阅读说明：本技术 一种甲壳素晶须液晶弹性体材料及其制备方法与应用 (Chitin whisker liquid crystal elastomer material and preparation method and application thereof ) 是由 罗丙红 唐盛月 刘坤 周长忍 于 2020-12-23 设计创作，主要内容包括：本发明公开了一种甲壳素晶须液晶弹性体材料及其制备方法与应用。该甲壳素晶须液晶弹性体材料的制备方法,包括以下步骤：步骤一：甲壳素晶须的制备；步骤二：将步骤一中的甲壳素晶须与交联剂配制成甲壳素晶须/交联剂混合悬浮液,其中甲壳素晶须/交联剂混合悬浮液中甲壳素晶须的质量浓度为3wt％-20wt％；步骤三：对混合悬浮液超声均化处理至液晶态,获得初步交联的甲壳素晶须液晶,并将其放置于25℃-50℃环境中进一步交联,得到甲壳素晶须液晶弹性体。本发明具有原材料来源广、制备方法简单、反应条件温和、无需使用有机溶剂等显著优点,适宜产业化生产和大规模推广应用。(The invention discloses a chitin whisker liquid crystal elastomer material and a preparation method and application thereof. The preparation method of the chitin whisker liquid crystal elastomer material comprises the following steps: the method comprises the following steps: preparing chitin whisker; step two: preparing the chitin whisker and the cross-linking agent in the step one into chitin whisker/cross-linking agent mixed suspension, wherein the mass concentration of the chitin whisker in the chitin whisker/cross-linking agent mixed suspension is 3-20 wt%; step three: and carrying out ultrasonic homogenization treatment on the mixed suspension liquid to a liquid crystal state to obtain preliminarily crosslinked chitin whisker liquid crystal, and further crosslinking the chitin whisker liquid crystal in an environment of 25-50 ℃ to obtain the chitin whisker liquid crystal elastomer. The invention has the obvious advantages of wide raw material source, simple preparation method, mild reaction condition, no need of using organic solvent and the like, and is suitable for industrial production and large-scale popularization and application.)

1. The preparation method of the chitin whisker liquid crystal elastomer material is characterized by comprising the following steps of:

the method comprises the following steps: preparing chitin whisker;

step two: preparing the chitin whisker and the cross-linking agent in the step one into chitin whisker/cross-linking agent mixed suspension, wherein the mass concentration of the chitin whisker in the chitin whisker/cross-linking agent mixed suspension is 3-20 wt%;

step three: and carrying out ultrasonic homogenization treatment on the mixed suspension liquid to a liquid crystal state to obtain preliminarily crosslinked chitin whisker liquid crystal, and further crosslinking the chitin whisker liquid crystal in an environment of 25-50 ℃ to obtain the chitin whisker liquid crystal elastomer.

2. The method for preparing chitin whisker liquid crystal elastomer material according to claim 1, wherein the chitin whisker in the first step is any one of acidolysis chitin whisker, maleic anhydride chitin whisker or deacetylation chitin whisker;

the acidolysis chitin whisker is prepared by an acidolysis method, and comprises the following specific preparation steps: taking 0.5-5mol/L hydrochloric acid, preparing raw materials according to the mass volume ratio of chitin powder to hydrochloric acid of 1:20-1:50, dispersing the chitin powder in the hydrochloric acid to form a suspension, heating the suspension to 60-110 ℃ under an inert atmosphere, stirring and reacting for 0.5-6h, after the reaction is finished, centrifugally separating solid and liquid, finally regulating the pH value of the suspension to be neutral through dialysis, freezing and drying, and grinding to obtain acidolysis chitin whiskers;

the maleic anhydrization chitin whisker is prepared by adopting the esterification reaction of chitin and maleic anhydride, and comprises the following specific preparation steps: melting maleic anhydride at 60-90 deg.C, adding chitin powder with mass ratio of chitin powder to maleic anhydride of 1:10-1:40, reacting at 55-150 deg.C for 0.5-8h under inert atmosphere, centrifuging to separate solid and liquid, dialyzing, adjusting pH to neutral, and freeze drying to obtain maleinated chitin whisker;

the deacetylated chitin whisker is prepared by an acidolysis method and an alkaline hydrolysis method: taking 0.5-15mol/L NaOH solution and prepared acidolysis chitin whisker, preparing raw materials according to the mass volume ratio of the acidolysis chitin whisker to the NaOH solution of 1:20-1:50, dispersing the acidolysis chitin whisker in the NaOH solution to prepare suspension, heating the suspension to 50-120 ℃ under an inert atmosphere, stirring and reacting for 0.5-8h, cooling, centrifuging, adjusting the pH to 1-3 by hydrochloric acid, shaking uniformly, standing, centrifuging for multiple times until the pH value of supernatant is neutral, and freeze-drying the obtained precipitate to obtain the deacetylated chitin whisker.

