Preparation method and application of flame-retardant conductive aramid fabric

Abstract

The invention discloses a preparation method and application of a flame-retardant conductive aramid fabric, and belongs to the field of functional textiles, the preparation method comprises the following steps: 1) dipping an aramid fabric base material in a solvent to remove oil, and then washing and drying; 2) adding a dopant A, a dopant B and the fabric obtained in the step 1) into a conductive polymer monomer solution, dropwise adding an oxidant solution, reacting at low temperature, washing and drying; and 3) mixing the PDMS main agent, the PDMS curing agent, the diluent and the flame retardant in proportion, immersing the fabric prepared in the step 2) into the mixed solution, stirring at room temperature, and curing at high temperature to obtain the flame-retardant conductive aramid fabric. The flame-retardant conductive aramid fiber fabric prepared by the invention has good conductive and flame-retardant properties, and high-temperature alarm can be realized when the flame-retardant conductive aramid fiber fabric is connected into an alarm circuit.

Description

Technical Field

[0001] The invention belongs to the field of functional textiles, and in particular relates to a preparation method and application of a flame-retardant conductive aramid fabric. Background Art

[0002] In the modern textile market, consumers are increasingly pursuing functional textiles, among which conductive and flame-retardant fabrics are particularly popular. These conductive and flame-retardant fabrics are widely used in personal protection, automotive interiors, special building materials and other fields.

[0003] Aramid fiber is widely used in military, fire protection, aerospace, construction, automobile and other fields due to its excellent mechanical and thermal properties. However, due to the highly regular molecular chain segments and fewer surface groups, aramid fiber has strong hydrophobicity and poor surface wettability. At the same time, the fiber has high crystallinity and a smooth surface, resulting in weak interfacial bonding, which limits its application as a conductive and flame-retardant fabric.

[0004] At present, the methods for preparing conductive flame-retardant fabrics include polymerization, impregnation, coating, blending, etc., and in-situ chemical oxidation polymerization of conductive polymer monomers is one of the effective ways to prepare conductive flame-retardant fabrics. For example, patent CN116607326 discloses a method for preparing a flame-retardant cotton fabric with a dual fire warning function. The conductive polymer monomer and the oxidant are respectively prepared into an ethanol solution A and a hydrochloric acid solution B, and the pretreated cotton fabric is immersed in solution A. After immersion for a period of time, the cotton fabric coated with solution A is immersed in solution B for reaction. The method of immersing in two solutions in turn, but the conductive material attached to the surface of the fabric is limited, resulting in limited conductive performance of the fabric. Summary of the invention

[0005] [Technical issues]

[0006] The technical problem to be solved by the present invention is to prepare conductive flame-retardant fabrics by in-situ chemical oxidation polymerization of conductive polymer monomers. The conductive material attached to the surface of the fabric is limited, resulting in poor conductive properties of the fabric.

[0007] [Technical solution]

[0008] In order to solve the above problems, the present invention provides a preparation method and application of flame retardant conductive aramid fabric. The in-situ polymerization method is adopted to immerse the aramid fabric in an aqueous solution of a conductive polymer monomer, a dopant A, a dopant B, and an aqueous solution of an oxidant. The amount of conductive material attached to the surface of the fabric is increased by reacting in a solution system, so that an aramid fabric with both flame retardancy and conductivity can be obtained.

[0009] The object of the present invention is to provide a method for preparing a flame retardant conductive aramid fabric, which specifically comprises the following steps:

[0010] (1) immersing the aramid fabric substrate in a solvent to remove oil, washing, and drying to obtain a pretreated aramid fabric;

[0011] (2) adding dopant A, dopant B and the aramid fabric pretreated in step (1) to the aqueous solution of the conductive polymer monomer, then dripping the aqueous solution of the oxidant, washing and drying after the reaction to obtain the conductive polymer modified aramid fabric;

[0012] (3) Mixing polydimethylsiloxane (PDMS), polydimethylsiloxane curing agent, diluent and flame retardant in proportion to obtain a mixed solution, immersing the conductive polymer modified aramid fabric prepared in step (2) in the mixed solution, stirring and curing to obtain a flame retardant conductive aramid fabric.

