WO2021223336A1 - Preparation method for fluorescent and transparent composite material - Google Patents

Abstract

A preparation method for a fluorescent and transparent composite material, comprising: (1) selecting a crab shell or crab shell piece having a complete form, washing, and saving in deionized water for later use; (2) sequentially using a low-concentration acid solution, a low-concentration alkaline solution, and an ethanol solution to immerse the complete crab shell or crab shell piece until completely removing calcium carbonate, proteins, lipids, and a pigment matrix, and saving the treated crab shell or crab shell piece in anhydrous ethanol for later use; (3) uniformly dispersing a fluorescent material in a polymer monomer by means of thermomechanical stirring, and then performing polymerization to obtain a polymer; and (4) taking out the treated crab shell or crab shell piece, immersing in the polymer obtained at step (3), performing vacuum pumping in a vacuum drying box and keeping pressure for 15 minutes, repeating three times, taking out the crab shell or crab shell piece and wrapping same with a tin foil, and performing isothermal curing. The prepared fluorescent and transparent composite material not only is high in light transmittance, but also has a complete crab shell form; and the addition of fluorescent powder makes a transparent crab shell present different colors under the irradiation of light and has little influence on the light transmittance.

Description

Preparation method of fluorescent transparent composite material Technical field

The invention relates to a preparation method of a fluorescent transparent composite material, in particular to a preparation method of a fluorescent transparent crab shell sheet and a transparent crab shell with a complete structural form.

Background technique

With the vigorous development of the optoelectronic industry and the urgent demand in the field of energy saving, the application of transparent materials in electronics and energy has become more and more extensive, the demand has increased, and their sources have become more diversified. In recent years, a large number of scholars at home and abroad have used the natural cellulose skeleton of wood to prepare flexible and transparent cellulose films based on the good mechanical properties of wood, which has shown great potential for applications in the electronic field. For example, Chinese patent CN110328727A uses ethanol to dissolve lignin at low temperature to maintain the original wood structure, and uses polymer matrix to fill wood holes to obtain transparent wood with 75% light transmittance; Chinese patent CN110603124A uses lignin content higher than 15% Carat pine, prepared a transparent wood with at least 60% optical transmittance; Chinese patent CN110181629A adds nano silver bromide and additive nano copper oxide to high transmittance resin to obtain a 65-85% optical transmittance High-speed reversible photochromic transparent wood; Chinese authorized patent CN106313221B is to solve the problem of wood opacity, non-magnetism and non-fluorescence. Fluorescent magnetic nanoparticles are added to transparent resin to prepare fluorescent transparent magnetic wood with 80% light transmittance; Chinese patent CN109049215A prepares transparent and conductive flexible wood by depositing a layer of silver nanowire ink on the surface of transparent wood.

Research on the preparation of transparent materials from wood cellulose skeletons is extensive and in-depth. At the same time, crab shells have a natural chitin fiber skeleton similar to the chemical structure of plant cellulose, but few people have prepared transparent chitin skeletons of crab shells. Materials for research. In addition, there are abundant crab shell resources in coastal areas of my country. Using crab shell chitin skeleton as raw material can not only obtain transparent fluorescent materials with complete crab shell shape and high light transmittance, but also be used in lighting and other photoelectric and artwork fields, and can also be used rationally. Natural resources and reduce environmental pollution.

technical problem

The invention aims to make rational use of my country's abundant crab shell resources, solve the problems of opacity, non-fluorescence, fragility, etc. of natural crab shells, and prepare a transparent composite material with a complete crab shell shape and a fluorescent transparent composite material.

Technical solutions

A method for preparing a fluorescent transparent composite material is characterized in that it comprises the following steps:

(1) Select crab shells or crab shell slices that are intact, clean them, and store them in deionized water for later use;

(2) Use low-concentration acid-base and ethanol solution to soak the whole crab shell or crab shell slices in sequence until calcium carbonate, protein, lipid and pigment matrix are completely removed, and store the processed crab shells or crab shell slices in a Reserve in water and ethanol;

(3) After the fluorescent material is uniformly dispersed in the polymer monomer by thermomechanical stirring, polymerization is performed to obtain the polymer;

(4) Take out the processed crab shells or crab shell pieces, immerse them in the polymer obtained in step (3), and vacuum and keep the pressure in a vacuum drying oven for 15 minutes, repeat three times, take out the crab shells or crab shell pieces and use After being wrapped in tin foil, it is cured at a constant temperature.

