CN112140264A - Transparent cellulose composite material and preparation method thereof - Google Patents

Abstract

The invention provides a transparent cellulose composite material, the preparation method of which includes the steps of cutting, lignin removal, hemicellulose removal, fiber size refinement, dispersion impregnation, curing and molding and the like. The transparent cellulose composite material retains the cellulose microporous structure, and can prepare finished products of any size after immersion in a polymer solution that matches the refractive index, and is mixed with functional additives at the same time, and has optical selectivity. The transparent cellulose composite material of the invention has the advantages of good visible light band transmittance, superior anti-ultraviolet and near-infrared properties, low haze, can be produced in any size, suitable for mass production, and has the advantages of broad application value.

Description

A kind of transparent cellulose composite material and preparation method thereof

technical field

The invention relates to the field of composite material preparation, in particular to a transparent cellulose composite material and a preparation method thereof.

Background technique

At present, with the rapid development of society and economy, people's living standards are gradually improving, and at the same time, there are serious environmental problems, such as pollution of air, soil and water resources, climate change and non-degradable garbage and other problems. Sustainable economic development is imminent. Wood is a rich organic polymer resource on the earth. As an environmentally friendly and sustainable material, it has good natural material properties, including low density, high modulus, high strength, high toughness, Low thermal conductivity, non-toxic, degradable, etc. Due to its growth characteristics, wood has a special structure and chemical composition, showing opacity. In recent years, some scientific researchers have learned from the process method of pulp production, bleached the wood, and then poured a resin solution with a similar refractive index to obtain transparent wood. Transparent wood is a light-weight, heat-insulating and transparent composite material prepared by de-lignining, hemicellulose and transparent treatment of wood. It is further compounded with different nanoparticles and can also make it optically selective. It has potential applications in many fields such as green building materials, LED lighting equipment, luminous magnetic switches, information storage, solar cells and anti-counterfeiting equipment, thereby replacing the use of traditional glass. However, with the processing of lignin, the mechanical strength of wood is greatly reduced, which is not conducive to retaining its complete structure, so it is limited to laboratory research. An environmentally friendly alternative to traditional glass for wood applications is essential. With the development of urbanization and the needs of people's life, about 4,000 to 5,000 tons of waste glass are produced in China every year, and it will take thousands of years for the glass to completely degrade. Waste glass is expensive to purify due to its color, purity, etc., so it is difficult to recycle it. As a non-degradable waste, glass brings many potential unsafeties to soil and human life and production activities.

For example, an existing ultraviolet light-curing adhesive film glass is coated with a layer of anti-ultraviolet polymer coating on the surface of the glass. The main part of the technical solution uses traditional glass materials, which is poor in environmental protection. Moreover, this solution only has a certain function of blocking ultraviolet rays, and the heat insulation effect is not good.

As an existing method for preparing UV-shielding transparent wood, the technical scheme uses wood flakes to remove lignin and bleaching, then impregnates PMMA resin solution, and solidifies to obtain UV-shielding transparent wood, but the transparent wood prepared by this technical solution Wood also has no shielding effect on near infrared rays.

SUMMARY OF THE INVENTION

Based on this, in order to solve the problems of poor environmental protection, poor thermal insulation effect and poor near-infrared shielding effect of the existing traditional transparent materials, the present invention provides a preparation method of a transparent cellulose composite material, and the specific technical scheme is as follows:

A preparation method of transparent cellulose composite material, comprising the following steps:

cutting the collected wood;

Soak the cut wood in lignin removal solution;

Immerse the de-lignined wood in a hemicellulose removal solution;

The wood from which hemicellulose has been removed is cleaned and stored in a liquid seal;

Crushing and refining the cleaned wood;

The ultraviolet shielding additive and the near-infrared shielding additive are added into the polymer solution and mixed uniformly to obtain a composite solution;

Impregnating and mixing the crushed and refined wood with the composite solution;

The mold is used for shaping and curing to obtain a transparent cellulose composite material.

