CN109400936B - Method for regulating and controlling photoelectricity haze and ultraviolet filtering effect of modified nano cellulose film - Google Patents
Method for regulating and controlling photoelectricity haze and ultraviolet filtering effect of modified nano cellulose film Download PDFInfo
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Abstract
The invention provides a method for regulating and controlling the photoelectricity haze and the ultraviolet filtering action of a modified nano cellulose film. The modified nano-cellulose film is obtained by modifying TEMPO-oxidized cellulose nano-fibers with a Zn (II) terpyridine complex, placing the modified nano-cellulose film in an alcohol solvent, taking out after soaking, and removing redundant solvent to obtain the modified nano-cellulose film after solvent treatment; and placing the modified nano-cellulose film subjected to solvent treatment in water, soaking for 10-150 min, taking out, and removing excessive water to obtain the modified nano-cellulose film subjected to water treatment. The haze value of the modified nano-cellulose film can be regulated and controlled through alcohol treatment, specifically, the haze is increased after the alcohol treatment, the ultraviolet filtering performance is enhanced, and the haze of the modified nano-cellulose film can be regulated according to different requirements, so that the application range of the modified nano-cellulose film is enlarged.
Description
Technical Field
The invention belongs to the field of biomass photoelectricity nano materials, and particularly relates to a method for regulating and controlling photoelectricity haze and ultraviolet ray filtering action of a modified nano cellulose film.
Background
Cellulose nanofibers, also called nanocellulose,the cellulose functional material is separated from the cell wall of plant fiber, which is the most widely distributed renewable resource on the earth, under the action of very large mechanical force or by combining pretreatment with the action of mechanical force, and has the diameter of nanometer and the length of micrometer. The cellulose nano-fiber has higher strength, rigidity (the modulus can reach 138GPa) and larger specific surface area (can reach 50 m)2G), very low coefficient of thermal expansion (CTE, 0.1ppm/k, close to quartz). Depending on the way of treating the plant fibers, the cellulose nanofibers are usually cellulose nanomaterials having a diameter of 5 to 50nm or 20 to 100nm, a length of several to ten and several micrometers, and a relatively large major diameter. Compared with cellulose nanofibers without oxidation treatment, the TEMPO-oxidized cellulose nanofibers are prepared by firstly carrying out oxidation pretreatment and then carrying out mechanical treatment, most of the cellulose nanofibers are oxidized into aldehyde groups or carboxyl groups, the hydrogen bond content is low, the dispersion effect is better, and the energy consumption is saved.
Generally, a papermaking process is applied to cellulose nanofibers to obtain a nanocellulose film, which may also be referred to as a nanopaper. Nanocellulose films are nano-functional materials with many excellent properties, such as: optical transparency, thermal stability, flexibility, printability, high mechanical strength, strong chemical modification ability, and the like. Also due to these properties, nanocellulose films can be used to make flexible energy storage and conversion devices, luminescent films and flexible electronic devices, such as solar cells, LEDs, UVA barrier functional materials, anti-counterfeiting security materials, supercapacitors, optical sensing devices, and the like.
Nanocellulose films have attracted increasing research interest in the field of optoelectronics. In addition, the haze can be adjusted by cellulose nanofibers with different sizes for preparing the nano-cellulose film, and the size and the assembly density of the cellulose nanofibers are important factors for determining the haze of the nano-cellulose film. For example, the light transmittance of the nanocellulose film can reach more than 90%, but the haze is between 20% and 60%. This is due to the size of the cellulose nanofibers and the pores between them causing light scattering, which creates the effect of haze. Although the haze value of the nanocellulose film can be designed according to the size of the cellulose nanofibers, the haze value is fixed and cannot be adjusted after the nanocellulose film is prepared. In addition, light such as sunlight, fluorescent light or other optical materials, which human beings come into contact with in daily life, emit a certain amount of ultraviolet rays, which may have adverse effects on the human body, such as skin cancer or skin photoaging. Furthermore, ultraviolet irradiation causes accelerated aging of commercial products to cause changes in properties of the commercial products, and current nanocellulose films lack an ultraviolet filtering function.
Disclosure of Invention
The invention aims to solve the problem that the haze value of a nano-cellulose film cannot be regulated and controlled, increase the ultraviolet filtering performance of the nano-cellulose film, and provide a method for regulating and controlling the photoelectric haze and the ultraviolet filtering effect of a modified nano-cellulose film.
