A PMMA light guide plate based on rayleigh scattering principle and a preparation method thereof
By modifying the nano-SiO2 raw material and using in-situ polymerization, the problem of uneven dispersion in the preparation of Rayleigh scattering light guide plates was solved, achieving high light transmittance and uniform scattering effect, simplifying the production process, and making it suitable for indoor lighting that simulates natural light.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUILIN UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2026-03-06
- Publication Date
- 2026-05-29
AI Technical Summary
The existing Rayleigh scattering light guide plate manufacturing process is cumbersome and complex. The nanoparticles are not evenly dispersed in the transparent polymer, resulting in unstable scattering effect and poor light transmittance, which limits its application and promotion.
Modified nano-SiO2 stock solution with a particle size of 50-100nm and a mass fraction of 1-5 parts is used. Combined with MMA solvent exchange treatment and in-situ polymerization process, the nanoparticles are uniformly dispersed in the PMMA matrix to form dense Rayleigh scattering centers, resulting in uniform scattering of short-wavelength light.
It achieves high light transmittance and uniform scattering effect, simplifies the production process, reduces costs, and is suitable for indoor lighting that simulates natural light, meeting the lighting environment needs of different scenarios.
Smart Images
Figure CN122103795A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of light guide plate technology, specifically to a PMMA light guide plate based on the Rayleigh scattering principle and its preparation method. Background Technology
[0002] Light plays an indispensable role in all aspects of human life, and the lighting environment it creates has a direct and profound positive impact on people's mental state and psychological well-being. In production, work, and study settings, a high-quality lighting environment can help improve work efficiency and product quality; while in public places such as rest and entertainment venues, a suitable lighting environment can create a variety of atmospheres, from comfortable and elegant to lively and vibrant or solemn and serious, to meet the needs of different scenarios. It is evident that optimizing the lighting environment is of great significance to people's daily lives and various activities.
[0003] Rayleigh scattering light guides, as a novel optical element, demonstrate broad application potential and high commercial value due to their unique working principle. Their core mechanism involves Rayleigh scattering, where short-wavelength blue-violet light is scattered in various directions, achieving a uniform illumination effect similar to natural light. By simulating natural light, these light guides can provide a more realistic and comfortable lighting experience for indoor spaces, allowing people to feel near-natural illumination indoors. This characteristic gives them promising application prospects in many fields.
[0004] However, current Rayleigh scattering light guide plate fabrication technology still has significant shortcomings and limitations. Existing fabrication processes are cumbersome and complex, increasing production difficulty and cost while also affecting production efficiency. More importantly, uneven dispersion of nanoparticles within the transparent polymer is a common problem during fabrication. The dispersion effect of nanoparticles directly affects the optical performance of the light guide plate; uneven dispersion leads to unstable scattering effects and poor light transmittance, thus affecting its ability to simulate natural light and limiting the practical application and widespread use of Rayleigh scattering light guide plates. Therefore, a novel fabrication method is urgently needed to solve these technical challenges and promote the further development of Rayleigh scattering light guide plate technology. Summary of the Invention
[0005] To address the aforementioned technical problems, the first aspect of this invention provides a PMMA (polymethyl methacrylate) light guide plate based on the Rayleigh scattering principle. The raw materials for its preparation, by mass, include 90-100 parts MMA monomer, 1-5 parts modified nano-SiO2 stock solution, and 1-2 parts initiator. The modified nano-SiO2 has a particle size of 50-100 nm. The raw materials for preparing the modified nano-SiO2 stock solution include a silicon source precursor, a silane coupling agent, a pH adjuster, and a solvent.
