A method for preparing conductive hemicellulose-based ion gel and gel

Abstract

The invention provides a method for preparing a conductive hemicellulose-based ion gel and the gel, belonging to the technical field of functional materials, comprising: obtaining a hemicellulose and DES solution with a set mass ratio, dissolving the hemicellulose in a set amount of DES solution to prepare a hemicellulose DES solution; adding acrylamide monomer and a cross-linking agent to the hemicellulose DES solution and fully dissolving them to obtain a first solution; adding an initiator to the first solution after cooling it and stirring it evenly to obtain a second solution; transferring the second solution into a mold after centrifugal defoaming, polymerizing it for a set time under a set temperature condition, and then cooling it to room temperature and continuing to polymerize it for a set time to obtain a hemicellulose-based ion gel with good conductivity, high transparency, high mechanical properties and good stability.

Description

Technical Field

[0001] The invention belongs to the technical field of functional materials, and in particular relates to a preparation method of a conductive hemicellulose-based ion gel and the gel. Background Art

[0002] Ion gel is a soft material with a three-dimensional network structure composed of molecular chains that are cross-linked or interpenetrated with electrolytes that can be electrolyzed into ions. Since ion gel does not contain water, the dispersion medium is not easy to volatilize, which makes it have good stability. At the same time, the dispersion medium is wrapped in a three-dimensional network structure and has good fluidity and conductivity, making its conductivity comparable to that of liquid electrolytes. In recent years, researchers have used ionic liquids and DES as dispersion media to prepare ion gels that are widely used in flexible materials such as biomedicine and electronic devices. With the rapid development of new electronic application industries such as artificial intelligence, the research on flexible electronic devices and flexible conductive devices has attracted widespread attention from researchers.

[0003] At present, there are many studies on the use of ionic liquids to prepare ion gels. According to whether the ionic liquid participates in the construction of the three-dimensional network structure, it can be divided into two categories: polyionic liquid gel (elastomer) and mixed ionic liquid that locks it in the polymer matrix network. DES has very similar physical and chemical properties to ionic liquids. As mentioned above, low eutectic solvents have the advantages of simple preparation methods, easy availability of raw materials, low volatility, good thermal properties and chemical stability, a wide electrochemical operating range, and high ionic conductivity. Compared with ionic liquids, DES has the characteristics of lower use conditions, low price, easy preparation, and good biodegradability. Therefore, it has received widespread attention in the field of ion gel preparation.

[0004] When ion gels are prepared alone, they generally exhibit low mechanical properties. Among natural plant fiber raw materials, cellulose and nanocellulose are usually used as reinforcing materials for acrylamide matrices due to their excellent aspect ratio. However, the preparation steps of nanocellulose are cumbersome, the cost is high, and it is generally insoluble in DES. After adding a certain amount at one time, the transparency of the ion gel can be reduced. Xylan is abundant in source, low in price, and has good solubility in DES. Therefore, it is very necessary to develop a conductive, highly transparent hemicellulose-based ion gel. Summary of the invention

[0005] In order to solve the shortcomings and deficiencies of the prior art, the primary purpose of the present invention is to provide a method for preparing a conductive hemicellulose-based ion gel and a gel having good conductivity, high transparency, high mechanical properties and good stability.

[0006] In order to achieve the above purpose, the technical solution adopted in this application is: In a first aspect, the present invention provides a method for preparing a conductive hemicellulose-based ion gel, comprising: obtaining a hemicellulose and DES solution of a set mass ratio, dissolving the hemicellulose in a set amount of the DES solution to prepare a hemicellulose DES solution; acrylamide and a cross-linking agent are added to the hemicellulose DES solution and fully dissolved to obtain a first solution; After the first solution is cooled, an initiator is added and stirred to obtain a second solution; The second solution is centrifuged and defoamed and then transferred into a mold, polymerized at a set temperature for a set time, and then cooled to room temperature and polymerized for a set time to obtain a conductive hemicellulose-based ion gel.

[0007] Furthermore, the hemicellulose includes hemicellulose from various coniferous woods, broadleaved woods, and grasses.

[0008] Furthermore, the temperature at which the DES solution dissolves hemicellulose is 80°C to 100°C.

[0009] Furthermore, the DES solution is composed of choline chloride:urea:glycerol in a molar ratio of 1:2:0.125.

[0010] Furthermore, the mass ratio of hemicellulose to DES solution is 0.1:120 to 1:120. Hemicellulose is used as a reinforcing agent in this solution to increase the strength of the ion gel.

[0011] Furthermore, the cross-linking agent is N'N-methylenebisacrylamide, which is a common cross-linking agent.

[0012] Furthermore, the initiator is ammonium persulfate, which is a common initiator.

[0013] Furthermore, the amount of acrylamide added is 20 to 100 times that of hemicellulose, and acrylamide is the main polymerization monomer of ion gel.

[0014] Furthermore, the amount of the initiator used is 0.6% of acrylamide.

