Preparation method of cellulose-based high-haze material based on microemulsion

Abstract

The present invention discloses a method for preparing a cellulose-based high-haze material based on a microemulsion, comprising the following steps: Step 1, preparing a microemulsion; Step 2, preparing a microemulsion-nanocellulose mixed solution based on the product obtained in Step 1; Step 3, preparing an undried cellulose film based on the product obtained in Step 2; and Step 4, drying the product obtained in Step 3. The cellulose-based haze material prepared using the present invention can achieve a haze of up to 98% and can be used as an anti-reflection layer on photovoltaic cells.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of photofunctional cellulose materials, and relates to a preparation method of a cellulose-based high-haze material based on microemulsion. Background Art

[0002] The performance of photovoltaic cell anti-reflection layers (ARLs) has a decisive impact on the cell's light-harvesting ability. Haze is one of the most important performance indicators of ARLs. However, existing ARLs are mostly made of non-renewable materials such as SiN, ZnS, SiO2, and SiC. These materials have low haze, which has long restricted the cell's photoelectric conversion efficiency. They are typically produced using sol-gel, chemical vapor deposition, and sputtering methods, which are energy-intensive, highly polluting, require multiple processes, and impose stringent preparation conditions. For example, in order to impart anti-reflection properties to SiO2, its surface morphology must be modified during production. This is achieved by etching the silicon dioxide surface with hydrofluoric acid. As a well-known volatile acid, the etching process inevitably pollutes the environment. Furthermore, the preparation of the SiO2 raw material itself is energy-intensive and requires multiple processes. Therefore, developing high-haze, high-quality ARLs is of great significance to the development of the photovoltaic industry. Cellulose is green and renewable, and the large number of cavity structures formed by cellulose accumulation helps to change the light path and improve the haze performance. With the increasingly prominent environmental protection issues and the rapid development of the photovoltaic industry, it is imperative to develop high-haze cellulose-based materials with simple preparation process, pollution-free and renewable properties. Summary of the Invention

[0003] The purpose of the present invention is to provide a preparation method of cellulose-based high-haze material based on microemulsion. The preparation process has the characteristics of simple process and pollution-free. The cellulose-based haze material prepared by this method has a haze of up to 98%, and can be used as an anti-reflection layer on photovoltaic cells.

[0004] The technical solution adopted by the present invention is a method for preparing a cellulose-based high-haze material based on a microemulsion, which specifically includes the following steps:

[0005] Step 1, preparing a microemulsion;

[0006] Step 2, preparing a microemulsion nanocellulose mixed solution according to the product obtained in step 1;

[0007] Step 3, preparing an undried cellulose film according to the product obtained in step 2;

[0008] Step 4, drying the product obtained in step 3 to obtain.

[0009] The present invention is also characterized in that:

[0010] The specific process of step 1 is:

[0011] At 25-35° C., Span-80, Tween-80, cyclohexane and hexanol were added to a beaker and stirred at 400-800 r / min using a magnetic stirrer for 10-15 minutes. During the stirring process, distilled water was added along the wall of the beaker to prepare a microemulsion.

[0012] The specific process of step 2 is:

[0013] The nanocellulose is mixed with the microemulsion obtained in step 1, and stirred with a magnetic stirrer at 800-1200 r / min for 20-30 min to obtain a microemulsion nanocellulose mixed solution.

[0014] The specific process of step 3 is:

[0015] The microemulsion nanocellulose mixed solution obtained in step 2 is ultrasonically treated for 15 to 30 minutes, and the temperature is maintained at 25 to 35° C. during the ultrasonic treatment. Then, the mixture is filtered using qualitative filter paper and a Buchner funnel under vacuum until no liquid drips out from the lower end of the Buchner funnel, and the filtration is stopped to obtain an undried microemulsion cellulose membrane.

[0016] The specific process of step 4 is:

[0017] The undried microemulsion cellulose mixed membrane is placed in a fume hood, and air is blown toward the surface of the qualitative filter paper for 60 to 120 minutes to separate the cellulose membrane from the filter paper to obtain a cellulose-based high haze material.

[0018] The beneficial effect of the present invention is that the present invention is a preparation method for preparing cellulose-based high-haze materials based on microemulsion. By taking advantage of the uniform and stable molecular dispersion of microemulsion, nanocellulose (CNF) is evenly dispersed in the microemulsion, and then filtered and dried through a filter membrane with a specific pore size, so that the cellulose accumulates to form a large number of evenly distributed cavity structures, thereby improving the haze performance of the obtained cellulose-based material. The preparation process has a few steps, simple operation, low energy consumption, and no pollution, and the obtained material has a high haze performance of 40g / m 2 The haze can reach up to 98% when quantitative. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a photo of the cellulose-based high-haze material obtained in Example 1 of the method for preparing a cellulose-based high-haze material based on microemulsion of the present invention;