[0006] To address the challenges of nanoparticles easily agglomerating in transparent polymer matrices, leading to unstable scattering effects and impaired optical properties, this invention specifies that the particle size range of modified nano-SiO2 in the modified nano-SiO2 stock solution is 50-100 nm, and further limits its mass fraction to 1-5 parts. This ensures effective scattering sites while avoiding excessive concentration that could cause aggregation and stacking. Existing technologies suffer from imbalances in scattering effects and transmittance due to improper raw material ratios. This invention limits the mass ratio of MMA monomer (90-100 parts) to modified nano-SiO2 stock solution (1-5 parts) to ensure good transparency of the PMMA matrix while allowing nanoparticles to form uniform scattering centers. Short-wavelength blue-violet light is fully scattered to simulate natural light. By controlling the amount of initiator, abnormal polymerization reactions are avoided to prevent them from affecting transmittance and structural stability.
[0007] The modified nano-SiO2 stock solution selected in this invention is not a simple SiO2 suspension, but a stable system formed by the hydrolysis of silicon source precursor and modification with silane coupling agent. At the same time, due to the MMA solvent exchange treatment step, the modified nano-SiO2 stock solution is a uniformly dispersed wet system with modified nano-SiO2 particles as Rayleigh scattering centers and MMA liquid as solvent. MMA solvent molecules form a steric hindrance layer on the particle surface, further preventing contact aggregation between particles. This ensures that the particles in the modified nano-SiO2 stock solution with MMA as solvent are always in a monodisperse, low-agglomeration state of 50-100nm during the in-situ polymerization of MMA monomers. The resulting PMMA light guide plate has no agglomerated large particles and can form dense and uniform Rayleigh scattering centers. Short-wavelength blue-violet light can be uniformly scattered in all directions in the light guide plate, achieving a natural blue light effect.
[0008] As an implementable example, the silicon source precursor includes one or more of tetraethyl silicate, tetramethyl silicate, methyltriethoxysilane, dimethyldiethoxysilane, phenylmethylsilane, hexamethyldisilazane, and mercaptopropyltriethoxysilane.
[0009] As an implementable example, the silane coupling agent includes one of KH-550 (γ-aminopropyltriethoxysilane), KH-560 (γ-glycidoxypropyltrimethoxysilane), KH-570 (γ-methacryloyloxypropyltrimethoxysilane), KH-580 (γ-mercaptopropyltrimethoxysilane), or A-1160 (γ-ureapropyltriethoxysilane).
[0010] As an example of implementation, the pH adjuster includes one of NaOH aqueous solution, KOH aqueous solution or ammonia solution.
[0011] As an example of implementation, the solvent includes at least one of water, ethanol, or isopropanol.
[0012] Furthermore, the mass ratio of the silicon source precursor to the silane coupling agent is 1:(3-5).
[0013] The core function of the silicon source precursor is to generate SiO2 nanoparticles through hydrolysis and condensation reactions. The key function of the silane coupling agent is to modify the surface of the generated SiO2 particles. The alkoxy groups in the silane coupling agent can react with the hydroxyl groups on the surface of the SiO2 particles, grafting hydrophobic organic functional groups onto the particle surface. If the amount of silane coupling agent is insufficient, it cannot completely cover the hydrophilic groups on the surface of the SiO2 particles, leaving some particle surfaces hydrophilic. This not only leads to easy aggregation of particles due to hydrogen bonding but also reduces its compatibility with the hydrophobic PMMA matrix, ultimately affecting the scattering uniformity of the light guide plate. However, when the amount of silane coupling agent is controlled at 3-5 times that of the silicon source precursor, it ensures that each SiO2 nanoparticle surface can be grafted with a sufficient amount of hydrophobic groups, eliminating the driving force for particle aggregation. Combined with solvent exchange and in-situ polymerization processes, the dispersion uniformity of nanoparticles in the PMMA matrix can be further improved, thereby enabling the light guide plate to achieve better Rayleigh scattering effects.
[0014] Furthermore, the preparation method of the modified nano-SiO2 stock solution includes the following steps: A solvent is added to the silicon source precursor and dissolved by ultrasonication to obtain a silicon source precursor solution. A pH adjuster is then added to the silicon source precursor solution to adjust the pH of the system to 9-12, thus obtaining the SiO2 stock solution. Add a silane coupling agent to the SiO2 stock solution, reflux the reaction, centrifuge after the reaction is complete, first use ethanol for solvent exchange, then use MMA for solvent exchange, and the modified nano SiO2 stock solution is obtained.