[0015] In a second aspect, the present invention provides a conductive hemicellulose-based ion gel, which is prepared by the conductive hemicellulose-based ion gel preparation method as described in the first aspect.

[0016] Compared with the prior art, the advantages and positive effects of the present invention are: The DES used in the present invention is clean and environmentally friendly, has a simple preparation method, is low in price, and can achieve complete dissolution of hemicellulose; hemicellulose is used as a reinforcing material to prepare a hemicellulose-based DES ion gel, which provides a new product of good quality for the high-value utilization of hemicellulose, and has a hemicellulose-based ion gel with good conductivity, high transparency, high mechanical properties and good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 This is an experimental data chart of a method for preparing a conductive hemicellulose-based ion gel according to the present invention. DETAILED DESCRIPTION

[0019] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0020] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0021] Embodiment 1, as Figure 1 As shown, the present application provides a method for preparing a conductive hemicellulose-based ion gel, comprising dissolving hemicellulose in a DES solution to prepare a hemicellulose DES solution for standby use; adding acrylamide monomer and a cross-linking agent to the hemicellulose DES solution and stirring to dissolve, then cooling to room temperature, adding an initiator and stirring evenly, transferring to a glass bottle after centrifugal defoaming, polymerizing at 100°C for 2h, and continuing to polymerize at room temperature for 24 hours to obtain a conductive hemicellulose-based ion gel. The present invention adopts DES to be green and environmentally friendly, and can make the hemicellulose-based ion gel have certain conductivity, stability and high transparency, while also realizing the high-value utilization of hemicellulose.

[0022] Hemicellulose includes hemicellulose from various coniferous woods, broad-leaved woods, and grasses. The temperature at which DES dissolves hemicellulose is 80°C. The composition of DES is a molar ratio of choline chloride: urea: glycerol of 1:2:0.125. The mass ratio of hemicellulose to DES is 0-1:120. The purity of the above-mentioned choline chloride, urea, and glycerol is 95%-98%. The crosslinking agent is N'N-methylenebisacrylamide. More preferably, the purity of the N'N-methylenebisacrylamide is 95%-98%. The initiator is ammonium persulfate, and more preferably, the purity of the ammonium persulfate is 95%-98%. The amount of acrylamide added is 20-100 times that of hemicellulose. Preferably, the melting temperature of acrylamide and the crosslinking agent in step (2) is 40°C. The amount of initiator used is 0.6% of acrylamide; the centrifugal defoaming conditions are 15°C, 8000rpm centrifugation for 5 minutes. The DES used is clean and environmentally friendly, has a simple preparation method, is inexpensive, and can achieve complete dissolution of hemicellulose. The hemicellulose used as a reinforcing material to prepare hemicellulose-based DES ion gel provides a new idea for the high-value utilization of hemicellulose.

[0023] Example 2 A method for preparing a conductive hemicellulose-based ion gel comprises: dissolving 0.03 g of xylan in 18 g of DES at 80°C, cooling to room temperature for standby use, then adding 3 g of AM and 0.018 g of MBA to the xylan DES solution, stirring at 40°C until completely dissolved, cooling to room temperature, then adding 0.018 g of APS and stirring until completely dissolved, centrifuging at 8000 rpm for 5 min at 15°C to defoam, and finally transferring the mixed solution to a glass bottle, polymerizing at 100°C for 2 hours, and then continuing to polymerize at room temperature for 24 hours. The conductivity was measured to be 0.71 mS·cm -1 The elongation at break is 340.37%, the UV transmittance is 96%, and the quality fluctuation is less than 3% after 30 days of storage.

[0024] Control group 1: The main difference between control group 1 and the experimental group is that xylan is not added: 3gAM and 0.018gMBA are added to the DES solution, stirred at 40℃ until completely dissolved and then cooled to room temperature, then 0.018gAPS is added and stirred until completely dissolved, centrifuged at 8000rpm for 5min at 15℃ to defoam, and finally the mixed solution is transferred to a glass bottle, polymerized at 100℃ for 2h, and then polymerized at room temperature for 24h. The conductivity is 0.73mS·cm-1, the elongation at break is 325.16%, the UV transmittance is 98%, and the quality fluctuation is less than 3% after 30 days.

[0025] Example 3 A method for preparing a conductive hemicellulose-based ion gel comprises: dissolving 0.09g of xylan in 18g of DES at 80°C, cooling to room temperature for standby use, then adding 3g of AM and 0.018g of MBA to the xylan DES solution, stirring at 40°C until completely dissolved, cooling to room temperature, then adding 0.018g of APS and stirring until completely dissolved, centrifuging at 8000rpm for 5min at 15°C to defoam, finally transferring the mixed solution to a glass bottle, polymerizing at 100°C for 2h, and then continuing to polymerize at room temperature for 24h. The conductivity is measured to be 0.77mS·cm-1, the elongation at break is 588.88%, the UV transmittance is 92%, and the quality fluctuation is less than 3% after being placed for 30 days.

