Method for protecting bulletproof fabric in seawater environment based on magnesium hydroxide modification

Abstract

The application relates to a method for modifying and protecting bulletproof fiber fabric under a seawater environment based on magnesium hydroxide, and belongs to the technical field of fiber fabric modification. Alkaline and acidic impurities on the surface of the fiber fabric are removed, and the activity and interface performance of the surface are improved; then, an aqueous solution containing magnesium nitrate, ammonia and silane coupling agent KH560 is used as a magnesium hydroxide seed solution to form a magnesium hydroxide seed layer on the surface of the fiber fabric; and then, an aqueous solution pre-reacted by magnesium acetate, urotropine and silane coupling agent KH560 is used as a magnesium hydroxide growth solution to form a magnesium hydroxide growth layer on the magnesium hydroxide seed layer, so that the preparation of the bulletproof fiber fabric under the seawater environment based on magnesium hydroxide modification protection is completed. The two-layer magnesium hydroxide composite layer prepared by using the two solutions can effectively enhance the resistance of the fiber fabric to the seawater corrosion environment, so that the bulletproof performance of the fiber fabric is improved and can be maintained for a long time.

Description

Technical Field

[0001] This invention relates to a method for modifying and protecting bulletproof fiber fabrics in seawater environments based on magnesium hydroxide, belonging to the field of fiber fabric modification technology. Background Technology

[0002] Fiber modification is a common method to improve the overall performance of fibers. The principle of fiber modification is to chemically bond or physically impregnate modified synthetic materials with the fiber surface through chemical generation and physical adhesion methods, so as to endow the fiber with the properties required in different application situations. For example, it can reduce the weakening of the mechanical properties of aramid fibers by the environment, increase the roughness of the fiber surface to increase the friction coefficient between yarns, and thus improve the ballistic performance of the fabric.

[0003] With the diversification of combat modes, amphibious and landing operations have become unavoidable and crucial components of modern warfare. The marine environment is a complex corrosive environment. Besides seawater itself being a strong corrosive medium, waves, tides, and currents generate low-frequency reciprocating stress and impacts on metal and organic components. Furthermore, marine microorganisms, attached organisms, and their metabolic products all directly or indirectly accelerate the corrosion process. Therefore, in seawater environments, fiber fabrics experience the breakage of their hydrogen bond networks, leading to corrosion and cracking on the fiber surface, forming randomly distributed gaps. The elastic modulus, tensile strength, and coefficient of friction between yarns all decrease, severely reducing the fabric's elastic resistance. Currently, to protect fiber fabrics in marine environments, this is often addressed by using waterproof sleeves on the outside of the fibers and placing absorbent materials inside. However, these external protective measures can only partially reduce the corrosive effects of seawater on fabrics in the short term; their protective effect is minimal when fibers are immersed in seawater for extended periods.

[0004] Magnesium hydroxide is a white amorphous powder or colorless hexagonal prismatic crystals. It is soluble in dilute acids and ammonium salt solutions, almost insoluble in water. The soluble portion completely ionizes, and its aqueous solution is weakly alkaline. When heated to 350℃, it loses water to form magnesium oxide. Currently, magnesium hydroxide is mainly used in fiber modification of fabrics to impart dielectric and flame-retardant properties through physical deposition. This utilizes magnesium hydroxide's electrical conductivity, high decomposition temperature, high heat capacity, and ability to form a carbonized layer to block oxygen. There are no reports of applying magnesium hydroxide to fiber fabrics to improve their ballistic performance in seawater environments. Summary of the Invention

[0005] To address the issue of reduced bulletproof performance of bulletproof fiber fabrics in seawater environments, this invention provides a method for protecting bulletproof fiber fabrics in seawater environments using magnesium hydroxide modification. Two different solutions are used to sequentially grow a magnesium hydroxide composite layer on the surface of the fiber fabric. The inner layer of magnesium hydroxide is covalently bonded to the fiber fabric (rather than through physical adhesion). The magnesium hydroxide particles have a high adhesion rate, and the inner layer consists of hemispherical particles with a large contact area with the fiber surface, exhibiting strong bonding stability and resistance to detachment. This effectively increases the friction coefficient between yarns in the fiber fabric, and the magnesium hydroxide implantation reduces fiber breakage sensitivity, thus improving performance to a certain extent. The tensile strength of the fiber; the outer layer of magnesium hydroxide is needle-shaped, and its contact area with seawater is significantly smaller than that of the inner layer of hemispherical magnesium hydroxide. Therefore, its abrasion resistance and erosion resistance in seawater are significantly better than those of the hemispherical magnesium hydroxide. The wear mode in seawater is along the needle-shaped pattern from the outside to the inside at a very slow rate, with a long performance stability period. It will not decompose in the seawater environment, so the outer layer of magnesium hydroxide can form a good protective barrier, avoiding the problem of decreased tensile strength and elastic modulus of the fiber fabric due to hydrogen bond breakage under long-term seawater immersion. This enhances the fiber fabric's resistance to seawater corrosion and improves and maintains the elasticity of the fiber fabric for a long time.

[0006] The objective of this invention is achieved through the following technical solutions.

[0007] A method for protecting bulletproof fiber fabrics in seawater environments based on magnesium hydroxide modification includes the following steps:

[0008] (1) Pretreatment of fiber fabrics

[0009] The fiber fabric is subjected to acid washing, alkali washing and water washing to remove alkaline and acidic impurities from the surface of the fiber fabric; then the fiber fabric is immersed in a methanol solution of butenoic acid to improve the surface activity and interfacial properties of the fiber fabric, and then taken out and washed to complete the pretreatment of the fiber fabric.

[0010] Furthermore, the methanol solution of butenoic acid is prepared by mixing butenoic acid and methanol in a mass ratio of 10:1 to 3:1. Accordingly, the fiber fabric is preferably immersed at 20 to 50°C for 2 to 3 hours.

