阅读说明：本技术 一种半纤维素基导电复合膜及其制备方法 (Hemicellulose-based conductive composite film and preparation method thereof ) 是由 关莹 高慧 吴玉乐 吴汉 于 2020-12-31 设计创作，主要内容包括：本发明公开一种半纤维素基导电复合膜,采用还原氧化石墨烯、季铵盐半纤维素和壳聚糖复合而成。本发明同时公开上述半纤维素基导电复合膜的制备方法,具体包括还原氧化石墨烯的制备、复合溶液的制备：将季铵盐半纤维素、壳聚糖和环氧氯丙烷制备成溶液,其特征在于,所述制备过程在60℃下反应1～3h、成膜,共三步骤。采用本发明方法制备的还原氧化石墨烯是通过绿色化学还原法制备,工艺简单,产物导电性能较高,且不仅成本低廉、工艺简单、易于投入工业生产,而且制备所得的复合膜具有强度高、耐热性好等特点。(The invention discloses a hemicellulose-based conductive composite film, which is formed by compounding reduced graphene oxide, quaternary ammonium salt hemicellulose and chitosan. The invention also discloses a preparation method of the hemicellulose-based conductive composite membrane, which specifically comprises the following steps of preparing reduced graphene oxide and preparing a composite solution: the preparation method is characterized in that the preparation process comprises three steps of reacting for 1-3 hours at 60 ℃ and forming a film. The reduced graphene oxide prepared by the method is prepared by a green chemical reduction method, the process is simple, the product conductivity is higher, the cost is low, the process is simple, the industrial production is easy to put into, and the prepared composite film has the characteristics of high strength, good heat resistance and the like.)

1. The hemicellulose-based conductive composite film is characterized by being formed by compounding reduced graphene oxide, quaternary ammonium salt hemicellulose and chitosan.

2. A method for preparing the hemicellulose-based conductive composite film according to claim 1, wherein the method comprises the following steps:

(1) preparing reduced graphene oxide: adding natural graphite powder and sodium nitrate into concentrated sulfuric acid, and stirring for 1h at 0 ℃ in an ice bath; after the reaction is finished, slowly adding potassium permanganate, transferring the system into an oil bath kettle, keeping the temperature at 30-40 ℃, and reacting for 30 min;

after the reaction is finished, slowly adding deionized water, keeping the temperature at 85-95 ℃, and reacting for 15 min; after the reaction is finished, adding deionized water, hydrogen peroxide and hydrochloric acid, and carrying out cleaning, filtering, dialysis and freeze-drying to obtain a graphene oxide sample;

adding a graphene oxide sample into deionized water, and adjusting the concentration to 0.01%;

reacting the graphene oxide suspension with a reducing agent L-ascorbic acid in a water bath at 95 ℃, and adjusting the pH of the dispersion to 9-10 by using a 25% ammonia water solution for 15min to obtain a reduced graphene oxide suspension; carrying out ultrasonic treatment on the obtained suspension by using an ultrasonic crusher to finally obtain reduced graphene oxide dispersion liquid;

(2) preparing a composite solution: preparing quaternary ammonium salt hemicellulose, chitosan and epoxy chloropropane into a solution, and is characterized in that the preparation process is carried out for 1-3 h at 60 ℃;

(3) film forming: and (3) mixing the reduced graphene oxide dispersion liquid prepared in the step (1) with the composite solution prepared in the step (2), stirring, air-drying after mixing, and air-drying to obtain the hemicellulose-based conductive composite membrane.

3. The preparation method of the hemicellulose-based conductive composite film according to claim 2, wherein the hemicellulose-based conductive composite film is prepared by adopting a tape-casting film-forming method after the reduced graphene oxide dispersion liquid and the composite solution are mixed and stirred.

4. The method for preparing the hemicellulose-based conductive composite film according to claim 3, wherein in the preparation of the composite solution, the weight ratio of the ingredients of the hemicellulose and the chitosan solution is 15: 1000.