The invention is realized by the following technical scheme:
a method for regulating and controlling photoelectricity haze and ultraviolet filtering effect of a modified nano cellulose film is characterized in that the modified nano cellulose film is obtained by modifying TEMPO-oxidized cellulose nano fibers through a Zn (II) terpyridine complex, the modified nano cellulose film is placed in an alcohol solvent, and is taken out after being soaked, and redundant solvent is removed, so that the modified nano cellulose film after being treated by the solvent is obtained.
Preferably, the alcohol solvent is n-butanol, isobutanol, benzyl alcohol, sec-butanol, tert-butanol, isopropanol, methanol, ethylene glycol, propylene glycol or polyethylene glycol.
Preferably, the soaking time is 10-150 min.
Preferably, the method further comprises the following steps: and placing the modified nano-cellulose film subjected to solvent treatment in water, soaking for 10-150 min, taking out, and removing excessive water to obtain the modified nano-cellulose film subjected to water treatment.
Preferably, the preparation method of the modified nano cellulose film comprises the following steps:
step 1, dispersing 4 '- (3,4, 5-trimethoxyphenyl) -2, 2': 6 ', 2' -terpyridine and zinc chloride in an ethanol solution, stirring for reaction, filtering to obtain a grey-white precipitate, and standing to obtain a white Zn (II) terpyridine complex;
and 2, taking TEMPO-oxidized cellulose nano-fibers, dispersing the TEMPO-oxidized cellulose nano-fibers in water, dissolving a Zn (II) terpyridine complex in a dimethyl sulfoxide solution, mixing and stirring uniformly, and filtering to obtain the modified nano-cellulose film.
Further, in the step 1, 4 '- (3,4, 5-trimethoxyphenyl) -2, 2': 6 ', 2' -terpyridine is prepared by the following method: dissolving 3,4, 5-trimethoxybenzaldehyde and KOH particles in an ethanol solution, then dropwise adding 2-acetylpyridine, and stirring to react until a light yellow solid is formed; then ammonia gas is introduced, then the solution is refluxed, the obtained light white solid is collected by filtration, washed and dried, and 4 '- (3,4, 5-trimethoxyphenyl) -2, 2': 6 ', 2' -terpyridine is obtained.
Further, in step 2, the TEMPO-oxidized cellulose nanofibers are prepared by the following method: adding a cellulose raw material into water, shearing, sequentially adding TEMPO and NaBr aqueous solutions, adding a NaOH aqueous solution to adjust the pH value of the solution to 10-11, adding a NaClO solution, and stirring for reaction; after the reaction is finished, adjusting the pH value of the reaction solution to be neutral by using dilute hydrochloric acid to obtain TEMPO oxidized cellulose suspension, washing, and carrying out high-pressure homogenization treatment to obtain TEMPO-oxidized cellulose nanofiber.
Compared with the prior art, the invention has the following beneficial technical effects:
the invention can regulate and control the haze value of the modified nano cellulose film through alcohol treatment, in particular to the method which increases the haze after the alcohol treatment and enhances the ultraviolet filtering performance. In combination with porosity data from BET measurements, the nanocellulose films obtained from the modified nanocellulose were transparent and had little porosity, but the increase in porosity after benzyl alcohol treatment was significant, probably due to wet-out after benzyl alcohol treatment, and therefore the film haze increased. It is also possible that after the benzyl alcohol treatment, the bonds between the small molecules and the nanocellulose film are broken, leading to an increase in haze. Therefore, the modified nano-cellulose film can be subjected to haze adjustment according to different requirements, and the application range of the modified nano-cellulose film is enlarged, so that the modified nano-cellulose film has good application prospects in the aspects of flexible optics and sensing materials.
Furthermore, after the modified nano-cellulose film treated by the solvent is subjected to water treatment, the haze is reduced, namely the haze of the modified nano-cellulose film can be reversibly regulated and controlled. Therefore, the modified nano-cellulose film can be subjected to haze adjustment according to different requirements, so that the application range of the modified nano-cellulose film is enlarged.
Drawings
Fig. 1 is a schematic diagram of the controllable reversible haze properties of a modified nanocellulose film.