[0011] Furthermore, in order to improve the uniformity of impregnation, the methanol solution of butenoic acid is alternately circulated between the bottom and surface of the fiber fabric (e.g., a circulating pump is used to extract the solution from the bottom and then spray it onto the fiber surface, repeating the process).

[0012] (2) Preparation of magnesium hydroxide seed layer

[0013] The pretreated fiber fabric is immersed in magnesium hydroxide seed solution to generate magnesium hydroxide on the surface of the fiber fabric. After the fiber fabric is removed from the magnesium hydroxide seed solution, it is then vacuum cultured to promote the covalent bond between magnesium hydroxide and the fiber fabric, forming a magnesium hydroxide seed layer on the surface of the fiber fabric.

[0014] Among them, magnesium hydroxide seed solution is an aqueous solution containing magnesium nitrate, ammonia and silane coupling agent KH560;

[0015] Furthermore, in the magnesium hydroxide seed solution, the concentration of magnesium nitrate is 0.1–0.2 mol / L, the concentration of concentrated ammonia water with a mass fraction of 25% is 40–80 g / L, and the mass percentage of KH560 is 3–6%; correspondingly, the pretreated fiber fabric is preferably immersed in the magnesium hydroxide seed solution at 30–70°C for 2–3 hours.

[0016] Furthermore, vacuum culture at 70–90°C for 1–2 hours;

[0017] (3) Preparation of magnesium hydroxide growth layer

[0018] The fiber fabric containing a magnesium hydroxide seed layer is immersed in a magnesium hydroxide growth solution, and a magnesium hydroxide growth layer is generated on the seed layer and in the empty areas of the fiber fabric. After the fiber fabric is removed from the magnesium hydroxide growth solution, it is then vacuum cultured to promote the growth of magnesium hydroxide on the magnesium hydroxide seed layer and the covalent bonding with the empty areas of the fiber fabric. Thus, a magnesium hydroxide growth layer is generated on the magnesium hydroxide seed layer and in the empty areas of the fiber fabric, forming a magnesium hydroxide composite modified layer on the fiber fabric, thus completing the preparation of a bulletproof fiber fabric based on magnesium hydroxide modification for protection in seawater environment.

[0019] Among them, the magnesium hydroxide growth solution is formed by pre-reacting an aqueous solution containing magnesium acetate, hexamethylenetetramine and silane coupling agent KH560 at 20-30°C for 1-2 hours;

[0020] Furthermore, before the reaction, the aqueous solution containing magnesium acetate, hexamethylenetetramine, and silane coupling agent KH560 has the following characteristics: the concentration of magnesium acetate is 0.05–0.1 mol / L, the concentration of hexamethylenetetramine is 0.1–0.2 mol / L, and the mass percentage of KH560 is 3–6%. Accordingly, the fiber fabric containing the magnesium hydroxide seed layer is preferably impregnated at 30–60°C for 2–3 hours.

[0021] Furthermore, vacuum culture was carried out at 80–110°C for 2–3 hours;

[0022] Furthermore, the mass increment of the fiber fabric after forming the magnesium hydroxide composite modified layer (i.e., containing a magnesium hydroxide seed layer and a magnesium hydroxide growth layer) is 4% to 21%, more preferably 7% to 12%.

[0023] Beneficial effects:

[0024] (1) In the prior art, the ethanol solution of vinyl acetic acid is used to pretreat the fiber fabric, mainly to increase the surface activity of the fiber fabric and increase the number of binding sites. However, the bond energy of the covalent bond at each binding site is not large, that is, the number of binding sites is large but the bonding stability is generally low. However, there is a lot of scouring and turbulence in the seawater environment, which puts forward high requirements for bonding stability. In this application, a methanol solution of butenoic acid is used to improve the surface activity of the fiber fabric. The number of binding sites is not as large as that of vinyl acetic acid, but the covalent bond energy of the binding sites generated by it is much greater than that given by vinyl acetic acid. Therefore, the bonding stability is much higher than that of the ethanol solution of vinyl acetic acid. It can still maintain excellent bonding stability in the harsh scouring and turbulent environment of seawater.

[0025] (2) This application utilizes magnesium nitrate, ammonia, and KH560 to easily form a hemispherical coating bond, resulting in a large contact area per unit volume. Each magnesium hydroxide seed unit forms more covalent bonds with the fiber fabric surface, leading to a larger total bond energy, more stable bonding, and more thorough contact, making it suitable as a stable base layer. Therefore, using it as an internal magnesium hydroxide seed layer can effectively resist seawater erosion and turbulence. Furthermore, its stable alkaline resistance and chemical properties prevent salt particles in seawater from contacting the fibers, thus preventing physical erosion corrosion and chemical corrosion from salts.

[0026] (3) The magnesium hydroxide produced by the reaction of magnesium acetate, hexamethylenetetramine and KH560 in this application grows in a needle-like extension. The contact area of ​​needle-like magnesium hydroxide is smaller than that of hemispherical particles. The corrosion probability of particles of this shape per unit volume is much smaller than that of hemispherical particles, which has a good morphological advantage. However, due to the small contact area, it is not suitable as an internal growth base layer. However, as an external growth layer (external defense layer) growing on the internal base layer, it can effectively play its morphological advantage. When subjected to physical and chemical corrosion in seawater, the growing magnesium hydroxide particles will be slowly consumed along the radial direction of the needle-like structure. The magnesium hydroxide growth layer can block the scouring of seawater and the corrosion of salts for a long time, and prevent the magnesium hydroxide base layer from being corroded accordingly, thereby protecting the integrity of the internal fiber structure and the stability of its performance.