[0015] As an example of implementation, the initiator includes peroxide initiators or azo initiators.
[0016] Furthermore, the peroxide initiator includes one or more of the following: benzoyl peroxide, dilauroyl peroxide, diacetyl peroxide, dipropionyl peroxide, dibutyryl peroxide, di(2,4-dichlorobenzoyl peroxide), di(o-methylbenzoyl peroxide), di(p-chlorobenzoyl peroxide), tert-butyl perpentanoate, tert-butyl peroxide-2-ethylhexanoate, tert-butyl peroxide-neodecanate, di(1-hydroxycyclohexyl peroxide), methyl ethyl ketone peroxide, diisopropyl peroxide dicarbonate, dicyclohexyl peroxide dicarbonate, di(2-ethylhexyl) peroxide dicarbonate, di(4-tert-butylcyclohexyl) peroxide dicarbonate, dimyristyl peroxide dicarbonate, cyclohexanone peroxide, and 1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane.
[0017] Furthermore, the azo initiator includes azobisisobutyronitrile (AIBN) or azobisisovalerate.
[0018] A second aspect of this invention provides a method for fabricating a PMMA light guide plate based on the Rayleigh scattering principle, comprising the following steps: S1. Mix MMA monomer, modified nano-SiO2 stock solution and initiator, and polymerize in situ under heating conditions. Stop heating when the viscosity of the system is 500-1000 mPa·s to obtain PMMA prepolymer. S2. Inject the PMMA prepolymer into a sealed glass mold, remove the gas from the mold, place it in an oven for postpolymerization for 4-6 hours, cure and cool, and then open the mold to obtain a PMMA light guide plate based on the Rayleigh scattering principle.
[0019] As an example of feasible implementation, the in-situ polymerization temperature is 75-85℃.
[0020] As an example of feasible implementation, the post-polymerization temperature is 60-70°C.
[0021] Beneficial effects (i) Based on the Rayleigh scattering principle, the PMMA light guide plate designed in this invention can naturally simulate the sunlight of a clear sky, so that the indoor lighting can obtain a real and comfortable natural light lighting effect, and meet the needs of high-quality light environment in different scenarios.
[0022] (ii) The present invention adopts an integrated process of in-situ polymerization and molding, which is simple and easy to operate, without complicated procedures, and can efficiently and quickly prepare Rayleigh scattering light guide plates, reducing production difficulty and cost, and facilitating large-scale production.
[0023] (III) This invention precisely controls the particle size of modified nano-SiO2 to 50~100nm and limits the mass amount of modified nano-SiO2 stock solution to 1~5 parts, adding it in the form of wet raw materials. This can make the nanoparticles in the light guide plate more uniformly dispersed. At the same time, the modified nano-SiO2 stock solution, after solvent exchange treatment, uses MMA as solvent. During the in-situ polymerization of MMA monomers, the possibility of particle agglomeration can be further reduced, and its dispersion uniformity in the product can be improved. Therefore, the PMMA light guide plate has high light transmittance and uniform scattering effect, which can avoid the optical performance imbalance caused by improper particle content or nanoparticle agglomeration. Attached Figure Description
[0024] Figure 1 This is a particle size distribution diagram of nano-SiO2 in Example 4.
[0025] Figure 2 Transmission electron microscope image of the PMMA light guide plate prepared in Example 4. Figure 3The transmittance test diagrams are for the PMMA light guide plates prepared in Example 4 and Comparative Example 1.
[0026] Figure 4 The glass transition temperature test diagrams are for the PMMA light guide plates prepared in Example 4 and Comparative Example 1.
[0027] Figure 5 The image shows the Rayleigh scattering effect of the PMMA light guide plate prepared in Example 4.
[0028] Figure 6 This is a particle size distribution diagram of nano-TiO2 in Comparative Example 2.
[0029] Figure 7 The transmittance test diagram of the PMMA light guide plate prepared for Comparative Example 2 is shown.