3. The method for preparing chitin whisker liquid crystal elastomer material according to any one of claims 1 or 2, wherein the inert atmosphere in the first step can be nitrogen, argon or other conventional inert atmosphere.

4. The method for preparing chitin whisker liquid crystal elastomer material according to any one of claims 1 or 2, wherein the cross-linking agent in the second step is any one of genipin, glutaraldehyde, epichlorohydrin or tannic acid.

5. The method for preparing the chitin whisker liquid crystal elastomer material according to claim 4, wherein when the cross-linking agent is genipin, the specific steps of the second step are as follows: preparing the genipin powder into a solution, and adding the chitin whisker prepared in the step one to prepare chitin whisker/genipin mixed suspension, wherein the mass concentration of the chitin whisker in the mixed suspension is 3-20 wt%, and the mass volume concentration of the genipin in the mixed suspension is 1.0-15.0 g/L;

or, when the cross-linking agent is glutaraldehyde, the specific steps of the second step are as follows: preparing the chitin whisker in the step one into aqueous suspension, and quickly dropwise adding glutaraldehyde into the aqueous suspension of the chitin whisker under the stirring condition to obtain chitin whisker/glutaraldehyde mixed suspension, wherein the mass concentration of the chitin whisker in the mixed suspension is 3-20 wt%, and the mass concentration of the glutaraldehyde in the mixed suspension is 0.05-8 wt%;

or, when the cross-linking agent is epichlorohydrin, the specific steps of the second step are as follows: preparing the chitin whisker in the step one into aqueous suspension, firstly adjusting the pH value of the aqueous suspension to 11.0 by using a sodium hydroxide solution, and then adding an epichlorohydrin solution to obtain chitin whisker/epichlorohydrin mixed suspension, wherein the mass concentration of the chitin whisker in the mixed suspension is 3-20 wt%, and the mass volume concentration of the epichlorohydrin in the mixed suspension is 1.0-15.0 g/L;

or, when the cross-linking agent is tannic acid, the specific steps of the second step are as follows: and (2) preparing the tannic acid powder into a solution, and adding the chitin whisker prepared in the step one to prepare a chitin whisker/tannic acid mixed suspension, wherein the mass concentration of the chitin whisker in the mixed suspension is 3-20 wt%, and the mass volume concentration of the tannic acid in the mixed suspension is 1.0-15.0 g/L.

6. The method for preparing chitin whisker liquid crystal elastomer material as claimed in any one of claims 1 to 5, wherein the ultrasonic homogenization treatment in the third step is carried out by using a cell crusher with power of 100-1000w and homogenization time of 0.5-10 h.

7. The method for preparing chitin whisker liquid crystal elastomer material according to claim 6, wherein when the cross-linking agent is genipin, the cross-linking time in step three is 24-168 h; and when the crosslinking agent is glutaraldehyde, tannic acid and epichlorohydrin, the crosslinking time in the third step is 0.5-72 h.

8. A chitin whisker liquid crystal elastomer material prepared by the preparation method of any one of claims 1 to 7.

9. Use of the chitin whisker liquid crystal elastomer as claimed in claim 8 in a bone tissue repair material.

Technical Field

The invention belongs to the technical field of biological nano materials and tissue engineering, and particularly relates to a chitin whisker liquid crystal elastomer material as well as a preparation method and application thereof.

Background

The research of bone tissue engineering is a research hotspot in the field of bone tissue repair in recent years, wherein the design and construction of the extracellular matrix-like scaffold material are the most central contents in the research of bone tissue engineering. The extracellular matrix (ECM) not only endows the structure and the function of bone tissues, determines the basic development direction of bone cells, but also provides a suitable place for the survival and the activity of the cells, plays roles of supporting, retaining water, protecting and the like, and further influences the morphology, the function, the migration, the proliferation, the differentiation and the like of the cells through a signal transduction system. Therefore, according to local requirements of cells and tissues, the extracellular matrix is simulated structurally and functionally, so that ordered regeneration and repair of bone tissues are guided, and the method is very important for developing novel scaffold materials for bone tissue engineering.

Liquid crystals are ordered fluids between anisotropic crystals and isotropic liquids. Lyotropic liquid crystals are widely present in nature and in living bodies, and are closely related to life. A large amount of lyotropic liquid crystalline collagen components are present in the extracellular matrix. The liquid crystal state collagen provides a water-insoluble framework for the extracellular matrix, determines the mechanical properties of the extracellular matrix, and can contact and guide the migration, adhesion, growth, differentiation and the like of osteoblasts due to the anisotropic surface, and also can regulate the deposition of inorganic mineral salts and promote mineralization, thereby promoting the repair of bone tissues. At present, the literature considers that ammonia vapor gelation liquid crystal state collagen is directly used as a bone tissue repair material, but the preparation method not only needs a great deal of time to carry out evaporation treatment, but also the whole shape of the prepared collagen film is not uniform enough, the mechanical strength of the material is not enough, and more importantly, liquid crystal textures are only generated at the interface between air and collagen solution. Therefore, the bionic natural collagen has very important significance for constructing the liquid crystal novel bone tissue engineering scaffold material.