Figure 2 is the BET test results for the modified nanocellulose films without and with alcohol treatment.
FIG. 3 is a haze diagram of a film of a nanocellulose modified by different solvent control.
Figure 4 is a graphical representation of the uv filtration performance of modified nanocellulose films of different haze values.
Figure 5 is a graphical representation of the stability of uv filtering properties of the modified nanocellulose membrane.
Detailed Description
The present invention will now be described in further detail with reference to specific examples, which are intended to be illustrative, but not limiting, of the invention.
The invention comprises the following steps:
(1) preparation of TEMPO-oxidized cellulose nanofibers
The bleached kraft pulp of the needle wood is used as a raw material, and TEMPO-NaBr-NaClO is used as a pretreatment system. Weighing 3-10 g of oven-dried bleached softwood fiber in deionized water, and shearing at a high speed for 5-10 min to uniformly disperse the fiber in water. Adding an aqueous solution of TEMPO and NaBr according to the proportion of 0.01-0.03 mmol of TEMPO and 6.0-10.0 mmol of NaBr to each gram of softwood fiber, adding an aqueous solution of NaOH to adjust the pH value of the aqueous solution to 10-11, adding a NaClO solution to the system according to the proportion of 6.0-10.0 mmol of NaClO to each gram of softwood fiber, and stirring for 3-5 hours. After the reaction was completed, the pH of the reaction solution was adjusted to neutral by dilute hydrochloric acid to obtain a TEMPO-oxidized cellulose suspension. Washing the fiber with deionized water to be neutral, adjusting the fiber to be a cellulose suspension with the concentration of 0.03-0.15 wt%, carrying out high-pressure homogenization treatment, and homogenizing for 25-40 times under the pressure of 60-120 MPa to obtain the TEMPO-oxidized cellulose nanofiber.
(2) Synthesis of small organic molecules
Dissolving 5-10 mmol (0.98-1.96 g) of 3,4, 5-trimethoxybenzaldehyde and 10-20 mmol (7.7-15.6 g) of KOH particles in 50-100 ml of ethanol solution, and then dropwise adding 10-20 mmol (1.2-2.4 g) of 2-acetylpyridine. The solution was stirred at room temperature for 12-16 h until a pale yellow solid formed. Then 30-60 ml of ammonia gas is introduced, and then the solution is refluxed for 12-16 h. The resulting pale white solid was collected by filtration and washed with ethanol until the filtrate was colorless. And finally, carrying out vacuum drying at the temperature of 45-50 ℃ to obtain 4 '- (3,4, 5-trimethoxyphenyl) -2, 2': 6 ', 2' -terpyridine (terpyridine ligand for short).
Terpyridine ligands (0.8-1.6 g) and ZnCl2·2H2Dispersing O (2-4 mmol) in 50-100 ml ethanol solution, and stirring at room temperature for 12-16 h. And then pouring the reaction liquid into ice water, filtering to obtain an off-white precipitate, and standing at room temperature for 3-5 days to obtain a white Zn (II) terpyridine complex modifier.
The reaction formula is shown below.
(3) Preparation of modified nano-cellulose film
Taking TEMPO-oxidized cellulose nanofiber as an absolute dry 12-36 mg, ultrasonically dispersing in 10-30 mL of deionized water, weighing 3-9 mg of modifier Zn (II) terpyridine complex, dissolving in 2-6 mL of dimethyl sulfoxide solution, and mixing and stirring for 12-24 hours. And carrying out vacuum filtration to obtain the modified nano cellulose film, namely the modified nano paper.
The reaction formula is shown below.
(4) Treatment of nanocellulose films with different solvents
(401) Treatment of unmodified nanocellulose films with different solvents
Placing the unmodified nano cellulose film in a weighing bottle, adding 10-50 ml of solvent, soaking for 10-60 min, taking out, and removing the redundant solvent to obtain the unmodified nano cellulose film treated by the solvent.
(402) Treatment of modified nanocellulose films with different solvents
Placing the modified nano-cellulose film in a weighing bottle, adding 10-50 ml of solvent, soaking for 10-60 min, taking out, removing the redundant solvent to obtain the modified nano-cellulose film treated by the solvent, and carrying out light transmittance test to obtain an ultraviolet-visible light transmittance map. And adding 10-50 ml of water, soaking for 10-60 min, taking out, removing excessive water to obtain the modified nano cellulose film after water treatment, and carrying out light transmittance test to obtain an ultraviolet-visible light transmittance spectrum.