[0030] Figure 8 Transmission electron microscope image of the PMMA light guide plate prepared for Comparative Example 3.
[0031] Figure 9 The particle size distribution of 3 nm SiO2 is shown in the comparative example.
[0032] Figure 10 This is a particle size distribution diagram of SiO2 in Comparative Example 4.
[0033] Figure 11 Rayleigh scattering effect of the PMMA light guide plate prepared for Comparative Example 4.
[0034] Figure 12 The image shows the blue light effect of the PMMA light guide plate prepared for Comparative Example 5. Detailed Implementation
[0035] Example 1 The first aspect of this example provides a PMMA light guide plate based on the Rayleigh scattering principle. The raw materials for its preparation include, by mass, 98 parts MMA monomer, 1 part modified nano-SiO2 stock solution, and 1 part initiator AIBN. The particle size of the modified nano-SiO2 is 50-100nm.
[0036] The raw materials for preparing the modified nano-SiO2 stock solution include tetraethyl silicate, silane coupling agent KH-570, ammonia, water, and isopropanol.
[0037] The preparation method of the modified nano-SiO2 stock solution includes: adding 80 mL of isopropanol, 30 mL of water and 2 mL of ammonia water to a three-necked flask by mass, turning on the stirrer and heating to 70°C, adding 1 part of tetraethyl silicate, and refluxing for 3 h to obtain the nano-SiO2 stock solution. Add 5 parts of silane coupling agent KH-570 and continue reflux for 3 hours. After the reaction is complete, centrifuge and first use ethanol for solvent exchange, then use MMA for solvent exchange to obtain the modified nano-SiO2 stock solution.
[0038] The second aspect of this example provides a method for fabricating a PMMA light guide plate based on the Rayleigh scattering principle, including the following steps: S1. Mix MMA monomer, modified nano-SiO2 stock solution and initiator AIBN, and polymerize in situ at 80℃. Stop heating when the viscosity of the system is 500-1000 mPa·s to obtain PMMA prepolymer. S2. Inject the PMMA prepolymer into a sealed glass mold, remove the gas from the mold, place it in an oven at 65°C for 6 hours to polymerize, cure and cool to room temperature of 25°C, open the mold, and you will get a PMMA light guide plate based on the Rayleigh scattering principle.
[0039] Example 2 The specific implementation method of this example is the same as that of Example 1, except that the raw materials for preparing the PMMA light guide plate include 97 parts MMA monomer, 2 parts modified nano SiO2 stock solution, and 1 part initiator AIBN by mass.
[0040] Example 3 The specific implementation method of this example is the same as that of Example 1, except that the raw materials for preparing the PMMA light guide plate include 96 parts of MMA monomer, 3 parts of modified nano SiO2 stock solution, and 1 part of initiator AIBN by mass.
[0041] Example 4 The specific implementation method of this example is the same as that of Example 1, except that the raw materials for preparing the PMMA light guide plate include 95 parts MMA monomer, 4 parts modified nano SiO2 stock solution, and 1 part initiator AIBN by mass.
[0042] Example 5 The specific implementation method of this example is the same as that of Example 1, except that the raw materials for preparing the PMMA light guide plate include 94 parts of MMA monomer, 5 parts of modified nano SiO2 stock solution, and 1 part of initiator AIBN by mass.
[0043] Comparative Example 1 (Blank Control) The first aspect of this example provides a PMMA light guide plate, the raw materials of which, by mass, include 99 parts MMA monomer and 1 part initiator AIBN.
[0044] The second aspect of this example provides a method for preparing a PMMA light guide plate, including the following steps: S1. Mix MMA monomer and initiator AIBN, and polymerize under heating at 80℃. Stop heating when the viscosity of the system is 500-1000 mPa·s to obtain PMMA prepolymer. S2. Inject the PMMA prepolymer into a sealed glass mold, remove the gas from the mold, place it in an oven at 65°C for 6 hours to polymerize, cure and cool to room temperature of 25°C, open the mold to obtain the PMMA light guide plate.