The liquid crystal elastomers reported at present mainly include polyolefin-based liquid crystal elastomers, silicone-based liquid crystal elastomers, polyacrylate-based liquid crystal elastomers, polyurethane-based liquid crystal elastomers, and the like, and most of them form liquid crystals by monomer condensation or addition polymerization. The liquid crystal elastomer materials not only have complex raw material components and troublesome preparation process, but also need a plurality of chemical reactions and use of organic solvents, and most of the liquid crystal elastomer materials have the defects of insufficient biocompatibility or biotoxicity, biodegradability and the like. For example, CN111607086A prepared liquid crystalline elastomers after using various organic solvents using vinyloxy monomer liquid crystals, involving a large number of chemical reactions. Another document reports a polyacrylate liquid crystal elastomer, which is characterized in that liquid crystal elastomer microspheres are prepared in microemulsion through photopolymerization as a three-dimensional cell scaffold, but the technology still has the following defects: the raw Materials are complex, the Materials comprise polymerized monomers, crosslinking agents, photoinitiators and the like, organic solvents such as toluene and the like are used in the synthesis process, the obtained Materials have poor degradability in vivo, and nematic Liquid Crystal elastomers are synthesized, and the Liquid Crystal structures of natural collagen are not completely similar (Liquid Crystal polymers as Three-Dimensional Cell scanning Supporting and promoting of Myoblasts Tanmay Bera, Ernest J.Freeman, Jennifer A.McDonough, Robert J.elements, Asaad Aladda, DonaW.Miller, Christypher Malcuit, Town Hegmann, and Elda Hegmann Applied Materials & Interfaces & 26, 14528 and 14535).

At present, although many researches consider the liquid crystal characteristics of chitin whisker suspension, no report is found for biomimetically constructing a novel bone tissue engineering scaffold material in a natural collagen-like liquid crystal state by utilizing the liquid crystal characteristics of the chitin whisker suspension; no report about adding a cross-linking agent to make the chitin whisker suspension liquid into a liquid crystal elastomer while maintaining the arrangement structure of the chiral nematic liquid crystal and applying the chitin whisker suspension liquid to bone tissue engineering is found; also, no research report that the chitin whisker-based liquid crystal elastomer is used for bone repair and plays roles in guiding, recruiting, regulating and the like on osteoblasts is found.

Disclosure of Invention

In order to overcome the defects and shortcomings of the prior art, the primary object of the invention is to provide a preparation method of a chitin whisker liquid crystal elastomer material, which overcomes the defects of the existing liquid crystal state collagen scaffold material and provides a simple and effective preparation method of a novel chitin whisker liquid crystal elastomer bone tissue engineering scaffold.

The second purpose of the invention is to provide a chitin whisker liquid crystal elastomer material, which is a novel chitin whisker liquid crystal elastomer bone tissue engineering scaffold material with bionic natural collagen liquid crystal state, good elasticity and osteogenic activity, and overcomes the defects of complex raw material components, troublesome preparation process, excessive chemical reaction, use of organic solvent, insufficient biocompatibility or biotoxicity of most parts, biodegradability and the like of the existing liquid crystal elastomer material.

The third objective of the present invention is to provide an application of the chitin whisker liquid crystal elastomer material, which overcomes the defects that lyotropic liquid crystal is easily affected by external environment and the properties are not stable enough, and provide a means for properly crosslinking chitin whisker liquid crystal to form a liquid crystal elastomer, so as to obtain a novel nano biomaterial with liquid crystal properties, elasticity and stability.

The primary purpose of the invention is realized by the following technical scheme:

a preparation method of chitin whisker liquid crystal elastomer material comprises the following steps:

the method comprises the following steps: preparing chitin whisker;

step two: preparing the chitin whisker and the cross-linking agent in the step one into chitin whisker/cross-linking agent mixed suspension, wherein the mass concentration of the chitin whisker in the chitin whisker/cross-linking agent mixed suspension is 3-20 wt%;

step three: and carrying out ultrasonic homogenization treatment on the mixed suspension liquid to a liquid crystal state to obtain preliminarily crosslinked chitin whisker liquid crystal, and further crosslinking the chitin whisker liquid crystal in an environment of 25-50 ℃ to obtain the chitin whisker liquid crystal elastomer.

