Photoresponse color-changing aviation organic glass and manufacturing method thereof

Abstract

The invention relates to photo-response color-changing aviation organic glass and a manufacturing method thereof.The photo-response color-changing aviation organic glass comprises a PMMA matrix and a photo-response color-changing compound, and the photo-response color-changing compound is dispersed in the PMMA matrix in a chemical bonding mode. The chemical bonding mode comprises at least one of the following modes: the photoresponse color-changing compound is dispersed in the PMMA matrix in a chemical bonding mode by carrying out ring-opening reaction on the photoresponse color-changing compound and a functional compound; the photoresponsive color-changing compound is copolymerized with a monomer for forming PMMA through an unsaturated unit and is dispersed in the PMMA matrix in a chemical bonding manner. The photoresponsive color-changing aviation organic glass is stable and reliable.

Description

Technical Field

[0001] This application relates to the field of optical materials technology, specifically to a photosensitive color-changing aerospace acrylic glass and its manufacturing method. Background Technology

[0002] Cockpit canopies, windows, and windshield components are typically made of PMMA (polymethyl methacrylate). As core components of aircraft, the richness of their colors directly impacts the passenger's flight experience. In recent years, significant progress has been made in photoresponsive materials, making the application of photoresponsive technology in the aircraft field possible. Photoresponsive technology can control the diverse colors of aviation-grade PMMA, enriching its color options and possessing significant application value.

[0003] However, the application of photosensitive color-changing technology in plexiglass still faces some significant challenges, such as the precipitation of color-changing materials during long-term use.

[0004] Therefore, it is necessary to develop stable and reliable light-responsive color-changing aerospace acrylic glass. Summary of the Invention

[0005] To address the aforementioned technical issues, this application provides a photosensitive color-changing aviation acrylic glass, which can improve the stability and reliability of photosensitive color-changing aviation acrylic glass.

[0006] To address the aforementioned technical problems, this application provides a photoresponsive color-changing aviation acrylic glass, comprising a PMMA matrix and a photoresponsive color-changing compound. The photoresponsive color-changing compound is dispersed in the PMMA matrix via chemical bonding. The chemical bonding method includes at least one of the following: the photoresponsive color-changing compound is dispersed in the PMMA matrix via a ring-opening reaction with a functional compound; or the photoresponsive color-changing compound is dispersed in the PMMA matrix via copolymerization of unsaturated units with monomers forming PMMA via chemical bonding.

[0007] In some embodiments, the photoresponsive color-changing compound accounts for ≤30% by mass, and the PMMA matrix accounts for ≥60% by mass.

[0008] In some embodiments, the photoresponsive color-changing compound includes at least one selected from photoresponsive color-changing compounds having epoxy groups and photoresponsive color-changing compounds having tertiary amine groups, and the functional compound includes at least one selected from a first functional compound and a second functional compound; wherein, The photoresponsive color-changing compound having an epoxy group unit undergoes a ring-opening reaction with the first functional compound through the epoxy group unit, and the photoresponsive color-changing compound having a tertiary amine group unit undergoes a ring-opening reaction with the second functional compound through the tertiary amine group unit.

[0009] In some embodiments, the first functional compound is a compound containing a maleimide group, and the second functional compound is an unsaturated compound containing an epoxy group.

[0010] This application also provides a method for manufacturing photosensitive color-changing aviation acrylic glass, comprising the following steps: S1: Provide MMA monomers and prepolymerize the MMA monomers to obtain a matrix material; S2: Prepare a homogeneous mixture, the homogeneous mixture comprising the matrix material, an initiator, and at least one of the following components: a photoresponsive color-changing compound that undergoes a ring-opening reaction with a functional compound; a photoresponsive color-changing compound having unsaturated units; S3: The homogeneous mixture is cured to disperse the photoresponsive color-changing compound in the PMMA matrix through at least one of the following chemical bonding methods: the photoresponsive color-changing compound is dispersed in the PMMA matrix through a ring-opening reaction with the functional compound, thereby chemically bonding the photoresponsive color-changing compound in the PMMA matrix; the photoresponsive color-changing compound is dispersed in the PMMA matrix through a copolymerization reaction between unsaturated units and MMA monomers in the matrix material, thereby obtaining the photoresponsive color-changing aviation acrylic glass.

[0011] In some embodiments, step S1, which involves prepolymerizing the MMA monomer to obtain a matrix material, includes at least one of the following: A photoresponsive color-changing compound with epoxy groups, an initiator, and the MMA monomer are mixed and polymerized to form a precursor mixture containing the polymerization precursor, thereby obtaining the matrix material. A photoresponsive color-changing compound having tertiary amine units, an initiator, and the MMA monomer are mixed and then subjected to a polymerization reaction to form a precursor mixture containing the polymerization precursor, thereby obtaining the matrix material; The photoresponsive color-changing compound with unsaturated units, the initiator, and the MMA monomer are mixed and then subjected to a polymerization reaction to form a precursor mixture containing the polymerization precursor, so as to obtain the matrix material. The ratio of the amount of at least one of the photoresponsive color-changing compounds having epoxy groups, the photoresponsive color-changing compounds having tertiary amino groups, and the photoresponsive color-changing compounds having unsaturated groups to the amount of the MMA monomer is less than or equal to 1:10.

[0012] In some embodiments, in the homogeneous mixture, at least one of the photoresponsive color-changing compound that undergoes a ring-opening reaction with the functional compound and the photoresponsive color-changing compound having unsaturated units, is present in a mass ratio of (5 ~ 30): (60 ~ 90) to the matrix material. The molar ratio of the functional compound to the photoresponsive color-changing compound that undergoes a ring-opening reaction with the functional compound is 1:1; the initiator has a mass percentage of ≤0.6% in the homogeneous mixture. In some embodiments, the photoresponsive color-changing compound that undergoes a ring-opening reaction with the functional compound includes at least one of a photoresponsive color-changing compound having an epoxy group and a photoresponsive color-changing compound having a tertiary amine group, and the functional compound includes at least one of a first functional compound and a second functional compound; wherein, The photoresponsive color-changing compound having an epoxy group unit undergoes a ring-opening reaction with the first functional compound, and the photoresponsive color-changing compound having a tertiary amine group unit undergoes a ring-opening reaction with the second functional compound.

[0013] In some embodiments, the step of curing the homogeneous mixture includes: a water bath at 35-65°C for 12-120 h, followed by a forced-air bath at 105-135°C for 10-80 h.

[0014] In some embodiments, the method further includes a step of modifying and preparing a photoresponsive color-changing compound, wherein the step of modifying and preparing a photoresponsive color-changing compound includes: Prepare an organic solution of the initial compound that exhibits photoresponsive color-changing function; The modified molecule is added to the organic solution, and the reaction is carried out under heat. After the reaction is completed, the mixture is washed, separated and purified to obtain a photosensitive color-changing compound with an epoxy group, a photosensitive color-changing compound with a tertiary amine group, or a photosensitive color-changing compound with an unsaturated group.

[0015] In the photoresponsive color-changing aviation acrylic glass of this application, the photoresponsive color-changing compound is dispersed in the PMMA matrix through a ring-opening reaction with a functional compound in a chemically bonded manner, or the photoresponsive color-changing compound is dispersed in the PMMA matrix through copolymerization of unsaturated units with monomers forming PMMA in a chemically bonded manner. Both bonding methods enable the photoresponsive color-changing compound and the PMMA matrix to be chemically bonded to each other, forming a strong whole and eliminating the generation of free state. This effectively solves the problem of photoresponsive color-changing compound precipitation under long-term use conditions in the prior art, ensuring stability and reliability. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart of a method for manufacturing a photosensitive color-changing aviation acrylic glass according to this application.

[0017] Figure 2 This is a schematic diagram of a process for preparing a modified photoresponsive color-changing compound according to this application.

[0018] Figure 3 This is a schematic diagram of the ring-opening reaction process between the epoxy group unit and the first functional compound in this application.