[0027] (4) This application uses two solutions to grow two types of magnesium hydroxide composite layers. The magnesium hydroxide in the inner seed layer is hemispherical with a larger total bond energy and a stable bond with the fiber. However, its large surface area makes it more susceptible to seawater erosion and salt corrosion, and it cannot protect the fiber for a long time. The magnesium hydroxide in the outer growth layer is needle-shaped. Due to its small cross-sectional area and fewer bonds, its bond with the fiber is not stable enough. When subjected to seawater erosion and salt corrosion, it is easy to fall off from the fiber surface. Therefore, the outer growth layer is not suitable as an internal base layer for protecting the fiber. However, the magnesium hydroxide in the growth layer and the magnesium hydroxide in the seed layer can form a stable connection and grow. The number and energy of their covalent bonds are much greater than the covalent bonds formed between the growth layer and the fiber layer. Therefore, by using the combination of inner and outer layers, a stable internal base layer is formed with the fiber, and an external consumption layer (i.e., the outer growth layer) that can resist seawater erosion for a long time is formed on the outside, which effectively protects the fiber from long-term immersion and erosion in seawater.

[0028] (5) In the method described in this invention, by optimizing the concentration of reactants and reaction conditions, the generated magnesium hydroxide composite modified layer can effectively resist the harsh environment of seawater corrosion, avoid causing redundant mass and increasing negative weight, thereby affecting the wearing comfort, lightness and mobility of the fiber fabric, and improving the overall elasticity of the fiber fabric.

[0029] In summary, the method described in this invention is simple to operate and easy to scale up for production. Moreover, this method can not only effectively enhance the resistance of fiber fabrics to seawater corrosion, but also further improve the protective effect of fiber fabrics against projectiles. It also has good application prospects in the fields of personal stab-proof vests, personal bulletproof vests, and military bulletproof tents. Attached Figure Description

[0030] Figure 1 This is a surface scanning electron microscope image of the magnesium hydroxide seed layer grown on the surface of the fibrous fabric in Example 1.

[0031] Figure 2 This is a surface scanning electron microscope image of the hydroxide growth layer grown on the magnesium hydroxide seed layer on the surface of the fiber fabric in Example 1. Detailed Implementation

[0032] The present invention will be further described below with reference to specific embodiments. Unless otherwise specified, the methods described are conventional methods, and the raw materials described are obtainable from publicly available commercial sources.

[0033] Example 1

[0034] (1) First, immerse the Twaron CT709 fiber fabric in a 30% acetic acid aqueous solution for 30 min, then immerse it in a 15 g / L NaOH aqueous solution for 30 min, and then immerse it in deionized water for 30 min to remove alkaline and acidic impurities from the surface of the fiber fabric. Dissolve 800 g of butenoic acid in 200 g of methanol to prepare a butenoic acid methanol solution. Then immerse the fiber fabric after immersion in deionized water in the butenoic acid methanol solution and immerse it at 40°C for 2 h. During the immersion, in order to improve the immersion uniformity, a circulating pump is used to extract the butenoic acid methanol solution from the bottom and spray it onto the surface of the fiber fabric. The circulation is repeated to achieve the alternating flow of the butenoic acid methanol solution at the bottom and the surface of the fiber fabric. Finally, the liquid on the surface of the fiber fabric is removed with flowing methanol to complete the pretreatment of the fiber fabric.

[0035] (2) The pretreated fiber fabric was immersed in magnesium hydroxide seed solution for 2 hours at 50°C to generate magnesium hydroxide on the surface of the fiber fabric. After the fiber fabric was removed from the magnesium hydroxide seed solution, it was placed in vacuum culture at 80°C for 2 hours to promote the covalent bond between magnesium hydroxide and the fiber fabric and to form a magnesium hydroxide seed layer on the surface of the fiber fabric.

[0036] Among them, the magnesium hydroxide seed solution is an aqueous solution containing magnesium nitrate, ammonia and silane coupling agent KH560; in the magnesium hydroxide seed solution, the concentration of magnesium nitrate is 0.1 mol / L, the concentration of ammonia with a mass fraction of 25% is 80 g / L, and the mass fraction of silane coupling agent KH560 is 3%.

[0037] (3) An aqueous solution containing magnesium acetate, hexamethylenetetramine and silane coupling agent KH560 is pre-reacted at 20°C for 1 hour to form a magnesium hydroxide growth solution; the fiber fabric containing the magnesium hydroxide seed layer is immersed in the magnesium hydroxide growth solution at 30°C for 2 hours to generate magnesium hydroxide on the magnesium hydroxide seed layer of the fiber fabric and in the empty parts of the fiber fabric; after the fiber fabric is taken out from the magnesium hydroxide growth solution, it is placed in vacuum culture at 100°C for 2 hours to promote the growth of the magnesium hydroxide growth layer on the magnesium hydroxide seed layer and the covalent bond with the empty parts of the fiber fabric, so that a magnesium hydroxide growth layer is generated on the magnesium hydroxide seed layer of the fiber fabric and in the empty parts of the fiber fabric, that is, a magnesium hydroxide composite modified layer is formed on the fiber fabric, thus completing the preparation of bulletproof fiber fabric based on magnesium hydroxide modification for protection in seawater environment;

[0038] In the aqueous solution containing magnesium acetate, hexamethylenetetramine, and silane coupling agent KH560, before the pre-reaction, the concentration of magnesium acetate was 0.05 mol / L, the concentration of hexamethylenetetramine was 0.1 mol / L, and the mass fraction of silane coupling agent KH560 was 3%.

[0039] Compared to the unmodified single-layer fiber fabric, the mass increased by 4.0% after the formation of the magnesium hydroxide composite modified layer on the surface of the fiber fabric in step (3). Correspondingly, the average areal density of the magnesium hydroxide modified single-layer fiber fabric was 208.0 g / m³. 2 The areal density of the two-layer modified fiber fabric modified with magnesium hydroxide composite is 416.0 g / m². 2 .

[0040] Figure 1 The image shows a scanning electron microscope image of the magnesium hydroxide seed layer formed on the surface of the fiber fabric in step (2). The image shows that the magnesium hydroxide particles are hemispherical and have a good bond with the fiber fabric, effectively covering and protecting the surface of the fiber fabric.