The preparation method of the above transparent cellulose composite material can effectively ensure that the content of lignin is less than 5% and the content of hemicellulose is less than 10% by removing lignin and hemicellulose from wood, and the cellulose content is preserved. Microporous channel structure; by impregnating and mixing wood fiber and composite solution, the structure of cellulose is filled with polymer solution, so the light transmittance of the obtained transparent cellulose composite material reaches 80%; it can be obtained by combining functional additives A composite material with a shielding rate of ultraviolet rays of more than 99% and a shielding rate of near-infrared rays of more than 70%; the transparent cellulose composite material of the invention has high visible light transmittance, can resist ultraviolet rays and near-infrared rays, has the advantages of wide application scenarios, and can be prepared The process is environmentally friendly, easier to degrade than traditional glass materials, and in line with sustainable development. Wood is used as a raw material, the material source is wide, the preparation process steps are simple, any size can be produced, and it is suitable for large-scale production.

Further, the wood is selected from one or more of balsa wood, paulownia wood, pine wood and basswood, and the size of the wood after the cutting is: length 3cm-30cm, width 3cm-30cm, and thickness 5mm-10mm .

Further, the lignin removal solution is a mixed solution of strong lye, sulfite and bisulfite, and the concentration of the strong lye is 0.5mol/L-5.0mol/L, sulfite and sulfite The concentrations of hydrogen salts are all 0.1 mol/L-2.0 mol/L.

Further, the hemicellulose removal solution is selected from hydrogen peroxide, hypochlorite or chlorite solution, and the mass percentage concentration is 5%-35%.

Further, the cleaning is to first use a weak acid aqueous solution for cleaning under ultrasonic conditions, and the mass fraction of the weak acid is 5%-50%, and the cleaning time is 20min-60min; and then use deionized water for 3-5 times cleaning to deionized water. The color of the water does not change, or it is boiled in heated boiling water for 12h-48h until the color of the boiled water does not change.

Further, the pulverizing and refining treatment is to preliminarily grind the cleaned wood, and then use the TEMPO oxidation method for treatment under the condition of stirring, after cleaning the wood particles after the treatment, the mass fraction of 3% is used. -10% hydrochloric acid to adjust the pH value to neutrality, then use the high pressure homogenization method to pulverize the particle size of the wood particles to the size of 20nm-200nm, and obtain the pulverized and refined wood after concentrating.

Further, the ultraviolet shielding additive and the near-infrared shielding additive include one or more of the following: nano-zinc oxide particles, nano-titanium dioxide particles, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxyl benzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-(2-hydroxy-3,5-di-tert-phenyl)-5-benzotriazole chloride, 2-( 2-Hydroxy-5-methylphenyl) benzotriazole, nano cesium tungsten bronze particles, nano tin antimony oxide particles.

Further, the dipping and mixing of the pulverized and refined wood with the composite solution is as follows: based on the assistance of ultrasonics, the pulverized and refined wood is mixed and impregnated with the polymer solution using a stirring device, and then vacuumed to 200Pa. , treated for 0.5h-1h to obtain a mixed solution.

Further, the shaping and curing process is as follows: casting the composite solution in a mold of a desired size, curing for 10h-30h at a temperature of 20°C-70°C, and finally performing a demoulding process.

Further, the present invention also provides a transparent cellulose composite material prepared by the above-mentioned preparation method.

Description of drawings

1 is a photo of the transparent cellulose composite material prepared in Example 1 of the present invention;

Fig. 2 is the light transmittance result of the transparent cellulose composite material prepared in Example 1 of the present invention;

Fig. 3 is the SEM photograph of the transparent cellulose composite material prepared in Example 1 of the present invention;

Fig. 4 is the light transmittance comparison result of the transparent cellulose composite material prepared in Example 1 of the present invention;

FIG. 5 is a comparison result of the thermal insulation effect of the transparent cellulose composite material prepared in Example 1 of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to its embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, and do not limit the protection scope of the present invention.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terms used herein in the description of the present invention are for the purpose of describing specific embodiments only, and are not intended to limit the present invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. If the specific conditions are not indicated in the examples, it is carried out according to the conventional conditions or the conditions suggested by the manufacturer. The reagents or instruments used without the manufacturer's indication are conventional products that can be purchased from the market.