[0019] Figure 4 This is a schematic diagram of the key reaction process involved in Example 1 of this application.

[0020] Figure 5 This is a schematic diagram illustrating the mechanism of the photoresponsive color-changing process of the photoresponsive color-changing aviation organic glass in Examples 1 to 4 of this application. Detailed Implementation

[0021] The following specific embodiments illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification.

[0022] In the following description, reference is made to the accompanying drawings, which illustrate several embodiments of the present application. It should be understood that other embodiments may also be used, and changes in mechanical composition, structure, electrical and operational aspects may be made without departing from the spirit and scope of the present application. The following detailed description should not be considered limiting, and the terminology used herein is for describing particular embodiments only and is not intended to limit the present application.

[0023] Although the terms first, second, etc., are used in some instances to describe various elements herein, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.

[0024] Furthermore, as used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context indicates otherwise. It should be further understood that the terms “comprising,” “including,” indicate the presence of the stated feature, step, operation, element, component, item, kind, and / or group, but do not preclude the presence, occurrence, or addition of one or more other features, steps, operations, elements, components, items, kinds, and / or groups. The terms “or” and “and / or” as used herein are to be interpreted inclusively, or mean any one or any combination thereof. Thus, “A, B, or C” or “A, B, and / or C” means “any one of: A; B; C; A and B; A and C; B and C; A, B, and C.” Exceptions to this definition occur only when combinations of elements, functions, steps, or operations are inherently mutually exclusive in some way.

[0025] Some embodiments of this application provide a photosensitive color-changing aviation acrylic glass, which includes a PMMA matrix (polymethyl methacrylate matrix) and a photosensitive color-changing compound. The photosensitive color-changing compound is dispersed in the PMMA matrix through chemical bonding. The chemical bonding method includes at least one of the following: the photosensitive color-changing compound is dispersed in the PMMA matrix through a ring-opening reaction with a functional compound; or the photosensitive color-changing compound is dispersed in the PMMA matrix through copolymerization of unsaturated units with monomers forming PMMA (i.e., MMA monomers) through chemical bonding.

[0026] Photosensitive color-changing compounds are dispersed in the PMMA matrix, giving the PMMA matrix photosensitive color-changing function. When this photosensitive color-changing acrylic glass is applied to the aerospace field, it can realize the diversified control of the color of aerospace acrylic glass parts and improve the color richness of aerospace transparent parts.

[0027] MMA monomers have unsaturated units. One end of the functional compound undergoes a ring-opening reaction with the photoresponsive color-changing compound, while the other end can copolymerize with the MMA monomer. This allows the photoresponsive color-changing compound to be dispersed in the PMMA matrix through chemical bonding. The photoresponsive color-changing compound and the PMMA matrix are chemically bonded together, forming a strong whole and eliminating the generation of free states. Under long-term use conditions, this effectively avoids or reduces the precipitation of the photoresponsive color-changing compound, resulting in stable and reliable photoresponsive color-changing aviation acrylic glass.

[0028] MMA monomers possess unsaturated units. The photoresponsive color-changing compound is directly copolymerized with the MMA monomers used to prepare the PMMA matrix through these unsaturated units, thus distributing itself within the PMMA matrix. In other words, the photoresponsive color-changing compound participates in the polymerization reaction to form the acrylic glass, achieving a chemical bond between the compound and the PMMA matrix. This ensures the stable distribution of the photoresponsive color-changing compound within the PMMA matrix, effectively preventing or reducing the precipitation of the compound under long-term use conditions. Therefore, this photoresponsive color-changing aviation acrylic glass is stable and reliable.

[0029] Both of the above methods of linking photosensitive color-changing compounds to the PMMA matrix are reliable chemical bonds. Compared to the free state of photosensitive color-changing compounds in the PMMA matrix, this method can effectively prevent the precipitation of photosensitive color-changing compounds under long-term use conditions, resulting in higher stability and reliability.

[0030] Furthermore, since the photosensitive color-changing compound is dispersed in the PMMA matrix in a chemically bonded form, its presence has very little interference with the physical and mechanical properties of the acrylic glass, enabling the photosensitive color-changing acrylic glass to maintain sufficient physical and mechanical properties to meet the requirements of use.

[0031] In some embodiments, the mass percentage of the photoresponsive color-changing compound is ≤30%, and the mass percentage of the PMMA matrix is ​​≥60%, in order to balance the photoresponsive color-changing function of the acrylic glass and its light transmittance.

[0032] In some embodiments, the mass percentage of the photoresponsive color-changing compound is ≤6%, and the mass percentage of the PMMA matrix is ​​≥90%, which makes the light transmittance of the plexiglass better while satisfying the photoresponsive color-changing function.

[0033] In some embodiments, the photoresponsive color-changing compound has a functional group that can cooperate with a functional compound, and the photoresponsive color-changing compound is dispersed in the PMMA matrix in a chemically bonded manner through a ring-opening reaction between the functional group and the functional compound.

[0034] In some embodiments, the photoresponsive color-changing compound has unsaturated units, and the photoresponsive color-changing compound is dispersed in the PMMA matrix in a chemically bonded manner by copolymerizing the unsaturated units with the monomers that form PMMA.

[0035] In other embodiments, photoresponsive color-changing compounds with functional groups and photoresponsive color-changing compounds with unsaturated units are selected simultaneously, so that two photoresponsive color-changing aviation acrylic glass contains two types of photoresponsive color-changing compounds, which are stably dispersed in the PMMA matrix through two chemical bonding methods: ring-opening reaction with functional compounds and copolymerization with monomers that form PMMA through unsaturated units.

[0036] Simultaneously, ring-opening and copolymerization reactions are employed to disperse different types of photosensitive color-changing compounds in the PMMA matrix. With the photosensitive color-changing compounds stably dispersed in the PMMA matrix precursor, a wider selection of different photosensitive color-changing compounds can be chosen. Through appropriate ratios, the photosensitive color-changing performance can be better adjusted. For example, by combining RGB (red, green, blue), the color diversification of aerospace acrylic parts can be achieved.

[0037] It should be noted that when different types of photosensitive color-changing compounds are dispersed in the PMMA matrix by chemical bonding using both ring-opening reaction and copolymerization reaction, this application does not impose specific restrictions on the ratio of photosensitive color-changing compounds using ring-opening reaction and those using copolymerization reaction. The ratio of the two different types of photosensitive color-changing compounds can be flexibly adjusted to obtain photosensitive color-changing aviation acrylic glass with diverse colors.

[0038] When dispersing photoresponsive color-changing compounds in a PMMA matrix using a ring-opening reaction, the photoresponsive color-changing compounds are required to have functional groups that can cooperate with functional compounds, and the ring-opening reaction is carried out between the functional groups and the functional compounds.

[0039] In some embodiments, the functional group is an epoxy unit, that is, the photoresponsive color-changing compound is a photoresponsive color-changing compound having an epoxy unit.

[0040] In some embodiments, the functional group is a tertiary amine unit, that is, the photoresponsive color-changing compound is a photoresponsive color-changing compound having a tertiary amine unit.

[0041] In other embodiments, the photoresponsive color-changing compounds include photoresponsive color-changing compounds having epoxy groups and photoresponsive color-changing compounds having tertiary amine groups.

[0042] It should be noted that for schemes using both photoresponsive color-changing compounds with epoxy groups and photoresponsive color-changing compounds with tertiary amine groups, this application does not impose specific restrictions on the ratio of these two photoresponsive color-changing compounds. Regardless of the ratio used, both can be stably and reliably dispersed in the PMMA matrix. Furthermore, by simultaneously using these two photoresponsive color-changing compounds that undergo ring-opening reactions with functional compounds, the color can be controlled by adjusting their ratio, which is beneficial for achieving photoresponsive color diversification of aerospace acrylic glasses.

