Preparation method of nickel coating PBO fiber with high conductivity and high electromagnetic shielding performance

Abstract

The invention discloses a preparation method of a nickel coating PBO fiber with high conductivity and high electromagnetic shielding performance. The preparation method is specifically implemented according to the following steps: step 1, sequentially carrying out modification treatment, sensitization treatment and activation treatment on the PBO fiber; step 2, soaking the PBO fibers subjected to activating treatment in a sodium citrate solution; 3, plating the PBO fiber treated in the step 2 in a chemical nickel plating solution in a water bath environment, washing with deionized water after plating, and drying to obtain a chemical nickel-plated PBO fiber; and 4, electroplating by using a nickel rod as an anode and the chemical nickel-plated PBO fiber obtained in the step 3 as a cathode, washing by using deionized water after electroplating is finished, and drying to obtain the nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance. The method is simple in process and low in time consumption, and the prepared nickel coating PBO fiber has good conductivity and electromagnetic shielding performance.

Description

Technical Field

[0001] The invention belongs to the technical field of PBO fiber preparation methods, and relates to a method for preparing nickel-coated PBO fibers with high electrical conductivity and high electromagnetic shielding performance. Background Art

[0002] PBO fiber not only has high strength and high modulus, but also has excellent chemical stability and heat resistance and flame retardancy. However, the surface activity of PBO fiber is very poor, resulting in poor interface bonding with other materials. In addition, traditional PBO fiber is relatively single in function and is mainly used in aerospace, military protection and sports equipment, mainly using its excellent mechanical properties. Adding conductivity and electromagnetic shielding properties to PBO fiber will greatly broaden its application areas.

[0003] At present, most of the technologies for PBO fiber modification are aimed at improving the problem of reduced strength after ultraviolet irradiation. There are relatively few studies on introducing conductivity and electromagnetic shielding properties into PBO fibers, and most of these studies involve expensive technical equipment, complex processes, and long time. Therefore, the present invention aims to provide a nickel-coated PBO fiber preparation technology with simple process and low equipment cost to address the above problems. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing nickel-coated PBO fibers with high conductivity and high electromagnetic shielding performance. The process is simple and time-saving, and the prepared nickel-coated PBO fibers have good conductivity and electromagnetic shielding performance.

[0005] The technical solution adopted by the present invention is a method for preparing nickel-coated PBO fibers with high conductivity and high electromagnetic shielding performance, which is specifically implemented according to the following steps: Step 1, sequentially performing modification treatment, sensitization treatment, and activation treatment on the PBO fiber; Step 2, soaking the activated PBO fiber in a sodium citrate solution; Step 3, placing the PBO fiber treated in step 2 in a chemical nickel plating solution in a water bath environment for plating, washing with deionized water after plating, and then drying to obtain the chemical nickel-plated PBO fiber; Step 4, using the nickel rod as an anode and the chemically nickel-plated PBO fiber obtained in step 3 as a cathode for electroplating, after the electroplating is completed, washing with deionized water and then drying to obtain a nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance.

[0006] The present invention is also characterized in that: The modification treatment in step 1 is specifically as follows: The PBO fiber is immersed in acetone, and then the PBO fiber immersed in acetone is placed in a mixed solution of HNO3 and H2SO4 and subjected to ultrasonic vibration to obtain a modified PBO fiber; The sensitization treatment in step 1 is specifically as follows: immersing the modified PBO fiber in a sensitizing solution in a water bath environment; The activation treatment in step 1 is specifically as follows: the sensitized PBO fiber is immersed in an activation solution in a water bath environment.

[0007] In the modification treatment of step 1, the PBO fiber is immersed in acetone for 15 to 60 minutes; the concentration of HNO3 in the mixed solution of HNO3 and H2SO4 is 100 to 200 mL / L, the concentration of H2SO4 is 100 to 200 mL / L, and the ultrasonic oscillation time is 15 to 60 minutes.

[0008] The water bath temperature of the sensitization treatment in step 1 is 20-60°C, and the immersion time in the sensitizing solution is 10-40 min. The sensitizing solution is prepared as follows: first, hydrochloric acid is diluted in deionized water to obtain a HCl solution with a concentration of 30-50 mL / L, and then SnCl2·H2O is added to the HCl solution to dissolve it to obtain a sensitizing solution, wherein the concentration of SnCl2·H2O is 5-15 g / L.