Further, the chitin whisker in the first step is any one of acidolysis chitin whisker, maleic anhydride chitin whisker or deacetylation chitin whisker;

the acidolysis chitin whisker is prepared by an acidolysis method, and comprises the following specific preparation steps: taking 0.5-5mol/L hydrochloric acid, preparing raw materials according to the mass volume ratio of chitin powder to hydrochloric acid of 1:20-1:50, dispersing the chitin powder in the hydrochloric acid to form a suspension, heating the suspension to 60-110 ℃ under an inert atmosphere, stirring and reacting for 0.5-6h, after the reaction is finished, centrifugally separating solid and liquid, finally regulating the pH value of the suspension to be neutral through dialysis, freezing and drying, and grinding to obtain acidolysis chitin whiskers;

the maleic anhydrization chitin whisker is prepared by adopting the esterification reaction of chitin and maleic anhydride, and comprises the following specific preparation steps: melting maleic anhydride at 60-90 deg.C, adding chitin powder with mass ratio of chitin powder to maleic anhydride of 1:10-1:40, reacting at 55-150 deg.C for 0.5-8h under inert atmosphere, centrifuging to separate solid and liquid, dialyzing, adjusting pH to neutral, and freeze drying to obtain maleinated chitin whisker;

the deacetylated chitin whisker is prepared by an acidolysis method and an alkaline hydrolysis method: taking 0.5-15mol/L NaOH solution and prepared acidolysis chitin whisker, preparing raw materials according to the mass volume ratio of the acidolysis chitin whisker to the NaOH solution of 1:20-1:50, dispersing the acidolysis chitin whisker in the NaOH solution to prepare suspension, heating the suspension to 50-120 ℃ under an inert atmosphere, stirring and reacting for 0.5-8h, cooling, centrifuging, adjusting the pH to 1-3 by hydrochloric acid, shaking uniformly, standing, centrifuging for multiple times until the pH value of supernatant is neutral, and freeze-drying the obtained precipitate to obtain the deacetylated chitin whisker.

Further, the inert atmosphere in the first step may be a conventional inert atmosphere such as nitrogen, argon, etc.

Further, the cross-linking agent in the second step is any one of genipin, glutaraldehyde, epichlorohydrin or tannic acid.

Further, when the cross-linking agent is genipin, the specific steps of the second step are as follows: preparing the genipin powder into a solution, and adding the chitin whisker prepared in the step one to prepare chitin whisker/genipin mixed suspension, wherein the mass concentration of the chitin whisker in the mixed suspension is 3-20 wt%, and the mass volume concentration of the genipin in the mixed suspension is 1.0-15.0 g/L.

Further, when the cross-linking agent is glutaraldehyde, the specific steps of the second step are as follows: preparing the chitin whisker in the step one into aqueous suspension, and quickly dropwise adding glutaraldehyde into the aqueous suspension of the chitin whisker under the stirring condition to obtain chitin whisker/glutaraldehyde mixed suspension, wherein the mass concentration of the chitin whisker in the mixed suspension is 3-20 wt%, and the mass concentration of the glutaraldehyde in the mixed suspension is 0.05-8 wt%;

or, when the cross-linking agent is epichlorohydrin, the specific steps of the second step are as follows: preparing the chitin whisker in the step one into aqueous suspension, firstly adjusting the pH value of the aqueous suspension to 11.0 by using a sodium hydroxide solution, and then adding an epichlorohydrin solution to obtain chitin whisker/epichlorohydrin mixed suspension, wherein the mass concentration of the chitin whisker in the mixed suspension is 3-20 wt%, and the mass volume concentration of the epichlorohydrin in the mixed suspension is 1.0-15.0 g/L.

Or, when the cross-linking agent is tannic acid, the specific steps of the second step are as follows: and (2) preparing the tannic acid powder into a solution, and adding the chitin whisker prepared in the step one to prepare a chitin whisker/tannic acid mixed suspension, wherein the mass concentration of the chitin whisker in the mixed suspension is 3-20 wt%, and the mass volume concentration of the tannic acid in the mixed suspension is 1.0-15.0 g/L.

Further, the ultrasonic homogenization treatment in the third step is carried out by adopting a cell crusher, the power is 100-1000w, and the homogenization time is 0.5-10 h.

Further, when the cross-linking agent is genipin, the cross-linking time in the third step is 24-168 h; and when the crosslinking agent is glutaraldehyde, tannic acid and epichlorohydrin, the crosslinking time in the third step is 0.5-72 h.

In the invention, the liquid crystal elastomer prepared from natural polymer chitin whiskers is used for simulating the liquid crystal state of natural collagen, and the novel liquid crystal state scaffold material is constructed and applied to bone tissue engineering.