[0041] Figure 2 The image shows a scanning electron microscope image of the magnesium hydroxide growth layer generated on the magnesium hydroxide seed layer of the fiber fabric and in the empty space of the fiber fabric in step (3). It can be seen from the image that the magnesium hydroxide particles grow in a needle-like manner on the hemispherical magnesium hydroxide seed layer and extend outward along the radial direction, thus achieving a long-term protective effect.

[0042] Example 2

[0043] (1) Same as step (1) in Example 1;

[0044] (2) The pretreated fiber fabric was immersed in magnesium hydroxide seed solution for 2 hours at 50°C to generate magnesium hydroxide on the surface of the fiber fabric. After the fiber fabric was removed from the magnesium hydroxide seed solution, it was placed in vacuum culture at 80°C for 2 hours to promote the covalent bond between magnesium hydroxide and the fiber fabric and to form a magnesium hydroxide seed layer on the surface of the fiber fabric.

[0045] Among them, the magnesium hydroxide seed solution is an aqueous solution containing magnesium nitrate, ammonia and silane coupling agent KH560; in the magnesium hydroxide seed solution, the concentration of magnesium nitrate is 0.2 mol / L, the concentration of ammonia with a mass fraction of 25% is 160 g / L, and the mass fraction of silane coupling agent KH560 is 6%.

[0046] (3) An aqueous solution containing magnesium acetate, hexamethylenetetramine and silane coupling agent KH560 is pre-reacted at 20°C for 1 hour to form a magnesium hydroxide growth solution; the fiber fabric containing the magnesium hydroxide seed layer is immersed in the magnesium hydroxide growth solution at 30°C for 2 hours to generate magnesium hydroxide on the magnesium hydroxide seed layer of the fiber fabric and in the empty parts of the fiber fabric; after the fiber fabric is taken out from the magnesium hydroxide growth solution, it is placed in vacuum culture at 100°C for 2 hours to promote the growth of the magnesium hydroxide growth layer on the magnesium hydroxide seed layer and the covalent bond with the empty parts of the fiber fabric, so that a magnesium hydroxide growth layer is generated on the magnesium hydroxide seed layer of the fiber fabric and in the empty parts of the fiber fabric, that is, a magnesium hydroxide composite modified layer is formed on the fiber fabric, thus completing the preparation of bulletproof fiber fabric based on magnesium hydroxide modification for protection in seawater environment;

[0047] In the aqueous solution containing magnesium acetate, hexamethylenetetramine, and silane coupling agent KH560, the concentration of magnesium acetate was 0.1 mol / L, the concentration of hexamethylenetetramine was 0.2 mol / L, and the mass fraction of silane coupling agent KH560 was 6% before the pre-reaction.

[0048] Compared to the unmodified single-layer fiber fabric, the mass increased by 10.0% after the formation of the magnesium hydroxide composite modified layer on the surface of the fiber fabric in step (3); correspondingly, the average areal density of the magnesium hydroxide modified single-layer fiber fabric was 220.0 g / m³. 2 The areal density of the two-layer modified fiber fabric modified with magnesium hydroxide composite is 440.0 g / m². 2 .

[0049] Example 3

[0050] (1) Same as step (1) in Example 1;

[0051] (2) The pretreated fiber fabric was immersed in magnesium hydroxide seed solution for 2 hours at 50°C to generate magnesium hydroxide on the surface of the fiber fabric. After the fiber fabric was removed from the magnesium hydroxide seed solution, it was placed in vacuum culture at 80°C for 2 hours to promote the covalent bond between magnesium hydroxide and the fiber fabric and to form a magnesium hydroxide seed layer on the surface of the fiber fabric.

[0052] Among them, the magnesium hydroxide seed solution is an aqueous solution containing magnesium nitrate, ammonia and silane coupling agent KH560; in the magnesium hydroxide seed solution, the concentration of magnesium nitrate is 0.15 mol / L, the concentration of ammonia with a mass fraction of 25% is 120 g / L, and the mass fraction of silane coupling agent KH560 is 4.5%.

[0053] (3) An aqueous solution containing magnesium acetate, hexamethylenetetramine and silane coupling agent KH560 is pre-reacted at 20°C for 1 hour to form a magnesium hydroxide growth solution; the fiber fabric containing the magnesium hydroxide seed layer is immersed in the magnesium hydroxide growth solution at 30°C for 2 hours to generate magnesium hydroxide on the magnesium hydroxide seed layer of the fiber fabric and in the empty parts of the fiber fabric; after the fiber fabric is taken out from the magnesium hydroxide growth solution, it is placed in vacuum culture at 100°C for 2 hours to promote the growth of the magnesium hydroxide growth layer on the magnesium hydroxide seed layer and the covalent bond with the empty parts of the fiber fabric, so that a magnesium hydroxide growth layer is generated on the magnesium hydroxide seed layer of the fiber fabric and in the empty parts of the fiber fabric, that is, a magnesium hydroxide composite modified layer is formed on the fiber fabric, thus completing the preparation of bulletproof fiber fabric based on magnesium hydroxide modification for protection in seawater environment;

[0054] In the aqueous solution containing magnesium acetate, hexamethylenetetramine, and silane coupling agent KH560, before the pre-reaction, the concentration of magnesium acetate was 0.075 mol / L, the concentration of hexamethylenetetramine was 0.15 mol / L, and the mass fraction of silane coupling agent KH560 was 4.5%.

[0055] Compared to the unmodified single-layer fiber fabric, the mass increased by 7.2% after the formation of the magnesium hydroxide composite modified layer on the surface of the fiber fabric in step (3). Correspondingly, the average areal density of the magnesium hydroxide modified single-layer fiber fabric was 214.4 g / m³. 2 The areal density of the two-layer modified fiber fabric modified with magnesium hydroxide composite is 428.8 g / m³. 2 .