[0020] Figure 2 The 80g / m2 obtained in Example 2 of the preparation method of the cellulose-based high haze material based on microemulsion of the present invention 2 Quantitative haze measurement results of cellulose-based high haze materials;

[0021] Figure 3The 40 g / m2 obtained in Example 3 of the preparation method of the cellulose-based high haze material based on microemulsion of the present invention 2 Quantitative haze measurement results of cellulose-based high haze materials. DETAILED DESCRIPTION

[0022] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] The present invention provides a method for preparing a cellulose-based high-haze material based on a microemulsion, which specifically comprises the following steps:

[0024] Step 1, preparing a microemulsion: mixing 5-10 g Span-80, 5-10 g Tween-80, 5-10 g cyclohexane, 3-5 g hexanol, and 30-100 g distilled water at 25-35° C. (first, add Span-80, Tween-80, cyclohexane, and hexanol to a beaker and stir at 400-800 rpm using a magnetic stirrer for 10-15 minutes. During the stirring process, 30-100 g distilled water is slowly added along the wall of the beaker) to prepare a microemulsion.

[0025] Step 2, preparation of a microemulsion nanocellulose (CNF) mixed solution: 6.387 g to 12.774 g of nanocellulose (CNF) with a mass fraction of 6% is mixed with the microemulsion obtained in step 1, and stirred with a magnetic stirrer at 800 to 1200 r / min for 20 to 30 minutes to obtain a microemulsion nanocellulose (CNF) mixed solution.

[0026] Step 3, preparing an undried cellulose membrane: the microemulsion nanocellulose (CNF) mixture is treated with an ultrasonic frequency of 100KHz for 15 to 30 minutes, and the temperature is maintained at 25 to 35°C during the treatment process. Then, a qualitative filter paper with a pore size of 20μm (7cm in diameter) and a Buchner funnel are used for suction filtration under a vacuum degree of 0.098Mpa until no liquid drips out from the lower end of the Buchner funnel within 5 minutes, and the filtration is stopped to obtain an undried microemulsion cellulose membrane.

[0027] Step 4, drying of the cellulose membrane: Place the undried microemulsion cellulose mixed membrane in a fume hood (cellulose mixed membrane face up, qualitative filter paper face down), blow 60°C hot air onto the qualitative filter paper surface for 60-120 minutes, separate the cellulose membrane from the filter paper, and obtain a cellulose-based high haze material.

[0028] Example 1

[0029] Step 1, preparation of microemulsion:

[0030] At 25°C, 7.5 g of Span-80, 7.5 g of Tween-80, 7.5 g of cyclohexane, 4 g of hexanol, and 60 g of distilled water were mixed (Span-80, Tween-80, cyclohexane, and hexanol were first added to a beaker and stirred at 600 rpm using a magnetic stirrer for 12 minutes. During the stirring process, 60 g of distilled water was slowly added along the wall of the beaker) to prepare a microemulsion.

[0031] Step 2, preparation of microemulsion nanocellulose (CNF) mixture:

[0032] 9.581 g of nanocellulose (CNF) with a mass fraction of 6% was mixed with the microemulsion obtained in step 1, and stirred at 1000 r / min for 25 min using a magnetic stirrer to prepare a microemulsion nanocellulose (CNF) mixed solution.

[0033] Step 3, preparing undried cellulose membrane:

[0034] The microemulsion nanocellulose (CNF) mixture was treated with an ultrasonic frequency of 100 kHz for 20 minutes, and the temperature was maintained at 25°C during the treatment process. Then, it was filtered using a qualitative filter paper with a pore size of 20 μm (diameter of 7 cm) and a Buchner funnel under a vacuum degree of 0.098 MPa until no liquid dripped out from the lower end of the Buchner funnel within 5 minutes, and the filtration was stopped to obtain an undried microemulsion cellulose membrane.

[0035] Step 4, drying of cellulose membrane: Place the undried microemulsion cellulose mixed membrane in a fume hood (cellulose mixed membrane face up, qualitative filter paper face down), blow 60℃ hot air onto the qualitative filter paper face for 90 minutes, separate the cellulose membrane from the filter paper, and obtain a cellulose-based high haze material. Figure 1 The figure shows the actual image of the cellulose-based high haze material obtained according to Example 1. Figure 1 It can be seen that the cellulose-based high-haze material obtained in the present invention has excellent divergence performance for point light sources.

[0036] Example 2

[0037] Step 1, preparing a microemulsion: 10 g of Span-80, 10 g of Tween-80, 10 g of cyclohexane, 5 g of hexanol, and 100 g of distilled water were mixed at 30° C. (Span-80, Tween-80, cyclohexane, and hexanol were first added to a beaker and stirred at 800 rpm using a magnetic stirrer for 15 minutes. During the stirring process, 100 g of distilled water was slowly added along the wall of the beaker) to prepare a microemulsion.