5. The method for preparing the hemicellulose-based conductive composite membrane according to claim 3, wherein in the preparation of the composite solution, the volume ratio of the ingredients of the hemicellulose and the chitosan solution is 15: 1000.

6. The method for preparing the hemicellulose-based conductive composite film according to claim 2, wherein in the step (3) of forming the film, the mixed material is stirred at normal temperature.

7. The method for preparing the hemicellulose-based conductive composite film according to claim 6, wherein in the film forming in the step (3), the mixed material is stirred for 24 hours at normal temperature.

Technical Field

The invention relates to a preparation method of a hemicellulose-based conductive composite film, in particular to a hemicellulose-based conductive composite film and a preparation method thereof.

Background

With the transitional exploitation and use of global energy, renewable biomass resources instead of fossil resources such as petroleum and the like have become the priority development theme of countries in the world. Among them, agricultural straws, forest processing residues, cellulose-rich industrial processing wastes, natural plants and other lignocellulose resources are important raw materials for replacing petroleum. The nano material is always reproducible, has a high specific surface area, has higher catalytic activity and chemical reaction activity, is small in expansion degree, high in strength and hardness, light in weight, easy to modify surface hydroxyl and wide in application. The nano material can be generally used as a reinforcing agent, and is an effective way for improving the mechanical property and the service performance of the material.

Hemicellulose is one of natural polysaccharides with rich content in plants, has the characteristics of no toxicity, biodegradability, renewability, wide sources and the like, and is an important raw material for green sustainable chemistry. Due to the complex structure of hemicellulose and the difficulty in dissolving in common organic solvents and deionized water, the hemicellulose is difficult to be directly used as a raw material for material preparation. Thus, chemical modification offers the possibility of producing biomass-based polymers with excellent properties. Graphene as a carbon material has excellent mechanical properties and extremely high thermal conductivity, and has great application potential in the fields of microelectronics, biosensors, energy storage materials and composite materials. Graphene oxide is an important derivative thereof and also an important precursor for chemically synthesizing graphene.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a hemicellulose-based conductive composite film, and provide a more economical and convenient method for reducing graphene oxide to reinforce a hemicellulose-based composite film material.

The invention solves the technical problems through the following technical scheme:

a hemicellulose-based conductive composite film is formed by compounding reduced graphene oxide, quaternary ammonium salt hemicellulose and chitosan.

The invention also discloses a preparation method of the hemicellulose-based conductive composite membrane, which comprises the following steps:

(1) preparing reduced graphene oxide: adding natural graphite powder and sodium nitrate into concentrated sulfuric acid, and stirring for 1h at 0 ℃ in an ice bath; after the reaction is finished, slowly adding potassium permanganate, transferring the system into an oil bath kettle, keeping the temperature at 30-40 ℃, and reacting for 30 min;

after the reaction is finished, slowly adding deionized water, keeping the temperature at 85-95 ℃, and reacting for 15 min; after the reaction is finished, adding deionized water, hydrogen peroxide and hydrochloric acid, and carrying out cleaning, filtering, dialysis and freeze-drying to obtain a graphene oxide sample;

adding a graphene oxide sample into deionized water, and adjusting the concentration to 0.01%;

reacting the graphene oxide suspension with a reducing agent L-ascorbic acid in a water bath at 95 ℃, and adjusting the pH of the dispersion to 9-10 by using a 25% ammonia water solution for 15min to obtain a reduced graphene oxide suspension; carrying out ultrasonic treatment on the obtained suspension by using an ultrasonic crusher to finally obtain reduced graphene oxide dispersion liquid;

(2) preparing a composite solution: preparing quaternary ammonium salt hemicellulose, chitosan and epoxy chloropropane into a solution, and is characterized in that the preparation process is carried out for 1-3 h at 60 ℃;

(3) film forming: and (3) mixing the reduced graphene oxide dispersion liquid prepared in the step (1) with the composite solution prepared in the step (2), stirring, air-drying after mixing, and air-drying to obtain the hemicellulose-based conductive composite membrane.