The crab shells or crab shell pieces are natural crab shells or crab shell pieces of hairy crabs or swimming crabs with a chitin fiber structure; the fluorescent material is ^{fluorescent powder including YAG: Ce 3+} ; the polymer monomer The body is an optically transparent polymer matrix of epoxy resin or methyl methacrylate.

The acid is a low-concentration acidic solution, which is _{a dilute solution of HCl, H 2} SO ₄ , HNO ₃ or CH ₃ COOH, with a concentration of 1-2 mol/L; the alkali is a low-concentration alkaline solution, which is NaOH, A dilute solution of KOH or NaHCO ₃ with a concentration of 1-2 mol/L.

The fluorescent material is in powder form, the particle size is 200-600 mesh, the addition amount is 0-1 wt% of the polymer monomer, and it is uniformly dispersed in the polymer monomer by thermomechanical stirring.

The polymer monomer is an epoxy resin, and a curing agent is added for curing, the curing agent is a mixture of polyether ammonia and benzyl alcohol, and the mass ratio of the epoxy resin to the curing agent is 3:1; The monomer is methyl methacrylate, and an initiator is used. The initiator is benzoyl peroxide. The mass ratio of methyl methacrylate to initiator is 1:0.005 to 1:0.02, and the prepolymerization temperature is 70-90. ℃, the thermal polymerization temperature is 50℃.

The vacuum dipping method is adopted to immerse the crab shell or crab shell flakes after removing the matrix in the pre-polymerized polymer matrix, the vacuum degree is 0.02-0.06 MPa, and the pressure is maintained for 15 minutes, repeated three times.

Beneficial effect

The transparent composite material and the fluorescent transparent composite material prepared by the invention have a light transmittance of 87.32%, and the doped fluorescent material has almost no effect on the light transmittance of the transparent crab shell. The addition of fluorescent powder expands the application range of transparent materials. It can not only be used in the fields of optoelectronics, construction and energy saving, but also can be used in art processing and other fields by using the natural and complete crab shell shape.

The invention combines the optically transparent polymer matrix with the chitin fiber skeleton structure of the crab shell, and due to the effect of light scattering, the originally opaque crab shell can exhibit higher light transmittance and realize optical transparency.

Description of the drawings

Figure 1 is a comparison diagram of the appearance of natural crab shells and the crab shells after removing the matrix;

Figure 2 is a comparison diagram of the appearance of crab shell slices after filling with different polymer matrices;

Figure 3 is a comparison diagram of crab shells in different states on the background font;

Figure 4 is a comparison diagram of the appearance of a complete crab shell in three states;

Figure 5 is a scanning electron micrograph of crab shells in different states;

Figure 6 is the infrared absorption spectrum of the crab shell before and after filling with EP;

Figure 7 is the infrared absorption spectrum of the crab shell before and after filling with PMMA;

Fig. 8 is the emission spectrum of EP with _{λ ex} =450nm and YAG:Ce ^{3+ phosphor doped;}

Figure 9 shows the excitation spectrum of EP doped with YAG: Ce ³⁺ _{phosphor with λ ex =537 nm.}

The best mode of the present invention

A method for preparing a fluorescent transparent composite material is characterized in that it comprises the following steps:

(1) Select crab shells or crab shell slices that are intact, clean them, and store them in deionized water for later use;

(2) Use low-concentration acid-base and ethanol solution to soak the whole crab shell or crab shell slices in sequence until calcium carbonate, protein, lipid and pigment matrix are completely removed, and store the processed crab shells or crab shell slices in a Reserve in water and ethanol;

(3) After the fluorescent material is uniformly dispersed in the polymer monomer by thermomechanical stirring, polymerization is performed to obtain the polymer;

(4) Take out the processed crab shells or crab shell pieces, immerse them in the polymer obtained in step (3), and vacuum and keep the pressure in a vacuum drying oven for 15 minutes, repeat three times, take out the crab shells or crab shell pieces and use After being wrapped in tin foil, it is cured at a constant temperature.