(5) Ultraviolet shielding stability detection of modified nanocellulose thin film after solvent treatment
And (3) irradiating the modified nano cellulose film treated by the solvent for 30-150 min under 365nm ultraviolet rays, and detecting the light transmittance after the modified nano cellulose film is taken out to obtain an ultraviolet-visible light transmittance spectrum.
The invention takes the bleached kraft pulp of the needle wood as the raw material to prepare the nano cellulose film, which comes from natural and renewable substances in the nature, reduces the waste of resources and realizes high-valued utilization.
The organic micromolecule Zn (II) terpyridine complex is used for carrying out coordination bond modification on the cellulose nano-fiber, and the modified nano-cellulose film not only has the characteristics of transparency, softness, degradability, high strength and thermodynamic stability of the nano-cellulose film, but also has good coordination and color development capabilities of micromolecules.
The present invention is further described below in conjunction with the conditions for preparing the nanocellulose films of the present invention, as well as the thickness of the films, the controllably reversible haze characteristics, and the like, and the following non-limiting examples are provided to enable one of ordinary skill in the art to more fully understand the present invention and are not intended to limit the invention in any way.
Example 1
3g of absolutely dry bleached softwood fiber is weighed into deionized water, and is sheared at a high speed for 5min, so that the fiber is uniformly dispersed in the water. An aqueous solution of TEMPO (0.01mmol/g) and NaBr (6.0mmol/g) were added sequentially, an aqueous NaOH solution was added to adjust the pH to 10, and a solution of NaClO (6.0mmol/g) was added to the system and stirred for 3 h. After the reaction was completed, the pH of the reaction solution was adjusted to neutral by dilute hydrochloric acid to obtain a TEMPO-oxidized cellulose suspension. Washing with deionized water to neutrality, adjusting to 0.03 wt% cellulose suspension, homogenizing under 60MPa for 40 times to obtain TEMPO-oxidized cellulose nanofiber.
5mmol (0.98g) of 3,4, 5-trimethoxybenzaldehyde and 10mmol (7.7g) of KOH as particles are dissolved in 50ml of an ethanol solution, and 10mmol (1.2g) of 2-acetylpyridine is added dropwise. The solution was stirred at room temperature for 12h until a pale yellow solid formed. 30ml of ammonia gas were introduced again and the solution was refluxed for a further 12 h. The resulting pale white solid was collected by filtration and washed with ethanol until the filtrate was colorless. Finally, vacuum drying is carried out at the temperature of 45 ℃ to obtain 4 '- (3,4, 5-trimethoxyphenyl) -2, 2': 6 ', 2' -terpyridine (terpyridine ligand for short).
Taking terpyridine ligand (0.8g) and ZnCl2·2H2O (2mmol) was dispersed in 50ml of ethanol solution and stirred at room temperature for 12 h. And then pouring the reaction liquid into ice water, filtering to obtain an off-white precipitate, and standing at room temperature for 3 days to obtain a white Zn (II) terpyridine complex.
TEMPO-oxidized cellulose nanofiber oven dry 24mg is taken, ultrasonically dispersed in 15mL deionized water, 6mg of Zn (II) terpyridine complex is weighed and dissolved in 5mL of dimethyl sulfoxide solution, and then the mixture is mixed and stirred for 12 hours. And carrying out vacuum filtration to obtain the modified nano cellulose film, namely the modified nano paper.
Placing the modified nano-cellulose film in a weighing bottle, adding 10ml of benzyl alcohol solvent, soaking for 60min, taking out, removing the excess benzyl alcohol solvent to obtain the modified nano-cellulose film treated by the benzyl alcohol solvent, and carrying out light transmittance test to obtain an ultraviolet-visible light transmittance map. And adding 10ml of water, soaking for 60min, taking out, removing excessive water to obtain the modified nano-cellulose film after water treatment, and carrying out light transmittance test to obtain an ultraviolet-visible light transmittance spectrum.
And (3) irradiating the modified nano cellulose film treated by the solvent for 30min under 365nm ultraviolet rays, and detecting the light transmittance after the modified nano cellulose film is taken out to obtain an ultraviolet-visible light transmittance spectrum.