Preferably, after the reduced graphene oxide dispersion liquid and the composite solution are mixed and stirred, the hemicellulose-based conductive composite film is prepared by adopting a tape-casting film-forming method.

Preferably, in the preparation of the composite solution, the weight ratio of the hemicellulose to the chitosan solution ingredients is 15: 1000.

Preferably, in the preparation of the composite solution, the volume ratio of the hemicellulose to chitosan solution ingredients is 15: 1000.

Preferably, in the step (3) of film formation, the mixed materials are stirred at normal temperature.

Preferably, in the step (3) of film forming, the mixed materials are stirred for 24 hours at normal temperature.

Compared with the prior art, the invention has the following advantages:

1. the reduced graphene oxide prepared by the method is prepared by a green chemical reduction method, the process is simple, and the product has high conductivity.

2. According to the invention, through one-step reaction, the reduced graphene oxide suspension, the quaternary ammonium salt hemicellulose solution and the chitosan solution are fully mixed, and then the composite film is formed by adopting a tape-casting film forming method.

3. The method has the advantages of low cost, simple process and easy industrial production, and the prepared composite membrane has the characteristics of high strength, good heat resistance and the like.

Drawings

FIG. 1 is an AFM image of graphene oxide and reduced graphene oxide according to examples 1-4 of the present invention;

the results disclosed in figure 1 show that: after reduction treatment, the graphene oxide and the reduced graphene oxide are of a nano flaky structure, and the thickness of the graphene oxide and the reduced graphene oxide is 1.5-2.5 nm;

FIG. 2 is an infrared spectrum of the raw material and the composite films of examples 1 to 4 according to the present invention;

the results disclosed in figure 2 show that: the reduced graphene oxide is used as a reinforcing phase and added into the hemicellulose/chitosan composite membrane for physical combination, and no chemical reaction occurs;

FIG. 3 is the conductivity results for the composite membranes of examples 1-4 of the present invention;

the results disclosed in figure 3 show that: with the addition of the reduced graphene oxide, the 3 composite films have certain conductivity, wherein the conductivity of the composite films with the addition of the reduced graphene oxide is in an increasing trend. When the addition amount is 7mL and 0.01 percent, the conductivity of the composite membrane is the maximum;

FIG. 4 is a graph showing the results of light transmittance of the composite films of examples 1 to 4 of the present invention;

the results disclosed in figure 4 show that: with the increase of the reduced graphene oxide, the light transmittance of the composite film is sequentially reduced, but the light transmittance is over 55%. Wherein, the light transmittance of the No. 1 and No. 2 samples is the highest and reaches more than 90 percent. Meanwhile, the light transmittance of the composite film in an ultraviolet light wave band is close to 0, and the composite film has better ultraviolet resistance;

FIG. 5 is a stress-strain diagram of composite films of examples 1-4 of the present invention;

the results disclosed in fig. 5 show that: the tensile breaking elongation strain of the hemicellulose-based composite film can be obviously improved by adding the reduced graphene oxide. When the addition amount is 5mL and 0.01 percent, the breaking tensile strain of the composite film is the highest.

Detailed Description

The following examples are given for the detailed implementation and specific operation of the present invention, but the scope of the present invention is not limited to the following examples.

Example 1

(1) Adding the natural graphite powder and sodium nitrate into concentrated sulfuric acid according to the mass ratio (2:1), and stirring for 1h at 0 ℃ in an ice bath. After the reaction is finished, slowly adding potassium permanganate, transferring the system into an oil bath kettle, and reacting for 30min while keeping the temperature at 35 +/-5 ℃. After the reaction is finished, deionized water is slowly added, the temperature is kept at 90 +/-5 ℃, and the reaction is carried out for 15 min. And after the reaction is finished, adding a certain amount of deionized water, hydrogen peroxide and hydrochloric acid, and carrying out cleaning, filtering, dialysis and freeze-drying to obtain the graphene oxide sample.