[0013] In one embodiment of the present invention, in step (1), the solvent is one of ethanol, acetone, and 0.5-3 mol / L sodium hydroxide solution; the immersion temperature is 50-95° C., and the immersion time is 15-120 min.

[0014] In one embodiment of the present invention, in step (2), the conductive polymer monomer is one or more of aniline, pyrrole, and thiophene.

[0015] In one embodiment of the present invention, in step (2), the concentration of the conductive polymer monomer aqueous solution is 0.1-5 mol / L.

[0016] In one embodiment of the present invention, in step (2), the dopant A is hydrochloric acid, sulfuric acid or a mixture of both, with a concentration of 0.5-5 mol / L.

[0017] In one embodiment of the present invention, in step (2), the dopant B is phytic acid, phosphoric acid or a mixture of both, with a concentration of 0.1-1 mol / L.

[0018] In one embodiment of the present invention, in step (2), the oxidant is one of ammonium persulfate and potassium dichromate.

[0019] In one embodiment of the present invention, in step (2), the concentration of the aqueous oxidant solution is 1-5 mol / L.

[0020] In one embodiment of the present invention, in step (2), the molar ratio of the oxidant to the conductive polymer monomer is 1:0.2-5.

[0021] In one embodiment of the present invention, in step (2), the molar ratio of the conductive polymer monomer to the dopant A is 1:1-5, and the molar ratio of the dopant A to the dopant B is 1:0.1-0.4

[0022] In one embodiment of the present invention, in step (2), the reaction temperature is 0-20°C and the reaction time is 5-48h.

[0023] In one embodiment of the present invention, in step (3), the diluent is any one of ethyl acetate, n-hexane, xylene, and silicone oil.

[0024] In one embodiment of the present invention, in step (3), the flame retardant is one or more of ammonium polyphosphate, 1H,1H,2H,2H-perfluorodecyltriethoxysilane, and trimethoxy (1H,1H,2H,2H-hexafluorodecyl) silane.

[0025] In one embodiment of the present invention, in step (3), the mass ratio of polydimethylsiloxane to polydimethylsiloxane curing agent is 5-20:1; the mass ratio of polydimethylsiloxane to diluent is 1:20-200; and the mass ratio of polydimethylsiloxane to flame retardant is 1-10:1.

[0026] In one embodiment of the present invention, in step (3), the stirring time is 0.5-5h; the curing temperature is 50-120°C; and the curing time is 0.5-3h.

[0027] The invention provides a flame-retardant conductive aramid fabric prepared by the method described above.

[0028] A fire alarm circuit is formed by connecting the flame-retardant conductive aramid fabric, an alarm lamp, a power supply and a resistor through a wire to form a high-temperature alarm circuit.

[0029] Beneficial effects:

[0030] (1) Aramid fabrics have good mechanical and thermal properties, and conductive polymers have excellent electrical conductivity. Aramid fabrics with both flame retardancy and conductivity can be prepared by polymerizing conductive polymers on the surface of aramid fabrics using an in-situ polymerization method.

[0031] (2) The present invention soaks the aramid fabric in a conductive polymer monomer aqueous solution, dopant A, dopant B, and oxidant aqueous solution, and reacts in a solution system. The fabric and the reactants have a long contact time during the preparation of the conductive fabric, which is conducive to the in-situ polymerization of a large amount of conductive polymers on the fabric surface, thereby enhancing the conductivity of the fabric;

[0032] (3) The present invention can effectively improve the conductivity of the conductive polymer by adding strong acids such as hydrochloric acid and sulfuric acid. Phytic acid, phosphoric acid, etc. contain elements such as sulfur and phosphorus, which can improve the flame retardant properties while improving the conductivity of the conductive polymer;

[0033] (4) The flame-retardant conductive aramid fabric is connected with an alarm light, a power source, and a resistor via a wire to form a high-temperature alarm circuit. DETAILED DESCRIPTION

[0034] The technical solution of the present invention is further described in detail below through specific embodiments. However, it is necessary to point out that the following embodiments are only used to describe the content of the invention and do not constitute a limitation on the protection scope of the present invention.

