CN109158058B - Attapulgite-chitosan composite gel and preparation method thereof - Google Patents
Attapulgite-chitosan composite gel and preparation method thereof Download PDFInfo
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- CN109158058B CN109158058B CN201811054046.6A CN201811054046A CN109158058B CN 109158058 B CN109158058 B CN 109158058B CN 201811054046 A CN201811054046 A CN 201811054046A CN 109158058 B CN109158058 B CN 109158058B
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Abstract
The invention relates to the field of clay deep processing, and discloses attapulgite-chitosan composite gel and a preparation method thereof, wherein the composite gel comprises the following components in percentage by mass: attapulgite clay: and (3) chitosan: glutaraldehyde: borax = 100: 12-35: 1.2-5.25: 3 to 5. The attapulgite-based composite hydrogel is prepared by taking attapulgite as a main material, chitosan as an auxiliary material, and glutaraldehyde and borax as double cross-linking agents through a sol-gel method. The composite hydrogel disclosed by the invention has an excellent three-dimensional pore structure and mechanical properties, has good adsorption, slow release performance and immobilization capacity, can be used as a medical functional material such as a mask, a medical dressing or a tissue engineering scaffold and the like, and can be further subjected to freeze-drying treatment to obtain aerogel with wider application. The aerogel prepared by the preparation process has excellent mechanical property, and the elastic modulus can be regulated and controlled within the range of 15-193 Mpa. The invention has simple process and short preparation period, and meets the requirement of large-scale production.
Description
Technical Field
The invention relates to the field of clay deep processing, in particular to a chitosan-attapulgite composite gel and a preparation method thereof.
Background
The chitosan-based gel material has excellent biocompatibility, biodegradability, nontoxicity, bacteriostasis and bioactivity, and has bright application prospect in a plurality of fields such as medicine, food, chemical industry, cosmetics, water treatment, biochemistry and biomedical engineering. Polysaccharides have been included in the national food additive use standard GB-2760. In recent years, studies have found that chitosan has a positive charge and human mucosa has a negative charge in a body fluid environment. The chitosan-based tissue engineering scaffold material or wound dressing can be adhered to human bodyThe membrane has good biocompatibility, thereby promoting tissue regeneration and wound healing. However, the physical gel mechanical properties of chitosan are very poor, which results in limited applications in many fields. The document reports that the mechanical property is compositely improved by using nano bentonite or carbon nanofibers and the like, but the reported composite gel mainly comprises chitosan, and the addition range of inorganic materials is less than or equal to 50 wt%. The clay and high molecular polymer composite gel can also be prepared into aerogel by a freeze-drying method. The density of the aerogel prepared at present is 0.05-0.1g/cm3In the meantime, the optimum modulus of elasticity has been reported to be 12.24 MPa.
Disclosure of Invention
The purpose of the invention is as follows: aiming at the problems in the prior art, the invention provides the chitosan-attapulgite composite gel and the preparation method thereof, the composite gel obtained by the preparation method has excellent three-dimensional pore structure and mechanical property, has good adsorption and slow release performance and solid carrying capacity, can be used as a mask or a medicinal dressing, and can be further freeze-dried into aerogel with wider application.
The technical scheme is as follows: the invention provides a chitosan-attapulgite composite gel, which consists of the following components in percentage by mass: attapulgite clay: and (3) chitosan: glutaraldehyde: borax = 100: 12-35: 1.2-5.25: 3 to 5.
The invention also provides a preparation method of the chitosan-attapulgite composite gel, which comprises the following steps: s1: preparing 2-5 wt% of attapulgite slurry; s2: after the pH value of the attapulgite slurry is adjusted to 4, adding a proper amount of 4wt% chitosan solution into the attapulgite slurry, uniformly stirring, then adding a proper amount of 2wt% glutaraldehyde solution, stirring for 30min, and continuously adding 0.4mol/L borax solution, and stirring to obtain mixed slurry; s3: and injecting the mixed slurry into a strong base dilute solution for gelling for 12h, and then placing the mixed slurry into deionized water at room temperature for aging for 12h to obtain the chitosan-attapulgite composite hydrogel.
Further, after S3, S4 is also included: and (2) freezing the chitosan-attapulgite composite hydrogel at-80 to-196 ℃ for 5min to obtain gel, and then freeze-drying the gel to obtain the chitosan-attapulgite composite aerogel. The aerogel obtained by freeze-drying treatment has low density (0.035 g/cm)3~0.055g/cm3) And the mechanical property is outstanding (the elastic modulus can be adjusted between 15 and 193 Mpa).