A preparation method of a transparent cellulose composite material in an embodiment of the present invention includes the following steps:

S1. Cut the collected wood;

S2, soak the cut wood in the lignin removal solution;

S3. Immerse the de-lignined wood in a hemicellulose removal solution;

S4. Clean the wood from which hemicellulose has been removed, and store it in a liquid seal;

S5. Pulverize and refine the cleaned wood;

S6, adding the ultraviolet shielding additive and the near-infrared shielding additive into the polymer solution and mixing uniformly to obtain a composite solution;

S7, impregnating and mixing the crushed and refined wood with the composite solution;

S8, using a mold to perform shaping and curing treatment to obtain a transparent cellulose composite material.

The preparation method of the above transparent cellulose composite material can effectively ensure that the content of lignin is less than 5% and the content of hemicellulose is less than 10% by removing lignin and hemicellulose from wood, and the cellulose content is preserved. Microporous channel structure; by impregnating and mixing wood fiber and composite solution, the structure of cellulose is filled with polymer solution, so the light transmittance of the obtained transparent cellulose composite material reaches 80%; it can be obtained by combining functional additives A composite material with a shielding rate of ultraviolet rays of more than 99% and a shielding rate of near-infrared rays of more than 70%; the transparent cellulose composite material of the invention has high visible light transmittance, can resist ultraviolet rays and near-infrared rays, has the advantages of wide application scenarios, and can be prepared The process is environmentally friendly, easier to degrade than traditional glass materials, and in line with sustainable development. Wood is used as a raw material, the material source is wide, the preparation process steps are simple, any size can be produced, and it is suitable for large-scale production.

In one embodiment, the wood is selected from one or more of balsa wood, paulownia wood, pine wood and basswood, and the size of the cut wood is: length 3cm-30cm, width 3cm-30cm, thickness 5mm-10mm.

In one embodiment, the lignin removal solution is a mixed solution of strong lye, sulfite and bisulfite, and the concentration of the strong lye is 0.5mol/L-5.0mol/L, and the sulfite is The concentrations of salt and bisulfite are both 0.1 mol/L-2.0 mol/L.

In one embodiment, the hemicellulose removal solution is selected from hydrogen peroxide, hypochlorite or chlorite solution, and the mass percentage concentration is 5%-35%.

In one embodiment, the cleaning is to firstly use a weak acid aqueous solution to wash under ultrasonic conditions, and the mass fraction of the weak acid is 5%-50%, and the cleaning time is 20min-60min; and then use deionized water to wash 3 times-5 Second, the color of deionized water does not change, or cook in heated boiling water for 12h-48h until the color of the brewed water does not change.

In one embodiment, the liquid seal preservation is to store the cleaned wood liquid seal in absolute ethanol.

In one embodiment, the pulverization and refinement treatment is to preliminarily grind the cleaned wood, and then use the TEMPO oxidation method to process under stirring conditions. After cleaning the wood particles after the treatment, use Hydrochloric acid with a mass fraction of 3%-10% is used to adjust the pH value to neutral, and then the particle size of the wood particles is pulverized to a size of 20nm-200nm by a high pressure homogenization method, and the pulverized and refined wood is obtained after concentration.

In one embodiment, the ultraviolet shielding additive and the near-infrared shielding additive comprise one or more of the following: nano-zinc oxide particles, nano-titanium dioxide particles, 2,4-dihydroxybenzophenone, 2-hydroxy- 4-Methoxybenzophenone, 2-hydroxy-4-n-octyloxybenzophenone, 2-(2-hydroxy-3,5-di-tert-phenyl)-5-benzotriazole chloride , 2-(2-hydroxy-5-methylphenyl) benzotriazole, nano cesium tungsten bronze particles, nano tin antimony oxide particles.

