阅读说明：本技术 抗菌性好耐高温可加工的羧甲基壳聚糖流体及其制备方法 (Carboxymethyl chitosan fluid with good antibacterial property and high-temperature resistance and capable of being processed and preparation method thereof ) 是由 殷先泽 李钰山 申晖 王罗新 王桦 于 2021-08-10 设计创作，主要内容包括：本发明涉及一种抗菌性好耐高温可加工的羧甲基壳聚糖流体及其制备方法,本发明通过羧甲基壳聚糖(N-CMC)溶液与聚乙二醇(PEG)取代的十八叔胺(PEG-STA)溶液共混,通过扩散-静电自组装法将反应后的混合溶液透析之后烘干,制备得到自流动羧甲基壳聚糖材料。通过本发明制备方法得到的壳聚糖材料其粒径分布均一,具有耐高温,抗菌性,可加工性,在温度为26℃无溶剂的状态下具有类似液体的流动,热降解温度达到250℃以上。本发明制备过程简单且环保不使用任何有机溶剂,低成本,可大规模生产。(The invention relates to a carboxymethyl chitosan fluid with good antibacterial property, high temperature resistance and processability and a preparation method thereof. The chitosan material prepared by the preparation method has uniform particle size distribution, high temperature resistance, antibacterial property and processability, has liquid-like flow under the condition of 26 ℃ without solvent, and the thermal degradation temperature reaches more than 250 ℃. The preparation method is simple in preparation process, environment-friendly, free of any organic solvent, low in cost and capable of realizing large-scale production.)

1. The preparation method of the carboxymethyl chitosan fluid with good antibacterial property and high temperature resistance and capable of being processed is characterized by comprising the following steps:

step 1, preparing a carboxymethyl chitosan solution with the mass fraction of 10 wt% -30 wt%, and preparing a PEG-substituted octadecyl tertiary amine solution with the mass fraction of 10 wt% -30 wt%;

step 2, dropwise adding PEG-substituted octadecyl tertiary amine solution into carboxymethyl chitosan solution, and stirring under ultrasonic condition;

step 3, soaking the solution reacted in the last step at 60-70 ℃ for 20-30h to obtain a reaction solution;

step 4, putting the reaction solution in the last step into a dialysis bag for dialysis;

and 5, drying the residual product after dialysis in a vacuum drying oven at 50-70 ℃ for 2-4 days to obtain the carboxymethyl chitosan fluid which has good antibacterial property, high temperature resistance and can be processed.

2. The method for preparing carboxymethyl chitosan fluid with good antibacterial property and high temperature resistance for processing according to claim 1, wherein the PEG-substituted octadecyl tertiary amine has the molecular formula of [ C₁₈H₃₇N(CH₂CH₂O)_nH(CH₂CH₂O)_mH(m+n＝10)]。

3. The method for preparing carboxymethyl chitosan fluid with good antibacterial property and high temperature resistance, which can be processed according to claim 1, wherein the amount of PEG-substituted octadecyl tertiary amine is 1-3 times of the molar mass of carboxymethyl chitosan.

4. The method for preparing the carboxymethyl chitosan fluid with good antibacterial property and high temperature resistance, which can be processed according to claim 1, wherein the carboxymethyl chitosan has a molecular weight of 10-30 kDa, a deacetylation degree of 90%, and a substitution degree of 80% or more.

5. The preparation method of the carboxymethyl chitosan fluid with good antibacterial property and high temperature resistance, which can be processed according to claim 1, wherein the method for preparing the carboxymethyl chitosan solution with the mass fraction of 10 wt% -30 wt% comprises the following steps: adjusting the pH value of the deionized water to 5-7, and dissolving the carboxymethyl chitosan in the deionized water to prepare a solution with the mass fraction of 10 wt% -30 wt%.

6. Carboxymethyl chitosan fluid with good antibacterial property and high temperature resistance, which is prepared by the preparation method of any one of claims 1 to 5.

Technical Field

The invention belongs to the field of preparation methods of high polymer materials, and particularly relates to a carboxymethyl chitosan fluid with good antibacterial property, high temperature resistance and processability and a preparation method thereof.