[0009] The method for preparing the activation solution in the activation treatment in step 1 is as follows: add 10% NH4OH solution to 1~5g / L AgNO3 solution until the solution is transparent to obtain the activation solution; the water bath temperature for the activation treatment is 20~60°C, and the soaking time of the PBO fiber is 10~40min.

[0010] In step 2, the concentration of the sodium citrate solution is 5-10 g / L, and the soaking time is 5-30 min.

[0011] In step 3, the water bath temperature is 70-90° C., and the plating time is 5-60 min.

[0012] The preparation method of chemical nickel plating solution in step 3 is: Dissolve NiSO4·6H2O, NaH2PO2·H2O and lactic acid in deionized water to obtain a solution, wherein the concentrations of NiSO4·6H2O, NaH2PO2·H2O and lactic acid in the solution are 20-40 g / L, 20-40 g / L and 20-35 mL / L respectively; Then, the pH of the dissolving solution is adjusted to 9-10 using 25% ammonia water to obtain a chemical nickel plating solution.

[0013] When electroplating is performed in step 4, the electroplating solution is: NiCl2, C6H 11NaO7 and (NH4)2SO4 are dissolved in deionized water to obtain an electroplating solution, wherein NiCl2 and C6H 11 The concentrations of NaO7 and (NH4)2SO4 are 80~150g / L, 10~50g / L, and 10~50g / L respectively; Alternatively, NiSO4·6H2O, NaH2PO2·H2O, and lactic acid are dissolved in deionized water to obtain an electroplating solution, wherein the concentrations of NiSO4·6H2O, NaH2PO2·H2O, and lactic acid in the electroplating solution are 20~40 g / L, 20~40 g / L, and 20~35 mL / L, respectively.

[0014] The electroplating process conditions are: the distance between the cathode and the anode is 2~6cm, and the current density is 600~1500mA / dm 2 , the electroplating time is 5~30min, the electroplating temperature is 50~80℃, and the pH value is 3~6. The beneficial effects of the present invention are: The process of the invention is simple and time-saving. A dense and continuous layer of nickel is completely coated on the surface of the PBO fiber, thereby improving the surface activity of the PBO fiber, making it easy to composite with other materials and increasing the interface bonding and stability of the composite material; the conductivity function is added to the PBO fiber, the PBO fiber has an electromagnetic shielding function, and the mechanical properties of the PBO fiber are still well maintained after the modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a scanning electron microscope image of the original PBO fiber used in Example 2 of the present invention; Figure 2 is a scanning electron microscope image of the chemical nickel-plated PBO fiber obtained in Example 2 of the present invention; Figure 3 is a scanning electron microscope image of the nickel-coated PBO fiber with high strength, high conductivity and high electromagnetic shielding performance obtained in Example 2 of the present invention; Figure 4 is a scanning electron microscope image of the nickel-coated PBO fiber with high strength, high conductivity and high electromagnetic shielding performance obtained in Example 3 of the present invention; Figure 5 It is a tensile performance graph of the PBO fiber in Example 2 of the present invention, the PBO fiber treated with a mixed solution of 100-200 mL / L HNO3 and 100-200 mL / L H2SO4, and the obtained nickel-coated PBO fiber with high strength, high conductivity, and high electromagnetic shielding performance; Figure 6 is a resistance data diagram of the nickel-coated PBO fiber with high strength, high conductivity and high electromagnetic shielding performance obtained in Example 2 of the present invention; Figure 7 This is a graph of the electromagnetic shielding effectiveness of the nickel-coated PBO fiber with high strength, high conductivity and high electromagnetic shielding performance obtained in Example 2 of the present invention. DETAILED DESCRIPTION

