CN108192118B

CN108192118B - High-wet-strength pure chitosan gel film and preparation method thereof

Info

Publication number: CN108192118B
Application number: CN201810169418.3A
Authority: CN
Inventors: 施晓文; 刘红雨; 邓红兵; 杜予民
Original assignee: Wuhan University WHU
Current assignee: Wuhan University WHU
Priority date: 2018-02-28
Filing date: 2018-02-28
Publication date: 2021-05-25
Anticipated expiration: 2038-02-28
Also published as: CN108192118A

Abstract

The invention provides a preparation method of a high-wet-strength pure chitosan gel film, which comprises the following steps: adding chitosan powder into deionized water, slowly dripping hydrochloric acid while stirring until the pH value is 4.5-5.5, and then stirring for 1-24h to obtain a chitosan solution with the mass fraction of 0.7% -1.4%; adding hydrogen peroxide into the chitosan solution, and stirring for 20-60 min; filtering the chitosan solution, and performing ultrasonic defoaming; electrodepositing the chitosan solution by a cathodic deposition method, wherein the current density of the deposition is 3.5-5.5A/m²And stripping the deposited gel film from the cathode to obtain the pure chitosan gel film. The invention overcomes the defects of weak mechanical strength and insufficient toughness of the chitosan hydrogel prepared by the existing electrodeposition method, the breaking strength of the wet film reaches 4.5-5.5MPa, and the wet breaking elongation reaches 120-180%.

Description

High-wet-strength pure chitosan gel film and preparation method thereof

Technical Field

The invention relates to the field of environmental chemistry and natural macromolecules, in particular to a high-wet-strength pure chitosan gel film and a preparation method thereof.

Background

The chitosan has rich chitosan resources in nature, wide sources, good biocompatibility, biodegradability, antibacterial property, polycation electrolyte property, multifunctional group reaction activity, easy film forming property and the like, and has important application prospects in the fields of textile printing, papermaking, heavy metal adsorption and recovery, wastewater treatment, food, biomedicine and the like based on the excellent properties. Meanwhile, chitosan has special electric responsiveness and film forming property, so that the chitosan becomes a preferred material for electrodeposition. The hydrophilic polymer hydrogel generally consists of a large number of water molecules and a high polymer which is not dissolved by contained liquid, can maintain the structure and the property of the hydrogel to a certain extent and keep stable, generally has the advantages of good swelling property, light transmission, strong biodegradability and biocompatibility and the like, and has wide application in the fields of food, industry, biomedical treatment, environment and the like. The research of polymer hydrogel generally relates to a plurality of crossed fields of polymer physics, material science, thermodynamics, life science, medicine and the like.

The pure chitosan hydrogel prepared by the traditional electrodeposition method has poor mechanical properties (wet breaking strength and wet breaking elongation), can only be used in the aspects of cell culture, electrode detection chips, drug release and the like, and greatly limits the application range of chitosan gel materials. The application of the chitosan in tissue engineering materials (such as membrane materials, nerve repair conduit materials, blood vessel repair materials and the like) needs certain support property and wet mechanical strength, so the development of the preparation method of the pure chitosan membrane with high wet strength has important significance.

Disclosure of Invention

Aiming at the technical problems, the invention provides a high-wet-strength pure chitosan gel film and a preparation method thereof in order to improve the wet strength of an electrodeposited chitosan gel film.

In order to solve the technical problem, the method is implemented by the following technical scheme:

a preparation method of a high-wet-strength pure chitosan gel film comprises the following steps:

step 1, adding chitosan powder into deionized water, slowly dripping hydrochloric acid while stirring until the pH value is 4.5-5.5, and then stirring for 1-24h to obtain a chitosan solution I, wherein the mass fraction of chitosan is 0.7% -1.4%;

step 2, adding 35% hydrogen peroxide by mass into the chitosan solution I, wherein the ratio of the hydrogen peroxide to the chitosan solution I is 2.0-3.0 mu l/ml, and stirring for 20-60min to obtain a chitosan solution II;

step 3, filtering undissolved chitosan powder from the chitosan solution II to obtain a chitosan solution III, and then carrying out ultrasonic treatment on the chitosan solution III for 10-20min to remove bubbles in the solution;

step 4, electrodepositing the chitosan solution III by using a cathode deposition method, wherein a platinum wire or a platinum sheet is used as an anode, a conductive metal material is used as a cathode, and the current density of the deposition is 3.5-5.5A/m²And stripping the deposited gel film from the cathode to obtain the pure chitosan gel film, and soaking the pure chitosan gel film in pure water to keep the pure chitosan gel film in a wet state.

The high-wet-strength pure chitosan gel film prepared by the method has the wet breaking strength of 4.5-5.5MPa and the wet breaking elongation of 120-180%.

Compared with the prior art, the method provided by the invention overcomes the defects of weak mechanical strength, insufficient toughness and the like of the chitosan hydrogel obtained by the existing electrodeposition method, the breaking strength of the wet film reaches 4.5-5.5MPa, and the wet breaking elongation reaches 120% -180%, so that the wet strength and toughness of the chitosan gel film are improved.