Background

The polysaccharide polymer has good biocompatibility, low toxicity, biodegradability and antibacterial activity, and the unique properties enable the polysaccharide polymer to be well developed in the fields of biomedicine, food packaging, dye adsorption and the like. However, the molecular chains of the polysaccharide polymer are semi-rigid and have high molecular weight, strong hydrogen bond interaction exists among the molecular chains, the molecular chain segments are difficult to move, and the solid state is macroscopically displayed. For polysaccharide polymers, the melting temperature is generally above the decomposition temperature, making them unusable for high temperature melt processing, severely limiting their application. The polysaccharide macromolecule derivatives reported in the literature at present are all solid, such as surface graft copolymerization and ionic liquid modification, so as to improve the processing performance of the polysaccharide macromolecule, but the problems of complex chemical modification, solvent consumption, limited processing temperature when being blended with other polymers, easy secondary agglomeration, phase separation and the like exist. Therefore, it is necessary to develop a polysaccharide polymer with processability, thermal stability and good solubility under the solvent-free condition. Inspired by the concept of solvent-free nano fluid, the conventional preparation method is broken through, and the working principle of inorganic nano particle liquefaction is applied to the construction of the liquefied polysaccharide high molecular fluid. Based on the unique thought, the aim of reducing the bulk viscosity of the polysaccharide macromolecule is to adjust the charge distribution of the polysaccharide molecular chain, introduce organic long-chain oligomer with opposite charges to assemble on the polysaccharide molecular chain by using a diffusion-static assembly strategy, and prevent hydrogen bond reconstruction and molecular chain aggregation by using the organic long-chain oligomer in the dehydration process. And the organic long-chain oligomer is used as a lubricant, so that the polysaccharide polymer can show liquid fluidity without a solvent, the processing viscosity of the polysaccharide polymer is reduced, the heat resistance is improved, and the key problems that the polysaccharide polymer has low concentration and high viscosity and is difficult to process at high temperature are solved. Compared with the traditional method, the new method has the following advantages: 1) the process is simple, and the product can be dissolved and dispersed in different solvents; 2) reducing the direct blending viscosity of the polymer or obtaining high-concentration low-viscosity electrostatic spinning solution; 3) expands the functions of polysaccharide polymer materials, and can realize antibacterial property, fluidity and high temperature resistance. Therefore, the method takes the viscosity regulation of the liquefied polysaccharide fluid as a main means to develop an environment-friendly preparation process with high concentration and reduced viscosity, and has important significance for establishing a new method for efficiently forming and processing the polysaccharide high-molecular regulation bio-based composite material.

Disclosure of Invention

The invention aims to solve the technical problem of providing a carboxymethyl chitosan fluid which has good antibacterial property, high temperature resistance and can be processed and a preparation method thereof.

The technical scheme for solving the technical problems is as follows:

the preparation method of the carboxymethyl chitosan fluid with good antibacterial property and high temperature resistance, which can be processed, comprises the following steps:

step 1, preparing a carboxymethyl chitosan solution with the mass fraction of 10 wt% -30 wt%, and preparing a PEG-substituted octadecyl tertiary amine solution with the mass fraction of 10 wt% -30 wt%;

step 2, dropwise adding PEG-substituted octadecyl tertiary amine solution into carboxymethyl chitosan solution, and stirring under ultrasonic condition;

step 3, soaking the solution reacted in the last step at 60-70 ℃ for 20-30h to obtain a reaction solution;

step 4, putting the reaction solution in the last step into a dialysis bag for dialysis;

and 5, drying the residual product after dialysis in a vacuum drying oven at 50-70 ℃ for 2-4 days to obtain the carboxymethyl chitosan fluid which has good antibacterial property, high temperature resistance and can be processed.

Further, the molecular formula of the PEG substituted octadeca-tertiary amine is [ C ]₁₈H₃₇N(CH₂CH₂O)_nH(CH₂CH₂O)_mH(m+n＝10)]。

Furthermore, the dosage of the PEG-substituted octadecyl tertiary amine is 1 to 3 times of the molar mass of the carboxymethyl chitosan.

Furthermore, the molecular weight of the carboxymethyl chitosan is 10-30 kDa, the deacetylation degree is 90 percent, and the substitution degree is more than or equal to 80 percent.

Further, the method for preparing the carboxymethyl chitosan solution with the mass fraction of 10 wt% -30 wt% specifically comprises the following steps: adjusting the pH value of the deionized water to 5-7, dissolving carboxymethyl chitosan in the deionized water to prepare a solution with the mass fraction of 10 wt% -30 wt%.