[0016] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0017] Example 1 The preparation method of nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance is specifically implemented according to the following steps: Step 1, sequentially performing modification treatment, sensitization treatment, and activation treatment on the PBO fiber; wherein the modification treatment is specifically as follows: The PBO fiber is soaked in acetone for 15-60 minutes, and then the PBO fiber soaked in acetone is placed in a mixed solution of HNO3 and H2SO4 and ultrasonically shaken at the same time, wherein the concentration of HNO3 in the mixed solution of HNO3 and H2SO4 is 100-200 mL / L, the concentration of H2SO4 is 100-200 mL / L, and the ultrasonic shaking time is 15-60 minutes, thereby obtaining the modified PBO fiber; The sensitization treatment is specifically as follows: the modified PBO fiber is immersed in a sensitizing solution for 10 to 40 minutes in a water bath environment at a water bath temperature of 20 to 60°C. The sensitizing solution is prepared as follows: hydrochloric acid is first diluted in deionized water to obtain a HCl solution with a concentration of 30 to 50 mL / L, and then SnCl2·H2O is added to the HCl solution to dissolve it to obtain a sensitizing solution, wherein the concentration of SnCl2·H2O is 5 to 15 g / L.

[0018] The activation treatment is specifically as follows: the sensitized PBO fiber is placed in an activation solution and immersed in a water bath at a temperature of 20-60°C for 10-40 minutes; the activation solution is prepared by adding a 10% NH4OH solution to a 1-5g / L AgNO3 solution until the solution becomes transparent to obtain the activation solution; Step 2, soaking the activated PBO fiber in a sodium citrate solution with a concentration of 5-10 g / L for 5-30 min; Step 3, placing the PBO fiber treated in step 2 in a chemical nickel plating solution in a water bath environment with a water bath temperature of 70-90° C. for plating for 5-60 min, washing with deionized water after plating and drying to obtain chemical nickel-plated PBO fiber; wherein the preparation method of the chemical nickel plating solution is: Dissolve NiSO4·6H2O, NaH2PO2·H2O and lactic acid in deionized water to obtain a solution, wherein the concentrations of NiSO4·6H2O, NaH2PO2·H2O and lactic acid in the solution are 20-40 g / L, 20-40 g / L and 20-35 mL / L respectively; Then, the pH of the dissolving solution is adjusted to 9-10 using 25% ammonia water to obtain a chemical nickel plating solution; Step 4, using a nickel rod as an anode and the chemically nickel-plated PBO fiber obtained in step 3 as a cathode for electroplating, and after the electroplating is completed, washing with deionized water and then drying to obtain a nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance; Among them, when electroplating, the electroplating solution is: NiCl2, C6H 11 NaO7 and (NH4)2SO4 are dissolved in deionized water to obtain an electroplating solution, wherein NiCl2 and C6H 11 The concentrations of NaO7 and (NH4)2SO4 are 80~150g / L, 10~50g / L, and 10~50g / L respectively; Alternatively, NiSO4·6H2O, NaH2PO2·H2O and lactic acid are dissolved in deionized water to obtain an electroplating solution, wherein the concentrations of NiSO4·6H2O, NaH2PO2·H2O and lactic acid in the electroplating solution are 20-40 g / L, 20-40 g / L and 20-35 mL / L respectively; The electroplating process conditions are: the distance between the cathode and the anode is 2~6cm, and the current density is 600~1500mA / dm 2 , the electroplating time is 5~30min, the electroplating temperature is 50~80℃, and the pH value is 3~6.

[0019] The scanning electron microscope image of the original PBO fiber used in Examples 2-3 of the present invention is as follows: Figure 1 shown.