[0043] It should also be noted that when ring-opening and copolymerization reactions are simultaneously used to disperse different types of photosensitive color-changing compounds in the PMMA matrix, the photosensitive color-changing compounds undergoing ring-opening reactions with the functional compounds include at least one photosensitive color-changing compound having epoxy groups and one having tertiary amine groups. When both photosensitive color-changing compounds having epoxy groups and those having tertiary amine groups are selected, this application does not limit the ratio of photosensitive color-changing compounds having epoxy groups, photosensitive color-changing compounds having tertiary amine groups, and photosensitive color-changing compounds undergoing copolymerization reactions. Simultaneously using photosensitive color-changing compounds linked to the PMMA matrix through both ring-opening and copolymerization reactions, and considering that the photosensitive color-changing compounds linked to the PMMA matrix through ring-opening reactions can themselves be of different types, further expands the range of selectable photosensitive color-changing compounds, thereby further improving the color diversity of aerospace glass sheets. In some embodiments, the functional compound includes at least one of a first functional compound and a second functional compound. The photoresponsive color-changing compound having an epoxy group undergoes a ring-opening reaction with the first functional compound via the epoxy group, and the photoresponsive color-changing compound having a tertiary amine group undergoes a ring-opening reaction with the second functional compound via the tertiary amine group.

[0044] In some embodiments, the first functional compound is a compound containing a maleimide group. The first functional compound can react with the epoxy unit of the MMA monomer and the photoresponsive color-changing compound, respectively. That is, one end of the first functional compound is attached to the PMMA matrix and the other end is attached to the photoresponsive color-changing compound, so that the photoresponsive color-changing compound is stably dispersed in the PMMA matrix.

[0045] Furthermore, because the first functional compound contains maleimide groups, the reaction between the photoresponsive color-changing compound with epoxy units, the first functional compound, and MMA introduces a cyclic structure into the main chain of the final PMMA matrix. This strongly inhibits the movement of matrix chain segments, thereby increasing the glass transition temperature of PMMA and improving the heat resistance of the acrylic glass. In addition, because the epoxy compound exhibits extremely low volume shrinkage during curing and maintains high transparency, the above reaction not only improves heat resistance but also enhances the dimensional stability of the product.

[0046] Furthermore, the maleimide group also contains unsaturated units, which can directly copolymerize with MMA to achieve chemical bonding, thus improving the heat resistance of photosensitive color-changing aerospace acrylic glass.

[0047] In some embodiments, the compound containing a maleimide group is selected from at least one of N-methylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide, N-benzylmaleimide, N-(4-fluorophenyl)maleimide, N-(2-hydroxyethyl)maleimide and N-(methoxycarbonyl)maleimide.

[0048] In some embodiments, the second functional compound is an unsaturated compound containing an epoxy group. The second functional compound can react with the MMA monomer and the tertiary amine unit of the photoresponsive color-changing compound, respectively. That is, one end of the second functional compound is attached to the PMMA matrix, and the other end is attached to the photoresponsive color-changing compound, so that the photoresponsive color-changing compound is stably dispersed in the PMMA matrix.

[0049] In one embodiment, the second functional compound is selected from at least one of glycidyl methacrylate, allyl glycidyl ether, 4-hydroxybutyl acrylate glycidyl ether, and glycidyl acrylate.

[0050] In the above embodiments, whether the photoresponsive color-changing compound with epoxy groups undergoes a ring-opening reaction with the first functional compound or the photoresponsive color-changing compound with tertiary amine groups undergoes a ring-opening reaction with the second functional compound, the ring-opening reaction always occurs between the epoxy group and the tertiary amine group. That is, one of the photoresponsive color-changing compound and the functional compound has an epoxy group, and the other has a tertiary amine group. Since the conditions (temperature and time) for the ring-opening reaction between the epoxy group and the tertiary amine group are completely covered by the process of polymerization with MMA monomers, the entire ring-opening reaction can be completed during the MMA polymerization process, thus enabling more efficient overall polymerization. On the one hand, this improves the manufacturing efficiency of photoresponsive color-changing aerospace acrylic glass; on the other hand, it reduces energy consumption, thereby reducing manufacturing costs.

[0051] In other embodiments, the ring-opening reaction may not be limited to the interaction between the epoxy unit and the tertiary amine unit; for example, it may occur between the epoxy unit and an anhydride compound. The anhydride is modified to be within the photoresponsive color-changing compound, and then reacted via the epoxy unit in the second functional compound.

[0052] In some embodiments, the photoresponsive color-changing compound that undergoes a ring-opening reaction with the functional compound may have a functional group that is capable of undergoing a ring-opening reaction with the functional compound, such as a photoresponsive color-changing compound having an epoxy group or a photoresponsive color-changing compound having a tertiary amine group.

[0053] In some embodiments, for compounds that have photoresponsive color-changing properties but do not inherently possess functional groups capable of ring-opening reactions with functional compounds (referred to herein as initial compounds), the initial compounds can be modified to introduce functional groups into their chemical structure, enabling them to undergo ring-opening reactions with the functional compounds. This broadens the selection range of photoresponsive color-changing compounds and improves the color richness of photoresponsive aerospace acrylic glass.

[0054] In some embodiments, the photoresponsive color-changing compound that is copolymerized with the monomer that forms PMMA through an unsaturated unit can be a photoresponsive color-changing compound that itself has an unsaturated unit.

[0055] In some embodiments, for some compounds that have photosensitive color-changing function but do not have unsaturated units (referred to herein as initial compounds), the initial compounds can be modified to introduce unsaturated units into the chemical structure of the initial compounds, thereby obtaining photosensitive color-changing compounds that can be directly copolymerized with MMA, which broadens the selection range of photosensitive color-changing compounds and improves the color richness of photosensitive color-changing aviation acrylic glass.

[0056] In some embodiments, the initial compound having photoresponsive color-changing function is selected from at least one of spiropyrans, spiroxazins, diarylethylenes, azobenzenes, and rhodamine (Rh). These initial compounds can be modified by epoxy oxidation, tertiary amine oxidation, or unsaturated group modification to obtain photoresponsive color-changing compounds.

[0057] In some embodiments, the initial compound of the azobenzene class with photoresponsive color-changing function is 4-benzanophenol.

[0058] In some embodiments, the photoresponsive color-changing compound having functional groups such as epoxy units or tertiary amine units that can undergo ring-opening reactions with functional compounds, or the photoresponsive color-changing compound having unsaturated units, is also selected from at least one of spiropyrans, spiroxazines, diarylethenes, azobenzenes, and rhodamine (Rh).

[0059] In some embodiments, the photoresponsive color-changing compound having a tertiary amine unit is at least one of 1,3,3-trimethylindole-6'-nitrobenzodihydropyranospirane and rhodamine B base. The photoresponsive color-changing compound having a tertiary amine unit is 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3'-[3H]naphtho[2,1-b][1,4]oxazine]. The photoresponsive color-changing compound having an unsaturated unit is 1,2-bis[2-methylbenzo[b]thiophene-3-yl]-3,3,4,4,5,5-hexafluoro-1-cyclopentene.

[0060] Please see Figure 1 This application also provides a method for manufacturing photosensitive color-changing aviation acrylic glass, comprising the following steps: S1: Provide MMA monomers and prepolymerize the MMA monomers to obtain the matrix material.

[0061] In step S1, the MMA monomer is prepolymerized to form a precursor mixture containing the polymerization precursor to obtain the matrix material. Prepolymerization yields a matrix material with a certain viscosity. Compared to direct polymerization and curing, this prepolymerization allows for the release of some of the heat of reaction, which helps control the total heat release during polymerization and prevents violent reactions caused by instantaneous overheating, i.e., burst polymerization. This is beneficial for controlling the quality of the finished product.

[0062] In some embodiments, prepolymerization is carried out at a reaction temperature of 60-80 °C until the required viscosity is reached, at which point heating is stopped and the temperature is lowered to end the prepolymerization process.

[0063] In some embodiments, the viscosity of the matrix material is such that the flow time at 25°C is 20 to 120 s for the Coat 4 cup.

[0064] In some embodiments, the conversion rate of MMA in the precursor mixture containing the polymerization precursor is 5 to 20%.