The carboxymethyl chitosan fluid with good antibacterial property and high temperature resistance is prepared by the preparation method.

The invention has the beneficial effects that: polysaccharide polymers have poor solubility and processability due to the presence of numerous hydrogen bonds between intra-and intermolecular chains. The method adopts a one-step grafting method, the PEG-substituted octadecyl tertiary amine solution is directly added into the carboxymethyl chitosan solution drop by drop, and the organic long-chain oligomer with opposite charges is assembled on a polysaccharide molecular chain through diffusion-electrostatic assembly, so that no organic solvent is used in the whole process, the reaction temperature is mild, and the grafted organic oligomer plays an important role in adjusting the rheological behavior of fluid and improving the dispersibility of the fluid in various solvents; and experiments on PEG-substituted octadecylamine with different m + n values found that only the PEG with the molecular formula [ C ]₁₈H₃₇N(CH₂CH₂O)_nH(CH₂CH₂O)_mH(m+n＝10)]The PEG substituted octadecyl tertiary amine can obtain fluid finally, and the final products obtained by adopting PEG substituted octadecyl tertiary amine with m + n equal to other numerical values are all solid.

The polysaccharide polymer fluid has high thermal stability and antibacterial capability due to the existence of the organic oligomer. These excellent properties would make the chitosan fluid of the present invention an antimicrobial coating on some substrates and a candidate material for 3D printing, spraying and doctor blading related applications.

Description of the drawings

FIG. 1 is a flow chart of the preparation of N-CMCFs;

FIG. 2 is a thermogravimetric analysis plot of N-CMC and N-CMCFs-1810;

FIG. 3 is a scanning electron microscope image of pure cotton fabric i and N-CMCFs-1810ii coated cotton fabric after being treated by staphylococcus aureus;

FIG. 4 is the antimicrobial activity of pure cotton fabric and N-CMC coated cotton fabric against Staphylococcus aureus and Escherichia coli;

FIG. 5 is a graph of the antimicrobial activity of pure cotton fabric and N-CMCFs-1810 coated cotton fabric against Staphylococcus aureus and Enterobacter coli.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.

Example 1

Dissolving carboxymethyl chitosan in deionized water with pH of 5-7 to prepare a solution with the mass fraction of 10 wt% -30 wt%; PEG-substituted tertiary amine C with the mass fraction of 10 wt% -30 wt%₁₈H₃₇N(CH₂CH₂O)_nH(CH₂CH₂O)_mGradually dropping a solution of H (m + N is 10) (the amount of the substance is 1-3 times of that of the N-CMC) into the carboxymethyl chitosan solution, and carrying out ultrasonic treatment and stirring; and the reacted solution was soaked at 65 ℃ for 24 h. And (5) dialyzing the post reaction solution in a dialysis bag for 5-7 days. And after the dialysis is finished, drying the dialyzed product in a vacuum drying oven at 60 ℃ for 3 days to obtain the carboxymethyl chitosan fluid which has high temperature resistance and antibacterial property and can be processed.

Example 2

Dissolving carboxymethyl chitosan in deionized water with pH of 5-7 to prepare a solution with the mass fraction of 10 wt% -30 wt%; PEG-substituted tertiary amine C with the mass fraction of 10 wt% -30 wt%₁₈H₃₇N(CH₂CH₂O)_nH(CH₂CH₂O)_mGradually dropping a solution of H (m + N is 10) (the amount of the substance is 1-3 times of that of the N-CMC) into the carboxymethyl chitosan solution, and carrying out ultrasonic treatment and stirring; and the reacted solution was soaked at 65 ℃ for 24 h. And (5) dialyzing the post reaction solution in a dialysis bag for 5-7 days. After dialysis is finishedDrying the dialyzed product in a vacuum drying oven at 60 ℃ for 3 days to obtain the carboxymethyl chitosan fluid which has high temperature resistance and antibacterial property and can be processed

Example 3

Dissolving carboxymethyl chitosan in deionized water with pH of 5-7 to prepare a solution with the mass fraction of 10 wt% -30 wt%; PEG-substituted tertiary amine C with the mass fraction of 10 wt% -30 wt%₁₈H₃₇N(CH₂CH₂O)_nH(CH₂CH₂O)_mGradually dropping a solution of H (m + N is 10) (the amount of the substance is 1-3 times of that of the N-CMC) into the carboxymethyl chitosan solution, and carrying out ultrasonic treatment and stirring; and the reacted solution was soaked at 65C for 24 h. And (5) dialyzing the post reaction solution in a dialysis bag for 5-7 days. And after the dialysis is finished, drying the dialyzed product in a vacuum drying oven for 3 days at the temperature of 60 ℃ to obtain the carboxymethyl chitosan fluid which has high temperature resistance and antibacterial property and can be processed.