In one of the embodiments, the impregnation and mixing of the pulverized and refined wood with the composite solution is as follows: based on the assistance of ultrasound, the pulverized and refined wood is mixed and impregnated with the polymer solution by using a stirring device, and then Evacuate to 200Pa and process for 0.5h-1h to obtain a mixed solution.

Further, the stirring device is selected from: paddle mechanical stirrer, open turbine stirrer, propeller stirrer, long-blade propeller stirrer, disc turbine stirrer, Brumarkin stirrer and magnetic force Stirrer; the stirring condition of the stirring device is 400-2000rpm.

In one embodiment, the shaping and curing treatment is as follows: casting the composite solution in a mold of a desired size, curing at a temperature of 20°C-70°C for 10h-30h, and finally performing demolding treatment.

In one embodiment, the soaking temperature of the soaking in the lignin removal solution is

80℃-100℃, soaking time is 4h-12h, so that the lignin content of the wood after soaking is less than 10%.

In one embodiment, the soaking temperature in the hemicellulose removal solution is 80°C-100°C, and the soaking time is 4h-12h, so that the hemicellulose content of the wood after soaking is less than 10% .

In one of the embodiments, the ultraviolet shielding additive and the near-infrared shielding additive are selected from one or more components in the following parts by weight, based on the weight of the polymer being 100 parts: nano-zinc oxide particles 0.01- 3.0 parts; nano titanium dioxide particles 0.01-5.0 parts; 2,4-dihydroxybenzophenone 0.01-2.0 parts; 2-hydroxy-4-methoxybenzophenone 0.02-2.0 parts; 2-hydroxy-4- n-Octyloxybenzophenone 0.02-2.5 parts; 2-(2-hydroxy-3,5-di-tert-phenyl)-5-benzotriazole chloride 0.01-1.5 parts; 2-(2-hydroxy- 0.01-2.0 part of 5-methylphenyl) benzotriazole; 0.001-1.0 part of nano cesium tungsten bronze particles; 0.001-1.5 part of nano tin and antimony oxide particles.

In one embodiment, the polymer is a thermoplastic or thermosetting polymer with a refractive index between 1.4 and 1.7, including but not limited to one of the following materials: polymethyl methacrylate, polyvinyl alcohol, cyclic Oxygen resin, polycarbonate, polystyrene, polyvinylpyrrolidone.

In one of the embodiments, a transparent cellulose composite material is also provided, and the composite material is prepared by the above-mentioned preparation method.

The embodiments of the present invention will be described in detail below with reference to specific examples.

Example 1:

A preparation method of transparent cellulose composite material, comprising the following steps:

S1. Cut paulownia wood into several pieces of 80mm*40mm*5mm samples;

S2, soak the cut wood in a mixed solution of sodium hydroxide and sodium sulfite, wherein the concentration of sodium hydroxide is 2.5mol/L, the concentration of sodium sulfite is 0.4mol/L, the soaking temperature is 95°C, and the soaking time is 8h, the lignin content of the wood after soaking is 5%;

S3. Soak the delignified wood in hydrogen peroxide, wherein the concentration of hydrogen peroxide is 35%, the soaking temperature is 95°C, the soaking time is 10h, and the hemicellulose content of the soaked wood is 8%;

S4. In the ultrasonic cleaning machine, the wood from which hemicellulose has been removed is first cleaned with an aqueous acetic acid solution with a mass fraction of 5% for 20 minutes, and then the wood is cleaned with deionized water for 5 times for 60 minutes until the color of the deionized water does not occur. Change; the cleaned wood is soaked in acetone/anhydrous ethanol to remove residual moisture, and finally sealed with anhydrous ethanol for preservation.

S5. Preliminarily grind the cleaned wood, under stirring conditions, use the TEMPO oxidation method to treat the wood. After cleaning with deionized water, use hydrochloric acid with a mass fraction of 5% to adjust the pH value to 7; then use the high pressure homogenization method. The particle size of the wood particles is pulverized to a size of 100 nm, and the solution is concentrated to obtain the pulverized and refined wood.