The obtained modified nano-cellulose film is uniform and transparent, has controllable and reversible haze characteristics, and has the thickness of 0.028mm, the light transmittance of 90 percent and the haze of 10 percent; after treatment with the solvent benzyl alcohol, the thickness increased to 0.034mm, the light transmittance decreased to 73%, and the haze was 37%; then deionized water is used for treatment, the thickness is reduced to 0.029mm again, the light transmittance is increased to 89%, and the haze is reduced to 12%; as shown in fig. 1.
Comparative example 1:
taking TEMPO-oxidized cellulose nano-fiber, oven drying 12mg, ultrasonically dispersing in 10mL deionized water, adding 2mL dimethyl sulfoxide solution, and stirring for 12 h. And carrying out vacuum filtration to obtain an unmodified nano cellulose film, namely unmodified nano paper.
Placing the unmodified nano-cellulose film in a weighing bottle, adding 10ml of benzyl alcohol solvent, soaking for 60min, taking out, and removing the redundant benzyl alcohol solvent to obtain the unmodified nano-cellulose film treated by the benzyl alcohol solvent.
The obtained unmodified nano cellulose film is uniform and transparent, but does not have controllable and reversible haze characteristics, the thickness is 0.020mm, the light transmittance is 89%, the haze is 9%, and after the treatment with the solvent benzyl alcohol, the thickness is almost unchanged, the thickness is 0.019mm, the light transmittance is 91%, and the haze is 9%.
As can be seen from the above example 1 and comparative example 1, the modified nanocellulose film retains the uniform and transparent characteristics thereof, and through modification, under the same preparation conditions, the film thickness is increased by 40%, but the light transmittance is not reduced, and the modified film has controllable and reversible haze characteristics. Therefore, it can be shown that the haze of the nano-cellulose film can be controlled by treating the nano-cellulose film with benzyl alcohol.
The BET measurement was performed on the modified nanocellulose film without benzyl alcohol treatment and the modified nanocellulose film with benzyl alcohol treatment of example 1, and the results are shown in fig. 2, and it can be seen from fig. 2 that the adsorption amount of the nanocellulose film without solvent treatment is substantially zero, and the pore volume is too small to be measured, because the binding between the nanocelluloses after film formation is very dense and there are almost no pores; the film after the benzyl alcohol treatment had an increased amount of gas absorption, which indicates that the number of pores between the nanocelluloses was increased after the solvent treatment, and the haze of the film was increased.
Example 2
And (3) placing 5 pieces of modified nano-cellulose films to be respectively treated with benzyl alcohol, wherein the soaking time is respectively 0min, 30min, 90min, 120min and 150min, removing the redundant benzyl alcohol solvent to obtain the modified nano-cellulose films treated with the benzyl alcohol solvent, and carrying out light transmittance test to obtain an ultraviolet-visible light transmittance spectrum, wherein the result is shown in figure 3. As can be seen from fig. 3, the modified nanocellulose film treated with benzyl alcohol has a significantly reduced absorption in the uv region compared to the modified nanocellulose film not treated with benzyl alcohol, which indicates that it has a high uv filtering performance after solvent treatment, and the uv filtering performance is continuously enhanced as the treatment time is prolonged, because the haze is increased as the treatment time is prolonged, that is, the haze is increased and the uv filtering performance is enhanced.
Example 3
The modified nano-cellulose film is prepared according to the method of the embodiment 1, the modified nano-cellulose film is placed in a weighing bottle, 25ml of glycol solvent is added, the modified nano-cellulose film is taken out after being soaked for 60min, the excessive glycol solvent is removed, the modified nano-cellulose film treated by the glycol solvent is obtained, and the light transmittance test is carried out, so that the ultraviolet-visible light transmittance spectrum is obtained.
Example 4
The modified nanocellulose film is prepared according to the method of example 1, the modified nanocellulose film is placed in a weighing bottle, 10ml of n-butyl alcohol solvent is added, the modified nanocellulose film is taken out after being soaked for 60min, the surplus n-butyl alcohol solvent is removed, the modified nanocellulose film treated by the n-butyl alcohol solvent is obtained, and the light transmittance test is carried out to obtain the ultraviolet-visible light transmittance spectrum.