[0020] Example 2 The preparation method of nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance is specifically implemented according to the following steps: Step 1, soaking the PBO fiber in acetone for 30 minutes; Step 2, placing the PBO fiber treated in step 1 in solution A for ultrasonic vibration for 60 minutes to obtain modified PBO fiber, wherein solution A is a mixed solution of HNO3 with a concentration of 100 mL / L and H2SO4 with a concentration of 100 mL / L; Step 3, placing the modified PBO fiber obtained in step 2 in a sensitizing solution and soaking it for 30 minutes in a water bath environment at a water bath temperature of 40°C; wherein the sensitizing solution is prepared as follows: first, hydrochloric acid is diluted in deionized water to obtain a 40mL / L HCl solution, and then SnCl2·H2O is added to the HCl solution to dissolve it, and the concentration of SnCl2·H2O is 10g / L to obtain a sensitizing solution; Step 4, preparing an activation solution, and then soaking the PBO fiber soaked in step 3 in the activation solution for 30 minutes in a water bath environment at a water bath temperature of 40°C; wherein the activation solution is prepared by adding a 10% NH4OH solution to a 5g / L AgNO3 solution until the solution becomes transparent to obtain the activation solution; Step 5, placing the PBO fiber soaked in step 4 in a sodium citrate solution with a concentration of 8 g / L for 15 minutes; Step 6, placing the PBO fiber treated in step 5 in a chemical nickel plating solution in a water bath environment with a water bath temperature of 70°C for 30 minutes, the chemical nickel plating solution comprises 30 g / L NiSO4·6H2O, 30 g / L NaH2PO2·H2O, and 30 mL / L lactic acid, and the solvent is deionized water. After the chemical nickel plating solution is prepared, a 25% concentration of ammonia solution is used to adjust the pH value of the chemical nickel plating solution to 4.5 to obtain the final chemical nickel plating solution. After the plating is completed, the fiber is washed with deionized water and dried to obtain the nickel-plated PBO fiber, and its scanning electron microscope image is as shown in FIG. Figure 2 As shown; Step 7: Use the PBO fiber treated in step 6 as the cathode of the electroplating equipment and the nickel rod as the anode for electroplating for 30 minutes. The distance between the cathode and the anode is 2.5 cm and the current density is 1000 mA / dm 2 , the plating temperature is 80℃, and the pH value is 4. The plating solution composition is NiCl2120g / L, C6H 11 NaO730g / L, (NH4)2SO430g / L. After electroplating, the nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance can be obtained by washing and drying. The scanning electron microscope image is as follows Figure 3 shown.

[0021] The tensile properties of the original PBO fiber, the PBO fiber treated with a mixed solution of 100-200 mL / L HNO3 and 100-200 mL / L H2SO4, and the obtained nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance were tested. The test results are shown in FIG. Figure 5As shown in the figure, the tensile strength of the original PBO fiber is 5.18GPa, and the tensile strength is reduced to 4.29GPa after acid treatment, but this step is indispensable because acid treatment can introduce active groups to the fiber surface and etch grooves on the fiber surface, providing chemical bonding and physical meshing for the coating and the fiber matrix at the same time, which is beneficial to improve the bonding strength of the coating. After the surface is plated with Ni, the tensile strength of the fiber is increased to 5.15GPa, returning to the original level, and still showing high-strength characteristics.

[0022] The nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance prepared in this embodiment was tested for resistance data. The test results are as follows: Figure 6 As shown in the figure, it can be seen that the resistance of a bundle of PBO fibers is reduced from non-conductive to 0.6Ω after chemical plating and electroplating, and the resistance change is also small after water washing and hot and cold shock, and the conductivity is better.

[0023] The nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance prepared in this embodiment was tested for electromagnetic shielding effectiveness. The results are as follows: Figure 7 As shown in the figure, it can be seen that the electromagnetic shielding capability of the nickel-plated fiber in the X-band can reach more than 64dB, and can shield more than 99.9999% of electromagnetic waves.

[0024] Example 3 The preparation method of nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance is specifically implemented according to the following steps: Step 1, soaking the PBO fiber in acetone for 40 minutes; Step 2, placing the PBO fiber treated in step 1 in solution A for ultrasonic vibration for 30 minutes to obtain modified PBO fiber, wherein solution A is a mixed solution of HNO3 with a concentration of 150 mL / L and H2SO4 with a concentration of 150 mL / L; Step 3, placing the modified PBO fiber obtained in step 2 in a sensitizing solution and soaking it for 40 minutes in a water bath environment at a water bath temperature of 50° C., wherein the sensitizing solution is prepared as follows: first, hydrochloric acid is diluted in deionized water to obtain a 30 mL / L HCl solution, and then SnCl2·H2O is added to the HCl solution to dissolve it, and the concentration of SnCl2·H2O is 12 g / L, to obtain a sensitizing solution; Step 4, preparing an activation solution, and then soaking the PBO fiber soaked in step 3 in the activation solution for 40 minutes in a water bath environment at a water bath temperature of 50° C., wherein the activation solution is prepared by adding a 10% NH4OH solution to a 3 g / L AgNO3 solution until the solution becomes transparent, thereby obtaining the activation solution; Step 5, placing the PBO fiber soaked in step 4 in a sodium citrate solution with a concentration of 10 g / L for 10 minutes; Step 6, placing the PBO fiber treated in step 5 in a chemical nickel plating solution in a water bath environment with a water bath temperature of 70° C. for plating for 20 minutes, wherein the components of the chemical nickel plating solution are NiSO4·6H2O 35 g / L, NaH2PO2·H2O 35 g / L, and lactic acid 30 mL / L, and the solvent is deionized water. After the chemical nickel plating solution is prepared, a 25% concentration of ammonia solution is used to adjust the pH of the chemical nickel plating solution to 9 to obtain the final chemical nickel plating solution. After the plating is completed, the fiber is washed with deionized water, and the nickel-plated PBO fiber is obtained after drying.