Description of the drawings:

FIG. 1 is a tensile stress-strain diagram of a pure chitosan gel film of example 1;

FIG. 2 is a tensile stress-strain diagram of a pure chitosan gel film of example 2;

FIG. 3 is a tensile stress-strain diagram of pure chitosan gel films of examples 1-6.

Detailed Description

Example 1:

(1) adding chitosan powder into deionized water, slowly dropwise adding hydrochloric acid while stirring, wherein the pH value is 5, and then stirring for 6 hours to obtain a chitosan solution, wherein the mass fraction of chitosan is 0.9%;

(2) adding 35 wt% hydrogen peroxide into the chitosan solution in the step (1), and stirring for 30min, wherein the ratio of hydrogen peroxide to the chitosan solution is 2.1 mul/ml;

(3) filtering undissolved chitosan powder from the chitosan solution obtained in the step (2), and then carrying out ultrasonic treatment on the filtered chitosan solution for 10min to remove bubbles in the solution;

(4) electrodepositing the chitosan solution in the step (3) by using a cathode deposition method, wherein a platinum wire or a platinum sheet is used as an anode, a stainless steel material or a titanium sheet is used as a cathode, and the current density of deposition is 3.5A/m²And stripping the deposited gel film from the cathode to obtain the pure chitosan gel film, and soaking the pure chitosan gel film in pure water to keep the pure chitosan gel film in a wet state.

Example 2:

(1) adding chitosan powder into deionized water, slowly dropwise adding hydrochloric acid while stirring, wherein the pH value is 5, and then stirring for 24h to obtain a chitosan solution, wherein the mass fraction of chitosan is 1.2%;

(2) adding 35 wt% hydrogen peroxide into the chitosan solution in the step (1), and stirring for 50min, wherein the ratio of hydrogen peroxide to the chitosan solution is 2.1 mul/ml;

(3) filtering undissolved chitosan powder from the chitosan solution obtained in the step (2), and then carrying out ultrasonic treatment on the filtered chitosan solution for 20min to remove bubbles in the solution;

(4) electrodepositing the chitosan solution in the step (3) by using a cathode deposition method, wherein a platinum wire or a platinum sheet is used as an anode, a stainless steel material or a titanium sheet is used as a cathode, and the current density of deposition is 4.5A/m²And stripping the deposited gel film from the cathode to obtain the pure chitosan gel film, and soaking the pure chitosan gel film in pure water to keep the pure chitosan gel film in a wet state.

Example 3:

(1) adding chitosan powder into deionized water, slowly dropwise adding hydrochloric acid while stirring, wherein the pH value is 5, and then stirring for 12h to obtain a chitosan solution, wherein the mass fraction of chitosan is 1.0%;

(2) adding 35 wt% hydrogen peroxide into the chitosan solution in the step (1), and stirring for 40min, wherein the ratio of hydrogen peroxide to the chitosan solution is 2.1 mul/ml;

(3) filtering undissolved chitosan powder from the chitosan solution obtained in the step (2), and then carrying out ultrasonic treatment on the filtered chitosan solution for 15min to remove bubbles in the solution;

(4) electrodepositing the chitosan solution in the step (3) by using a cathode deposition method, wherein a platinum wire or a platinum sheet is used as an anode, a stainless steel material or a titanium sheet is used as a cathode, and the current density of deposition is 1.5A/m²And stripping the deposited gel film from the cathode to obtain the pure chitosan gel film, and soaking the pure chitosan gel film in pure water to keep the pure chitosan gel film in a wet state.

Example 4:

the preparation method is the same as example 3, except that the current density of the deposition is adjusted to 2.5A/m²。

Example 5

The preparation process is the same as example 3, except that the current density of the deposition is adjusted to5.5A/m²。

Example 6

The preparation method is the same as example 3, except that the current density of the deposition is adjusted to 6.5A/m²。

The pure chitosan gel film prepared in the embodiment 1-6 is tested for mechanical property, and the reference standard is 'plastic-film property experiment method', GB 13022-1991. The results are shown in Table 1, and it can be seen that the ratio of the total of the components is 3.5-5.5A/m²The prepared chitosan film has better mechanical property and higher wet breaking strength.

TABLE 1 mechanical Properties of pure chitosan gel films of examples 1-8

Examples	Current Density (A/m)²)	Wet breaking Strength (MPa)	Wet elongation at break (%)
				1	3.5	4.6	159.8
2	4.5	5.6	172.2
				3	1.5	1.2	52.1
4	2.5	3.1	126.8
				5	5.5	5.7	161.1
6	6.5	4.2	158.8

Claims

1. A preparation method of a high-wet-strength pure chitosan gel film is characterized by comprising the following steps:

step 4, electrodepositing the chitosan solution III by using a cathode deposition method, wherein a platinum wire or a platinum sheet is used as an anode, a conductive metal material is used as a cathode, and the current density of the deposition is 3.5-5.5A/m²Stripping the deposited gel film from the cathode to obtain the pure chitosan gelA glue film, which is soaked in pure water to keep the wet state.

2. A high wet strength pure chitosan gel film prepared according to the method of claim 1, wherein:

the wet breaking strength is 4.5-5.5MPa, and the wet breaking elongation is 120-180%.