Example 5
The modified nano-cellulose film is prepared according to the method of the embodiment 1, the modified nano-cellulose film is placed in a weighing bottle, 50ml of isopropanol solvent is added, the modified nano-cellulose film is taken out after being soaked for 60min, the excess isopropanol solvent is removed, the modified nano-cellulose film treated by the isopropanol solvent is obtained, and the light transmittance test is carried out to obtain an ultraviolet-visible light transmittance map.
Example 6
The modified nanocellulose film is prepared according to the method of example 1, the modified nanocellulose film is placed in a weighing bottle, 10ml of isobutanol solvent is added, the modified nanocellulose film is taken out after being soaked for 60min, the excess isobutanol solvent is removed, the modified nanocellulose film treated by the isobutanol solvent is obtained, and the light transmittance test is carried out to obtain an ultraviolet-visible light transmittance spectrum.
Example 7
The modified nano-cellulose film is prepared according to the method in the embodiment 1, the modified nano-cellulose film is placed in a weighing bottle, 10ml of sec-butyl alcohol solvent is added, the modified nano-cellulose film is taken out after being soaked for 60min, the surplus sec-butyl alcohol solvent is removed, the modified nano-cellulose film treated by the sec-butyl alcohol solvent is obtained, and the light transmittance test is carried out, so that the ultraviolet-visible light transmittance map is obtained.
Example 8
The modified nano-cellulose film is prepared according to the method of the embodiment 1, the modified nano-cellulose film is placed in a weighing bottle, 20ml of tert-butyl alcohol solvent is added, the modified nano-cellulose film is taken out after being soaked for 60min, the surplus tert-butyl alcohol solvent is removed, the modified nano-cellulose film treated by the tert-butyl alcohol solvent is obtained, and the light transmittance test is carried out, so that the ultraviolet-visible light transmittance map is obtained.
Example 9
The modified nanocellulose film is prepared according to the method of the embodiment 1, the modified nanocellulose film is placed in a weighing bottle, 25ml of methanol solvent is added, the modified nanocellulose film is taken out after being soaked for 60min, the excessive methanol solvent is removed, the modified nanocellulose film treated by the methanol solvent is obtained, and the light transmittance test is carried out to obtain the ultraviolet-visible light transmittance spectrum.
Example 10
The modified nanocellulose film is prepared according to the method of the embodiment 1, the modified nanocellulose film is placed in a weighing bottle, 25ml of glycerol solvent is added, the modified nanocellulose film is taken out after being soaked for 60min, the excess glycerol solvent is removed, the modified nanocellulose film processed by the glycerol solvent is obtained, and the ultraviolet-visible light transmittance spectrum is obtained after the light transmittance test.
Example 11
The modified nano-cellulose film is prepared according to the method of the embodiment 1, the modified nano-cellulose film is placed in a weighing bottle, 25ml of polyethylene glycol 400 solvent is added, the modified nano-cellulose film is taken out after being soaked for 60min, the excessive polyethylene glycol 400 solvent is removed, the modified nano-cellulose film treated by the polyethylene glycol 400 solvent is obtained, and the light transmittance test is carried out, so that the ultraviolet-visible light transmittance map is obtained.
The haze characteristics of the modified nanocellulose films treated by different solvents in example 1 and examples 3-11 are shown in fig. 4, and it can be seen from fig. 4 that the haze of the modified nanocellulose films can be controlled by various solvents, wherein the control effect of n-butanol is the best.
The uv-visible absorption of the modified nanocellulose films of example 1 and examples 3-11 treated with different solvents is shown in figure 5. As can be seen from fig. 5, the modified nanocellulose film treated by the solvents respectively has the light transmittance which is smaller as the haze is larger, i.e. the modified nanocellulose film has the ultraviolet ray filtering effect as the haze is larger.
The invention provides a method for regulating and controlling the photoelectricity haze characteristic of a modified nano cellulose film. Firstly, obtaining cellulose nano-fiber by taking bleached softwood kraft pulp as a raw material through TEMPO oxidation pretreatment and high-pressure homogenization, then carrying out modification treatment by using an organic micromolecule Zn (II) terpyridine complex, and obtaining a modified nano-cellulose film by using a papermaking process. The modified nano-cellulose film has the characteristics of transparency, softness, degradability, high strength, thermodynamic stability, controllable and reversible haze characteristic, can react to different solvent stimuli to obtain nano-cellulose films with different haze, and has the characteristics of visible light transmission and ultraviolet light filtration, so that the modified nano-cellulose film has a good application prospect in the aspects of flexible optics and sensing materials, and has great significance in reducing resource waste and realizing high-value utilization of cellulose.