[0056] Example 4

[0057] (1) Same as step (1) in Example 1;

[0058] (2) The pretreated fiber fabric was immersed in magnesium hydroxide seed solution for 2 hours at 50°C to generate magnesium hydroxide on the surface of the fiber fabric. After the fiber fabric was removed from the magnesium hydroxide seed solution, it was placed in vacuum culture at 80°C for 2 hours to promote the covalent bond between magnesium hydroxide and the fiber fabric and to form a magnesium hydroxide seed layer on the surface of the fiber fabric.

[0059] Among them, the magnesium hydroxide seed solution is an aqueous solution containing magnesium nitrate, ammonia and silane coupling agent KH560; in the magnesium hydroxide seed solution, the concentration of magnesium nitrate is 0.025 mol / L, the concentration of ammonia with a mass fraction of 25% is 20 g / L, and the mass fraction of silane coupling agent KH560 is 3%.

[0060] (3) An aqueous solution containing magnesium acetate, hexamethylenetetramine and silane coupling agent KH560 is pre-reacted at 20°C for 1 hour to form a magnesium hydroxide growth solution; the fiber fabric containing the magnesium hydroxide seed layer is immersed in the magnesium hydroxide growth solution at 30°C for 2 hours to generate magnesium hydroxide on the magnesium hydroxide seed layer of the fiber fabric and in the empty parts of the fiber fabric; after the fiber fabric is taken out from the magnesium hydroxide growth solution, it is placed in vacuum culture at 100°C for 2 hours to promote the growth of the magnesium hydroxide growth layer on the magnesium hydroxide seed layer and the covalent bond with the empty parts of the fiber fabric, so that a magnesium hydroxide growth layer is generated on the magnesium hydroxide seed layer of the fiber fabric and in the empty parts of the fiber fabric, that is, a magnesium hydroxide composite modified layer is formed on the fiber fabric, thus completing the preparation of bulletproof fiber fabric based on magnesium hydroxide modification for protection in seawater environment;

[0061] In the aqueous solution containing magnesium acetate, hexamethylenetetramine, and silane coupling agent KH560, before the pre-reaction, the concentration of magnesium acetate was 0.0125 mol / L, the concentration of hexamethylenetetramine was 0.025 mol / L, and the mass fraction of silane coupling agent KH560 was 3%.

[0062] Compared to the unmodified single-layer fiber fabric, the mass increased by 1.1% after the formation of the magnesium hydroxide composite modified layer on the surface of the fiber fabric in step (3). Correspondingly, the average areal density of the magnesium hydroxide modified single-layer fiber fabric was 202.2 g / m³. 2 The areal density of the two-layer modified fiber fabric modified with magnesium hydroxide composite is 404.4 g / m³. 2 .

[0063] Example 5

[0064] (1) Same as step (1) in Example 1;

[0065] (2) The pretreated fiber fabric was immersed in magnesium hydroxide seed solution for 2 hours at 50°C to generate magnesium hydroxide on the surface of the fiber fabric. After the fiber fabric was removed from the magnesium hydroxide seed solution, it was placed in vacuum culture at 80°C for 2 hours to promote the covalent bond between magnesium hydroxide and the fiber fabric and to form a magnesium hydroxide seed layer on the surface of the fiber fabric.

[0066] Among them, the magnesium hydroxide seed solution is an aqueous solution containing magnesium nitrate, ammonia and silane coupling agent KH560; in the magnesium hydroxide seed solution, the concentration of magnesium nitrate is 0.4 mol / L, the concentration of ammonia with a mass fraction of 25% is 320 g / L, and the mass fraction of silane coupling agent KH560 is 6%.

[0067] (3) An aqueous solution containing magnesium acetate, hexamethylenetetramine and silane coupling agent KH560 is pre-reacted at 20°C for 1 hour to form a magnesium hydroxide growth solution; the fiber fabric containing the magnesium hydroxide seed layer is immersed in the magnesium hydroxide growth solution at 30°C for 2 hours to generate magnesium hydroxide on the magnesium hydroxide seed layer of the fiber fabric and in the empty parts of the fiber fabric; after the fiber fabric is taken out from the magnesium hydroxide growth solution, it is placed in vacuum culture at 100°C for 2 hours to promote the growth of the magnesium hydroxide growth layer on the magnesium hydroxide seed layer and the covalent bond with the empty parts of the fiber fabric, so that a magnesium hydroxide growth layer is generated on the magnesium hydroxide seed layer of the fiber fabric and in the empty parts of the fiber fabric, that is, a magnesium hydroxide composite modified layer is formed on the fiber fabric, thus completing the preparation of bulletproof fiber fabric based on magnesium hydroxide modification for protection in seawater environment;

[0068] In the aqueous solution containing magnesium acetate, hexamethylenetetramine, and silane coupling agent KH560, the concentration of magnesium acetate was 0.2 mol / L, the concentration of hexamethylenetetramine was 0.4 mol / L, and the mass fraction of silane coupling agent KH560 was 6% before the pre-reaction.

[0069] Compared to the unmodified single-layer fiber fabric, the mass increased by 21.0% after the formation of the magnesium hydroxide composite modification layer on the surface of the fiber fabric in step (3). Correspondingly, the average areal density of the magnesium hydroxide-modified single-layer fiber fabric was 242.0 g / m³. 2 The areal density of the two-layer modified fiber fabric modified with magnesium hydroxide composite is 484.0 g / m². 2 .

[0070] Example 6

[0071] Compared with Example 2, except for the different conditions for pretreatment of the fiber fabric in step (1), the conditions for growing the magnesium hydroxide seed layer on the pretreated fiber fabric in step (2) and growing the magnesium hydroxide growth layer on the fiber fabric in step (3) in Example 6 are the same as those in Example 2. Accordingly, a magnesium hydroxide composite modified layer is formed on the fiber fabric in Example 6.