[0065] Since the conversion rate of MMA is highly correlated with the viscosity of the matrix material, and there is a functional relationship between the two, only the viscosity value is specified in this application.

[0066] In some embodiments, a photosensitive color-changing compound is added in step S1. The photosensitive color-changing compound undergoes a copolymerization reaction with the MMA monomer, introducing the photosensitive color-changing compound into the polymer chain of the partially polymerized precursor, so that the photosensitive color-changing compound is more uniformly distributed in the final plexiglass sheet.

[0067] The photosensitive color-changing compound added in step S1 is selected from at least one of photosensitive color-changing compounds that undergo ring-opening reactions with functional compounds and photosensitive color-changing compounds having unsaturated units.

[0068] In some embodiments, the photoresponsive color-changing compound that undergoes a ring-opening reaction with the functional compound is selected from at least one of photoresponsive color-changing compounds having an epoxy group and a tertiary amine group.

[0069] In some embodiments, step S1, which involves prepolymerizing the MMA monomer to obtain the matrix material, includes at least one of the following: A photoresponsive color-changing compound with epoxy groups, an initiator, and an MMA monomer are mixed and polymerized to form a precursor mixture containing the polymerization precursor, thereby obtaining the matrix material. A photoresponsive color-changing compound with tertiary amine units, an initiator, and an MMA monomer are mixed and polymerized to form a precursor mixture containing the polymerization precursor, thereby obtaining the matrix material. A photoresponsive color-changing compound with unsaturated units, an initiator, and an MMA monomer are mixed and polymerized to form a precursor mixture containing the polymerization precursor, thereby obtaining the matrix material.

[0070] In some embodiments, the molar ratio of the photoresponsive color-changing compound to the MMA monomer is less than or equal to 1:10. At this ratio, the photoresponsive color-changing compound can achieve a substantially complete reaction.

[0071] It should be noted that the ratio of the amount of photoresponsive color-changing compound to MMA monomer being less than or equal to 1:10 means that when only one type of photoresponsive color-changing compound is used, the ratio of the amount of that photoresponsive color-changing compound to the amount of MMA monomer is less than or equal to 1:10; when two or more different types of photoresponsive color-changing compounds are used, the ratio of the sum of the amounts of the two or more different types of photoresponsive color-changing compounds to the amount of MMA monomer is also less than or equal to 1:10.

[0072] In some embodiments, the initiator accounts for less than or equal to 0.6% of the mass of the mixture of the photoresponsive color-changing compound, the initiator, and the MMA monomer.

[0073] In some embodiments, the initiator is selected from at least one of benzoyl peroxide (BPO), azobisisobutyronitrile (AIBN), and azobisisoheptanenitrile (ABVN).

[0074] In some embodiments, the initial compound having photoresponsive color-changing function can be modified to obtain a photoresponsive color-changing compound having an unsaturated unit, a photoresponsive color-changing compound having an epoxy group unit, or a photoresponsive color-changing compound having a tertiary amine group unit, thereby selecting at least one of the above three modified products.

[0075] like Figure 2 As shown, in some embodiments, the steps for modifying and preparing the photoresponsive color-changing compound include: S11: Prepare an organic solution of the initial compound that has a photosensitive color-changing function.

[0076] An organic solution was prepared by dissolving the initial compound with photosensitive color-changing function in an organic solvent.

[0077] In some embodiments, the initial compound having photoresponsive color-changing function is selected from at least one of spiropyrans, spiroxazines, diarylethylenes, azobenzenes, and rhodamine (Rh).

[0078] In some embodiments, the organic solvent is selected from at least one of ethyl acetate, ethanol, butyl acetate, methanol, acetone, and isobutanol.

[0079] In some embodiments, the mass concentration of the organic solution is 5%, that is, the mass concentration of the initial compound with photoresponsive color-changing function in the solution is 5%.

[0080] S12: Add the modified molecule to the organic solution, keep it at a constant temperature for reaction, and after the reaction is complete, wash, separate and purify to obtain a photosensitive color-changing compound with an epoxy group, a photosensitive color-changing compound with a tertiary amine group, or a photosensitive color-changing compound with an unsaturated group.

[0081] In some embodiments, the process further includes adding an acid-binding agent. The acid-binding agent is used to adsorb and capture acidic leaving products and precipitated salt compounds generated during the substitution reaction, thereby promoting the forward progress of the reaction.

[0082] The acid-binding agent is an organic amine. In some embodiments, the acid-binding agent is selected from at least one of triethylamine, diisopropylethylamine, and pyridine. In some embodiments, the mass of the acid-binding agent is 0.5% to 2% of the mass of the organic solution.

[0083] Specifically, an acid-binding agent is added to the organic solution obtained in step S11, and the mixture is mixed evenly to obtain a mixed solution. After adjusting the mixed solution to a preset temperature, a modified molecule is added to the mixed solution, and a heat preservation reaction is carried out. After purification, a photoresponsive color-changing compound is obtained.

[0084] In some embodiments, the chemical structure of the modified molecule includes an active group and an unsaturated unit, or includes an active group and an epoxy group. The active group includes one of acyl chloride, acyl bromide, acid anhydride, methoxysilane, ethoxysilane, chlorosilane, and isocyanate groups.

[0085] In some embodiments, the chemical structure of the modified molecule includes an active group and an unsaturated unit.

[0086] When the active group is an acyl chloride or acyl bromide, the modified molecule is selected from one of methacryloyl chloride, but-3-enoyl chloride, 10-undecenoyl chloride, oxalyl chloride monoallyl ester, allyl chloroformate, hexaallyl chloride, acryloyl chloride, acryloyl bromide and methacryloyl bromide.

[0087] When the active group is an acid anhydride, the modified molecule is selected from one of methacrylic anhydride, maleic anhydride, allyl succinic anhydride, (2-methyl-2-propenyl) succinic anhydride, 2-buten-1-yl succinic anhydride, (2,7-octadien-1-yl) succinic anhydride, 2-octenyl succinic anhydride, and octadecenyl succinic anhydride.

[0088] When the active group is methoxysilane, ethoxysilane, or chlorosilane, the modified molecule is selected from one of the following: methyl methacrylate (triethoxysilyl), methyl methacrylate (dimethoxy(methyl)silyl), propyl 3-[dimethoxy(methyl)silyl]methacrylate, propyl 3-(trimethoxysilyl)acrylate, propyl 3-[diethoxy(methyl)silyl]methacrylate, allyltrimethoxysilane, propyl 3-(trimethoxysilyl)propyl vinylcarbamate, propyl 3-(ethoxydimethylsilyl)methacrylate, allyldimethylchlorosilane, allyl(dichloro)methylsilane, allyltrichlorosilane, norbornene-alkenylethyltrichlorosilane, and methylphenylvinylchlorosilane.

[0089] When the active group is an isocyanate group, the modified molecule is selected from allyl isocyanate, 3-isopropenyl-α,α-dimethylbenzyl isocyanate and isocyanoethyl methacrylate.

[0090] In some embodiments, the chemical structure of the modified molecule includes an active group and an epoxy unit.

[0091] Wherein, when the active group is methoxysilane, ethoxysilane or chlorosilane, the modified molecule is selected from one of the following: triethoxy(3-epoxypropyloxypropyl)silane, trimethoxy(3-epoxypropyloxypropyl)silane, 3-[(2,3)-epoxypropoxy]propylmethyldimethoxysilane, 3-[(2,3)-epoxypropoxy]propylmethyldiethoxysilane, [8-(epoxypropyloxy)-n-octyl]trimethoxysilane, [8-(epoxypropyloxy)-n-octyl]triethoxysilane, diethoxy(3-glycidyloxypropyl)methylsilane, dimethoxy(3-glycidyloxypropyl)methylsilane, 3-glycidyloxypropyltrimethoxysilane and 3-glycidyloxypropyltriethoxysilane.