S6. Weigh 3 parts by weight of nano-zinc oxide particles, 0.5 parts by weight of nano-cesium tungsten bronze particles, and 100 parts by weight of epoxy resin, and under ultrasonic as an auxiliary condition, use a mechanical stirrer to disperse uniformly until there is no obvious particle agglomeration to obtain compound solution.

S7. Weigh 30 parts by weight of the pulverized and refined wood and 100 parts by weight of the composite solution, and use a mechanical stirrer to disperse evenly under the assisted condition of ultrasound, until there is no obvious particle agglomeration, and then vacuumize to 200Pa for 2 hours to make The wood is impregnated with the composite solution to completeness to obtain a mixed solution.

S8. The mixed solution is cast in a mold with a size of 65mm×65mm×5mm, cured at a temperature of 70° C. for 20 hours, and finally demolded to obtain the transparent cellulose composite material.

The photo of the transparent cellulose composite material prepared in this example is shown in FIG. 1 , and the SEM (scanning electron microscope) photo is shown in FIG. 3 .

Example 2:

A preparation method of transparent cellulose composite material, comprising the following steps:

S1. Cut the balsa wood into several pieces of 80mm*40mm*5mm samples;

S2, soak the cut wood in a mixed solution of sodium hydroxide and sodium sulfite, wherein the concentration of sodium hydroxide is 2.5mol/L, the concentration of sodium sulfite is 0.4mol/L, the soaking temperature is 95°C, and the soaking time is 8h, the lignin content of the wood after soaking is 3%;

S3. Soak the delignified wood in hydrogen peroxide, wherein the concentration of hydrogen peroxide is 35%, the soaking temperature is 90°C, the soaking time is 10h, and the hemicellulose content of the soaked wood is 5%;

S4. In the ultrasonic cleaning machine, the wood from which hemicellulose has been removed is first cleaned with an aqueous acetic acid solution with a mass fraction of 5% for 20 minutes, and then the wood is cleaned with deionized water for 4 times and the cleaning time is 60 minutes until the color of the deionized water disappears. Changes occur; the cleaned wood is soaked in acetone/absolute ethanol to remove residual moisture, and finally stored in anhydrous ethanol liquid seal.

S5. Preliminarily grind the cleaned wood, and under stirring conditions, use the TEMPO oxidation method to treat the wood. After cleaning with deionized water, use hydrochloric acid with a mass fraction of 5% to adjust the pH to 7; then use the high-pressure homogenization method. The particle size of the wood particles is pulverized to a size of 200 nm, and the solution is concentrated to obtain pulverized and refined wood.

S6. Weigh 1 part by weight of 2-(2-hydroxy-5-methylphenyl) benzotriazole, 0.1 part by weight of nano-cesium tungsten bronze particles, and 100 parts by weight of epoxy resin. Disperse uniformly with a mechanical stirrer until there is no obvious particle agglomeration to obtain a composite solution.

S7. Weigh 20 parts by weight of the pulverized and refined wood and 100 parts by weight of the composite solution, and use a mechanical stirrer to disperse evenly under the assisted condition of ultrasound until there is no obvious particle agglomeration, and then vacuum to 200Pa for 1 hour to make The wood is impregnated with the composite solution to completeness to obtain a mixed solution.

S8. The mixed solution is cast in a mold with a size of 65mm×65mm×5mm, cured at a temperature of 50° C. for 30 hours, and finally demolded to obtain the transparent cellulose composite material.

Example 3:

A preparation method of transparent cellulose composite material, comprising the following steps:

S1. Cut paulownia wood into several pieces of 80mm*40mm*5mm samples;

S2, soak the cut wood in a mixed solution of sodium hydroxide and sodium sulfite, wherein the concentration of sodium hydroxide is 2.5mol/L, the concentration of sodium sulfite is 0.4mol/L, the soaking temperature is 95°C, and the soaking time is 8h, the lignin content of the wood after soaking is 5%;

S3. Soak the delignified wood in hydrogen peroxide, wherein the concentration of hydrogen peroxide is 35%, the soaking temperature is 85°C, the soaking time is 10h, and the hemicellulose content of the soaked wood is 3%;

S4. In the ultrasonic cleaning machine, the wood from which hemicellulose has been removed is first cleaned with an aqueous acetic acid solution with a mass fraction of 5% for 20 minutes, and then the wood is cleaned with deionized water 3 times for 60 minutes until the color of the deionized water does not occur. Change; the cleaned wood is soaked in acetone/anhydrous ethanol to remove residual moisture, and finally sealed with anhydrous ethanol for preservation.