The crab shells or crab shell pieces are natural crab shells or crab shell pieces of hairy crabs or swimming crabs with a chitin fiber structure; the fluorescent material is ^{fluorescent powder including YAG: Ce 3+} ; the polymer monomer The body is an optically transparent polymer matrix of epoxy resin or methyl methacrylate.

The acid is a low-concentration acidic solution, which is _{a dilute solution of HCl, H 2} SO ₄ , HNO ₃ or CH ₃ COOH, with a concentration of 1-2 mol/L; the alkali is a low-concentration alkaline solution, which is NaOH, A dilute solution of KOH or NaHCO ₃ with a concentration of 1-2 mol/L.

The fluorescent material is in powder form, the particle size is 200-600 mesh, the addition amount is 0-1 wt% of the polymer monomer, and it is uniformly dispersed in the polymer monomer by thermomechanical stirring.

The polymer monomer is an epoxy resin, and a curing agent is added for curing, the curing agent is a mixture of polyether ammonia and benzyl alcohol, and the mass ratio of the epoxy resin to the curing agent is 3:1; The monomer is methyl methacrylate, and an initiator is used. The initiator is benzoyl peroxide. The mass ratio of methyl methacrylate to initiator is 1:0.005 to 1:0.02, and the prepolymerization temperature is 70-90. ℃, the thermal polymerization temperature is 50℃.

The vacuum dipping method is adopted to immerse the crab shell or crab shell flakes after removing the matrix in the pre-polymerized polymer matrix, the vacuum degree is 0.02-0.06 MPa, and the pressure is maintained for 15 minutes, repeated three times.

The transparent composite material and the fluorescent transparent composite material prepared by the invention have a light transmittance of 87.32%, and the doped fluorescent material has almost no effect on the light transmittance of the transparent crab shell.

Specific Example 1

Preparation of transparent crab shell flakes and crab shells with resin (EP) as polymer matrix

(1) Select crab shells or crab shell slices that are intact, clean them, and store them in deionized water for later use.

(2) Place the crab shells or crab shell pieces in a beaker, and soak them in a dilute HCl solution for 12 h. Repeat more than 2 times until the CaCO _{3 is} completely removed; at 55°C, the crab shells or crabs after the _{CaCO 3 are removed} Soak the shell pieces in the prepared NaOH dilute solution for 2 hours, repeat more than 4 times to completely remove the protein and lipids in the crab shell; at room temperature, use absolute ethanol to soak the crab shell after the above treatment for more than 12 hours until Remove the pigment in the crab shell and store it in absolute ethanol for later use.

(3) Add epoxy resin and curing agent with a mass ratio of 3:1 into the mold and mix them evenly. The processed crab shells and crab shell pieces are completely immersed in the configured epoxy resin. Put the mold into the vacuum drying oven, set the vacuum degree to 0.03 MPa, hold the pressure for 15 minutes, and repeat this step more than 3 times until the epoxy resin has completely penetrated into the crab shell, and then take out the crab shell sheet filled with the polymer matrix After placing it on the watch glass at room temperature for 24 hours, firm and transparent crab shells and crab shell pieces are obtained.

Specific embodiment 2

Preparation of transparent crab shell flakes with methyl methacrylate as polymer matrix

The processing method for removing the matrix inside the crab shell is the same as the steps (1) and (2) in Example 1.

Weigh 0.02g of benzoyl peroxide and 20g of methyl methacrylate into a closed Erlenmeyer flask, heat it in a water bath at 85°C until the solution has a significant viscosity change, quickly take out the Erlenmeyer flask and put it in ice water, and continue Shake to accelerate cooling to obtain pre-polymerized methyl methacrylate. Put the processed crab shell pieces into a small beaker, immerse the crab shell pieces with pre-polymerized methyl methacrylate, and then put the small beaker into a vacuum drying oven. When the vacuum degree is 0.03 MPa, keep the pressure for 15 minutes. Repeat this step 3 times, and finally keep the pressure at a vacuum of 0.05 MPa for 24h. Use tweezers to take out the completely infiltrated crab shell pieces, wrap them in tin foil, and put them in an oven at 50°C for 12 hours. After the polymer is fully polymerized, a transparent crab shell piece can be obtained.

Specific embodiment 3

Preparation of fluorescent transparent crab shell flakes

The processing method for removing the matrix inside the crab shell is the same as the steps (1) and (2) in Example 1.