[0072] In Example 6, step (1) of the pretreatment operation is as follows: Twaron CT709 fiber fabric is first immersed in acetic acid aqueous solution with a mass fraction of 30% for 30 minutes, then immersed in NaOH aqueous solution with a concentration of 15g / L for 30 minutes, and then immersed in deionized water for 30 minutes to remove alkaline and acidic impurities on the surface of the fiber fabric; 200g of butenoic acid is dissolved in 200g of methanol to prepare butenoic acid methanol solution, and then the fiber fabric after being immersed in deionized water is immersed in butenoic acid methanol solution and immersed at 40°C for 2 hours. During the immersion, in order to improve the immersion uniformity, a circulating pump is used to extract the butenoic acid methanol solution at the bottom and then spray it onto the surface of the fiber fabric. The circulation is repeated to realize that the butenoic acid methanol solution flows alternately at the bottom and surface of the fiber fabric. Finally, the liquid on the surface of the fiber fabric is removed with flowing methanol, thus completing the pretreatment of the fiber fabric.

[0073] Compared to the unmodified single-layer fiber fabric, the mass increased by 6.3% after the formation of the magnesium hydroxide composite modified layer on the surface of the fiber fabric in step (3). Correspondingly, the average areal density of the magnesium hydroxide modified single-layer fiber fabric was 212.6 g / m³. 2 The areal density of the two-layer modified fiber fabric modified with magnesium hydroxide composite is 425.2 g / m². 2 .

[0074] Example 7

[0075] Compared with Example 2, except for the different conditions for pretreatment of the fiber fabric in step (1), the conditions for growing the magnesium hydroxide seed layer on the pretreated fiber fabric in step (2) and growing the magnesium hydroxide growth layer on the fiber fabric in step (3) in Example 7 are the same as those in Example 2. Accordingly, a magnesium hydroxide composite modified layer is formed on the fiber fabric in Example 7.

[0076] In Example 7, step (1) of the pretreatment operation is as follows: Twaron CT709 fiber fabric is first immersed in acetic acid aqueous solution with a mass fraction of 30% for 30 minutes, then immersed in NaOH aqueous solution with a concentration of 15g / L for 30 minutes, and then immersed in deionized water for 30 minutes to remove alkaline and acidic impurities on the surface of the fiber fabric; 2000g of butenoic acid is dissolved in 200g of methanol to prepare butenoic acid methanol solution, and then the fiber fabric after being immersed in deionized water is immersed in butenoic acid methanol solution and immersed at 40°C for 2 hours. During the immersion, in order to improve the immersion uniformity, a circulating pump is used to extract the butenoic acid methanol solution at the bottom and then spray it onto the surface of the fiber fabric. The circulation is repeated to realize that the butenoic acid methanol solution flows alternately at the bottom and surface of the fiber fabric. Finally, the liquid on the surface of the fiber fabric is removed with flowing methanol, thus completing the pretreatment of the fiber fabric.

[0077] Compared to the unmodified single-layer fiber fabric, the mass increased by 15.8% after the formation of the magnesium hydroxide composite modified layer on the surface of the fiber fabric in step (3). Correspondingly, the average areal density of the magnesium hydroxide modified single-layer fiber fabric was 231.6 g / m³. 2 The areal density of the two-layer modified fiber fabric modified with magnesium hydroxide composite is 463.2 g / m². 2 .

[0078] Comparative Example 1

[0079] The areal density of a single-layer unmodified Twaron CT709 fiber fabric is 200 g / m². 2 The areal density of the two layers of unmodified TwaronCT709 fiber fabric is 400 g / m². 2 .

[0080] Comparative Example 2

[0081] Compared with Example 2, except for the different conditions for pretreatment of the fiber fabric in step (1), the conditions for growing the magnesium hydroxide seed layer on the pretreated fiber fabric in step (2) and growing the magnesium hydroxide growth layer on the fiber fabric in step (3) in Comparative Example 2 are the same as those in Example 2. Accordingly, a magnesium hydroxide composite modified layer is formed on the fiber fabric in Comparative Example 2.

[0082] In Comparative Example 2, step (1) is specifically pre-treated as follows: Twaron CT709 fiber fabric is first immersed in an acetic acid aqueous solution with a mass fraction of 30% for 30 minutes, then immersed in a NaOH aqueous solution with a concentration of 15 g / L for 30 minutes, and then immersed in deionized water for 30 minutes to remove alkaline and acidic impurities from the surface of the fiber fabric, thus completing the pre-treatment of the fiber fabric.

[0083] Compared to the unmodified single-layer fiber fabric, the mass of Comparative Example 2 increased by 2.1% after a magnesium hydroxide composite modification layer was formed on the surface of the fiber fabric. Correspondingly, the average areal density of the magnesium hydroxide-modified single-layer fiber fabric was 204.2 g / m³. 2 The areal density of the two-layer modified fiber fabric modified with magnesium hydroxide composite is 408.4 g / m³. 2 .

[0084] Comparative Example 3

[0085] (1) Same as step (1) in Example 1;

[0086] (2) The pretreated fiber fabric was immersed in magnesium hydroxide seed solution for 2 hours at 50°C to generate magnesium hydroxide on the surface of the fiber fabric. After the fiber fabric was removed from the magnesium hydroxide seed solution, it was placed in vacuum culture at 80°C for 2 hours to promote the covalent bond between magnesium hydroxide and the fiber fabric and to form a magnesium hydroxide seed layer on the surface of the fiber fabric.

[0087] Among them, the magnesium hydroxide seed solution is an aqueous solution containing magnesium nitrate, ammonia and silane coupling agent KH560; in the magnesium hydroxide seed solution, the concentration of magnesium nitrate is 0.2 mol / L, the concentration of ammonia with a mass fraction of 25% is 160 g / L, and the mass fraction of silane coupling agent KH560 is 6%.