Preferably, in S2, the mass ratio of the attapulgite in the attapulgite slurry to the chitosan in the chitosan solution is 1:0.12 to 0.35.
Preferably, in S2, the mass of glutaraldehyde in the glutaraldehyde solution is 10% to 15% of the mass of chitosan in the chitosan solution.
Preferably, in S2, the adding amount of borax is 3% -5% of the mass of attapulgite in the attapulgite slurry.
Preferably, the strong alkali dilute solution is sodium hydroxide or lithium hydroxide.
Preferably, the concentration of the strong alkali dilute solution is 0.3wt% to 0.45 wt%.
Further, in S1, the attapulgite slurry was prepared as follows: the attapulgite clay is crushed to 200 meshes, acidified for 6 hours by 2wt% of acetic acid, centrifugally settled to remove non-clay impurities on the lower layer, and then the slurry is reconfigured to be 2wt% to 5wt% of attapulgite clay slurry.
Has the advantages that: the invention takes the attapulgite as the main material and the chitosan as the auxiliary material, adopts the sol-gel method to prepare the chitosan-attapulgite composite hydrogel, and has the following advantages compared with the prior art:
(1) the invention has the innovation points that the attapulgite is taken as a main material, the proportion of the attapulgite is 70-90%, compared with the chitosan-attapulgite composite gel which takes chitosan as the main material and the attapulgite accounts for about 5-10% in the prior art, the preparation cost is obviously reduced, and the chitosan gel has very low mechanical strength, so the composite gel can be endowed with higher gel speed and good mechanical property due to the introduction of a large amount of attapulgite; while the good biocompatibility of the chitosan gel is kept, the introduction of the fiber type attapulgite can effectively regulate and control the pore structure of the gel; the raw materials of the invention are all natural green materials, thus being safe and environment-friendly and having simple process;
(2) because the attapulgite slurry is alkalescent, the chitosan can only be dissolved in acid, and if the mixed solution is not ensured to be sufficiently acidic, the attapulgite and the chitosan are difficult to disperse fully; the attapulgite clay is used as a main material, so that the pH of the attapulgite clay slurry is adjusted to about 4 by using acid and then mixed with 4wt% of chitosan solution, thereby being beneficial to reducing the viscosity of the system and promoting the thorough compounding of the attapulgite clay and the chitosan. (3) According to the invention, the mixed slurry is injected into the strong alkali dilute solution for gelation, the strong alkali dilute solution is treated into mild gelation, and a three-dimensional network is formed more uniformly and completely. According to the invention, through mild gelation and freeze-drying treatment, the obtained gel is aerogel, the density is greatly reduced, and the porosity is rich. (4) According to the invention, the organic cross-linking agent and the inorganic cross-linking agent are used in a matching manner, the organic cross-linking agent glutaraldehyde is firstly added, the inorganic cross-linking agent borax is added after basic cross-linking, and the two cross-linking agents act synergistically, so that the ultralow density of the gel is ensured, and the mechanical property of the composite gel is greatly improved.
(5) In the prior art, a cross-linking agent is usually added after gelation, and the cross-linking agent enters the interior of the gel through diffusion and is further cross-linked, so that the cross-linking degree decreases progressively along with the diffusion concentration of the cross-linking agent, and the cross-linking is not uniform and is not easy to control; the invention adds the cross-linking agent before gelation, and the cross-linking and the gelation are carried out simultaneously, and the invention is homogeneous cross-linking, and the three-dimensional network regulation of the gel is more accurate.
Drawings
FIG. 1 is an appearance of the chitosan-attapulgite composite hydrogel water pressure test of example 1;
FIG. 2 is microscopic SEM images of glutaraldehyde-crosslinked attapulgite-chitosan composite aerogel and glutaraldehyde-borax double-crosslinked attapulgite-chitosan composite aerogel of example 2;
fig. 3 is an appearance diagram of example 3 chitosan-attapulgite composite aerogel.
Detailed Description
The present invention will be described in detail with reference to the accompanying drawings.