[0038] Step 2, preparation of microemulsion nanocellulose (CNF) mixture:

[0039] 12.774 g of nanocellulose (CNF) with a mass fraction of 6% was mixed with the microemulsion obtained in step 1, and stirred at 1200 r / min for 30 min using a magnetic stirrer to prepare a microemulsion nanocellulose (CNF) mixed solution.

[0040] Step 3, preparing undried cellulose membrane:

[0041] The microemulsion nanocellulose (CNF) mixture was treated with an ultrasonic frequency of 100 kHz for 30 minutes, and the temperature was maintained at 30°C during the treatment. Then, it was filtered using a qualitative filter paper with a pore size of 20 μm (diameter of 7 cm) and a Buchner funnel under a vacuum degree of 0.098 MPa until no liquid dripped out from the lower end of the Buchner funnel within 5 minutes, and the filtration was stopped to obtain an undried microemulsion cellulose membrane.

[0042] Step 4, drying of cellulose membrane:

[0043] Place the undried microemulsion cellulose mixed membrane in a fume hood (cellulose mixed membrane face up, qualitative filter paper face down), blow 60℃ hot air onto the qualitative filter paper face for 120min, separate the cellulose membrane from the filter paper, and obtain a cellulose-based high haze material. Figure 2 As shown, the haze test of the material obtained in Example 2 is 80g / m 2 Under quantitative conditions, the haze value of the material obtained by the present invention can still reach 95% at a wavelength of 400-800 nm, and has excellent light scattering performance.

[0044] Example 3

[0045] Step 1, preparing a microemulsion: 5 g of Span-80, 5 g of Tween-80, 5 g of cyclohexane, 3 g of hexanol, and 30 g of distilled water were mixed at 35° C. (Span-80, Tween-80, cyclohexane, and hexanol were first added to a beaker and stirred at 400 rpm using a magnetic stirrer for 10 min. During the stirring, 30 g of distilled water was slowly added along the wall of the beaker) to prepare a microemulsion.

[0046] Step 2, preparation of microemulsion nanocellulose (CNF) mixture:

[0047] 6.387 g of nanocellulose (CNF) with a mass fraction of 6% was mixed with the microemulsion obtained in step 1, and stirred at 800 r / min for 20 min using a magnetic stirrer to prepare a microemulsion nanocellulose (CNF) mixed solution.

[0048] Step 3: Prepare an undried cellulose membrane. The microemulsion nanocellulose (CNF) mixture is treated with a 100 kHz ultrasonic frequency for 15 minutes, maintaining the temperature at 35°C. The mixture is then filtered using a 20 μm pore size qualitative filter paper (7 cm diameter) and a Büchner funnel under a vacuum of 0.098 MPa. Filtration is stopped until no liquid drips from the lower end of the Büchner funnel within 5 minutes, thereby obtaining an undried microemulsion cellulose membrane.

[0049] Step 4: Drying of the cellulose film. Place the undried microemulsion cellulose mixed film in a fume hood (cellulose mixed film side up, qualitative filter paper side down), blow 60°C hot air onto the qualitative filter paper surface for 60 minutes, separate the cellulose film from the filter paper, and obtain a cellulose-based high haze material. Figure 3 As shown, the haze test of the material obtained in Example 3 is 40g / m 2 The haze value of the material obtained by the present invention can be stabilized at 98% at a wavelength of 400-800 nm under quantitative conditions, and has excellent light scattering performance.

Claims

1. A method for preparing a cellulose-based high-haze material based on a microemulsion, characterized in that: The specific steps include: Step 1, preparing a microemulsion; The specific process of step 1 is: At 25-35°C, Span-80, Tween-80, cyclohexane, and hexanol were added to a beaker and stirred at 400-800 rpm using a magnetic stirrer for 10-15 minutes. During the stirring process, distilled water was added along the wall of the beaker to prepare a microemulsion. Step 2, preparing a microemulsion nanocellulose mixed solution according to the product obtained in step 1; The specific process of step 2 is: Mix the nanocellulose with the microemulsion obtained in step 1, and stir with a magnetic stirrer at 800-1200 r / min for 20-30 min to prepare a microemulsion nanocellulose mixture; Step 3, preparing an undried cellulose film according to the product obtained in step 2; The specific process of step 3 is: The microemulsion nanocellulose mixture obtained in step 2 is ultrasonically treated for 15 to 30 minutes, while maintaining the temperature at 25 to 35°C during the ultrasonic treatment. The mixture is then filtered under vacuum using qualitative filter paper and a Buchner funnel until no liquid drips out from the lower end of the Buchner funnel, thereby obtaining an undried microemulsion cellulose membrane. Step 4, drying the product obtained in step 3 to obtain; The specific process of step 4 is as follows: The undried microemulsion cellulose mixed membrane was placed in a fume hood and air was blown toward the surface of the qualitative filter paper for 60 to 120 minutes to separate the cellulose membrane from the filter paper to obtain a cellulose-based high haze material.

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