Nylon conductive fiber and its preparation method and sensing application

Abstract

The application relates to a nylon conductive fiber and a preparation method and sensing application thereof, and the preparation method comprises the following steps: adding nylon 66 fibers and dialdehyde cellulose nanocrystals into a silver salt solution and uniformly dispersing, continuously reacting at 60-90 DEG C for 0.1-2h, cleaning and vacuum drying after the reaction is completed, and preparing the nylon conductive fiber; the nylon conductive fiber is connected with a microprocessor, a battery, an alarm and the like module as a sensing element and can be integrated into a sensor device for high-altitude and deep-sea monitoring. The sensing material is simple to prepare, easy to mass-produce, continuously modified by interface multiple reactions, and has more superior performance; the conductivity is as high as 634s / m, the tensile strength can reach 304.2MPa, the surface is loaded with nano-silver and has the performances of conductivity and deep-sea corrosion resistance, underwater monitoring can be realized, the sensing material has good sensing performance and environmental adaptability, in addition, the flexibility can be integrated into a cable for high-altitude and deep-sea use, and high-altitude and deep-sea operation conditions can be monitored in real time.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of sensing technology, and particularly relates to a nylon conductive fiber, a preparation method thereof and sensing application. BACKGROUND

[0002] With the development of 5G technology and artificial intelligence, flexible sensors have wide application prospects in the fields of health monitoring, electronic skin, human-computer interaction, soft robots and intelligent prostheses. With the progress of nanotechnology, fiber sensors are considered to be the most promising new generation of flexible sensors due to their advantages of lightness, flexibility, breathability, comfort and integrability. Among them, nylon 66 fiber is widely used in the preparation of flexible sensors due to its excellent corrosion resistance, wear resistance, self-lubrication and excellent mechanical properties. However, the inherent insulating property and poor interfacial adhesion of nylon fiber limit its rapid development in the fields of flexible sensors and intelligent textiles.

[0003] Due to the relatively close arrangement of the molecular structure of nylon 66, the high crystallinity and low surface energy of the fiber, it is difficult to load conductive materials, so how to improve the interfacial adhesion of nylon fiber and construct stable and sensitive conductive functional units on its surface is still a major challenge in research. Many practical methods have been tried, and the methods currently explored mainly include fabric immersion method, layer-by-layer coating method, vapor deposition method, oxidation polymerization method and low-temperature plasma dyeing; another electrospinning method, although simple, but the conductive material is encapsulated inside the fiber, greatly weakening the mechanical advantage and conductive performance of the fiber.

[0004] Currently, chemical silver plating method is commonly used to prepare conductive nylon fiber, such as the patent document with application number CN202110603872.7 which discloses a kind of silver-plated nylon conductive fiber prepared by tea polyphenol oxidation and its preparation method, and again, the patent document with application number 201910343930.X discloses an anti-oxidation silver-plated nylon fiber with a protective film. The chemical silver plating method is relatively complex, and generally a strong oxidizing agent is used to pretreat the surface of the nylon fiber before silver plating, which causes a significant decrease in fiber strength; if no oxidizing agent pretreatment is performed, the silver plating layer is not firmly combined with the nylon fiber, and the conductive material is easy to fall off, the conductive stability is poor, and it is not easy to integrate. In addition, the production process is complex, easy to produce pollution, and harmful to the human body and the environment.

[0005] Therefore, there is an urgent need in the art to develop a kind of nylon conductive fiber with simple process, environmental protection, firm conductive layer combination and easy integration. SUMMARY

[0006] Based on the above-mentioned shortcomings and deficiencies in the prior art, one of the objects of the present invention is to at least solve one or more of the above-mentioned problems in the prior art. In other words, one of the objects of the present invention is to provide a nylon conductive fiber and its preparation method and sensing application that meet one or more of the above-mentioned needs.

[0007] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0008] A method for preparing nylon conductive fiber comprises the following steps:

[0009] Nylon 66 fiber and dialdehyde cellulose nanocrystals are added to a silver salt solution and dispersed evenly, and reacted continuously at 60-90° C. for 0.1-2 hours. After the reaction is completed, the fiber is cleaned and vacuum-dried to obtain nylon conductive fiber.