Screen out transparent materials with better performance. When preparing transparent polymers, add 1wt% YAG: Ce ³⁺ phosphor to the polymer monomer and stir it with thermomechanical stirring to make it evenly dispersed, and then repeat the above-mentioned Example 1 The step of infiltrating the polymer matrix can obtain fluorescent transparent crab shell pieces.

The comparison diagram of the appearance of the crab shell slices before and after the removal of the substrate according to the present invention is as follows: Figure 1 is a comparison diagram of the appearance of the crab shell before and after the acid-base treatment. Figure 1a is a natural crab shell piece, which is orange-red and completely opaque; Figure 1b is a crab shell piece that has been soaked in ethanol for use after removing calcium carbonate, protein and pigment and other substrates. It is obvious that the crab shell piece has become thinner and more colorful. It fades and becomes white and slightly transparent; Figure 1c shows the crab shell slices after being dried in an oven to remove ethanol. It can be seen that the crab shell slices are completely opaque and wrinkled. This is due to the fact that the crab shell slices contain a large amount of After drying, the ethanol evaporates and the volume of the crab shell shrinks and becomes wrinkled.

Figure 2 is a comparison diagram of the appearance of crab shell pieces filled with different polymer matrices. 2a is a crab shell filled with PMMA. It can be clearly seen that the crab shell becomes transparent, but the degree of transparency is average; Figure 2b is a crab shell filled with epoxy resin (EP). The crab shell is completely transparent and has a high light transmittance. Observation shows that filling EP is more transparent than PMMA, so epoxy resin is chosen and 1wt% YAG: Ce ^{3 +} phosphor is added to prepare fluorescent transparent composite material; Figure 2c is filled epoxy + YAG: Ce ^{3 +} The picture of the phosphor, it can be seen that the transparency of the crab shell flakes after ^{adding YAG: Ce 3+ phosphor has not been significantly reduced.}

Figure 3 is a comparison diagram of crab shells in different states on the background font. Figure 3d is a picture of the original crab shell placed on the background font. The characters are completely invisible, indicating that the original crab shell is opaque; Figure 3e is the crab shell slices soaked in alcohol after removing the calcium carbonate and other substrates on the background In the picture on the font, the words can be seen vaguely, indicating that the transparency of the crab shell slices has been improved; Figure 3f is the picture of the dried crab shell slices in Figure 3e on the background font, and the words cannot be seen, indicating that the crab shell slices are dried The transparency of the shell decreases; Figure 3g is the crab shell slice filled with PMMA, and the background font can be seen, and the definition is relatively high; Figure 3h is the crab shell slice filled with EP, the background font seen is very clear, and the transparency effect is better than PMMA Better; Figure 3i is the crab shell slice filled with epoxy resin and YAG: Ce ³⁺ phosphor. The definition of the background font is slightly lower than that of the crab shell slice filled with epoxy resin only, but it is better than that after filling with PMMA. The clarity is good.

Figure 4 is a comparison diagram of the appearance of a complete crab shell in three states. Figure 4a is a natural crab shell; Figure 4b is the crab shell after removing the matrix, and it can be seen that the volume of the entire crab shell has more obvious shrinkage; Figure 4c is the complete crab shell after filling with epoxy resin, which shows that the crab shell is retained In the case of morphology, the entire crab shell becomes transparent, which lays a certain foundation for the application of transparent crab shells in the fields of optoelectronics and art.

The quality records of the crab shell flakes under several conditions of the present invention are shown in Table 1 and Table 2: Table 1 and Table 2 are the quality of the crab shell flakes before and after removing the matrix and after penetrating into the polymer matrix, respectively. It can be seen that the processed crab shell pieces are much lighter than the original crab shells. This is because calcium carbonate accounts for the largest proportion of the internal mass of the crab shells. When the matrix such as calcium carbonate is removed, only chitin nanometers are left. Fiber skeleton, so the quality of the crab shell flakes has been significantly reduced. When the polymer matrix was refilled with crab shell flakes, the overall quality increased significantly.