[0035] The solvent of the solutions described in the following examples is water.

[0036] Test method:

[0037] Conductivity test: The conductivity of the fabric was measured using a four-probe conductivity meter;

[0038] Vertical combustion test: Fix a sample with a size of 30mm×8mm in a fixture and hang it vertically on the methane flame. Remove the flame after 200s and record the sample's continued combustion, smoldering, and fracture damage.

[0039] The afterflame time refers to the time that the material continues to burn with flames after the ignition source is removed; the smoldering time refers to the time that the material continues to burn without flames after the flaming combustion stops, or if it is originally burning without flames.

[0040] Example 1

[0041] 1) 30 cm × 8 cm aramid fabric was immersed in 1 mol / L NaOH solution, kept at 95°C for 60 min to remove oil, and then washed and dried to obtain pretreated aramid fabric;

[0042] 2) immersing the pretreated aramid fabric in a mixed solution consisting of 1 mol / L aniline aqueous solution, 2 mol / L hydrochloric acid, and 0.8 mol / L phytic acid, wherein the molar ratio of aniline to hydrochloric acid in the mixed solution is 1:2, and the molar ratio of hydrochloric acid to phytic acid is 1:0.1, using ammonium persulfate as an oxidant, and preparing an oxidant solution with a concentration of 2.5 mol / L according to a molar ratio of the oxidant to aniline of 1:1.25, adding the oxidant solution dropwise at a rate of 3 mL / min, and reacting at 5° C. for 12 h to obtain a conductive polymer modified aramid fabric;

[0043] 3) The PDMS main agent, PDMS curing agent, ethyl acetate, 1H,1H,2H,2H-perfluorodecyltriethoxysilane and ammonium polyphosphate were mixed uniformly in a mass ratio of 1:0.1:50:0.2:0.3, and the conductive polymer modified aramid fabric was immersed in the above mixed solution. After shaking at room temperature for 2.5 hours, it was cured in an environment of 100°C for 2 hours to obtain a flame retardant conductive aramid fabric.

[0044] The conductivity of the fabric was measured by a four-probe conductivity meter, and the flame retardant performance of the fabric was measured by a vertical combustion method. The performance test results are shown in Table 1. After testing, the conductivity of the fabric was 9.02S / m; after the flame burned for 200s, there was no afterburning or smoldering, and the damage length was 1.53mm.

[0045] A fire alarm circuit is provided. The flame-retardant conductive aramid fabric prepared in Example 1, an alarm light, a power supply, and a resistor are connected via wires to form a high-temperature alarm circuit. The flame-retardant conductive aramid fabric is connected to the high-temperature alarm circuit. When the flame of an alcohol lamp contacts the fabric for 3.0 seconds, the alarm light starts to alarm.

[0046] Example 2

[0047] 1) immersing a 30 cm × 8 cm aramid fabric in anhydrous ethanol, keeping it at 70° C. for 15 min to remove oil, and then washing and drying to obtain a pretreated aramid fabric;

[0048] 2) immersing the pretreated aramid fabric in a mixed solution consisting of a 0.1 mol / L pyrrole aqueous solution, 0.5 mol / L hydrochloric acid, and 0.1 mol / L phosphoric acid, wherein the molar ratio of pyrrole to hydrochloric acid in the mixed solution is 1:5, and the molar ratio of hydrochloric acid to phosphoric acid is 1:0.2; potassium dichromate is used as an oxidant, and an oxidant solution with a concentration of 1 mol / L is prepared according to a molar ratio of the oxidant to the conductive polymer monomer of 1:0.2; the oxidant solution is added dropwise at a rate of 0.3 mL / min, and reacted in an environment of 0° C. for 5 hours to obtain a conductive polymer modified aramid fabric;