[0010] As a preferred embodiment, in step (1), the mass ratio of nylon 66 fiber, dialdehyde cellulose nanocrystals and silver salt is 1:1:(0.1-1).

[0011] As a preferred embodiment, in step (1), the silver salt solution is a silver nitrate aqueous solution or a silver ammonia solution.

[0012] The present invention also provides nylon conductive fiber prepared by the preparation method described in the above scheme as a sensing element.

[0013] As a preferred solution, the conductivity of the nylon conductive fiber is not less than 600s / m, and the tensile strength is not less than 250MPa.

[0014] The present invention also provides a sensing application of the nylon conductive fiber as described in the above solution, wherein the conductive nylon fiber is used as a strain sensor and is integrated with a microprocessor, a battery, and an alarm to form a sensor device.

[0015] As a preferred solution, the sensor device is integrated into a cable for deep-sea monitoring.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The present invention uses nylon 66 fiber, which has excellent mechanical properties, a wide range of sources, low cost, and a surface rich in amino groups, making it an ideal flexible substrate;

[0018] (2) The present invention utilizes the amino groups on the surface of nylon 66 fibers and the hydroxyl and aldehyde groups on dialdehyde cellulose nanocrystals, which can act as a reducing agent while undergoing Schiff base reaction at the nylon fiber interface to reduce nanosilver in situ;

[0019] (3) The present invention utilizes in-situ reduction of nanosilver to generate stable and orderly nanosilver conductive units on nylon fibers. The selected conductive material has the advantages of high conductivity, easy synthesis, antibacterial and corrosion resistance;

[0020] (4) The present invention connects the conductive nylon fiber with modules such as a microprocessor, a battery, Bluetooth, an alarm, and an LED light to form a multifunctional nylon 66 fiber sensor device for high-altitude deep-sea monitoring.

[0021] (5) The conductive nylon fiber of the present invention is simple to prepare as a sensing material and is easy to mass-produce. The continuous interface multiple reaction modification of the nylon fiber makes its performance more superior; its conductivity is as high as 634s / m, and its tensile strength can reach above 304.2MPa. The surface-loaded nanosilver has both conductivity and deep-sea corrosion resistance, which can realize underwater monitoring. It has good sensing performance and environmental adaptability. In addition, its flexibility can be integrated into cables for high altitude and deep sea use, and real-time monitoring of high altitude and deep sea operations. When encountering danger, it can achieve intelligent early warning based on the resistance change rate. The market demand is large and has considerable social and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a field emission scanning electron microscope (FE-SEM) test image of the nylon 66 conductive fiber of Example 1 of the present invention;

[0023] Figure 2 Graphs showing the mechanical properties of nylon 66 conductive fibers according to various embodiments of the present invention;

[0024] Figure 3 1 is a comparison chart of the conductivity of nylon 66 conductive fibers of Example 1 of the present invention and various comparative examples;

[0025] Figure 4 This is a performance diagram of the nylon 66 conductive fiber of Example 1 of the present invention, which shows relatively stable conductivity after washing;

[0026] Figure 5 This is the circuit design for the integrated multifunctional nylon 66 fiber sensor system of Example 1 of the present invention;

[0027] Figure 6 This is the application of the multifunctional nylon 66 fiber sensor device in deep-sea exploration according to Example 1 of the present invention. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further explained below through specific embodiments.

[0029] Example 1:

[0030] The method for preparing the conductive nylon fiber of this embodiment includes the following steps:

[0031] 1g of nylon 66 fiber wrapped on a scaffold and 1g of dialdehyde cellulose nanocrystals were added to 100mL of an aqueous solution of 0.3g of silver nitrate and reacted at 70℃ for 1.5 hours to achieve continuous grafting of dialdehyde cellulose nanocrystals on the surface of the nylon fiber by alkali reaction and in-situ reduction deposition of nanosilver. After washing and vacuum drying, silver-coated nylon 66 conductive fiber was obtained, named NFACAg 0.3 .