[0092] In some embodiments, the molar ratio of the modified molecule to the initial compound having photoresponsive color-changing function is 2:1 to 1:1.

[0093] In some embodiments, the preset temperature is 30~50 ℃.

[0094] In some embodiments, the reaction time is 30 to 60 minutes.

[0095] S2: Prepare a homogeneous mixture comprising a matrix material, an initiator, and at least one of the following components: a photoresponsive color-changing compound that undergoes a ring-opening reaction with a functional compound; or a photoresponsive color-changing compound having unsaturated units.

[0096] In some embodiments, the homogeneous mixture includes a matrix material, an initiator, and a photoresponsive color-changing compound that undergoes a ring-opening reaction with the functional compound.

[0097] In some embodiments, the homogeneous mixture includes a matrix material, an initiator, and a photoresponsive color-changing compound having unsaturated units.

[0098] In some embodiments, the homogeneous mixture includes a matrix material, an initiator, a photoresponsive color-changing compound that undergoes a ring-opening reaction with a functional compound, and a photoresponsive color-changing compound having unsaturated units.

[0099] Regardless of whether a photosensitive color-changing compound is added in step S1, a photosensitive color-changing compound is added in step S2. When a photosensitive color-changing compound is added in step S1, the photosensitive color-changing compound added in step S2 can be the same as or different from the photosensitive color-changing compound in step S1.

[0100] In some embodiments, regardless of the type of photoresponsive color-changing compound added, the mass ratio of the photoresponsive color-changing compound added in step S2 to the matrix material in the homogeneous mixture is (5~30):(60~90). That is, the mass ratio of at least one of the photoresponsive color-changing compound undergoing a ring-opening reaction with the functional compound and the photoresponsive color-changing compound having unsaturated units to the matrix material is (5~30):(60~90). More specifically, the photoresponsive color-changing compound undergoing a ring-opening reaction with the functional compound or the photoresponsive color-changing compound having unsaturated units: matrix material = (5~30):(60~90); or, (photoresponsive color-changing compound undergoing a ring-opening reaction with the functional compound + photoresponsive color-changing compound having unsaturated units): matrix material = (5~30):(60~90).

[0101] In some embodiments, when the photosensitive color-changing compound added in step S2 includes at least two types, there are no requirements on the ratio of different types of photosensitive color-changing compounds. It is only necessary that the total amount of the added photosensitive color-changing compound meets certain requirements so that the photosensitive color-changing aviation plexiglass prepared subsequently has photosensitive color-changing function and meets the corresponding performance requirements.

[0102] When the homogeneous mixture includes a photoresponsive color-changing compound that undergoes a ring-opening reaction with the functional compound, the corresponding functional compound needs to be added to allow the functional compound to react with the photoresponsive color-changing compound and the MMA monomer.

[0103] In some embodiments, the functional compound includes a first functional compound and a second functional compound, which are the same as the first functional compound and the second functional compound described above, and will not be repeated here.

[0104] When the photosensitive color-changing compound added in step S2 includes at least one of a photosensitive color-changing compound having an epoxy group and a photosensitive color-changing compound having a tertiary amine group, and includes a photosensitive color-changing compound having an unsaturated unit; or when the photosensitive color-changing compound added in step S2 includes only at least one of a photosensitive color-changing compound having an epoxy group and a photosensitive color-changing compound having a tertiary amine group, at least one of the first functional compound and the second functional compound is mixed with the corresponding photosensitive color-changing compound, the matrix material and the initiator to prepare a homogeneous mixture.

[0105] That is, when the mixed system of the photosensitive color-changing aviation acrylic glass to be manufactured contains a photosensitive color-changing compound with an epoxy group, a first functional compound is required to react with it; when the mixed system of the photosensitive color-changing aviation acrylic glass to be manufactured contains a photosensitive color-changing compound with a tertiary amine group, a second functional compound is required to react with it; so that the photosensitive color-changing compound can be stably and reliably dispersed in the photosensitive color-changing aviation acrylic glass.

[0106] When the photosensitive color-changing compound added in step S2 only includes a photosensitive color-changing compound with unsaturated units, the photosensitive color-changing compound with unsaturated units is mixed with the matrix material and the initiator to prepare a homogeneous mixture.

[0107] In some embodiments, the molar ratio of at least one of the first and second functional compounds in step S2 to the photoresponsive color-changing compound added in this step that undergoes a ring-opening reaction with the functional compound is 2:1 to 1:2. That is, taking a 1:1 molar ratio as an example, when only the first functional compound is included, the ratio of the first functional compound to the photoresponsive color-changing compound having an epoxy group is 1:1 (molar amount); when only the second functional compound is included, the ratio of the second functional compound to the photoresponsive color-changing compound having a tertiary amine group is 1:1 (molar amount); when both the first and second functional compounds are included, the ratio of (first functional compound + second functional compound) to (photoresponsive color-changing compound having an epoxy group + photoresponsive color-changing compound having a tertiary amine group) is 1:1 (molar amount). When only one type of photoresponsive color-changing compound and its corresponding functional compound are used, the amounts of substances in the proportions are the amounts of the single photoresponsive color-changing compound and the corresponding functional compound, respectively. When at least two types of photoresponsive color-changing compounds and their corresponding functional compounds are used simultaneously, the amounts of substances in the proportions are the sum of the amounts of the functional compounds corresponding to the sum of the amounts of the at least two types of photoresponsive color-changing compounds.

[0108] The above example illustrates the ratio of the functional compound to the photosensitive color-changing compound using the example of the functional compound being selected from at least one of the first and second functional compounds. It can be understood that in other embodiments, when the functional compound is selected from other functional compounds different from the first and second functional compounds, the above ratio is also applicable. In some embodiments, the initiator added in step S2 accounts for ≤0.6% of the mass of the homogeneous mixture.

[0109] In some embodiments, the initiator added in step S2 includes a low-temperature initiator and a high-temperature initiator. The low-temperature initiator is selected from at least one of benzoyl peroxide (BPO), azobisisobutyronitrile (AIBN), and azobisisoheptanenitrile (ABVN); the high-temperature initiator is selected from at least one of dicumyl peroxide, di-tert-butyl peroxide, and tert-butyl peroxide.

[0110] In some embodiments, the mass ratio of the low-temperature initiator to the high-temperature initiator is 1:1.

[0111] It should be noted that when no photosensitive color-changing compound is added in step S1, or when the added photosensitive color-changing compound does not need to be obtained through modification, and when a photosensitive color-changing compound obtained through modification is used in step S2, the order of the above-mentioned modification preparation of photosensitive color-changing compound and step S1 is not limited. The modification preparation of photosensitive color-changing compound can be carried out first, or the prepolymerization in step S1 can be carried out first, or the modification and prepolymerization can be carried out simultaneously.

[0112] S3: The homogeneous mixture is cured to disperse the photoresponsive color-changing compound in the PMMA matrix through at least one of the following chemical bonding methods: the photoresponsive color-changing compound is dispersed in the PMMA matrix through a ring-opening reaction with a functional compound, thereby chemically bonding the photoresponsive color-changing compound in the PMMA matrix; the photoresponsive color-changing compound is dispersed in the PMMA matrix through a copolymerization reaction between unsaturated units and MMA monomers in the matrix material, thereby obtaining photoresponsive color-changing aerospace acrylic glass.

[0113] During the curing process, the photoresponsive color-changing compound with unsaturated units undergoes a copolymerization reaction with the MMA monomer in the matrix material. At the same time, the matrix material polymerizes to form a PMMA matrix, thereby distributing the photoresponsive color-changing compound in the PMMA matrix, resulting in photoresponsive color-changing aerospace acrylic glass.

[0114] And / or, during the curing process, the matrix material polymerizes to form a PMMA matrix. At the same time, the photoresponsive color-changing compound with epoxy units undergoes a ring-opening reaction with the first functional compound through the epoxy units. One end of the first functional compound undergoes a ring-opening reaction with the photoresponsive color-changing compound, and the other end can copolymerize with the MMA monomer. This allows the first functional compound to act as a connecting medium to connect the photoresponsive color-changing compound to the PMMA, thereby distributing the photoresponsive color-changing compound on the PMMA matrix and obtaining photoresponsive color-changing aerospace acrylic glass.