[0025] Step 7: Use the PBO fiber treated in step 6 as the cathode of the electroplating equipment and the nickel rod as the anode for electroplating for 30 minutes. The distance between the cathode and the anode is 2.5 cm and the current density is 600 mA / dm 2 The electroplating temperature is 80℃ and the pH value is 4.5. The electroplating solution composition is NiSO4·6H2O 30g / L, NaH2PO2·H2O 30g / L, and lactic acid 30mL / L. After the electroplating is completed, the nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance can be obtained by washing and drying. The scanning electron microscope image is as follows Figure 4 shown.

[0026] The nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance prepared in this embodiment was subjected to resistance test, electromagnetic shielding test and tensile strength test, and the test results showed that the resistance was 0.8Ω, the electromagnetic shielding effectiveness was 60dB, and the tensile strength was 5.07GPa.

[0027] Example 4 The preparation method of nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance is specifically implemented according to the following steps: Step 1, soaking the PBO fiber in acetone for 20 minutes; Step 2, placing the PBO fiber treated in step 1 in solution A for ultrasonic vibration for 15 minutes to obtain modified PBO fiber, wherein solution A is a mixed solution of HNO3 with a concentration of 200 mL / L and H2SO4 with a concentration of 200 mL / L; Step 3, placing the modified PBO fiber obtained in step 2 in a sensitizing solution and soaking it for 15 minutes in a water bath environment with a water bath temperature of 60°C; wherein the sensitizing solution is prepared as follows: firstly dilute hydrochloric acid in deionized water to obtain a 30mL / L HCl solution, then add SnCl2·H2O to the HCl solution to dissolve it, the concentration of SnCl2·H2O is 10g / L, and a sensitizing solution is obtained; Step 4, preparing an activation solution, and then soaking the PBO fiber soaked in step 3 in the activation solution for 15 minutes in a water bath environment at a water bath temperature of 60°C; wherein the activation solution is prepared by adding a 10% NH4OH solution to a 3g / L AgNO3 solution until the solution becomes transparent to obtain the activation solution; Step 5, placing the PBO fiber soaked in step 4 in a sodium citrate solution with a concentration of 5 g / L for 30 minutes; Step 6, placing the PBO fiber treated in step 5 in a chemical nickel plating solution in a water bath environment with a water bath temperature of 80° C. for plating for 15 minutes, wherein the chemical nickel plating solution comprises 35 g / L NiSO4·6H2O, 35 g / L NaH2PO2·H2O, and 35 mL / L lactic acid, and the solvent is deionized water. After the chemical nickel plating solution is prepared, a 25% concentration of ammonia solution is used to adjust the pH value of the chemical nickel plating solution to 9.5 to obtain a final chemical nickel plating solution, and after the plating is completed, the fiber is washed with deionized water, and the nickel-plated PBO fiber is obtained after drying; Step 7: Use the PBO fiber treated in step 6 as the cathode of the electroplating equipment and the nickel rod as the anode for electroplating for 30 minutes. The distance between the cathode and the anode is 4 cm and the current density is 1200 mA / dm 2 , the plating temperature is 70℃, and the pH value is 4. The plating solution composition is NiCl2100g / L, C6H 11 NaO740g / L, (NH4)2SO440g / L. After electroplating, the nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance can be obtained by washing and drying.

[0028] The nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance prepared in this embodiment was subjected to resistance test, electromagnetic shielding test and tensile strength test, and the test results showed that the resistance was 0.6Ω, the electromagnetic shielding effectiveness was 62dB, and the tensile strength was 5.09GPa.