[0032] The conductive nylon fiber NFACAg 0.3 The multifunctional nylon 66 fiber sensor device is integrated with modules such as a microprocessor, battery, Bluetooth, alarm and LED light. The specific integrated structure can refer to the existing technology and will not be described here.

[0033] Example 2:

[0034] The method for preparing the conductive nylon fiber of this embodiment includes the following steps:

[0035] 1g of nylon 66 fiber wrapped on a scaffold and 1g of dialdehyde cellulose nanocrystals were added to 100mL of an aqueous solution of 0.1g of silver nitrate and reacted at 70℃ for 1.5 hours to achieve continuous grafting of dialdehyde cellulose nanocrystals on the surface of the nylon fiber by alkali reaction and in-situ reduction deposition of nanosilver. After washing and vacuum drying, silver-coated nylon 66 conductive fiber was obtained, named NFACAg 0.1 .

[0036] Conductive nylon fiber NFACAg 0.1 The multifunctional nylon 66 fiber sensor device is integrated with modules such as a microprocessor, battery, Bluetooth, alarm and LED light. The specific integrated structure can refer to the existing technology and will not be described here.

[0037] Example 3:

[0038] The method for preparing the conductive nylon fiber of this embodiment includes the following steps:

[0039] 1g of nylon 66 fiber wrapped on a scaffold and 1g of dialdehyde cellulose nanocrystals were added to 100mL of an aqueous solution of 0.5g of silver nitrate and reacted at 70℃ for 1.5 hours to achieve continuous grafting of dialdehyde cellulose nanocrystals on the surface of the nylon fiber by alkali reaction and in-situ reduction deposition of nanosilver. After washing and vacuum drying, silver-coated nylon 66 conductive fiber was obtained, named NFACAg 0.5 .

[0040] Conductive nylon fiber NFACAg 0.5 The multifunctional nylon 66 fiber sensor device is integrated with modules such as a microprocessor, battery, Bluetooth, alarm and LED light. The specific integrated structure can refer to the existing technology and will not be described here.

[0041] Comparative Example 1:

[0042] The preparation method of the conductive nylon fiber of this comparative example comprises the following steps:

[0043] 1 g of dialdehyde cellulose nanocrystals (DACN) was added to 100 mL of an aqueous solution of 0.3 g of silver nitrate and reacted at 70°C for 1 hour, and an obvious silver mirror phenomenon appeared.

[0044] 1g of nylon 66 fiber was immersed in CNC / Ag conductive suspension for 0.5h, washed and vacuum dried to obtain conductive nylon fiber with DACN / Ag surface coating, named ACNFAg 0.3 .

[0045] Conductive nylon fibers are connected to modules such as microprocessors, batteries, Bluetooth, alarms, and LED lights to integrate nylon 66 fiber sensor devices.

[0046] Comparative Example 2:

[0047] The preparation method of the conductive nylon fiber of this comparative example comprises the following steps:

[0048] 1 g of non-dialdehyde cellulose nanocrystals (CNC) was added to 100 mL of an aqueous solution of 0.3 g of silver nitrate and reacted at 70°C for 1 hour. No silver mirror phenomenon occurred.

[0049] 1 g of nylon 66 fiber was immersed in CNC / silver salt suspension for 0.5 h, washed and vacuum dried to obtain conductive nylon fiber, named CNFAg 0.3 .

[0050] Comparative Example 3:

[0051] The preparation method of the conductive nylon fiber in this comparative example is different from that in Example 1 in that:

[0052] Only dialdehyde cellulose-modified nylon 66 fibers were prepared without in-situ reduction using an aqueous solution of silver nitrate. The modified nylon 66 fibers were named NFDACN.

[0053] Comparative Example 4:

[0054] The preparation method of the conductive nylon fiber in this comparative example is different from that in Example 1 in that:

[0055] 1g of nylon 66 silk fiber was directly placed in 100mL of 0.3g of silver nitrate aqueous solution. It was not possible to in situ reduce and deposit nanosilver. The obtained nylon fiber was named NFAg 0.3 .