[0088] Compared to the unmodified single-layer fiber fabric, the mass increased by 5.3% after the formation of the magnesium hydroxide composite modified layer on the surface of the fiber fabric in step (3); correspondingly, the average areal density of the magnesium hydroxide modified single-layer fiber fabric was 210.6 g / m³. 2 The areal density of the two-layer modified fiber fabric modified with magnesium hydroxide seed layer is 421.2 g / m². 2 .

[0089] Comparative Example 4

[0090] (1) Same as step (1) in Example 1;

[0091] (2) An aqueous solution containing magnesium acetate, hexamethylenetetramine and silane coupling agent KH560 is pre-reacted at 20°C for 1 hour to form a magnesium hydroxide growth solution; the fiber fabric containing the magnesium hydroxide seed layer is immersed in the magnesium hydroxide growth solution at 30°C for 2 hours to generate magnesium hydroxide on the magnesium hydroxide seed layer of the fiber fabric and in the empty parts of the fiber fabric; after the fiber fabric is taken out from the magnesium hydroxide growth solution, it is placed in vacuum culture at 100°C for 2 hours to promote the growth of the magnesium hydroxide growth layer on the magnesium hydroxide seed layer and the covalent bond with the empty parts of the fiber fabric, so that a magnesium hydroxide growth layer is generated on the magnesium hydroxide seed layer of the fiber fabric and in the empty parts of the fiber fabric, that is, a magnesium hydroxide composite modified layer is formed on the fiber fabric, thus completing the preparation of bulletproof fiber fabric based on magnesium hydroxide modification for protection in seawater environment;

[0092] In the aqueous solution containing magnesium acetate, hexamethylenetetramine, and silane coupling agent KH560, the concentration of magnesium acetate was 0.1 mol / L, the concentration of hexamethylenetetramine was 0.2 mol / L, and the mass fraction of silane coupling agent KH560 was 6% before the pre-reaction.

[0093] Compared to the unmodified single-layer fiber fabric, the mass increased by 4.7% after the formation of the magnesium hydroxide composite modified layer on the surface of the fiber fabric in step (3); correspondingly, the average areal density of the magnesium hydroxide modified single-layer fiber fabric was 209.4 g / m³. 2 The areal density of the two-layer modified fiber fabric modified with the magnesium hydroxide growth layer is 418.8 g / m². 2 .

[0094] Comparative Example 5

[0095] (1) First, immerse the Twaron CT709 fiber fabric in a 30% acetic acid aqueous solution for 30 min, then immerse it in a 15 g / L NaOH aqueous solution for 30 min, and then immerse it in deionized water for 30 min to remove alkaline and acidic impurities from the surface of the fiber fabric; dissolve 800 g of vinyl acetic acid in 200 g of ethanol to prepare an ethanol solution of vinyl acetic acid, then immerse the fiber fabric after immersion in deionized water in the ethanol solution of vinyl acetic acid and immerse it at 40°C for 2 h. During the immersion, in order to improve the immersion uniformity, a circulating pump is used to extract the ethanol solution of vinyl acetic acid from the bottom and spray it onto the surface of the fiber fabric. The circulation is repeated to achieve the alternating flow of the solution at the bottom and the surface of the fiber fabric. Finally, the liquid on the surface of the fiber fabric is removed with flowing methanol, thus completing the pretreatment of the fiber fabric.

[0096] In Comparative Example 5, the conditions for growing a magnesium hydroxide seed layer on the pretreated fiber fabric in step (2) and growing a magnesium hydroxide growth layer on the fiber fabric in step (3) are the same as those in Example 2. Accordingly, a magnesium hydroxide composite modified layer is formed on the fiber fabric in Comparative Example 2.

[0097] Compared to the unmodified single-layer fiber fabric, the mass increased by 14.1% after the formation of the magnesium hydroxide composite modified layer on the surface of the fiber fabric in step (3); correspondingly, the average areal density of the magnesium hydroxide modified single-layer fiber fabric was 228.2 g / m³. 2 The areal density of the two-layer modified fiber fabric modified with magnesium hydroxide composite is 456.4 g / m². 2 .

[0098] Extreme environment treatment: The fiber fabrics prepared in the examples and comparative examples were first placed in a 25°C circulating seawater treatment tank for 14 days, and then the seawater-treated fiber fabrics were placed in an indoor environment at 25°C for 1 day to dry. After that, the ballistic performance of the fiber fabrics was tested.

[0099] Ballistic performance testing: The ballistic performance of the fiber fabric after extreme environment treatment was tested separately. Eight steel bolts with a diameter of 8mm were used to fix and connect the pressure ring (used to hold the fiber fabric in place and prevent excessive deformation), the fiber fabric after extreme environment treatment, and a steel plate with a central through hole (used to fix the fiber fabric and prevent it from detaching from the target plate due to projectile impact) together in sequence to form the target plate. A projectile sabot (2-4mm thick steel plate) was set in front of the target plate to block the projectile sabot and prevent interference with the test parameters. A spherical projectile with a diameter of 10mm was used to impact the target plate, and the impact point of the projectile was controlled to be the center of the fiber fabric. The distance between the projectile and the fiber fabric only needed to ensure that the projectile flew stably. The ballistic performance test results are detailed in Table 1.