Table 1 The quality of crab shell pieces before and after filling with resin

sample	Original Crab Shell Pieces	Crab shell pieces after removing the substrate	Crab shell slices filled with EP
Measured average value/g	0.7232	0.1189	0.6674

Table 2 The quality of crab shell pieces before and after filling with PMMA

sample	Original Crab Shell Pieces	Crab shell pieces after removing the substrate	Crab shell slices filled with PMMA
Measured average value/g	0.6260	0.1141	1.0541

The light transmittances of the transparent crab shell flakes and fluorescent transparent crab shell flakes prepared by the present invention are shown in the following table: Tables 3 and 4 are natural crab shell flakes, crab shell flakes after removing the matrix, and the ones filled with PMMA and resin respectively. Comparison of light transmittance of crab shell pieces. From the data, it can be seen that the light transmittance of natural crab shell flakes is about 30%. After removing the matrix, the crab shell flakes have no light absorption factors such as calcium carbonate and pigment, which makes the light transmittance of crab shells increase significantly, reaching Around 65%. The light transmittance of the crab shell sheet after filling with PMMA is more than 70%. At the same time, the light transmittance of the crab shell sheet after filling with resin can reach more than 85%, and the effect is the best. Therefore, we use resin to make fluorescent transparent composite materials. Table 5 shows the light transmittance of the crab shell sheet after only filled with resin, filled resin and YAG: Ce ³⁺ phosphor. It can be seen that the addition of phosphor has almost no effect on the light transmittance of the transparent crab shell sheet.

Table 3 Transmittance of samples before and after filling with PMMA

sample	without	Original Crab Shell Pieces	Crab shell pieces after removing the substrate	Crab shell slices filled with PMMA
Measured average value/100Lux	29.7	8.7	19.07	21.37
Transmittance/%	100	29.41	64.20	71.94

Table 4 Light transmittance of crab shells before and after filling with resin

sample	without	Original Crab Shell Pieces	Crab shell pieces after removing the substrate	Crab shell pieces filled with resin
Measured average value/100Lux	29.7	9.3	19.5	25.9
Transmittance/%	100	31.31	65.66	87.32

Table 5 Transmittance of transparent crab shell flakes doped with phosphor

sample	without	Crab shell pieces filled with resin	Crab shell pieces filled with resin+1wt%YAG:Ce 3+
Measured average value/100Lux	29.7	25.9	25.6
Transmittance/%	100	87.32	86.31

The scanning electron microscope (SEM) of the present invention is shown in FIG. 5. Figures 5a, 5b, and 5c are scanning electron micrographs of natural crab shell at 1000, 5000, and 10000 times respectively; Figures 5d, 5e, and 5f are respectively 1000, 5000, and 10000 times scanning of the chitin skeleton of crab shell after matrix removal Electron microscope images; 5g, 5h, and 5i are respectively 1000, 5000 and 10000 times scanning electron microscope images of transparent crab shell slices filled with PMMA; Figures 5j, 5k, and 5l are 1000, 5000 times of transparent crab shell slices filled with EP, respectively And the scanning electron micrograph of 10000 times.

The infrared absorption spectrum of the present invention is measured as follows: Fig. 6 and Fig. 7 respectively show the infrared analysis spectra of the natural crab shell, the crab shell after removing the matrix, and the crab shell after filling with EP. As can be seen from the figure, compared to the native crab, the crab remove matrix ^{875cm -1, 1220-1330cm -1, 1600-1700cm -1} , the absorption peak intensity at 1700cm ^-1 significantly decreased, 875cm ^-1 is calcium carbonate in CO single bond, 1700cm ^-1 calcium carbonate in the C = O double bonds, 1220-1330cm ^-1 amide. ⅰ proteins, 1600-1700cm ^-1 protein amide ⅲ With this, it means that calcium carbonate and protein are processed relatively cleanly during the processing. In Figure 6, after filling with resin, new absorption peaks appear ^{at 829cm -1} and 1249cm ^{-1 . 829cm -1} is the benzene ring of bisphenol A in the ^{epoxy resin, and 1249cm -1} is the CO bond in the epoxy resin. Epoxy resin filled the inside of the crab shell. 7, after filling in the infrared spectrum PMMA 1160cm ^{-1, -1} new absorption peak 1700cm, 1160cm ^-1 is methyl methacrylate CO bond, 1700cm ^-1 methyl methacrylate is a C =O key, indicating that PMMA is filled into the gaps in the chitin skeleton of the crab shell.