[0045] Comparative Example 2 The specific implementation method of this example is the same as that of Example 4, except that: the modified nano-SiO2 stock solution is replaced with an equal mass fraction of modified nano-TiO2 stock solution, wherein the particle size of the modified nano-TiO2 in the modified nano-TiO2 stock solution is 400-500nm.
[0046] The modified nano-TiO2 stock solution is prepared as follows: 80 mL of isopropanol and 30 mL of water are added to a three-necked flask by mass. Stirring is started and the temperature is raised to 70°C. 1 part of isopropyl titanate is added, and the mixture is refluxed for 3 hours. Then, 3 parts of silane coupling agent KH-570 are added and the mixture is refluxed for another 3 hours. After the reaction is completed, the mixture is centrifuged, and the solvent is exchanged with ethanol and MMA to obtain the modified nano-TiO2 stock solution.
[0047] Comparative Example 3 The specific implementation method of this example is the same as that of Example 4, except that an equal mass of unmodified nano-SiO2 with a particle size of 100-150nm is used to replace the modified nano-SiO2 stock solution as the raw material for the PMMA light guide plate.
[0048] Comparative Example 4 The specific implementation method in this example is the same as in Example 4, except that the modified nano-SiO2 stock solution is dried before being added to the reaction system as a raw material.
[0049] Comparative Example 5 The specific implementation method of this example is the same as that of Example 4, except that the raw materials for preparing the PMMA light guide plate include 93 parts MMA monomer, 6 parts modified nano SiO2 stock solution, and 1 part initiator AIBN by mass.
[0050] The blue light effect of the PMMA light guide plate prepared in this example is shown in the image below. Figure 12 As shown.
[0051] Performance testing The PMMA light guide plates prepared in the above embodiments and comparative examples were subjected to particle size and light transmittance tests.
[0052] In the above implementation examples, the particle size distribution diagram of nano-SiO2 in Example 4 is as follows: Figure 1As shown; the transmission electron microscope image of the PMMA light guide plate prepared in Example 4 is shown. Figure 2 As shown; the transmittance diagrams of the PMMA light guide plates prepared in Example 4 and Comparative Example 1 are shown below. Figure 3 As shown; the glass transition temperature diagrams of the PMMA light guide plates prepared in Example 4 and Comparative Example 1 are shown in the figure. Figure 4 As shown; Rayleigh scattering effect of the PMMA light guide plate prepared in Example 4 is shown in the figure. Figure 5 As shown; the particle size distribution of nano-TiO2 in Comparative Example 2 is shown in the figure. Figure 6 As shown; the transmittance test diagram of the PMMA light guide plate prepared in Comparative Example 2 is shown in the figure. Figure 7 As shown; the transmission electron microscope image of the PMMA light guide plate prepared in Comparative Example 3 is shown below. Figure 8 As shown; the particle size distribution of 3 nm SiO2 in the comparative example is shown in the figure. Figure 9 As shown; the particle size distribution of SiO2 in Comparative Example 4 is shown in the figure. Figure 10 As shown; the Rayleigh scattering effect of the PMMA light guide plate prepared in Comparative Example 4 is shown in the figure. Figure 11 As shown; the blue light effect of the PMMA light guide plate prepared in Comparative Example 5 is shown in the figure. Figure 12 As shown.
[0053] The test results of Example 4 and Comparative Example 5 show that when the amount of added nanoparticles is small, the transmittance of the Rayleigh scattering light guide plate can meet the lighting requirements; when too many nanoparticles are added (e.g., 6 parts), the Rayleigh scattering effect of the light guide plate is poor, the product appears white overall, and there is almost no blue light effect. Therefore, it is necessary to control the content of nanoparticles in PMMA to simultaneously meet the requirements of lighting and scattering effect. Therefore, Example 4 was selected as the subject of subsequent tests.
[0054] As can be seen from Example 4 and Comparative Example 1, the PMMA light guide plate with added nanoparticles exhibits Rayleigh scattering effect, and the addition of modified nano-SiO2 solution does not significantly affect the thermodynamic properties and light transmittance of the PMMA substrate.