The chitin whisker is nano-scale microcrystal obtained by removing amorphous structural domain of natural polysaccharide material chitin under the conditions of acidolysis and the like. The chitin whisker has high length-diameter ratio, excellent biocompatibility, biodegradability, osteogenic activity, mechanical property and the like, and can be subjected to a shearing force by ultrasound and the like, so that charged chitin whiskers are arranged in parallel with each other at a slightly twisted angle in water by depending on hydrogen bond action, electrostatic interaction and the like, a chiral nematic phase layer is formed between adjacent layers, and finally, the chitin whisker lyotropic liquid crystal with a cholesteric liquid crystal texture is formed, which is very similar to a collagen structure in a living body. However, lyotropic liquid crystals such as chitin whisker liquid crystals are very susceptible to the external environment and have unstable properties. The liquid crystal elastomer not only has excellent optical and mechanical properties, but also has porosity, surface property and stimulus responsiveness, can provide space for the growth and migration of cells, and the specific anisotropic three-dimensional structure can promote the adhesion, growth and differentiation of the cells. Therefore, we prepared natural polymer chitin whisker liquid crystal elastomer as a novel bone tissue engineering material.

The second purpose of the invention is realized by the following technical scheme:

the chitin whisker liquid crystal elastomer material is prepared by the preparation method of the chitin whisker liquid crystal elastomer material.

The third purpose of the invention is realized by the following technical scheme:

an application of chitin whisker liquid crystal elastomer in bone tissue repair material.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) the invention has the advantages of wide material source, low cost, simple preparation method, no need of using organic solvent, controllable quality and realization of high-efficiency and low-cost industrialized production.

(2) The chitin whisker liquid crystal elastomer with both liquid crystal property and viscoelasticity is designed, constructed and prepared by adopting a simple and effective technical route, so that the liquid crystal property of the chitin whisker suspension is well reserved, and the material is endowed with good stability.

(3) The chitin whisker liquid crystal elastomer prepared by the invention not only has excellent mechanical property and elasticity, can bear certain external force load, but also has a three-dimensional structure and has the characteristic of bionic natural collagen cholesteric liquid crystal.

(4) The chitin whisker liquid crystal elastomer has excellent osteogenesis activity, can promote the adhesion and proliferation of osteoblasts, can guide the migration and osteogenic differentiation of cells, and is an ideal novel liquid crystal bone tissue repair scaffold material.

Drawings

FIG. 1 shows TEM morphology and zeta potential of chitin whiskers in examples 5, 6 and 7 of the present invention, where example 5 corresponds to graph A, example 6 corresponds to graph B, and example 7 corresponds to graph C;

FIG. 2 shows polarization micrographs of chitin whisker suspensions in examples 2, 3 and 4 of the invention, wherein example 2 corresponds to Panel A, example 3 corresponds to Panel B, and example 4 corresponds to Panel C;

fig. 3 shows polarization micrographs of the crosslinked chitin whisker liquid crystal elastomer in examples 1 and 2 of the invention, wherein example 1 corresponds to picture a and example 2 corresponds to picture B;

fig. 4 shows photographs of real objects of examples 1 and 9 of the invention, as well as compressive strength and modulus, where example 1 corresponds to 0CHWs on the left of the figure and example 9 corresponds to 2CHWs on the right of the figure.

Detailed Description

The present invention will be described in further detail with reference to the following examples and accompanying drawings, it being understood that the embodiments of the present invention are illustrative only and should not be construed as limiting the scope of the present invention. The invention is not limited to the embodiments described above, but rather, various modifications and changes may be made by those skilled in the art without departing from the scope of the invention. The specific process parameters and the like in the following examples are also only one example in a suitable range, and a person skilled in the art can make appropriate modifications and selections through the description herein, and are not limited to the specific values in the following examples. All the raw materials and reagents used in the present invention are commercially available raw materials and reagents, unless otherwise specified.

Example 1

The method comprises the following steps: preparing raw materials according to the mass volume ratio of chitin powder to hydrochloric acid of 1:50 by taking 1.5mol/L hydrochloric acid, dispersing the chitin powder in the hydrochloric acid to prepare a suspension, heating the suspension to 110 ℃ in a nitrogen atmosphere, stirring and reacting for 2 hours, after the reaction is finished, centrifugally separating solid and liquid, finally regulating the pH value of the suspension to be neutral by dialysis, freeze-drying, and grinding to obtain acidolysis chitin whiskers;

step two: preparing the genipin powder into a solution, and adding the acidolysis chitin whisker prepared in the step one to prepare chitin whisker/genipin mixed suspension, wherein the mass concentration of the chitin whisker in the mixed suspension is 10 wt%, and the mass volume concentration of the genipin in the mixed suspension is 5.0 g/L.

Step three: and (3) carrying out ultrasonic homogenization treatment on the mixed suspension by using a cell crusher, wherein the power is 500w, the homogenization time is 4h, obtaining preliminary cross-linked chitin whisker liquid crystal, and further cross-linking the preliminary cross-linked chitin whisker liquid crystal at the temperature of 35 ℃ for 24h to obtain the chitin whisker liquid crystal elastomer.