[0029] Example 5 The preparation method of nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance is specifically implemented according to the following steps: Step 1, soaking the PBO fiber in acetone for 10 minutes; Step 2, placing the PBO fiber treated in step 1 in solution A for ultrasonic vibration for 50 minutes to obtain modified PBO fiber, wherein solution A is a mixed solution of HNO3 with a concentration of 120 mL / L and H2SO4 with a concentration of 120 mL / L; Step 3, placing the modified PBO fiber obtained in step 2 in a sensitizing solution and soaking it for 40 minutes in a water bath environment at a water bath temperature of 60°C; wherein the sensitizing solution is prepared as follows: first, hydrochloric acid is diluted in deionized water to obtain a 30mL / L HCl solution, and then SnCl2·H2O is added to the HCl solution to dissolve it, and the concentration of SnCl2·H2O is 5g / L to obtain a sensitizing solution; Step 4, preparing an activation solution, and then soaking the PBO fiber soaked in step 3 in the activation solution for 40 minutes in a water bath environment at a water bath temperature of 50°C; wherein the activation solution is prepared by adding a 10% NH4OH solution to a 2g / L AgNO3 solution until the solution becomes transparent to obtain the activation solution; Step 5, placing the PBO fiber soaked in step 4 in a sodium citrate solution with a concentration of 10 g / L for 5 minutes; Step 6, placing the PBO fiber treated in step 5 in a chemical nickel plating solution in a water bath environment with a water bath temperature of 90° C. for plating for 10 minutes, wherein the chemical nickel plating solution comprises 40 g / L NiSO4·6H2O, 40 g / L NaH2PO2·H2O, and 35 mL / L lactic acid, and the solvent is deionized water. After the chemical nickel plating solution is prepared, a 25% concentration of ammonia solution is used to adjust the pH value of the chemical nickel plating solution to 10 to obtain a final chemical nickel plating solution, and after the plating is completed, the fiber is washed with deionized water, and the nickel-plated PBO fiber is obtained after drying; Step 7: Use the PBO fiber treated in step 6 as the cathode of the electroplating equipment and the nickel rod as the anode for electroplating for 20 minutes. The distance between the cathode and the anode is 3 cm and the current density is 1300 mA / dm 2 , the plating temperature is 80℃, and the pH value is 4. The plating solution composition is NiCl2150g / L, C6H 11 NaO750g / L, (NH4)2SO450g / L. After electroplating, the nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance can be obtained by washing and drying.

[0030] The nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance prepared in this embodiment was subjected to resistance test, electromagnetic shielding test and tensile strength test, and the test results showed that the resistance was 0.7Ω, the electromagnetic shielding effectiveness was 62dB, and the tensile strength was 5.18GPa.

[0031] Example 6 The preparation method of nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance is specifically implemented according to the following steps: Step 1, soaking the PBO fiber in acetone for 60 minutes; Step 2, placing the PBO fiber treated in step 1 in solution A for ultrasonic vibration for 15 minutes to obtain modified PBO fiber, wherein solution A is a mixed solution of HNO3 with a concentration of 200 mL / L and H2SO4 with a concentration of 200 mL / L; Step 3, placing the modified PBO fiber obtained in step 2 in a sensitizing solution and soaking it for 10 minutes in a water bath environment at a water bath temperature of 30°C; wherein the sensitizing solution is prepared as follows: firstly dilute hydrochloric acid in deionized water to obtain a 50mL / L HCl solution, then add SnCl2·H2O to the HCl solution to dissolve it, the concentration of SnCl2·H2O is 15g / L, and a sensitizing solution is obtained; Step 4, preparing an activation solution, and then soaking the PBO fiber soaked in step 3 in the activation solution for 10 minutes in a water bath environment at a water bath temperature of 50°C; wherein the activation solution is prepared by adding a 10% NH4OH solution to a 5g / L AgNO3 solution until the solution becomes transparent to obtain the activation solution; Step 5, placing the PBO fiber soaked in step 4 in a sodium citrate solution with a concentration of 8 g / L for 15 minutes; Step 6, placing the PBO fiber treated in step 5 in a chemical nickel plating solution in a water bath environment with a water bath temperature of 90° C. for plating for 5 minutes, wherein the chemical nickel plating solution comprises 40 g / L NiSO4·6H2O, 40 g / L NaH2PO2·H2O, and 35 mL / L lactic acid, and the solvent is deionized water. After the chemical nickel plating solution is prepared, a 25% concentration of ammonia solution is used to adjust the pH value of the chemical nickel plating solution to 10 to obtain a final chemical nickel plating solution, and after the plating is completed, the fiber is washed with deionized water, and the nickel-plated PBO fiber is obtained after drying; Step 7: Use the PBO fiber treated in step 6 as the cathode of the electroplating equipment and the nickel rod as the anode. Electroplating is performed for 5 minutes. The distance between the cathode and the anode is 3 cm and the current density is 1500 mA / dm 2 The electroplating temperature is 80℃ and the pH value is 4. The electroplating solution composition is NiSO4·6H2O40g / L, NaH2PO2·H2O40g / L, and lactic acid 35mL / L. After the electroplating is completed, the nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance can be obtained by washing and drying.