Embodiment 1:
the embodiment provides a chitosan-attapulgite composite gel, which consists of the following components in percentage by mass: attapulgite clay: and (3) chitosan: glutaraldehyde: borax = 100: 12: 1.44: 3.
pulverizing attapulgite to 200 mesh, acidifying with 2wt% acetic acid for 6 hr, centrifuging to remove lower layer non-clay impurities, reconfiguring the slurry to 2wt% attapulgite slurry, and adjusting attapulgiteAnd (2) adding a proper amount of 4wt% chitosan solution (wherein the mass ratio of the attapulgite in the attapulgite slurry to the chitosan in the chitosan solution is 1: 0.12), uniformly stirring, continuously adding a proper amount of 5wt% glutaraldehyde solution, stirring for 30min (wherein the amount of glutaraldehyde in the glutaraldehyde solution is 12% of the mass of the chitosan in the chitosan solution), continuously adding 0.4mol/L borax solution, and stirring (wherein the amount of borax is 3% of the mass of the attapulgite in the attapulgite slurry), thereby obtaining the mixed slurry. And then, injecting the mixed slurry into 0.4wt% of lithium hydroxide solution for gelling for 12h, and then placing the mixed slurry in deionized water for aging for 12h at room temperature to obtain the chitosan-attapulgite composite hydrogel. Freezing the composite hydrogel at-196 ℃ for 5min to obtain gel, and finally freeze-drying the gel to obtain the chitosan-attapulgite composite aerogel. The density of the prepared composite aerogel is 0.037g/cm3The modulus of elasticity is 20 MPa.
Fig. 1 is an appearance diagram of the chitosan-attapulgite composite hydrogel in the embodiment of the invention in a water pressure test, and it can be seen from the figure that the composite hydrogel remains intact after being impacted by water, which indicates that the hydrogel has excellent mechanical properties.
Embodiment 2:
the embodiment provides a chitosan-attapulgite composite gel, which consists of the following components in percentage by mass: attapulgite clay: and (3) chitosan: glutaraldehyde: borax = 100: 25: 2.5: 4.
crushing attapulgite to 200 meshes, acidifying with 2wt% acetic acid for 6 hours, centrifuging and settling to remove non-clay impurities on the lower layer, then reconfiguring the slurry into 3.5wt% attapulgite slurry, adjusting the pH of the attapulgite slurry to about 4, further adding a proper amount of 4wt% chitosan solution (wherein the mass ratio of the attapulgite in the attapulgite slurry to the chitosan in the chitosan solution is 1:0.25), uniformly stirring, continuously adding a proper amount of 5wt% glutaraldehyde solution, stirring for 30min (wherein the amount of glutaraldehyde in the glutaraldehyde solution is 10% of the mass of the chitosan in the chitosan solution), continuously adding 0.4mol/L borax solution, and stirring (wherein the amount of borax is 4% of the mass of the attapulgite in the attapulgite slurry), thus obtaining the mixed slurry. Then the mixed slurry is injected into 0.3wt% sodium hydroxide mesogel for 12 hours, and then the mixed slurry is placed in deionized water for aging for 12 hours at room temperature to obtain the chitosan-attapulgite compositeAnd (3) hydrating the hydrogel. Freezing the composite hydrogel at-196 ℃ for 5min to obtain gel, and finally freeze-drying the gel to obtain the chitosan-attapulgite composite aerogel. The density of the prepared composite aerogel is 0.042g/cm3The modulus of elasticity is 40 MPa.
Fig. 2 is a microscopic SEM image of the glutaraldehyde-crosslinked attapulgite-chitosan composite aerogel and the glutaraldehyde-borax double-crosslinked attapulgite-chitosan composite aerogel in the present embodiment. As can be seen from the figure, compared with the single glutaraldehyde crosslinking composite aerogel, the glutaraldehyde-borax double crosslinking composite aerogel has more compact particle spacing. The method can further improve the mechanical property of the composite aerogel.
Embodiment 3:
the embodiment provides a chitosan-attapulgite composite gel, which consists of the following components in percentage by mass: attapulgite clay: and (3) chitosan: glutaraldehyde: borax = 100: 30: 4.5: 5.
crushing attapulgite to 200 meshes, acidifying with 2wt% acetic acid for 6 hours, centrifuging and settling to remove non-clay impurities on the lower layer, then reconfiguring the slurry into 4wt% attapulgite slurry, adjusting the pH of the attapulgite slurry to about 4, further adding a proper amount of 4wt% chitosan solution (wherein the mass ratio of the attapulgite in the attapulgite slurry to the chitosan in the chitosan solution is 1: 0.3), uniformly stirring, continuously adding a proper amount of 5wt% glutaraldehyde solution, stirring for 30min (wherein the amount of glutaraldehyde in the glutaraldehyde solution is 15% of the mass of the chitosan in the chitosan solution), continuously adding 0.4mol/L borax solution, and stirring (wherein the amount of borax is 5% of the mass of the attapulgite in the attapulgite slurry), thus obtaining the mixed slurry. And then injecting the mixed slurry into 0.45wt% of sodium hydroxide for 12 hours, and then placing the mixed slurry in deionized water for aging for 12 hours at room temperature to obtain the chitosan-attapulgite composite hydrogel. Freezing the composite hydrogel at-196 ℃ for 5min to obtain gel, and finally freeze-drying the gel to obtain the chitosan-attapulgite composite aerogel. The density of the prepared composite aerogel is 0.048g/cm3The modulus of elasticity is 170 MPa.