As shown by the three examples, N-CMCFs-1810(m + N ═ 10) exhibited gel-like behavior at 26 ℃, while the original N-CMC, N-CMCFs-1815(m + N ═ 15) and N-CMCFs-1820(m + N ═ 20) still appeared solid at 196 ℃. In one aspect, the molecular chain length (CH) of the N-CMCFs increases with the molecular weight of the grafted PEG-STA₂CH₂O) increases, and the melting temperature increases in turn, so that the flow temperature of N-CMCFs-1810 is lower than that of N-CMCFs-1815 and N-CMCFs-1820. On the other hand, as the temperature increases, the increase in thermal energy enables the molecular chain to overcome the energy barrier. The longer the molecular chain of the grafted PEG-STA, the greater the probability of molecular chain entanglement. Therefore, for the PEG-STA-1810 with relatively short molecular chains, the energy required for the side chain movement is reduced, and meanwhile, when the PEG-STA-1810 is deformed by external force or heating, the long-range slippage and the charge repulsion of the PEG-STA-1810 chains in the PEG-CMC main chain cause the orderly assembly between the PEG-STA-1810 chains, thereby causing the easy rearrangement between the adjacent N-CMC, so that the whole N-CMC material has the fluidity.

FIG. 1 shows a flow chart of the preparation of N-CMCFs of the present invention. The N-CMC solution was adjusted to pH 5-7 and then the polyethylene glycol substituted tertiary amine (according to (CH)₂CH₂O) number of m + N repeating units (m + N10, 15, 20) was named PEG-STA-1810, PEG-STA-1815 and PEG-STA-1820) attached to the backbone of N-CMC by ionic bonds between carboxylic acid and tertiary amine groups. Then dialyzed to remove the residual unreacted PEG-STA, and finally different N-CMCFs (according to the structure (CH) of PEG-STA) were obtained₂CH₂O) the number of m + N repeating units (m + N ═ 10, 15, 20) is shown as N-CMCFs-1810, N-CMCFs-1815 and N-CMCFs-1820).

As shown in FIG. 2, N-CMC and N-CMCFs-1810 have heat resistance. Wherein the N-CMCFs-1810 still maintains thermal stability above 250 ℃.

As shown in figure 3, the adhesiveness of bacteria on the surface of the pure cotton fabric is observed through a scanning electron microscope, and compared with the N-CMCFs-1810 coated cotton fabric, the observation shows that the bacteria are easily attached to the surface of the pure cotton fabric, and on the contrary, the number of the bacteria on the surface of the N-CMCFs-1810 coated cotton fabric is obviously reduced. These results indicate that the N-CMCFs-1810 coated cotton fabric has a certain capability of resisting bacterial adhesion.

As shown in fig. 4, after 24 hours of culture using the agar dish diffusion method, the antibacterial activity of N-CMC and pure cotton fabric con against staphylococcus aureus (s. aureus) and escherichia coli (e. coli) was evaluated quantitatively. No zones of inhibition (ZOI) were observed for pure cotton fabric con and N-CMC coated cotton fabric, indicating that pure cotton fabric con and N-CMC have poor ability to inhibit bacterial growth.

As shown in FIG. 5, the ZOI value of the N-CMCFs-1810 coated cotton fabric was 20/10 mm for Staphylococcus aureus and 16/10 mm for Escherichia coli (FIGS. 5a and 5b), and the N-CMCFs-1810 showed a significant reduction in the number of colonies of Staphylococcus aureus and Escherichia coli, indicating that the antibacterial activity of the N-CMCFs-1810 against Staphylococcus aureus and Escherichia coli was as high as 91.6% and 95.3%, respectively (FIGS. 5c-5 f).

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.