Claims (6)
1. A method for regulating and controlling the photoelectricity haze and ultraviolet filtering effect of a modified nano cellulose film is characterized in that the modified nano cellulose film is obtained by modifying TEMPO-oxidized cellulose nano fibers with a Zn (II) terpyridine complex, the modified nano cellulose film is placed in an alcohol solvent, and is taken out after being soaked, and redundant solvent is removed to obtain the modified nano cellulose film after being treated by the solvent;
the preparation method of the modified nano cellulose film comprises the following steps:
step 1, dispersing 4 '- (3,4, 5-trimethoxyphenyl) -2, 2': 6 ', 2' -terpyridine and zinc chloride in an ethanol solution, stirring for reaction, filtering to obtain a grey-white precipitate, and standing to obtain a white Zn (II) terpyridine complex;
and 2, taking TEMPO-oxidized cellulose nano-fibers, dispersing the TEMPO-oxidized cellulose nano-fibers in water, dissolving a Zn (II) terpyridine complex in a dimethyl sulfoxide solution, mixing and stirring uniformly, and filtering to obtain the modified nano-cellulose film.
2. The method for modulating the electro-optical haze and the ultraviolet filtering effect of the modified nanocellulose film of claim 1, wherein said alcohol solvent is n-butanol, iso-butanol, benzyl alcohol, sec-butanol, tert-butanol, iso-propanol, methanol, ethylene glycol, propylene glycol or polyethylene glycol.
3. The method for regulating and controlling the photoelectric haze and the ultraviolet filtering effect of the modified nano-cellulose film according to claim 1, wherein the soaking time is 10-150 min.
4. The method for regulating and controlling the electro-optical haze and the ultraviolet filtering effect of the modified nano-cellulose film according to claim 1, further comprising the following steps: and placing the modified nano-cellulose film subjected to solvent treatment in water, soaking for 10-150 min, taking out, and removing excessive water to obtain the modified nano-cellulose film subjected to water treatment.
5. The method for regulating and controlling the photoelectric haze and the ultraviolet filtering effect of the modified nano-cellulose film as claimed in claim 1, wherein in the step 1, 4 '- (3,4, 5-trimethoxyphenyl) -2, 2': 6 ', 2' -terpyridine is prepared by the following method: dissolving 3,4, 5-trimethoxybenzaldehyde and KOH particles in an ethanol solution, then dropwise adding 2-acetylpyridine, and stirring to react until a light yellow solid is formed; then ammonia gas is introduced, then the solution is refluxed, the obtained light white solid is collected by filtration, washed and dried, and 4 '- (3,4, 5-trimethoxyphenyl) -2, 2': 6 ', 2' -terpyridine is obtained.
6. The method for regulating and controlling the optical haze and the ultraviolet filtering of the modified nanocellulose film according to claim 1, characterized in that, in step 2, the TEMPO-oxidized cellulose nanofibers are prepared by: adding a cellulose raw material into water, shearing, sequentially adding TEMPO and NaBr aqueous solutions, adding a NaOH aqueous solution to adjust the pH value of the solution to 10-11, adding a NaClO solution, and stirring for reaction; after the reaction is finished, adjusting the pH value of the reaction solution to be neutral by using dilute hydrochloric acid to obtain TEMPO oxidized cellulose suspension, washing, and carrying out high-pressure homogenization treatment to obtain TEMPO-oxidized cellulose nanofiber.
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| CN113417167B (en) * | 2021-06-22 | 2022-08-02 | 陕西科技大学 | Method for constructing haze nanopaper by metal polymer modified nanocellulose |
| CN113563615B (en) * | 2021-07-08 | 2022-07-26 | 陕西科技大学 | Preparation method of cellulose nanocrystal doped high-transmittance-haze cellulose membrane |
| CN117050360B (en) * | 2023-10-10 | 2024-01-09 | 天津永续新材料有限公司 | High-transparency high-haze cellulose nanofiber/thermosetting resin composite film and preparation method thereof |
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