[0055] As can be seen from Example 4 and Comparative Example 2, the particle size of nano-SiO2 particles is smaller than that of nano-TiO2 particles, and the light guide plate with added nano-SiO2 particles has higher transmittance than the light guide plate with added nano-TiO2 particles. This indicates that the modified nano-SiO2 particles are not easy to agglomerate and have better stability.
[0056] As can be seen from Example 4 and Comparative Example 3, the modified nano-SiO2 particles have a smaller particle size, and the light guide plate has better transmittance. Therefore, modifying SiO2 can significantly improve the optical performance of the Rayleigh scattering light guide plate.
[0057] As can be seen from Example 4 and Comparative Example 4, in this invention, the addition of wet modified nano-SiO2 particle stock solution treated with MMA solvent exchange as raw material to prepare PMMA light guide plate, combined with in-situ polymerization process, makes the nanoparticles in the PMMA light guide plate obtained by MMA monomer polymerization more uniformly dispersed. Therefore, the product has excellent Rayleigh scattering effect. However, when using dried nano-SiO2 particles as raw material, the particles are more prone to agglomeration after drying, so the light guide plate does not have Rayleigh scattering effect.
Claims
1. A PMMA light guide plate based on Rayleigh scattering principle, characterized in that, The raw materials for preparation, by mass, include 90-100 parts MMA monomer, 1-5 parts modified nano-SiO2 stock solution, and 1-2 parts initiator; wherein, the particle size of the modified nano-SiO2 is 50-100 nm. The raw materials for preparing the modified nano-SiO2 stock solution include a silicon source precursor, a silane coupling agent, a pH adjuster, and a solvent.
2. The PMMA light guide plate according to claim 1, characterized in that, The silicon source precursor includes one or more of tetraethyl silicate, tetramethyl silicate, methyltriethoxysilane, dimethyldiethoxysilane, phenylmethylsilane, hexamethyldisilazane, and mercaptopropyltriethoxysilane.
3. The PMMA light guide plate according to claim 1, characterized in that, The silane coupling agent includes one of γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, or γ-ureapropyltriethoxysilane.
4. The PMMA light guide plate according to claim 1, characterized in that, The pH adjuster includes one of NaOH aqueous solution, KOH aqueous solution, or ammonia solution.
5. The PMMA light guide plate according to claim 1, characterized in that, The mass ratio of the silicon source precursor to the silane coupling agent is 1:(3-5).
6. The PMMA light guide plate according to claim 1, characterized in that, The preparation method of the modified nano-SiO2 stock solution includes the following steps: A solvent is added to the silicon source precursor and dissolved by ultrasonication to obtain a silicon source precursor solution. A pH adjuster is then added to the silicon source precursor solution to adjust the pH of the system to 9-12, thus obtaining the SiO2 stock solution. Add a silane coupling agent to the SiO2 stock solution, reflux the reaction, centrifuge after the reaction is complete, first use ethanol for solvent exchange, then use MMA for solvent exchange, and the modified nano SiO2 stock solution is obtained.
7. The PMMA light guide plate according to claim 1, characterized in that, The initiator includes peroxide initiators or azo initiators.
8. A method for preparing a PMMA light guide plate based on Rayleigh scattering principle according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Mix MMA monomer, modified nano-SiO2 stock solution and initiator, and polymerize in situ under heating conditions. Stop heating when the viscosity of the system is 500-1000 mPa·s to obtain PMMA prepolymer. S2. Inject the PMMA prepolymer into a sealed glass mold, remove the gas from the mold, place it in an oven for postpolymerization for 4-6 hours, cure and shape it, cool it, and open the mold to obtain the PMMA light guide plate based on the Rayleigh scattering principle.
9. The method for preparing the PMMA light guide plate according to claim 8, characterized in that, The in-situ polymerization temperature is 75-85℃.
10. The method for preparing the PMMA light guide plate according to claim 8, characterized in that, The post-polymerization temperature is 60-70℃.