[0115] And / or, during the curing process, the matrix material polymerizes to form a PMMA matrix. At the same time, the photoresponsive color-changing compound with tertiary amine units undergoes a ring-opening reaction with a second functional compound through the tertiary amine units. One end of the second functional compound undergoes a ring-opening reaction with the photoresponsive color-changing compound, while the other end can copolymerize with the MMA monomer. This allows the second functional compound to act as a connecting medium, linking the photoresponsive color-changing compound to the PMMA, thereby distributing the photoresponsive color-changing compound on the PMMA matrix and obtaining photoresponsive color-changing aerospace acrylic glass.

[0116] When the first functional compound is a compound containing a maleimide group and the second functional compound is an unsaturated compound containing an epoxy group, both have unsaturated bonds and can copolymerize with MMA. Therefore, by reacting at least one of the first and second functional compounds with the photosensitive color-changing compound and the MMA matrix, not only can the photosensitive color-changing compound be reliably linked to the PMMA matrix, but also, after using the first and second functional compounds, the physical properties of the introduced maleimide group or epoxy group (which can respectively improve heat resistance and dimensional stability) can be utilized to improve the heat resistance and dimensional stability of PMMA plexiglass during storage.

[0117] The ring-opening reaction process of the epoxy group unit with the first functional compound is as follows: Figure 3 As shown, the nitrogen atom in the maleimide group is connected by three single bonds, classifying it as a tertiary amine. Although tertiary amines lack active hydrogen, they catalyze the ring-opening of epoxy groups, thus serving as catalysts for epoxide compounds. The optimal temperature for this ring-opening reaction is 70–80 °C, providing relatively mild reaction conditions that do not adversely affect the photoresponsive color-changing function of the compound. Furthermore, this can improve the manufacturing efficiency of photoresponsive aerospace acrylic glass and reduce energy consumption.

[0118] In some embodiments, the step of curing the homogeneous mixture includes: water bath at 35-65°C for 12-120 h, followed by forced air bath at 105-135°C for 10-80 h.

[0119] In some embodiments, the step of a forced-air bath at 105-135°C for 10-80 h includes a continuous forced-air bath at 100°C for 5-60 h, a continuous forced-air bath at 120°C for 3-15 h, and a continuous forced-air bath at 135°C for 2-5 h.

[0120] The aforementioned method for manufacturing photoresponsive photochromic aviation acrylic glass involves distributing the photoresponsive compound within a PMMA matrix through ring-opening and / or copolymerization reactions. This method not only reliably links the photoresponsive compound to the PMMA matrix, but also ensures that the highest temperature condition during the entire reaction process is 135 °C for several hours, thus preventing damage to the structure of the photoresponsive compound used in this method and preserving its photoresponsive color-changing function. Therefore, it is possible to manufacture photoresponsive photochromic aviation acrylic glass with stable and reliable performance.

[0121] When the above-mentioned method for manufacturing photoresponsive color-changing aviation acrylic glass uses a photoresponsive color-changing compound that is coordinated with at least one of the first and second functional compounds, the entire ring-opening reaction process can be completed during the bulk polymerization reaction of the MMA monomer. This method can efficiently prepare photoresponsive color-changing aviation acrylic glass with stable and reliable performance and superior high-temperature resistance.

[0122] It is important to emphasize that while the photoresponsive color-changing aviation acrylic glass and its manufacturing method provided in this application highlight its significant application value in the aerospace field, photoresponsive color-changing materials possess core application value in multiple fields due to their light-controlled reversible color transformation and structural heterogeneity. For example, in the information storage field, they can achieve high-density optical storage and repeated erasing and rewriting; in the intelligent control field, they can be used for light response adjustment in smart windows and photochromic glasses; in the sensing and detection field, they can be used to construct light-controlled probes for precise detection of environmental factors or biomolecules; and in the anti-counterfeiting field, they endow materials with dynamic anti-counterfeiting functions. Their significance lies in breaking through the limitations of traditional materials' static functions, providing novel photoresponsive core units for optoelectronic devices, biomedicine, and smart materials, and promoting the upgrading of related technologies towards high efficiency, controllability, and multifunctionality. Therefore, the scope of protection of the photoresponsive color-changing aviation acrylic glass and its manufacturing method involved in this application, in addition to the aerospace field, also includes the aforementioned many other fields.

[0123] The following more specific embodiments further illustrate the photoresponsive color-changing aviation acrylic glass and its manufacturing method of this application.

[0124] Example 1 The initial compound with photoresponsive color-changing function is selected from at least one of spiropyrans, spiroxazines, diarylethenes, azobenzenes and rhodamine (Rh). In this example, azobenzenes are selected.

[0125] (1) Specifically, 4-phenylazophenol was used as the initial compound with photoresponsive color-changing function. 4-phenylazophenol was chemically modified to obtain a photoresponsive color-changing compound with unsaturated units. The modification method is as follows: 4-Benzoazophenol was dissolved in ethyl acetate to prepare a 5% (w / w) organic solution. Diisopropylethylamine (an acid-binding agent) was added to the organic solution and stirred until homogeneous, yielding a mixture. The mass of diisopropylethylamine was 0.5% of the mass of the organic solution. The temperature of the mixture was adjusted to 50 °C, and methacryloyl chloride (a modifying molecule) was added, with a molar ratio of methacryloyl chloride to 4-Benzoazophenol of 1:1. The mixture was then reacted at 50 °C for 60 min. Finally, the mixture was washed, separated, and purified to obtain a photosensitive color-changing compound with unsaturated units.

[0126] Simultaneously, 4-phenylazophenol was used as the initial compound with photoresponsive color-changing function. The 4-phenylazophenol was chemically modified to obtain a photoresponsive color-changing compound with epoxy groups. The modification method is as follows: 4-Benzoazophenol was dissolved in ethyl acetate to prepare a 5% (w / w) organic solution. Diisopropylethylamine was added to the organic solution and stirred until homogeneous, yielding a mixture. The mass of diisopropylethylamine was 0.5% of the mass of the organic solution. The temperature of the mixture was adjusted to 50 °C, and triethoxy(3-epoxypropyloxypropyl)silane was added, with a mass ratio of triethoxy(3-epoxypropyloxypropyl)silane to 4-Benzoazophenol of 1:1. The mixture was then reacted at 50 °C for 60 min. Finally, the mixture was washed, separated, and purified to obtain a photosensitive color-changing compound with epoxy groups.

[0127] The above reaction process is as follows Figure 4 As shown.

[0128] (2) Under the action of the initiator azobisisobutyronitrile (AIBN), the MMA monomer and the photoresponsive color-changing compound with unsaturated units obtained in step (1) were prepolymerized at a temperature of 60 °C. The reaction was stopped when the viscosity reached the required level, and the temperature was lowered to end the prepolymerization process. The prepolymerization formed a precursor mixture containing part of the polymerization precursor, which yielded the matrix material. The amount of the photoresponsive color-changing compound with unsaturated units accounted for 10% of the molar amount of the MMA monomer. The viscosity of the matrix material was 20 s at 25 °C with a flow time of 20 s in a Forte 4 cup.

[0129] (3) The matrix material obtained in step (2), the photoresponsive color-changing compound with epoxy groups obtained in step (1), the first functional compound, and the initiator are mixed to prepare a homogeneous mixture. The first functional compound is N-cyclohexylmaleimide, and the mass ratio of the photoresponsive color-changing compound with epoxy groups to the matrix material is 5:90. The molar ratio of the photoresponsive color-changing compound with epoxy groups to the first functional compound is 1:1. The initiator is azobisisobutyronitrile and di-tert-butyl peroxide in a mass ratio of 1:1, and the initiator accounts for 0.6% of the mass of the homogeneous mixture.