The fluorescence spectrum analysis of the present invention is shown in FIG. 8 and FIG. 9. Figure 8 is the emission spectrum ^{of YAG: Ce 3+} phosphor in the transparent fluorescent crab shell material measured at λ=458nm. It can be seen from the figure that the peak of the emission spectrum is at 527nm, which is due to ^{the characteristic transition of Ce 3+} in the YAG phosphor at 5d→4f; Figure 9 is the YAG in the transparent fluorescent crab shell measured by light at λ=527nm ：Excitation spectrum of ^{Ce 3+ phosphor.} It can be seen that there are two excitation spectral peaks at 340nm and 458nm, and the peak at 458nm is the largest. This is because YAG: Ce ³⁺ phosphor 4f energy level ground state orbital ² F splits into ² F _5/2 and ² F _{7/ 2} Two spectral branch orbits, the excitation peak at 340 nm corresponds to ^{the transition of 2} F _5/2 → 5D, and the excitation peak at 450 nm corresponds to the transition of ² F _{7/2 → 5D.} In Fig. 8 and Fig. 9, no peak was detected in the crab shell filled with EP only, which confirmed that the crab shell filled with epoxy resin + 1 wt% YAG: Ce ³⁺ can prepare a transparent composite material with fluorescent properties.

Claims (6)

1. A method for preparing a fluorescent transparent composite material is characterized in that it comprises the following steps:

   (1) Select crab shells or crab shell slices that are intact, clean them, and store them in deionized water for later use;

   (2) Use low-concentration acid-base and ethanol solution to soak the whole crab shell or crab shell slices in sequence until calcium carbonate, protein, lipid and pigment matrix are completely removed, and store the processed crab shells or crab shell slices in a Reserve in water and ethanol;

   (3) After the fluorescent material is uniformly dispersed in the polymer monomer by thermomechanical stirring, polymerization is performed to obtain the polymer;

   (4) Take out the processed crab shells or crab shell pieces, immerse them in the polymer obtained in step (3), and vacuum and keep the pressure in a vacuum drying oven for 15 minutes, repeat three times, take out the crab shells or crab shell pieces and use After being wrapped in tin foil, it is cured at a constant temperature.
2. The method for preparing a fluorescent transparent composite material according to claim 1, wherein the crab shell or crab shell piece is a natural crab shell or crab shell piece with a chitin fiber structure of hairy crabs or swimming crabs; The fluorescent material is ^{fluorescent powder including YAG: Ce 3+} ; the polymer monomer is an optically transparent polymer matrix of epoxy resin or methyl methacrylate.
3. The method for preparing a fluorescent transparent composite material according to claim 1, wherein the acid is a low-concentration acidic solution, which is _{a dilute solution of HCl, H 2} SO ₄ , HNO ₃ or CH ₃ COOH, with a concentration of 1 -2mol/L; the alkali is a low-concentration alkaline solution, which is _{a dilute solution of NaOH, KOH or NaHCO 3} , with a concentration of 1-2 mol/L.
4. The method for preparing a fluorescent transparent composite material according to claim 1, 2 or 3, characterized in that: the fluorescent material is in powder form, the particle size is 200-600 mesh, and the addition amount is 0- to the polymer monomer. 1wt%, and uniformly dispersed in the polymer monomer by thermomechanical stirring.
5. The method for preparing a fluorescent transparent composite material according to claim 4, wherein the polymer monomer is an epoxy resin, and a curing agent is added for curing, and the curing agent is a mixture of polyether ammonia and benzyl alcohol, The mass ratio of epoxy resin and curing agent is 3:1; the polymer monomer is methyl methacrylate, and an initiator is used. The initiator is benzoyl peroxide, methyl methacrylate and initiator The agent mass ratio is 1:0.005 to 1:0.02, the prepolymerization temperature is 70-90℃, and the thermal polymerization temperature is 50℃.
6. The method for preparing a fluorescent transparent composite material according to claim 5, characterized in that: using a vacuum dipping method, the crab shell or crab shell sheet after the substrate is removed is immersed in the pre-polymerized polymer matrix, and the vacuum degree is 0.02- 0.06MPa, keep the pressure for 15min, repeat three times.