S5. Preliminarily grind and clean the wood. Under the condition of stirring, use the TEMPO oxidation method to treat the wood. After cleaning with deionized water, use 8% hydrochloric acid to adjust the pH value to 7; then use the high-pressure homogenization method. Pulverize the particle size of the wood particles to a size of 180 nm, and concentrate the solution to obtain the pulverized and refined wood.

S6. Weigh 2 parts by weight of nano-zinc oxide particles, 0.8 parts by weight of nano-cesium tungsten bronze particles, and 100 parts by weight of epoxy resin, and under ultrasonic as an auxiliary condition, use a mechanical stirrer to disperse uniformly until there is no obvious particle agglomeration, and obtain compound solution.

S7. Weigh 10 parts by weight of the pulverized and refined wood and 100 parts by weight of the composite solution, and use a mechanical stirrer to disperse evenly under the assisted condition of ultrasound, until there is no obvious particle agglomeration, and then vacuumize to 200Pa for 2 hours to make The wood is impregnated with the composite solution to completeness to obtain a mixed solution.

S8, casting the mixed solution in a mold with a size of 65mm×65mm×5mm, curing at 20° C. for 10 hours, and finally performing demoulding treatment to obtain the transparent cellulose composite material.

In order to understand more clearly the anti-ultraviolet and near-infrared effects prepared in this application, the following comparative examples are also set.

Comparative Example 1:

The preparation method of a kind of transparent cellulose composite material in this comparative example is as follows:

S1. Cut the balsa wood into several pieces of 80mm*40mm*5mm samples;

S2, soak the cut wood in a mixed solution of sodium hydroxide and sodium sulfite, wherein the concentration of sodium hydroxide is 2.5mol/L, the concentration of sodium sulfite is 0.4mol/L, the soaking temperature is 95°C, and the soaking time is 8h, the lignin content of the wood after soaking is 1%;

S3. Soak the delignified wood in hydrogen peroxide, wherein the concentration of hydrogen peroxide is 35%, the soaking temperature is 90°C, the soaking time is 10h, and the hemicellulose content of the soaked wood is 3%;

S4. In the ultrasonic cleaning machine, the wood from which hemicellulose has been removed is first cleaned with an aqueous acetic acid solution with a mass fraction of 5% for 20 mins, and then the wood is cleaned with deionized water for 4 times, and the cleaning time is 60 mins, until the color of the deionized water does not change. Changes occurred; the cleaned wood was soaked in acetone/absolute ethanol to remove residual moisture, and finally sealed with anhydrous ethanol for preservation.

S5. Preliminarily grind the cleaned wood, and under stirring conditions, use the TEMPO oxidation method to treat the wood. After cleaning with deionized water, use hydrochloric acid with a mass fraction of 5% to adjust the pH to 7; then use the high-pressure homogenization method. The particle size of the wood particles is pulverized to a size of 200 nm, and the solution is concentrated to obtain pulverized and refined wood.

S6. Weigh 20 parts by weight of the pulverized and refined wood and 100 parts by weight of epoxy resin, and use a mechanical stirrer to disperse evenly under the condition of ultrasound, until there is no obvious particle agglomeration. The above solution is evacuated to 200Pa for 0.5h-2h, so that the wood is fully impregnated with epoxy resin to obtain a mixed solution.

S7, casting the mixed solution in a mold with a size of 65mm×65mm×5mm, curing at a temperature of 50° C. for 30 hours, and finally performing demoulding treatment to obtain the transparent cellulose composite material.

