-based composite material modified by the self-assembled silicon nanowire, the composite materials prepared in example 1 and comparative example 3 were sampled and subjected to mechanical property testing, and the test results are shown in table 2:

table 2 results of performance testing of the composites of example 1 and comparative example 3

Through the test of the mechanical properties of the composite materials in the embodiment 1 and the comparative example 3, as can be seen from table 2, the silicon nanowires show that the tensile property, the impact resistance and the interlaminar shear property of the modified basalt fiber composite material are all remarkably improved, and the modified basalt fiber composite material has good comprehensive mechanical properties. The silicon nanowires grow in situ on the basalt fiber surface in a self-assembly mode, a large number of silicon nanowires are uniformly coated on the fiber surface, the roughness of the basalt fiber surface is improved, meanwhile, a large number of active groups such as hydroxyl groups exist on the silicon nanowires, a mechanical meshing effect and a chemical bonding effect are formed between the silicon nanowires and resin, the affinity between the fiber and the resin is obviously improved, the fiber and the resin are not easy to separate, and the mechanical property of the composite material is obviously improved.

In conclusion, the method adopts the solution method to grow the silicon nano-wire in situ to modify the surface of the basalt fiber; the method is characterized in that methyltriethoxysilane is used as a precursor, basalt fiber is used as a matrix, piranha solution is used as an activation solution, reaction parameters are controlled, methyltriethoxysilane can be hydrolyzed under an acidic condition, and silicon nanowires with the diameter of 100-600 nm and the length of 10-15 mu m grow on the surface of the fibers in a self-assembly manner. A large number of silicon nanowires are uniformly coated on the surface of the basalt fiber, so that the roughness of the surface of the basalt fiber is improved, and meanwhile, a large number of active groups such as hydroxyl groups exist on the silicon nanowires, so that the mechanical meshing and chemical bonding effects between the basalt fiber and resin are enhanced, and the basalt fiber and the resin can be bonded together more firmly. The prepared composite material has obviously improved tensile property, impact resistance and interlaminar shear property. The self-assembled silicon nanowire prepared by the method can effectively optimize the interface performance of the basalt reinforced resin matrix composite material.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A method for optimizing the interface of a basalt reinforced resin matrix composite material is characterized by comprising the following steps:

s1, cleaning the surface of the basalt fiber by adopting an organic solvent and plasma water in sequence;

s2, immersing the cleaned basalt fiber into a piranha solution, heating to 90 ℃, soaking at constant temperature for 10-40 min, then cleaning for 2-3 times by using plasma water, and placing in a 60 ℃ drying oven for drying to obtain the basalt fiber with activated surface;

s3, carrying out dehydration and deoxidization treatment on toluene, putting activated basalt fibers wound and fixed on a carrier into the dehydrated and deoxidized toluene under the condition of continuously introducing nitrogen for protection, then adding methyltriethoxysilane into the toluene, then adding hydrochloric acid to keep the solution acidic, stirring at the rotating speed of 30-40 rpm for reaction for 6-10 h, taking out the basalt fibers, cleaning, and drying in an oven at the temperature of 60 ℃ to obtain modified basalt fibers; the hydrochloric acid is a hydrochloric acid solution with the volume fraction of 32%, and the volume ratio of the hydrochloric acid solution to the dehydrated and deoxygenated toluene is 1: 1500;

2. The method for optimizing the interface of the basalt reinforced resin matrix composite material according to claim 1, wherein in step S1, the basalt fiber is heated and refluxed and cleaned in a mixed solution of acetone and petroleum ether at 60 ℃ for 4-8 h, then cleaned with plasma water for 3-4 times, and then put into a vacuum oven to be dried for 12h at 80 ℃ to obtain the basalt fiber with the surface thereof being desized.

3. The method for interface optimization of basalt reinforced resin-based composite material according to claim 1, wherein in the step S2, the piranha solution is a mixed solution of 30% by mass of hydrogen peroxide and concentrated sulfuric acid in a volume ratio of 7:3, and the hydrogen peroxide is added to the concentrated sulfuric acid during preparation.

4. The method for interface optimization of basalt reinforced resin based composite material according to claim 3, wherein the cleaned basalt fiber is immersed in the piranha solution and then is immersed for the activation time of 30min at 90 ℃ in step S2.

5. The method for interface optimization of basalt reinforced resin based composite material according to claim 1, wherein the activated basalt fiber is wound and fixed on a glass plate or a glass rod carrier and then put into the dehydrated and oxygen-removed toluene solvent in step S3.

6. The method for interface optimization of basalt reinforced resin based composite material according to claim 5, wherein the volume ratio of the hydrochloric acid solution, the toluene dehydrated and deoxygenated and the methyl triethoxysilane is 1:1500:20 in the step S3.

7. The method for interface optimization of basalt reinforced resin based composite material according to claim 6, wherein the reaction time in step S3 is 8 h.

8. The method for interface optimization of basalt reinforced resin based composite material according to claim 7, wherein in step S3, the basalt fiber after the reaction is sequentially washed with acetone, absolute ethyl alcohol, and plasma water.

9. The method for optimizing the interface of the basalt reinforced resin-based composite material according to claim 8, wherein silicon nanowires are grown on the surface of the modified basalt fiber obtained in the step S3, and the silicon nanowires have a diameter of 100-600 nm and a length of 10-15 μm.