[0049] 3) The PDMS main agent, PDMS curing agent, n-hexane, and 1H,1H,2H,2H-perfluorodecyltriethoxysilane were mixed uniformly in a mass ratio of 1:0.05:200:0.1, and the conductive polymer modified aramid fabric was immersed in the above mixed solution. After shaking at room temperature for 0.5 h, it was cured in an environment of 50° C. for 0.5 h to obtain a flame retardant conductive aramid fabric.

[0050] The conductivity of the fabric was measured by a four-probe conductivity meter, and the flame retardant performance of the fabric was measured by a vertical combustion method. The performance test results are shown in Table 1. After testing, the conductivity of the fabric was 2.75S / m; after the flame burned for 200s, there was no afterburning, the smoldering time was 4.5s, and the damaged length was 26.27mm.

[0051] A fire alarm circuit is provided. The flame-retardant conductive aramid fabric prepared in Example 2, an alarm light, a power supply, and a resistor are connected via wires to form a high-temperature alarm circuit. The flame-retardant conductive aramid fabric is connected to the high-temperature alarm circuit. When the flame of the alcohol lamp contacts the fabric for 11.4 seconds, the alarm light starts to alarm.

[0052] Example 3

[0053] 1) immersing a 30 cm × 8 cm aramid fabric in acetone, keeping it at 50° C. for 120 min to remove oil, and then washing and drying to obtain a pretreated aramid fabric;

[0054] 2) immersing the pretreated aramid fabric in a mixed solution consisting of a 5 mol / L aniline aqueous solution, a 5 mol / L sulfuric acid, and a 1 mol / L phytic acid solution, wherein the molar ratio of aniline to sulfuric acid in the mixed solution is 1:1, and the molar ratio of sulfuric acid to phytic acid is 1:0.2; using ammonium persulfate as an oxidant, and preparing an oxidant solution with a concentration of 5 mol / L according to a molar ratio of the oxidant to the conductive polymer monomer of 1:5; adding the oxidant solution dropwise at a rate of 30 mL / min, and reacting for 12 h in an environment of 20° C. to obtain a conductive polymer modified aramid fabric;

[0055] 3) The PDMS main agent, PDMS curing agent, silicone oil and ammonium polyphosphate were mixed in a mass ratio of 1:0.2:20:1, and the conductive polymer modified aramid fabric was immersed in the above mixed solution. After shaking at room temperature for 5 hours, it was cured in an environment of 120° C. for 3 hours to obtain a flame retardant conductive aramid fabric.

[0056] The conductivity of the fabric was measured by a four-probe conductivity meter, and the flame retardant performance of the fabric was measured by a vertical combustion method. The performance test results are shown in Table 1. After testing, the conductivity of the fabric was 7.68S / m; after the flame burned for 200s, there was no afterburning or smoldering, and the damage length was 1.14mm.

[0057] A fire alarm circuit is provided. The flame-retardant conductive aramid fabric prepared in Example 3, an alarm light, a power supply, and a resistor are connected via wires to form a high-temperature alarm circuit. The flame-retardant conductive aramid fabric is connected to the high-temperature alarm circuit. When the flame of the alcohol lamp contacts the fabric for 5.7 seconds, the alarm light starts to alarm.