And (3) observing the chitin whisker liquid crystal elastomer prepared in the step three by using a polarizing microscope, wherein the chitin whisker liquid crystal elastomer has liquid crystal characteristics as shown in a figure 3 (A).

Example 2

The method comprises the following steps: preparing a raw material by taking 2.0mol/L NaOH solution, dispersing acidolysis chitin whisker prepared in the step one of the embodiment 1 and the NaOH solution according to the mass-to-volume ratio of 1:30, preparing a suspension, heating the suspension to 100 ℃ under the argon atmosphere, stirring and reacting for 5 hours, cooling, centrifuging, adjusting the pH to 3 by using 1mol/L hydrochloric acid, uniformly shaking, standing, centrifuging for multiple times until the pH value of supernatant is neutral, and freeze-drying the obtained precipitate to obtain deacetylated chitin whisker;

step two: preparing genipin powder into a solution, and adding the deacetylated chitin whisker prepared in the step one to prepare deacetylated chitin whisker/genipin mixed suspension, wherein the mass concentration of the chitin whisker in the mixed suspension is 8 wt%, and the mass volume concentration of the genipin in the mixed suspension is 2.0 g/L.

Step three: and (3) carrying out ultrasonic homogenization treatment on the mixed suspension by using a cell crusher, wherein the power is 550w, the homogenization time is 3h, obtaining preliminary cross-linked chitin whisker liquid crystal, and further cross-linking the preliminary cross-linked chitin whisker liquid crystal at the temperature of 50 ℃ for 168h to obtain the chitin whisker liquid crystal elastomer.

Observing the chitin whisker liquid crystal prepared in the third step by using a polarizing microscope, wherein the result is shown in fig. 2(a), the liquid crystal texture of the chitin whisker liquid crystal is shown, and meanwhile, observing the chitin whisker liquid crystal elastomer prepared in the third step is also shown in fig. 3(B), and the chitin whisker liquid crystal elastomer has liquid crystal characteristics.

Example 3

The method comprises the following steps: preparing raw materials according to the mass ratio of chitin powder to maleic anhydride of 1:25, melting the maleic anhydride at 60 ℃, adding the chitin powder, reacting for 3 hours at 130 ℃ in a nitrogen atmosphere, centrifugally separating solid and liquid, finally regulating the pH value to be neutral through dialysis, and freeze-drying to obtain maleinated chitin whiskers;

step two: preparing the maleic anhydride chitin whisker in the step one into aqueous suspension, adjusting the pH value of the aqueous suspension to 11.0 by using a sodium hydroxide solution, and adding an epichlorohydrin solution to obtain maleic anhydride chitin whisker/epichlorohydrin mixed suspension, wherein the mass concentration of the maleic anhydride chitin whisker in the mixed suspension is 3 wt%, and the mass volume concentration of the epichlorohydrin in the mixed suspension is 3.0 g/L.

Step three: and (3) carrying out ultrasonic homogenization treatment on the mixed suspension by using a cell crusher, wherein the power is 700w, the homogenization time is 2h, obtaining preliminary cross-linked chitin whisker liquid crystal, and further cross-linking the preliminary cross-linked chitin whisker liquid crystal in 25 ℃ for 72h to obtain the chitin whisker liquid crystal elastomer.

Observing the chitin whisker liquid crystal prepared in the third step by using a polarizing microscope, wherein the result is shown in fig. 2(B), and the liquid crystal texture of the chitin whisker liquid crystal is shown.

Example 4

The method comprises the following steps: preparing raw materials according to the mass-to-volume ratio of chitin powder to hydrochloric acid of 1:20 by taking 4mol/L hydrochloric acid solution, dispersing the chitin powder in the hydrochloric acid to prepare suspension, heating the suspension to 70 ℃ in an argon atmosphere, stirring and reacting for 1h, after the reaction is finished, centrifugally separating solid and liquid, finally regulating the pH value of the suspension to be neutral by dialysis, freeze-drying, and grinding to obtain acidolysis chitin whiskers;

step two: preparing the tannic acid powder into a solution, and adding the acidolysis chitin whisker prepared in the step one to prepare acidolysis chitin whisker/tannic acid mixed suspension, wherein the mass concentration of the acidolysis chitin whisker in the mixed suspension is 9 wt%, and the mass volume concentration of the tannic acid in the mixed suspension is 2.0 g/L.

Step three: and (3) carrying out ultrasonic homogenization treatment on the mixed suspension by using a cell crusher, wherein the power is 500w, the homogenization time is 4h, obtaining preliminary cross-linked chitin whisker liquid crystal, and further cross-linking the preliminary cross-linked chitin whisker liquid crystal at the temperature of 30 ℃ for 48h to obtain the chitin whisker liquid crystal elastomer.