[0130] (4) The obtained homogeneous mixture was placed in a water bath at 45 °C for 100 h, and then subjected to continuous forced-air baths at 100 °C, 120 °C and 135 °C in sequence. The mixture was placed in an air bath at 100 °C for 25 h, at 120 °C for 15 h, and at 135 °C for 2 h. After natural cooling to below 60 °C, the mixture was removed to obtain a photosensitive color-changing aviation organic glass with a thickness of 40 mm.

[0131] The photosensitive color-changing aviation organic glass formed in this embodiment changes from orange to colorless under ultraviolet light.

[0132] Please combine Figure 5 The color-changing mechanism of the photosensitive color-changing aviation acrylic glass formed in this embodiment is as follows: Trans state (orange, stable state): The azo bond (-N=N-) is in a "trans configuration" (the two benzene rings are in the same plane, at a 180° angle). The π electrons of the benzene ring and the π electrons of the azo bond form a continuous conjugated system, which absorbs visible light.

[0133] Irradiation with ultraviolet light (300~400 nm): the azo bond undergoes cis-trans isomerism, changing from trans (180°) to "cis configuration" (the two benzene rings are at a 60° angle, and the steric hindrance increases).

[0134] cis state (colorless): The cis configuration disrupts the coplanarity of the two benzene rings, the π-electron conjugated system is sterically blocked, the conjugation length is shortened, it only absorbs ultraviolet light, and has no absorption in the visible light region.

[0135] Example 2 The initial compound with photoresponsive color-changing function is selected from at least one of spiropyrans, spiroxazines, diarylethylenes, azobenzenes and rhodamine (Rh). In this example, rhodamine (Rh) is selected.

[0136] (1) Rhodamine (Rh), specifically Rhodamine B base, is used as a photosensitive color-changing compound. Rhodamine B base has a tertiary amine unit.

[0137] (2) Under the action of benzoyl peroxide as an initiator, MMA monomer and rhodamine B base were prepolymerized at 80°C. The reaction was stopped when the required viscosity was reached, and the temperature was lowered to end the prepolymerization process. The prepolymerization formed a precursor mixture containing some of the polymerization precursors, which yielded the matrix material. The molar amount of rhodamine B base accounted for 10% of the molar amount of MMA monomer. The viscosity of the matrix material was 120 s at 25°C and the flow time in a Forte 4 cup was 4.

[0138] (3) The matrix material obtained in step (2), rhodamine B base, the second functional compound, and the initiator are mixed to prepare a homogeneous mixture. The second functional compound is allyl glycidyl ether, and the mass ratio of the matrix material to the rhodamine B base is 60:30. The molar ratio of the rhodamine B base to the second functional compound is 1:1. The initiator is azobisisobutyronitrile and diisopropylbenzene peroxide in a mass ratio of 1:1, and the initiator accounts for 0.3% of the mass of the homogeneous mixture.

[0139] (4) The obtained homogeneous mixture was placed in a water bath at 65 °C for 12 h, and then subjected to continuous forced-air baths at 100 °C, 120 °C and 135 °C in sequence. The mixture was placed in an air bath at 100 °C for 60 h, at 120 °C for 2 h, and at 135 °C for 5 h. After natural cooling to below 60 °C, the mixture was removed to obtain a photosensitive color-changing aviation organic glass with a thickness of 40 mm.

[0140] The photosensitive color-changing aviation acrylic sheet material formed in this embodiment changes from colorless to pink under ultraviolet light.

[0141] Please combine Figure 5 The color-changing mechanism of the photosensitive color-changing aviation acrylic glass formed in this embodiment is as follows: Before irradiation (closed-ring state): The molecule exists in the form of a spironolactone ring structure. The closure of the CO bond causes the conjugated system to be cut off. It only absorbs ultraviolet light and has no obvious absorption in the visible light region, appearing colorless or very pale yellow (almost colorless at low concentrations).

[0142] After ultraviolet light irradiation (open ring state): the CO bond of the spirocyclic ring breaks, and the oxanthracene ring forms a continuous large π conjugated system with 2-carboxyphenyl. The electron transition absorbs visible light at 550~580 nm, showing a bright red color, accompanied by strong fluorescence (emission peak ~580 nm).

[0143] Reversible recovery: After irradiation is stopped, place in the dark for several minutes to tens of minutes. Molecular thermal vibration causes the spiro ring to close again, the color fades and returns to colorless or very pale yellow, and the fluorescence disappears simultaneously.

[0144] Example 3 The photosensitive color-changing compound is selected from at least one of spiropyrans, spiroxazines, diarylethylenes, azobenzenes and rhodamine (Rh). In this example, spiropyrans are selected.

[0145] (1) Specifically, spiropyran compounds, namely 1,3,3-trimethylindole-6'-nitrobenzodihydropyranospirane, are used as photoresponsive color-changing compounds.

[0146] (2) Under the action of the initiator azobisisobutyronitrile, the MMA monomer was prepolymerized at 70 °C. The reaction was stopped when the viscosity reached the required level, and the temperature was lowered to end the prepolymerization process. The prepolymerization formed a precursor mixture containing some of the polymerization precursors, which yielded the matrix material. The viscosity of the matrix material was such that the flow time in a Forte 4 cup at 25 °C was 50 s.

[0147] (3) The matrix material obtained in step (2), 1,3,3-trimethylindole-6'-nitrobenzodihydropyranospirane, the second functional compound, and the initiator are mixed to prepare a homogeneous mixture. The second functional compound is glycidyl methacrylate, and the mass ratio of the matrix material to 1,3,3-trimethylindole-6'-nitrobenzodihydropyranospirane is 60:18. The molar ratio of 1,3,3-trimethylindole-6'-nitrobenzodihydropyranospirane to the second functional compound is 1:1. The initiator is azobisisobutyronitrile and dicumyl peroxide in a mass ratio of 1:1, and the initiator accounts for 0.1% of the mass of the homogeneous mixture.

[0148] (4) The obtained homogeneous mixture was placed in a water bath at 50 °C for 10 h, and then subjected to continuous forced-air baths at 100 °C, 120 °C and 135 °C in sequence. The mixture was placed in an air bath at 100 °C for 30 h, at 120 °C for 8 h, and at 135 °C for 3 h. After natural cooling to below 60 °C, it was taken out to obtain a photosensitive color-changing aviation organic glass with a thickness of 40 mm.

[0149] The photosensitive color-changing aviation acrylic sheet material formed in this embodiment changes from colorless to blue under ultraviolet light.

[0150] Please combine Figure 5 The color-changing mechanism of the photosensitive color-changing aviation acrylic glass formed in this embodiment is as follows: Closed-ring state (colorless): The CO bond on the spiroring is in a closed state, the indoline ring and the pyran ring are in a "vertical configuration", and the conjugated system is cleaved (limited to a single ring only).

[0151] Ultraviolet light (300~400 nm) irradiation: CO spiro-ring bonds break, and the two rings change from perpendicular to a "coplanar configuration".

[0152] Open-ring state (blue): Formation part of the anthocyanin structure, the π-electron conjugation system of the indoline ring and the pyran ring is greatly expanded (continuous conjugation across the two rings), the electron transition energy is reduced, and it absorbs visible light to exhibit color.

[0153] In the dark: CO bonds reform, spiro rings close, conjugated systems break, and the colorless state is restored.

[0154] Example 4 The photosensitive color-changing compound is selected from at least one of spiropyrans, spiroxazines, diarylethylenes, azobenzenes and rhodamine (Rh). In this example, spiroxazines are selected.

[0155] (1) Specifically, spiroxazine compounds, namely 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3'-[3H]naphtho[2,1-b][1,4]oxazine], are used as photosensitive color-changing compounds.

[0156] (2) Under the action of the initiator azobisisobutyronitrile, the MMA monomer was prepolymerized at 70 °C. The reaction was stopped when the viscosity reached the required level, and the temperature was lowered to end the prepolymerization process. The prepolymerization formed a precursor mixture containing some of the polymerization precursors, which yielded the matrix material. The viscosity of the matrix material was the same as the flow-out time of 90 s in a Forte 4 cup at 25 °C.