[0058] Example 4

[0059] 1) immersing a 30 cm × 8 cm aramid fabric in ethanol, keeping it at 70° C. for 60 min to remove oil, and then washing and drying to obtain a pretreated aramid fabric;

[0060] 2) immersing the pretreated aramid fabric in a mixed solution consisting of 1 mol / L thiophene aqueous solution, 5 mol / L hydrochloric acid, and 0.1 mol / L phosphoric acid (the molar ratio of the conductive polymer monomer to the dopant A is 1:5, and the molar ratio of the dopant A to the dopant B is 1:0.2), using ammonium persulfate as an oxidant, and preparing an oxidant solution with a concentration of 2 mol / L according to a molar ratio of the oxidant to the conductive polymer monomer of 1:2, adding the oxidant solution dropwise at a rate of 15 mL / min, and reacting in an environment of 10° C. for 15 hours to obtain a conductive polymer modified aramid fabric;

[0061] 3) The PDMS main agent, PDMS curing agent, ethyl acetate, and 1H,1H,2H,2H-perfluorodecyltriethoxysilane are mixed uniformly in a mass ratio of 1:0.1:100:0.2, and the conductive polymer modified aramid fabric is immersed in the above mixed solution. After shaking at room temperature for 2 hours, it is cured in an environment of 80° C. for 1 hour to obtain a flame retardant conductive aramid fabric.

[0062] The conductivity of the fabric was measured by a four-probe conductivity meter, and the flame retardant performance of the fabric was measured by a vertical combustion method. The performance test results are shown in Table 1. After testing, the conductivity of the fabric was 5.14S / m; after the flame burned for 200s, there was no afterburning, the smoldering time was 2.8s, and the damaged length was 21.54mm.

[0063] A fire alarm circuit is provided. The flame-retardant conductive aramid fabric prepared in Example 4, an alarm light, a power source, and a resistor are connected via wires to form a high-temperature alarm circuit. The flame-retardant conductive aramid fabric is connected to the high-temperature alarm circuit. When the flame of an alcohol lamp contacts the fabric for 7.1 seconds, the alarm light starts to alarm.

[0064] Comparative Example 1

[0065] The preparation method is consistent with that of Example 1, except that phytic acid is not added in step (2). Polyaniline aramid flame retardant conductive fabric is prepared. The performance test results are shown in Table 1.

[0066] Comparative Example 2

[0067] The preparation method is consistent with that of Example 1, except that hydrochloric acid is not added in step (2). Polyaniline aramid flame retardant conductive fabric is prepared. The performance test results are shown in Table 1.

[0068] Comparative Example 3

[0069] The preparation method is consistent with that of Example 1, except that step (3) is omitted. The performance test results of the obtained polyaniline aramid flame retardant conductive fabric are shown in Table 1.

[0070] Comparative Example 4

[0071] The difference from Example 1 is that the pretreated aramid fabric is first immersed in a 1 mol / L aniline solution for 30 min, and then immersed in a hydrochloric acid solution containing 1.25 mol / L ammonium persulfate (hydrochloric acid concentration is 0.3 M) for 30 min, and then step (3) is performed. The performance test results of the obtained polyaniline aramid flame retardant conductive fabric are shown in Table 1.

[0072] Table 1 Properties of flame retardant conductive fabrics of embodiments and comparative examples

[0073] <![CDATA[Conductivity / S·m -1 > Afterburning time / s Smoldering time / s Damaged length / mm Example 1 9.02 0 0 1.31 Example 2 2.75 0 4.5 19.58 Example 3 7.68 0 0 1.14 Example 4 5.14 0 2.8 5.96 Comparative Example 1 6.81 1.4 5.4 30.51 Comparative Example 2 1.08 0 0 2.29 Comparative Example 3 9.11 0 0 2.09 Comparative Example 4 1.51 1.8 6.1 35.79

[0074] In the present invention, phytic acid or phosphoric acid is added during the preparation process of the conductive polymer. The conductivity of polyaniline is related to the acidity of the reaction solution. The enhanced acidity helps to improve the conductivity of polyaniline. Phytic acid and phosphoric acid contain a large amount of phosphorus, which can form a NP synergistic effect with polyaniline, effectively improving the flame retardant properties of the material. The flame retardant properties increase with the increase in the amount of phytic acid (or phosphoric acid) added. Compared with the method of first immersing in an aniline solution and then immersing in a hydrochloric acid solution of ammonium persulfate, and then immersing in two solutions in turn, the aramid fabric of the present invention is immersed in a conductive polymer monomer aqueous solution, a dopant A, a dopant B, and an oxidant aqueous solution, and reacts in a solution system. The fabric and the reactant have a long contact time during the preparation of the conductive fabric, which is conducive to the in-situ polymerization of a large amount of conductive polymers on the fabric surface, and the addition of phytic acid (or phosphoric acid) in this process can give the fabric a certain flame retardant property, and then the encapsulation of the flame retardant coating can give the fabric good flame retardant properties.