[0056] like Figure 1As shown, in Example 1, multifunctional nylon 66 conductive fibers that can be used for high-altitude deep-sea monitoring were successfully prepared by multiple covalent modifications of the nylon interface, and the nanosilver particles deposited in situ on the surface of the nylon fibers formed a continuous conductive network.

[0057] like Figure 2 As shown in the figure, the tensile strength and elongation at break of nylon fiber NFDACN modified with dialdehyde cellulose nanocrystals are slightly improved; the tensile strength and elongation at break of NFACAg after nanosilver in situ deposition are both improved, among which the NFACAg in Example 1 is 0.3 The strength and elongation at break properties are optimal.

[0058] like Figure 3 As shown, multifunctional nylon 66 conductive fiber NFACAg based on interface multiple covalent bond modification 0.3 ACNFAg with non-multiple covalently modified nylon 66 fibers 0.3 、CNFAg 0.3 、NFAg 0.3 Compared with the conductivity of NFDACN, it is significantly improved, up to 634S / m.

[0059] like Figure 4 As shown, the conductive network on the surface of the nylon 66 conductive fiber of Example 1 is very stable, and the conductivity remains stable after multiple strong washings.

[0060] like Figure 5 As shown, the circuit design of the nylon 66 conductive fiber of Example 1 is connected to modules such as a microprocessor, a battery, a Bluetooth, an alarm, and an LED light to integrate a nylon 66 fiber sensor device. For details, please refer to the existing technology and will not be repeated here.

[0061] like Figure 6 As shown, the nylon 66 fiber of Example 1 can still transmit signals of human movement underwater and can monitor changes in seawater pressure and cable breakage in real time, and can be integrated into a sensor device for high-altitude and deep-sea monitoring.

[0062] In the above embodiment and its alternatives, the mass ratio of nylon fiber / dialdehyde cellulose nanocrystals / silver nitrate solution can also be determined within the range of 1:1:0.1-1 according to actual application requirements; as an example, the mass ratio of nylon fiber / dialdehyde cellulose nanocrystals / silver nitrate solution can also be 1:1:0.2, 1:1:0.4, 1:1:0.6, etc.

[0063] In the above embodiment and its alternatives, the silver nitrate solution may be replaced by a silver ammonia solution.

[0064] In the above embodiment and its alternatives, the reaction temperature can also be determined between 60-90°C according to actual application requirements, and the reaction time can also be determined between 0.1-2h according to actual application requirements; as an example, the reaction time is 0.5h, 1h, 2h, etc., and the reaction temperature is 60°C, 80°C, 90°C, etc.

[0065] In view of the numerous embodiments of the present invention, each embodiment can be determined according to actual application requirements within the limited range of each parameter. The experimental data is huge and it is not suitable to list them one by one here. However, the content that needs to be verified and the final conclusions obtained in each embodiment are similar.

[0066] The above description is only a detailed description of the preferred embodiments and principles of the present invention. For ordinary technicians in this field, based on the ideas provided by the present invention, there may be changes in the specific implementation methods, and these changes should also be considered as the scope of protection of the present invention.

Claims

1. A method for preparing nylon conductive fiber, characterized in that: The following steps are involved: Nylon 66 fiber and dialdehyde cellulose nanocrystals are added to a silver salt solution and dispersed evenly, reacted continuously at 60-90°C for 0.1-2 hours, and washed and vacuum-dried after the reaction to obtain nylon conductive fiber. The mass ratio of nylon 66 fiber, dialdehyde cellulose nanocrystals and silver salt is 1:1:(0.1-1); The conductivity of the nylon conductive fiber is not less than 600S / m, and the tensile strength is not less than 250MPa.

2. The preparation method according to claim 1, characterized in that The silver salt solution is a silver nitrate aqueous solution or a silver ammonia solution.

3. The nylon conductive fiber obtained by the preparation method according to any one of claims 1 to 2, characterized in that: As a sensing element.

4. The sensing application of nylon conductive fiber according to claim 3, characterized in that: Conductive nylon fiber is used as a strain sensor and is integrated with a microprocessor, a battery, and an alarm to form a sensor device.

5. The sensing application according to claim 4, characterized in that: The sensor device is integrated into the cable and is used for deep-sea monitoring.

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