[0032] The nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance prepared in this embodiment was subjected to resistance test, electromagnetic shielding test and tensile strength test, and the test results showed that the resistance was 0.6Ω, the electromagnetic shielding effectiveness was 60dB, and the tensile strength was 5.02GPa.

[0033] Example 7 The preparation method of nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance is specifically implemented according to the following steps: Step 1, soaking the PBO fiber in acetone for 45 minutes; Step 2, placing the PBO fiber treated in step 1 in solution A for ultrasonic vibration for 20 minutes to obtain modified PBO fiber, wherein solution A is a mixed solution of HNO3 with a concentration of 170 mL / L and H2SO4 with a concentration of 170 mL / L; Step 3, placing the modified PBO fiber obtained in step 2 in a sensitizing solution and soaking it for 20 minutes in a water bath environment at a water bath temperature of 45°C; wherein the sensitizing solution is prepared as follows: firstly dilute hydrochloric acid in deionized water to obtain a 35mL / L HCl solution, then add SnCl2·H2O to the HCl solution to dissolve it, the concentration of SnCl2·H2O is 10g / L, and a sensitizing solution is obtained; Step 4, preparing an activation solution, and then soaking the PBO fiber soaked in step 3 in the activation solution for 20 minutes in a water bath environment at a water bath temperature of 45°C; wherein the activation solution is prepared by adding a 10% NH4OH solution to a 3 g / L AgNO3 solution until the solution becomes transparent to obtain the activation solution; Step 5, placing the PBO fiber soaked in step 4 in a sodium citrate solution with a concentration of 7 g / L for 20 minutes; Step 6, placing the PBO fiber treated in step 5 in a chemical nickel plating solution in a water bath environment with a water bath temperature of 85° C. for plating for 40 minutes, wherein the chemical nickel plating solution comprises 20 g / L NiSO4·6H2O, 20 g / L NaH2PO2·H2O, and 20 mL / L lactic acid, and the solvent is deionized water. After the chemical nickel plating solution is prepared, a 25% concentration of ammonia solution is used to adjust the pH value of the chemical nickel plating solution to 9.5 to obtain a final chemical nickel plating solution, and after the plating is completed, the fiber is washed with deionized water, and the nickel-plated PBO fiber is obtained after drying; Step 7: Use the PBO fiber treated in step 6 as the cathode of the electroplating equipment and the nickel rod as the anode for electroplating for 40 minutes. The distance between the cathode and the anode is 6 cm and the current density is 1500 mA / dm 2 , the electroplating temperature is 85℃, and the pH value is 5. The electroplating solution composition is NiSO4·6H2O 20g / L, NaH2PO2·H2O 20g / L, and lactic acid 20mL / L. After the electroplating is completed, the nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance can be obtained by washing and drying.

[0034] The nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance prepared in this embodiment was subjected to resistance test, electromagnetic shielding test and tensile strength test, and the test results showed that the resistance was 0.5Ω, the electromagnetic shielding effectiveness was 59dB, and the tensile strength was 5.05GPa.