Observing the chitin whisker liquid crystal prepared in the third step by using a polarizing microscope, wherein the result is shown in fig. 2(C), and the liquid crystal texture of the chitin whisker liquid crystal is shown.

Example 5

The method comprises the following steps: taking 3mol/L hydrochloric acid solution, preparing raw materials according to the mass-to-volume ratio of chitin powder to hydrochloric acid solution of 1:10, dispersing chitin powder in hydrochloric acid to prepare suspension, heating the suspension to 90 ℃ in nitrogen atmosphere, stirring and reacting for 3 hours, after the reaction is finished, centrifugally separating solid and liquid, finally regulating the pH value of the suspension to be neutral by dialysis, freeze-drying, and grinding to obtain acidolysis chitin whiskers;

step two: preparing the acidolysis chitin whisker in the step one into aqueous suspension, and quickly dropwise adding glutaraldehyde into the aqueous suspension of the acidolysis chitin whisker under the stirring condition to obtain acidolysis chitin whisker/glutaraldehyde mixed suspension, wherein the mass concentration of the chitin whisker in the mixed suspension is 15 wt%, and the mass volume concentration of the glutaraldehyde in the mixed suspension is 3 wt% of the mass of the chitin whisker.

Step three: and (3) carrying out ultrasonic homogenization treatment on the mixed suspension by using a cell crusher, wherein the power is 900w, the homogenization time is 3h, obtaining preliminary cross-linked chitin whisker liquid crystal, and further carrying out cross-linking on the preliminary cross-linked chitin whisker liquid crystal at the temperature of 35 ℃ for 36h to obtain the chitin whisker liquid crystal elastomer.

Observing the shape of the acidolysis chitin whisker prepared in the first step by a transmission electron microscope and testing the zeta potential value of the acidolysis chitin whisker, wherein the result is shown in figure 1(A), and the obtained chitin whisker is in a needle-bar structure and has a high length-diameter ratio, the length and the diameter of the chitin whisker are respectively concentrated in the ranges of 170-380 nm and 10-28 nm, and the zeta potential value is +3.85 mV.

Example 6

The method comprises the following steps: preparing raw materials according to the mass ratio of chitin powder to maleic anhydride of 1:40, melting the maleic anhydride at 80 ℃, adding the chitin powder to prepare a suspension, reacting the suspension at 70 ℃ for 1h in a nitrogen atmosphere, centrifugally separating solid from liquid, finally dialyzing, adjusting the pH value to be neutral, and freeze-drying to obtain the maleinized chitin whisker;

step two: preparing the tannic acid powder into a solution, and adding the maleic anhydride chitin whisker prepared in the step one to prepare a maleic anhydride chitin whisker/tannic acid mixed suspension, wherein the mass concentration of the maleic anhydride chitin whisker in the mixed suspension is 6 wt%, and the mass volume concentration of the tannic acid in the mixed suspension is 8.0 g/L.

Step three: and (3) carrying out ultrasonic homogenization treatment on the mixed suspension by using a cell crusher, wherein the power is 600w, the homogenization time is 2h, obtaining preliminary cross-linked chitin whisker liquid crystal, and further cross-linking the preliminary cross-linked chitin whisker liquid crystal at 37 ℃ for 10h to obtain the chitin whisker liquid crystal elastomer.

The appearance and zeta potential value of the maleic anhydride chitin whisker are observed by a transmission electron microscope, and the result is shown in figure 1(B), which shows that the maleic anhydride chitin whisker obtained by the steps is in a needle-bar structure, has a high length-diameter ratio, the length and the diameter of the maleic anhydride chitin whisker are respectively concentrated in the ranges of 170-310 nm and 10-22 nm, and the zeta potential value is-30.11 mV, which shows that the maleic anhydride chitin whisker is negatively charged.

Example 7

The method comprises the following steps: taking 5mol/L NaOH solution, preparing raw materials according to the mass-to-volume ratio of the acid hydrolysis chitin whisker to the NaOH solution of 1:20, dispersing the acid hydrolysis chitin whisker prepared in the step one in the embodiment 4 in the 5mol/L NaOH solution to prepare suspension, and heating the suspension to 70 ℃ under the argon atmosphere, and stirring for reaction for 1 h. Cooling, centrifuging, adjusting pH to 2 with 1mol/L hydrochloric acid, shaking, standing, and centrifuging for several times until the pH value of supernatant is neutral. Freeze drying the obtained precipitate to obtain deacetylated chitin whisker;

step two: and (2) preparing the deacetylated chitin whisker in the step one into aqueous suspension, and quickly dropwise adding glutaraldehyde into the aqueous suspension of the chitin whisker under the stirring condition to obtain deacetylated chitin whisker/glutaraldehyde mixed suspension, wherein the mass concentration of the chitin whisker in the mixed suspension is 7.5 wt%, and the mass volume concentration of the glutaraldehyde in the mixed suspension is 0.5 wt% of the mass of the chitin whisker.