The graphene oxide obtained by preparation is observed under an atomic force microscope, the structure is shown in fig. 1, and as can be seen from fig. 1, after reduction treatment, the graphene oxide and the reduced graphene oxide are nano-sheet structures, and the thickness is 1.5-2.5 nm.

(2) And adding the graphene oxide sample into deionized water, and adjusting the concentration to 0.01%. And (3) reacting the graphene oxide suspension with a reducing agent L-ascorbic acid in a water bath at 95 ℃, and adjusting the pH of the dispersion to 9-10 by using a 25% ammonia water solution, wherein the reaction time is 15min, so as to obtain the reduced graphene oxide suspension. And carrying out ultrasonic treatment on the obtained suspension by using an ultrasonic crusher to finally obtain the reduced graphene oxide dispersion liquid.

(3) 5mL of a 1.5% quaternary ammonium salt hemicellulose solution was mixed with 5mL of a 1.5% chitosan solution, and stirred for 1 hour to mix thoroughly. Adding 0.5mL of epoxy chloropropane, stirring continuously, and reacting for 1h at 60 ℃. After the reaction is finished, casting the mixed solution into a film, and drying the film at room temperature to obtain a composite film sample which is marked as FQC;

performance test: tensile strength at break of 32.11MPa, elongation at break of 38.62%, Young's modulus of 83.14MPa, and electrical conductivity of 0.

Example 2

(1) Adding the natural graphite powder and sodium nitrate into concentrated sulfuric acid according to the mass ratio (2:1), and stirring for 1h at 0 ℃ in an ice bath. After the reaction is finished, slowly adding potassium permanganate, transferring the system into an oil bath kettle, and reacting for 30min while keeping the temperature at 35 +/-5 ℃. After the reaction is finished, deionized water is slowly added, the temperature is kept at 90 +/-5 ℃, and the reaction is carried out for 15 min. After the reaction is finished, adding a certain amount of deionized water, hydrogen peroxide and hydrochloric acid, and carrying out cleaning, filtering, dialysis and freeze-drying to obtain a graphene oxide sample;

(2) and adding the graphene oxide sample into deionized water, and adjusting the concentration to 0.01%. And (3) reacting the graphene oxide suspension with a reducing agent L-ascorbic acid in a water bath at 95 ℃, and adjusting the pH of the dispersion to 9-10 by using a 25% ammonia water solution, wherein the reaction time is 15min, so as to obtain the reduced graphene oxide suspension. And carrying out ultrasonic treatment on the obtained suspension by using an ultrasonic crusher to finally obtain the reduced graphene oxide dispersion liquid.

(3) 5mL of a 1.5% quaternary ammonium salt hemicellulose solution was mixed with 5mL of a 1.5% chitosan solution, and stirred for 1 hour to mix thoroughly. Adding 0.5mL of epoxy chloropropane, stirring continuously, and reacting for 1h at 60 ℃. After the reaction, 3mL of 0.01% reduced graphene oxide dispersion was added to the mixture, and the mixture was stirred at room temperature for 24 hours. Casting the mixed solution into a film, and drying the film in a vacuum drying oven at 40 ℃ to obtain a composite film sample which is marked as FK 3R;

performance test: the composite film obtained in example 1 had a tensile strength at break of 23.53MPa, an elongation at break of 29.78%, a Young' S modulus of 79.01MPa, and an electrical conductivity of 3.1X 10-2S/cm.