Fig. 3 is an appearance diagram of the chitosan-attapulgite composite aerogel in the embodiment, and it can be seen from the figure that the whole block aerogel with ultra-light weight and ultra-low density can be prepared by the method.
The above embodiments are merely illustrative of the technical concepts and features of the present invention, and the purpose of the embodiments is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Claims (5)
1. The chitosan-attapulgite composite gel is characterized by comprising the following components in percentage by mass:
attapulgite clay: and (3) chitosan: glutaraldehyde: borax = 100: 25-35: 1.2-2.5: 3-5;
the preparation method comprises the following steps:
s1: preparing 2-5 wt% of attapulgite slurry;
s2: after the pH value of the attapulgite slurry is adjusted to 4, adding a proper amount of 4wt% chitosan solution into the attapulgite slurry, uniformly stirring, then adding a proper amount of 2wt% glutaraldehyde solution, stirring for 30min, and continuously adding 0.4mol/L borax solution, and stirring to obtain mixed slurry;
s3: and injecting the mixed slurry into a strong base dilute solution for gelling for 12h, and then placing the mixed slurry into deionized water at room temperature for aging for 12h to obtain the chitosan-attapulgite composite hydrogel.
2. The method for preparing chitosan-attapulgite composite gel according to claim 1, further comprising, after S3, S4: and (3) freezing the chitosan-attapulgite composite hydrogel for 5min at-80 to-196 ℃ to obtain gel, and then freeze-drying the gel to obtain the chitosan-attapulgite composite aerogel.
3. The method of preparing chitosan-attapulgite composite gel according to claim 1, wherein in S3, the strong alkali dilute solution is a sodium hydroxide dilute solution or a lithium hydroxide dilute solution.
4. The method for preparing chitosan-attapulgite composite gel according to claim 1, wherein the concentration of the strong alkali dilute solution is 0.3wt% to 0.45wt% in S3.
5. The method for preparing chitosan-attapulgite composite gel according to any one of claims 1 to 4, wherein in S1, the attapulgite slurry is formulated as follows:
crushing attapulgite to 200 meshes, acidifying with 2wt% of acetic acid for 6 hours, centrifuging and settling to remove non-clay impurities on the lower layer, and then reconfiguring the slurry into the attapulgite slurry with the weight percent of 2-5 wt%.
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| CN109942904A (en) * | 2019-02-28 | 2019-06-28 | 淮阴工学院 | A kind of attapulgite clay compounded chitosan gel rubber and preparation method thereof |
| CN110813247A (en) * | 2019-10-25 | 2020-02-21 | 淮阴工学院 | Preparation method and application of attapulgite-based chitosan aerogel adsorbent |
| CN113680288A (en) * | 2020-05-18 | 2021-11-23 | 淮阴工学院 | Preparation method of hydrophobic attapulgite composite aerogel |
| CN113210022A (en) * | 2021-05-12 | 2021-08-06 | 北京工业大学 | Preparation method of Cu-attapulgite-chitosan chelate microsphere catalyst applied to catalytic wet oxidation |
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| DE3265697D1 (en) * | 1981-02-05 | 1985-10-03 | Nippon Oil Co Ltd | Process for preparing a hydrogel |
| CN101880440A (en) * | 2010-06-11 | 2010-11-10 | 新疆大学 | Novel nano-composite double network hydrogel and preparation method thereof |
| CN101914226B (en) * | 2010-08-12 | 2011-12-21 | 淮阴工学院 | Method for preparing chitosan/attapulgite composite material for medicament sustained release |
| CN101942167B (en) * | 2010-09-10 | 2012-05-23 | 天津工业大学 | Nanometer clay-containing high absorptive hydrogel as well as preparation method and application thereof |
| CN102649045A (en) * | 2011-02-24 | 2012-08-29 | 中国科学院兰州化学物理研究所 | Method for preparing attapulgite clay composite gel adsorption microsphere by spray drying |
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| CN103157410A (en) * | 2013-03-13 | 2013-06-19 | 中国科学院化学研究所 | Aerogel preparation method |
| CN103599734B (en) * | 2013-11-22 | 2016-08-17 | 中国工程物理研究院核物理与化学研究所 | A kind of aerogel material and preparation method thereof |
| CN103709346B (en) * | 2013-11-27 | 2015-09-09 | 中国科学技术大学 | A kind of preparation method of phenolic resin aerogel |
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