[0100] Table 1

[0101]

[0102]

[0103] According to the test results in Table 1, the fiber fabrics modified with magnesium hydroxide composite in the examples all showed improved ballistic resistance under harsh seawater corrosion conditions compared to the unmodified fiber fabrics. The test results for Examples 1-5 show that as the content of the magnesium hydroxide composite layer loaded on the fiber fabric increases, the ballistic resistance of the fiber fabric under harsh seawater corrosion conditions first gradually increases and then remains essentially unchanged. However, in Example 5, the higher content of the magnesium hydroxide composite layer did not significantly improve the ballistic resistance of the fiber fabric in seawater conditions compared to Example 2; instead, it created redundant mass for the fiber fabric. The test results of Examples 2, 2, and 5 show that the treatment of the fiber fabric surface with methanol solution of butenoic acid and ethanol solution of vinyl acetic acid can significantly improve the grafting rate of hydroxide particles, further enhancing the ballistic performance of the modified fiber fabric in seawater. However, the ballistic performance of the fiber fabric surface treated with methanol solution of butenoic acid is significantly better than that treated with ethanol solution of vinyl acetic acid. In addition, the test results of Examples 2, 6, and 7 also show that the concentration of methanol solution of butenoic acid affects the degree of surface treatment of the fiber fabric, thereby affecting the grafting rate of hydroxide particles. The test results of Examples 2, 3, and 4 show that the surface modification layer of the modified fiber fabric with only magnesium hydroxide seed layer or only magnesium hydroxide growth layer is rapidly consumed by seawater corrosion. Some of the seawater that enters the fiber fabric will corrode the fiber surface, negatively affecting the mechanical and ballistic properties of the fiber.

[0104] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for protecting bulletproof fiber fabrics in seawater environments based on magnesium hydroxide modification, characterized in that, Includes the following steps: (1) The fiber fabric is subjected to acid washing, alkali washing and water washing to remove alkaline and acidic impurities from the surface of the fiber fabric; The fiber fabric is then immersed in a methanol solution of butenoic acid to improve the surface activity and interfacial properties of the fiber fabric. After that, it is taken out and washed to complete the pretreatment of the fiber fabric. (2) The pretreated fiber fabric is immersed in magnesium hydroxide seed solution to generate magnesium hydroxide on the surface of the fiber fabric; After the fiber fabric is removed from the magnesium hydroxide seed solution, it is then subjected to vacuum culture to promote the covalent bonding between magnesium hydroxide and the fiber fabric, forming a magnesium hydroxide seed layer on the surface of the fiber fabric. (3) The fiber fabric containing the magnesium hydroxide seed layer is immersed in the magnesium hydroxide growth solution to generate a magnesium hydroxide growth layer on the seed layer of the fiber fabric and in the empty space of the fiber fabric. After the fiber fabric is removed from the magnesium hydroxide growth solution, it is then subjected to vacuum culture to promote the growth of magnesium hydroxide on the magnesium hydroxide seed layer and the covalent bonding with the empty parts of the fiber fabric. Thus, a magnesium hydroxide growth layer is generated on the magnesium hydroxide seed layer of the fiber fabric and in the empty parts of the fiber fabric, thereby completing the preparation of bulletproof fiber fabric based on magnesium hydroxide modification for protection in seawater environment. Among them, the magnesium hydroxide seed solution is an aqueous solution containing magnesium nitrate, ammonia and silane coupling agent KH560; the magnesium hydroxide growth solution is formed by pre-reacting an aqueous solution containing magnesium acetate, hexamethylenetetramine and silane coupling agent KH560 at 20-30℃ for 1-2 hours; the mass increment of the fiber fabric after the formation of magnesium hydroxide seed layer and magnesium hydroxide growth layer is 4%-21%.

2. The method for modifying and protecting bulletproof fiber fabrics in seawater environments based on magnesium hydroxide according to claim 1, characterized in that, The butenoic acid methanol solution mentioned in step (1) is prepared by mixing butenoic acid and methanol in a mass ratio of 10:1 to 3:

1.

3. The method for modifying and protecting bulletproof fiber fabrics in seawater environments based on magnesium hydroxide according to claim 2, characterized in that, The fiber fabric was immersed in a methanol solution of butenoic acid at 20–50°C for 2–3 hours.

4. The method for modifying and protecting bulletproof fiber fabrics in seawater environments based on magnesium hydroxide according to claim 1, characterized in that, The methanol solution of butenoic acid mentioned in step (1) flows alternately at the bottom and surface of the fiber fabric in a circulating manner.

5. The method for modifying and protecting bulletproof fiber fabrics in seawater environments based on magnesium hydroxide according to any one of claims 1 to 4, characterized in that, In the magnesium hydroxide seed solution mentioned in step (2), the concentration of magnesium nitrate is 0.1-0.2 mol / L, the concentration of concentrated ammonia water with a mass fraction of 25% is 40-80 g / L, and the mass percentage of KH560 is 3-6%. or / and, Before the reaction, the aqueous solution containing magnesium acetate, hexamethylenetetramine, and silane coupling agent KH560 in step (3) has a concentration of 0.05-0.1 mol / L, a concentration of 0.1-0.2 mol / L, and a mass percentage of 3-6% for magnesium acetate, hexamethylenetetramine, and silane coupling agent KH560.

6. The method for modifying and protecting bulletproof fiber fabrics in a seawater environment based on magnesium hydroxide according to claim 5, characterized in that, The pretreated fiber fabric in step (2) is immersed in magnesium hydroxide seed solution at 30-70°C for 2-3 hours; or / and, In step (3), the fiber fabric containing the magnesium hydroxide seed layer is immersed at 30-60°C for 2-3 hours.

7. The method for modifying and protecting bulletproof fiber fabrics in a seawater environment based on magnesium hydroxide according to claim 6, characterized in that, After the pretreated fiber fabric in step (2) is taken out of the magnesium hydroxide seed solution, it is vacuum cultured at 70-90℃ for 1-2 hours. or / and, In step (3), the fiber fabric containing the magnesium hydroxide seed layer is removed from the magnesium hydroxide growth solution and then vacuum cultured at 80-110°C for 2-3 hours.

8. The method for modifying and protecting bulletproof fiber fabrics in seawater environments based on magnesium hydroxide according to claim 1, characterized in that, The mass increment of the fiber fabric after the formation of the magnesium hydroxide seed layer and the magnesium hydroxide growth layer is 7-12%.

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