Comparative Example 2:

The preparation method of a kind of transparent cellulose composite material in this comparative example is as follows:

S1. Cut the balsa wood into several pieces of 80mm*40mm*5mm samples;

S2, soak the cut wood in a mixed solution of sodium hydroxide and sodium sulfite, wherein the concentration of sodium hydroxide is 2.5mol/L, the concentration of sodium sulfite is 0.4mol/L, the soaking temperature is 95°C, and the soaking time is 8h, the lignin content of the wood after soaking is 1%;

S3. Soak the delignified wood in hydrogen peroxide, wherein the concentration of hydrogen peroxide is 35%, the soaking temperature is 90°C, the soaking time is 10h, and the hemicellulose content of the soaked wood is 3%;

S4. In the ultrasonic cleaning machine, the wood from which hemicellulose has been removed is first cleaned with an aqueous acetic acid solution with a mass fraction of 5% for 20 mins, and then the wood is cleaned with deionized water for 4 times, and the cleaning time is 60 mins, until the color of the deionized water does not change. Changes occurred; the cleaned wood was soaked in acetone/absolute ethanol to remove residual moisture, and finally sealed with anhydrous ethanol for preservation.

S5. Put the cleaned wood into a container, add epoxy resin according to the mass ratio of wood to epoxy resin of 1:5, and vacuum to 200Pa for 0.5h-2h, so that the wood is completely impregnated with epoxy resin.

S6, taking out the impregnated wood, sandwiching it between two pieces of glass, curing at 20°C-70°C for 10-30 hours, and finally demoulding and taking out to obtain a transparent cellulose composite material.

Comparative Example 3:

Commercially available flat glass for construction serves as an example of conventional glass.

Test example:

1. Light transmittance test

The transparent cellulose composite material prepared in Example 1 was tested for light transmittance by using a spectrophotometer. The results are shown in Figure 2. The results show that the ultraviolet shielding rate of the composite material prepared in Example 1 is more than 99%, and the near infrared ray shielding rate is more than 99%. The shielding rate is over 70%.

The flat glass of Comparative Example 3 was used as a traditional glass, and the light transmittance test was also carried out by using a spectrophotometer. The results show that the transparent cellulose composite material prepared in Example 1 of the present application has better shielding effect on ultraviolet rays and near-infrared rays than the flat glass in Comparative Example 3.

The transparent cellulose composite materials prepared in Examples 1-3, the transparent cellulose composite materials prepared in Comparative Examples 1-2, and Comparative Example 3 were subjected to light transmittance test analysis, and the results are shown in Table 1.

Table 1:

It can be seen from the data analysis in Table 1 that the transparent cellulose composite material prepared in the present application has excellent anti-ultraviolet and near-infrared performance, and its performance is obviously better than that of the comparative samples randomly purchased on the market.

2. Haze test

Table 2 shows the transparent cellulose composite materials prepared in Examples 1-3, the transparent cellulose composite materials prepared in Comparative Examples 1-2, and the finished products introduced in Comparative Example 3 and other patents (publication number CN110603124A) for haze test and Data comparison and analysis, the haze test method refers to the method described in the patent application with publication number CN110603124A. The results show that the haze result of the transparent cellulose composite material prepared in this application is smaller than that of Comparative Example 2 and the product of the published patent.

Table 2:

3. Tensile test

Table 3 shows the transparent cellulose composite materials prepared in Examples 1-3, the transparent cellulose composite materials prepared in Comparative Examples 1-2, and Comparative Example 3 for mechanical property testing. The results show that the transparent cellulose composite materials prepared in the present application The mechanical properties of the composites are better than those of the comparative examples.

table 3:

To sum up, the ultraviolet shielding effect of the present invention reaches 99%, the near-infrared shielding effect reaches 70%, the visible light transmittance in the wavelength range of 380nm-780nm reaches 80%, and the haze is less than 25%. Therefore, the transparent cellulose composite material of the present invention has good visible light band transmittance, superior anti-ultraviolet and near-infrared properties, low haze, can be made in any size, is suitable for mass production, and has broad application value.