[0026] Control group 1: 3gAM and 0.018gMBA were added to the DES solution, stirred at 40℃ until completely dissolved, then cooled to room temperature, and then 0.018gAPS was added and stirred until completely dissolved, centrifuged at 8000rpm for 5min at 15℃ to defoam, and finally the mixed solution was transferred to a mold, polymerized at 100℃ for 2h, and then continued to polymerize at room temperature for 24h. The conductivity was 0.73mS·cm-1, the elongation at break was 325.16%, the UV transmittance was 98%, and the quality fluctuation was less than 3% after 30 days.

[0027] Example 4 A method for preparing a conductive hemicellulose-based ion gel comprises: dissolving 0.12g of xylan in 18g of DES at 80°C, cooling to room temperature for standby use, then adding 3g of AM and 0.018g of MBA to the xylan DES solution, stirring at 40°C until completely dissolved, cooling to room temperature, then adding 0.018g of APS and stirring until completely dissolved, centrifuging at 8000rpm for 5min at 15°C to defoam, finally transferring the mixed solution to a glass bottle, polymerizing at 100°C for 2h, and then continuing to polymerize at room temperature for 24h. The conductivity is measured to be 0.73mS·cm-1, the elongation at break is 427.68%, the UV transmittance is 90%, and the quality fluctuation is less than 3% after being placed for 30 days.

[0028] Control group 1: 3gAM and 0.018gMBA were added to the DES solution, stirred at 40℃ until completely dissolved, then cooled to room temperature, and then 0.018gAPS was added and stirred until completely dissolved, centrifuged at 8000rpm for 5min at 15℃ to defoam, and finally the mixed solution was transferred to a mold, polymerized at 100℃ for 2h, and then continued to polymerize at room temperature for 24h. The conductivity was 0.73mS·cm-1, the elongation at break was 325.16%, the UV transmittance was 98%, and the quality fluctuation was less than 3% after 30 days.

[0029] in, Figure 1 There are experimental data of Examples 1-4, Figure 1 a. Ion gel conductivity, b. Ion gel UV transmittance at 550nm, c. Ion gel tensile strength, d. Ion gel weight within 30 days; Note: X0~X4 are xylan contents of 0~4% (relative to the mass of acrylamide); By comparing the properties of the final product, the conductive hemicellulose-based ion gel used in this example has high transparency, high mechanical properties, good conductivity and good stability. By comparing the properties of the final product, the conductive hemicellulose-based ion gel used in Example 3 has better conductivity, high transparency, high mechanical properties and good stability.

[0030] Example 5 A conductive hemicellulose-based ion gel is obtained by the above-mentioned preparation method and has good conductivity, high transparency, high mechanical properties and good stability.

[0031] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. A method for preparing a conductive hemicellulose-based ion gel, characterized in that: include: obtaining a hemicellulose and DES solution of a set mass ratio, dissolving the hemicellulose in a set amount of the DES solution to prepare a hemicellulose DES solution; acrylamide and a cross-linking agent are added to the hemicellulose DES solution and fully dissolved to obtain a first solution; After the first solution is cooled, an initiator is added and stirred to obtain a second solution; The second solution is centrifuged and defoamed and then transferred into a mold, polymerized at a set temperature for a set time, and then cooled to room temperature and polymerized for a set time to obtain a conductive hemicellulose-based ion gel.

2. The method for preparing a conductive hemicellulose-based ion gel according to claim 1, characterized in that: The hemicellulose includes hemicellulose from various coniferous woods, broad-leaved woods, and grasses.

3. The method for preparing a conductive hemicellulose-based ion gel according to claim 1, characterized in that: The temperature at which the DES solution dissolves hemicellulose is 80°C to 100°C.

4. The method for preparing a conductive hemicellulose-based ion gel according to claim 1, characterized in that: The DES solution is composed of choline chloride:urea:glycerol in a molar ratio of 1:2:0.

125.

5. The method for preparing a conductive hemicellulose-based ion gel according to claim 1, characterized in that: The mass ratio of the hemicellulose to the DES solution is 0.1:120 to 1:

120.

6. The method for preparing a conductive hemicellulose-based ion gel according to claim 1, characterized in that: The cross-linking agent is N'N-methylenebisacrylamide.

7. The method for preparing a conductive hemicellulose-based ion gel according to claim 1, characterized in that: The initiator is ammonium persulfate.

8. The method for preparing a conductive hemicellulose-based ion gel according to claim 1, characterized in that: The amount of acrylamide added is 20 to 100 times that of hemicellulose.

9. The method for preparing a conductive hemicellulose-based ion gel according to claim 1, characterized in that: The amount of initiator used is 0.6% of acrylamide.

10. A conductive hemicellulose-based ion gel, characterized in that: The conductive hemicellulose-based ion gel is prepared by the method for preparing the conductive hemicellulose-based ion gel as described in any one of claims 1 to 9.

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