Step three: and (3) carrying out ultrasonic homogenization treatment on the mixed suspension by using a cell crusher, wherein the power is 550w, the homogenization time is 4h, obtaining preliminary cross-linked chitin whisker liquid crystal, and further cross-linking the preliminary cross-linked chitin whisker liquid crystal at the temperature of 30 ℃ for 3h to obtain the chitin whisker liquid crystal elastomer.

Observing the morphology and the zeta potential value of the deacetylated chitin whisker prepared in the first step by a transmission electron microscope, wherein the result is shown in fig. 1(C), and the result shows that the obtained chitin whisker has a needle-bar-shaped structure and a high length-diameter ratio, the length and the diameter of the chitin whisker are respectively concentrated in the ranges of 170-310 nm and 10-22 nm, and the zeta potential value is +19.60mV, which shows that the acidolysis chitin whisker is subjected to alkali treatment, so that the deacetylation degree of the chitin whisker is increased, the content of free amino is increased, and the zeta potential value is increased.

Example 8

The method comprises the following steps: preparing raw materials according to the mass-to-volume ratio of chitin powder to hydrochloric acid of 1:15 by taking 2mol/L hydrochloric acid, dispersing the chitin powder in the hydrochloric acid to prepare a suspension, heating the suspension to 80 ℃ in a nitrogen atmosphere, stirring and reacting for 2 hours, after the reaction is finished, centrifugally separating solid and liquid, finally regulating the pH value of the suspension to be neutral by dialysis, freeze-drying, and grinding to obtain acidolysis chitin whiskers;

step two: preparing the acidolysis chitin whisker in the step one into aqueous suspension, firstly adjusting the pH value of the aqueous suspension to 11.0 by using a sodium hydroxide solution, and then adding an epichlorohydrin solution to obtain acidolysis chitin whisker/epichlorohydrin mixed suspension, wherein the mass concentration of the acidolysis chitin whisker in the mixed suspension is 12.5 wt%, and the mass volume concentration of the epichlorohydrin in the mixed suspension is 8.0 g/L.

Step three: and (3) carrying out ultrasonic homogenization treatment on the mixed suspension by using a cell crusher, wherein the power is 650w, and the homogenization time is 3.5h, so as to obtain the primary crosslinked chitin whisker liquid crystal, and further crosslinking the primary crosslinked chitin whisker liquid crystal at the temperature of 45 ℃ for 7h, so as to obtain the chitin whisker liquid crystal elastomer.

Example 9

The method comprises the following steps: taking 12.5mol/L NaOH solution, preparing raw materials according to the mass volume ratio of the acid hydrolysis chitin whisker to the NaOH solution of 1:20, dispersing the acid hydrolysis chitin whisker prepared in the embodiment 5 in the NaOH solution to prepare suspension, heating the suspension to 90 ℃ in nitrogen atmosphere, and stirring for reaction for 2 hours. Cooling, centrifuging, adjusting pH to 1 with 1mol/L hydrochloric acid, shaking, standing, and centrifuging for several times until the pH value of supernatant is neutral. Freeze drying the obtained precipitate to obtain deacetylated chitin whisker;

step two: preparing genipin powder into a solution, and adding the deacetylated chitin whisker prepared in the step one to prepare deacetylated chitin whisker/genipin mixed suspension, wherein the mass concentration of the deacetylated chitin whisker in the mixed suspension is 7.5 wt%, and the mass volume concentration of the genipin in the mixed suspension is 3.0 g/L.

Step three: and carrying out ultrasonic homogenization treatment on the mixed suspension liquid to a liquid crystal state to obtain a preliminarily crosslinked chitin whisker liquid crystal, and further crosslinking the chitin whisker liquid crystal at 37 ℃ for 120h to obtain the chitin whisker liquid crystal elastomer.

The photo of the prepared chitin whisker liquid crystal elastomer is shown in fig. 4, a dynamic universal tester is used for testing the compressive strength and modulus of the chitin whisker liquid crystal elastomer prepared in the third step, and the result is shown in fig. 4 (see sample 2CHWs), compared with the acidolysis chitin whisker liquid crystal elastomer prepared in the third step of the example 1 (see sample 0CHWs), the deacetylated chitin whisker liquid crystal elastomer in the embodiment generates more-NH 2 groups due to the removal of part of acetyl groups under the action of alkali, is more beneficial to genipin crosslinking reaction, forms a rigid crosslinking network with higher degree, can provide more load than soft gel, and therefore has higher compressive strength and modulus.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations, and simplifications are intended to be included in the scope of the present invention.