The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity, all possible combinations of the technical features in the above-described embodiments are not described. However, as long as there is no contradiction between the combinations of these technical features, All should be regarded as the scope described in this specification.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are specific and detailed, but should not be construed as a limitation on the scope of the invention patent. It should be pointed out that for those skilled in the art, without departing from the concept of the present invention, several modifications and improvements can be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the appended claims.

Claims (10)

1. A preparation method of a transparent cellulose composite material is characterized by comprising the following steps:

cutting the collected wood;

soaking the cut wood in a lignin removal solution;

soaking the wood with the lignin removed in a hemicellulose removing liquid;

cleaning the wood without hemicellulose, and storing in a liquid seal manner;

crushing and thinning the cleaned wood;

adding the ultraviolet shielding additive and the near-infrared shielding additive into the polymer solution and uniformly mixing to obtain a composite solution;

impregnating and mixing the crushed and refined wood with the composite solution;

and (5) carrying out shaping and curing treatment by using a mould to obtain the transparent cellulose composite material.

2. The method for preparing a transparent cellulose composite according to claim 1, wherein the wood is selected from one or more of balsa, tung, pine and basswood, and the cut wood has a size of: the length is 3cm-30cm, the width is 3cm-30cm, and the thickness is 5mm-10 mm.

3. The method for preparing the transparent cellulose composite material according to claim 1, wherein the delignification solution is a mixed solution of strong alkali solution, sulfite and bisulfite, the concentration of the strong alkali solution is 0.5mol/L-5.0mol/L, and the concentrations of the sulfite and bisulfite are both 0.1mol/L-2.0 mol/L.

4. The preparation method of the transparent cellulose composite material according to claim 1, wherein the hemicellulose-removed liquid is selected from hydrogen peroxide, hypochlorite or chlorite solution, and the mass percentage concentration is 5-35%.

5. The preparation method of the transparent cellulose composite material according to claim 1, wherein the cleaning is performed by firstly using a weak acid aqueous solution under an ultrasonic condition, the mass fraction of the weak acid is 5-50%, and the cleaning time is 20-60 min; and then deionized water is adopted for cleaning for 3-5 times until the color of the deionized water is not changed, or the deionized water is soaked and boiled in heating boiling water for 12-48 hours until the color of the soaking and boiling water is not changed.

6. The preparation method of the transparent cellulose composite material as claimed in claim 1, wherein the pulverization and refinement treatment is to primarily grind the cleaned wood, then treat the wood by using a TEMPO oxidation method under stirring, clean the treated wood particles, adjust the pH value to be neutral by using hydrochloric acid with the mass fraction of 3% -10%, then pulverize the particle size of the wood particles to the size of 20nm-200nm by using a high-pressure homogenization method, and concentrate the pulverized and refined wood.

7. The method of preparing a transparent cellulosic composite according to claim 1, wherein the ultraviolet shielding additive and near infrared shielding additive comprise one or more of: nano zinc oxide particles, nano titanium dioxide particles, 2, 4-dihydroxy benzophenone, 2-hydroxy-4-methoxy benzophenone, 2-hydroxy-4-n-octoxy benzophenone, 2- (2-hydroxy-3, 5-di-tert-phenyl) -5-chlorinated benzotriazole, 2- (2-hydroxy-5-methylphenyl) benzotriazole, nano cesium tungsten bronze particles and nano tin antimony oxide particles.

8. The method for preparing a transparent cellulose composite material according to claim 1, wherein the impregnating and mixing of the pulverized and refined wood with the composite solution is: based on the assistance of ultrasonic, mixing and impregnating the crushed and refined wood with a polymer solution by using stirring equipment, then vacuumizing to 200Pa, and treating for 0.5h-1h to obtain a mixed solution.

9. The method for preparing a transparent cellulose composite material according to claim 1, wherein the setting and curing treatment is: casting the composite solution in a mould with required size, curing for 10-30 h at the temperature of 20-70 ℃, and finally demoulding.

10. A transparent cellulose composite material, characterized in that the composite material is prepared by the preparation method of any one of claims 1 to 9.

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