Example 3

(1) Adding the natural graphite powder and sodium nitrate into concentrated sulfuric acid according to the mass ratio (2:1), and stirring for 1h at 0 ℃ in an ice bath. After the reaction is finished, slowly adding potassium permanganate, transferring the system into an oil bath kettle, and reacting for 30min while keeping the temperature at 35 +/-5 ℃. After the reaction is finished, deionized water is slowly added, the temperature is kept at 90 +/-5 ℃, and the reaction is carried out for 15 min. After the reaction is finished, adding a certain amount of deionized water, hydrogen peroxide and hydrochloric acid, and carrying out cleaning, filtering, dialysis and freeze-drying to obtain a graphene oxide sample;

(2) and adding the graphene oxide sample into deionized water, and adjusting the concentration to 0.01%. And (3) reacting the graphene oxide suspension with a reducing agent L-ascorbic acid in a water bath at 95 ℃, and adjusting the pH of the dispersion to 9-10 by using a 25% ammonia water solution, wherein the reaction time is 15min, so as to obtain the reduced graphene oxide suspension. And carrying out ultrasonic treatment on the obtained suspension by using an ultrasonic crusher to finally obtain the reduced graphene oxide dispersion liquid.

(3) 5mL of a 1.5% quaternary ammonium salt hemicellulose solution was mixed with 5mL of a 1.5% chitosan solution, and stirred for 1 hour to mix thoroughly. Adding 0.5mL of epoxy chloropropane, stirring continuously, and reacting for 1h at 60 ℃. After the reaction, 5mL of 0.01% reduced graphene oxide dispersion was added to the mixture, and the mixture was stirred at room temperature for 24 hours. Casting the mixed solution into a film, and drying the film in a vacuum drying oven at 40 ℃ to obtain a composite film sample which is marked as FK 5R;

performance test: the composite film obtained in example 1 had a tensile strength at break of 17.33MPa, an elongation at break of 57.46%, a Young' S modulus of 30.16MPa, and an electrical conductivity of 10.3X 10-2S/cm.

Example 4

(1) Adding the natural graphite powder and sodium nitrate into concentrated sulfuric acid according to the mass ratio (2:1), and stirring for 1h at 0 ℃ in an ice bath. After the reaction is finished, slowly adding potassium permanganate, transferring the system into an oil bath kettle, and reacting for 30min while keeping the temperature at 35 +/-5 ℃. After the reaction is finished, deionized water is slowly added, the temperature is kept at 90 +/-5 ℃, and the reaction is carried out for 15 min. After the reaction is finished, adding a certain amount of deionized water, hydrogen peroxide and hydrochloric acid, and carrying out cleaning, filtering, dialysis and freeze-drying to obtain a graphene oxide sample;

(2) and adding the graphene oxide sample into deionized water, and adjusting the concentration to 0.01%. And (3) reacting the graphene oxide suspension with a reducing agent L-ascorbic acid in a water bath at 95 ℃, and adjusting the pH of the dispersion to 9-10 by using a 25% ammonia water solution, wherein the reaction time is 15min, so as to obtain the reduced graphene oxide suspension. And carrying out ultrasonic treatment on the obtained suspension by using an ultrasonic crusher to finally obtain the reduced graphene oxide dispersion liquid.

(3) 5mL of a 1.5% quaternary ammonium salt hemicellulose solution was mixed with 5mL of a 1.5% chitosan solution, and stirred for 1 hour to mix thoroughly. Adding 0.5mL of epoxy chloropropane, stirring continuously, and reacting for 1h at 60 ℃. After the reaction, 7mL of 0.01% reduced graphene oxide dispersion was added to the mixture, and the mixture was stirred at room temperature for 24 hours. Casting the mixed solution into a film, and drying the film in a vacuum drying oven at 40 ℃ to obtain a composite film sample which is marked as FK 7R;

performance test: the composite film obtained in example 1 had a tensile strength at break of 25.52MPa, an elongation at break of 44.81%, a Young' S modulus of 56.95MPa, and an electrical conductivity of 12.8X 10-2S/cm.

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 and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.