[0075] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing a flame retardant conductive aramid fabric, characterized in that: The steps include: (1) immersing the aramid fabric substrate in a solvent to remove oil, washing, and drying to obtain a pretreated aramid fabric; (2) adding dopant A, dopant B and the aramid fabric pretreated in step (1) to the aqueous solution of the conductive polymer monomer, then dripping the aqueous solution of the oxidant, washing and drying after the reaction to obtain the conductive polymer modified aramid fabric; (3) Mixing polydimethylsiloxane, polydimethylsiloxane curing agent, diluent and flame retardant to obtain a mixed solution, immersing the conductive polymer modified aramid fabric prepared in step (2) in the mixed solution, stirring and curing to obtain a flame retardant conductive aramid fabric.

2. The method for preparing a flame retardant conductive aramid fabric according to claim 1, characterized in that: In step (1), the solvent is one of ethanol, acetone, and 0.5-3 mol / L sodium hydroxide solution; the immersion temperature is 50-95° C., and the immersion time is 15-120 min.

3. The method for preparing a flame-retardant conductive aramid fabric according to claim 1, characterized in that: In step (2), the conductive polymer monomer is one or more of aniline, pyrrole, and thiophene; the dopant A is one or both of hydrochloric acid and sulfuric acid, with a concentration of 0.5-5 mol / L; and the dopant B is one or both of phytic acid and phosphoric acid, with a concentration of 0.1-1 mol / L.

4. The method for preparing a flame-retardant conductive aramid fabric according to claim 1, characterized in that: In step (2), the concentration of the conductive polymer monomer aqueous solution is 0.1-5 mol / L, the molar ratio of the conductive polymer monomer to the dopant A is 1:1-5, and the molar ratio of the dopant A to the dopant B is 1:0.1-0.

4.

5. The method for preparing a flame retardant conductive aramid fabric according to claim 1, characterized in that: In step (2), the oxidant is one of ammonium persulfate and potassium dichromate; the molar ratio of the oxidant to the conductive polymer monomer is 1:0.2-5, and the concentration of the oxidant aqueous solution is 1-5 mol / L.

6. The method for preparing a flame-retardant conductive aramid fabric according to claim 1, characterized in that: In step (3), the diluent is one of ethyl acetate, n-hexane, xylene, and silicone oil; the flame retardant is one or more of ammonium polyphosphate, 1H,1H,2H,2H-perfluorodecyltriethoxysilane, and trimethoxy (1H,1H,2H,2H-hexafluorodecyl) silane.

7. The method for preparing a flame-retardant conductive aramid fabric according to claim 1, characterized in that: In step (3), the mass ratio of polydimethylsiloxane to polydimethylsiloxane curing agent is 5-20:1; the mass ratio of polydimethylsiloxane to diluent is 1:20-200; and the mass ratio of polydimethylsiloxane to flame retardant is 1-10:

1.

8. The method for preparing a flame-retardant conductive aramid fabric according to claim 1, characterized in that: In step (3), the curing temperature is 50-120° C. and the curing time is 0.5-3 h.

9. The flame-retardant conductive aramid fabric prepared by the method according to any one of claims 1 to 8.

10. A fire alarm circuit, comprising the flame-retardant conductive aramid fabric according to claim 9, an alarm lamp, a power source, and a resistor connected via wires to form a high-temperature alarm circuit.