Claims

1. A method for preparing nickel-coated PBO fibers with high electrical conductivity and high electromagnetic shielding performance, characterized in that: The specific steps are as follows: Step 1, sequentially performing modification treatment, sensitization treatment, and activation treatment on the PBO fiber; Step 2, soaking the activated PBO fiber in a sodium citrate solution; Step 3, placing the PBO fiber treated in step 2 in a chemical nickel plating solution in a water bath environment for plating, washing with deionized water after plating, and then drying to obtain the chemical nickel-plated PBO fiber; Step 4, using the nickel rod as an anode and the chemically nickel-plated PBO fiber obtained in step 3 as a cathode for electroplating, after the electroplating is completed, washing with deionized water and then drying to obtain a nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance.

2. The method for preparing nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance according to claim 1, characterized in that: The modification treatment in step 1 is specifically as follows: The PBO fiber is immersed in acetone, and then the PBO fiber immersed in acetone is placed in a mixed solution of HNO3 and H2SO4 and subjected to ultrasonic vibration to obtain a modified PBO fiber; The sensitization treatment in step 1 is specifically as follows: immersing the modified PBO fiber in a sensitizing solution in a water bath environment; The activation treatment in step 1 is specifically: immersing the sensitized PBO fiber in an activation solution in a water bath environment.

3. The method for preparing nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance according to claim 2, characterized in that: In the modification treatment of step 1, the PBO fiber is immersed in acetone for 15 to 60 minutes; the concentration of HNO3 in the mixed solution of HNO3 and H2SO4 is 100 to 200 mL / L, the concentration of H2SO4 is 100 to 200 mL / L, and the ultrasonic oscillation time is 15 to 60 minutes.

4. The method for preparing nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance according to claim 3, characterized in that: The water bath temperature of the sensitization treatment in step 1 is 20-60° C., and the immersion time in the sensitizing solution is 10-40 min. The sensitizing solution is prepared as follows: first, hydrochloric acid is diluted in deionized water to obtain a HCl solution with a concentration of 30-50 mL / L, and then SnCl2·H2O is added to the HCl solution to dissolve it to obtain a sensitizing solution, wherein the concentration of SnCl2·H2O is 5-15 g / L.

5. The method for preparing nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance according to claim 4, characterized in that: The method for preparing the activation solution in the activation treatment in step 1 is as follows: add 10% NH4OH solution to 1~5g / L AgNO3 solution until the solution is transparent to obtain the activation solution; the water bath temperature for the activation treatment is 20~60°C, and the soaking time of the PBO fiber is 10~40min.

6. The method for preparing nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance according to claim 5, characterized in that: The concentration of the sodium citrate solution in step 2 is 5-10 g / L, and the soaking time is 5-30 min.

7. The method for preparing nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance according to claim 6, characterized in that: In step 3, the water bath temperature is 70-90° C., and the plating time is 5-60 min.

8. The method for preparing nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance according to claim 7, characterized in that: The preparation method of chemical nickel plating solution in step 3 is: Dissolve NiSO4·6H2O, NaH2PO2·H2O and lactic acid in deionized water to obtain a solution, wherein the concentrations of NiSO4·6H2O, NaH2PO2·H2O and lactic acid in the solution are 20-40 g / L, 20-40 g / L and 20-35 mL / L respectively; Then, the pH of the dissolving solution is adjusted to 9-10 using 25% ammonia water to obtain a chemical nickel plating solution.

9. The method for preparing nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance according to claim 8, characterized in that: When the electroplating is performed in step 4, the electroplating solution is: NiCl2, C6H 11 NaO7 and (NH4)2SO4 are dissolved in deionized water to obtain an electroplating solution, wherein NiCl2 and C6H 11 The concentrations of NaO7 and (NH4)2SO4 are 80~150g / L, 10~50g / L, and 10~50g / L respectively; Alternatively, NiSO4·6H2O, NaH2PO2·H2O, and lactic acid are dissolved in deionized water to obtain an electroplating solution, wherein the concentrations of NiSO4·6H2O, NaH2PO2·H2O, and lactic acid in the electroplating solution are 20~40 g / L, 20~40 g / L, and 20~35 mL / L, respectively.

10. The method for preparing nickel-coated PBO fiber with high conductivity and high electromagnetic shielding performance according to claim 9, characterized in that: The electroplating process conditions are: the distance between the cathode and the anode is 2-6 cm, the current density is 600-1500 mA / dm 2 , the electroplating time is 5~30min, the electroplating temperature is 50~80℃, and the pH value is 3~6.

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