[0157] (3) The matrix material obtained in step (2), 1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3'-[3H]naphtho[2,1-b][1,4]oxazine], the second functional compound and the initiator are mixed to prepare a homogeneous mixture. The second functional compound is glycidyl acrylate, and the mass ratio of the matrix material to [1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3'-[3H]naphtho[2,1-b][1,4]oxazine] is 60:18. The molar ratio of [1,3-dihydro-1,3,3-trimethylspiro[2H-indole-2,3'-[3H]naphtho[2,1-b][1,4]oxazine] to the second functional compound is 1:1. The initiator is azobisisobutyronitrile and di-tert-butyl peroxide in a mass ratio of 1:1, and the initiator accounts for 0.2% of the mass of the homogeneous mixture.

[0158] (4) The obtained homogeneous mixture was placed in a water bath at 50 °C for 10 h, and then subjected to continuous forced-air baths at 100 °C, 120 °C and 135 °C in sequence. The mixture was placed in an air bath at 100 °C for 30 h, at 120 °C for 8 h, and at 135 °C for 3 h. After natural cooling to below 60 °C, it was taken out to obtain a photosensitive color-changing aviation organic glass with a thickness of 40 mm.

[0159] The photosensitive color-changing aviation acrylic sheet material formed in this embodiment changes from colorless to blue under ultraviolet light.

[0160] Please combine Figure 5 The color-changing mechanism of the photosensitive color-changing aviation acrylic glass formed in this embodiment is as follows: Closed-ring state (colorless): The CO spirocyclic bond is closed, and the indoline ring and oxazine ring are in a non-conjugated "separated configuration", with a limited range of π-electron conjugation.

[0161] Ultraviolet light (300~400 nm) irradiation: CO bond heterolytic cleavage occurs, the oxazine ring opens, and the π electrons of the indoline ring are connected to the conjugated system of the oxazine ring.

[0162] Open-ring state (blue): Forms a coplanar partocyanine cation structure (indoline ring is positively charged, oxazine ring is conjugated and extended), the conjugation length increases, and electronic transitions absorb visible light.

[0163] Thermal reversibility in the dark: CO bonds reform, spiro ring closes, conjugated system is dissociated, and colorless state is restored (fatigue resistance is better than spiropyran because the NO structure of the oxazine ring is more stable).

[0164] Example 5 The photosensitive color-changing compound is selected from at least one of spiropyrans, spiroxazines, diarylethylenes, azobenzenes and rhodamine (Rh). In this example, diarylethylenes are selected.

[0165] (1) Specifically, diarylethene compounds, namely 1,2-bis[2-methylbenzo[b]thiophen-3-yl]-3,3,4,4,5,5-hexafluoro-1-cyclopentene, are used as photosensitive color-changing compounds.

[0166] (2) Under the action of the initiator azobisisobutyronitrile, MMA monomer and 1,2-bis[2-methylbenzo[b]thiophene-3-yl]-3,3,4,4,5,5-hexafluoro-1-cyclopentene were prepolymerized at 60 °C. The reaction was stopped when the required viscosity was reached, and the temperature was lowered to end the prepolymerization process. The prepolymerization formed a precursor mixture containing some of the polymerization precursors, which yielded the matrix material. The amount of 1,2-bis[2-methylbenzo[b]thiophene-3-yl]-3,3,4,4,5,5-hexafluoro-1-cyclopentene accounted for 10% of the molar amount of MMA monomer. The viscosity of the matrix material was determined by a Forte 4 cup outflow time of 35 s at 25 °C.

[0167] (3) The matrix material obtained in step (2), 1,2-bis[2-methylbenzo[b]thiophen-3-yl]-3,3,4,4,5,5-hexafluoro-1-cyclopentene, and the initiator are mixed to prepare a homogeneous mixture. The mass ratio of the matrix material to 1,2-bis[2-methylbenzo[b]thiophen-3-yl]-3,3,4,4,5,5-hexafluoro-1-cyclopentene is 60:18. The initiator is azobisisobutyronitrile and di-tert-butyl peroxide in a mass ratio of 1:1, and the initiator accounts for 0.5% of the mass of the homogeneous mixture.

[0168] (4) The obtained homogeneous mixture was placed in a water bath at 50 °C for 10 h, and then subjected to continuous forced air baths at 100 °C, 120 °C and 135 °C in sequence. The mixture was placed in an air bath at 100 °C for 30 h, at 120 °C for 8 h, and at 135 °C for 3 h. After natural cooling to below 60 °C, the mixture was removed to obtain a photosensitive color-changing aviation organic glass with a thickness of 40 mm.

[0169] The photosensitive color-changing aviation acrylic sheet material formed in this embodiment changes from colorless to purple under ultraviolet light.

[0170] The color-changing mechanism of the photoresponsive color-changing aviation acrylic glass formed in this embodiment is as follows: Open-ring state (colorless, ground state) structure: Two benzothiophene rings are connected by a C=C double bond in perfluorocyclopentene, exhibiting an "inverse parallel separable configuration". Conjugation is limited to a single benzothiophene ring (the fused ring structure makes local conjugation longer), there is no transmolecular large conjugation, and it only absorbs ultraviolet light.

[0171] Under ultraviolet light (320~380 nm) irradiation, the chemical bonds that transform into a closed-ring state (blue, colorimetric) are as follows: the C=C double bond undergoes a photocyclization reaction, and the carbon atoms at the 3-position of the two benzothiophene rings form a new C-C single bond, constructing a four-membered ring bridge. The benzothiophene ring changes from a separated state to a "coplanar fused configuration," and the π electrons of the fused ring form a large π-conjugated system (covering the two benzothiophene rings and the perfluorocyclopentene skeleton) through the four-membered ring bridge.

[0172] control group The manufacturing process is consistent with existing techniques for producing ordinary polymethyl methacrylate (PMMA) glass. A liquid PMMA matrix material (polymerized from MMA monomers under the action of an initiator, with the specific process identical to Example 3) is provided. This liquid matrix material comprises only a prepolymerized liquid formed from the bulk polymerization of MMA, 1,3,3-trimethylindole-6'-nitrobenzodihydropyranospirane, and an oil-soluble initiator ABVN, wherein the mass ratio of the prepolymerized liquid to 1,3,3-trimethylindole-6'-nitrobenzodihydropyranospirane is 90:5. A polymerization reaction is carried out to form a solid matrix from the liquid matrix material. The viscosity of the prepolymerized liquid is 120 s. The oil-soluble initiator ABVN accounts for 0.5% of the mass of the liquid matrix material. In this control group, the thickness was 40 mm. The polymerization process involved a water bath at 45 ℃ for 100 h, followed by continuous forced-air baths at 100 ℃ / 60 h, 120 ℃ / 15 h, and 135 ℃ / 5 h. Finally, the heating power was turned off, and the mixture was allowed to cool naturally to below 60 ℃ before being removed from the oven and ready for use. Since 1,3,3-trimethylindole-6'-nitrobenzodihydropyranospirane is chemically bonded to the PMMA matrix through a ring-opening reaction with a second functional compound, and since the control group did not contain a second functional compound, the connection between 1,3,3-trimethylindole-6'-nitrobenzodihydropyranospirane and PMMA was not through chemical bonding.

[0173] The performance of the photoresponsive color-changing aviation acrylic glass prepared in Examples 1-5 and the control group is evaluated below. The specific testing process is as follows: the shape, size and quantity of the test strips used in Examples 1-5 and the control group meet the standard requirements of the corresponding tests, and the results are taken as the average value.

[0174] Referring to the requirements and methods in relevant standards such as GB / T 7134-2008 Cast Industrial Acrylic Glass Sheets, GB / T 40911.3-2021 Types, Dimensions and Properties of Polymethyl methacrylate Sheets for Plastic Products Part 3: Continuously Cast Sheets, GB / T 2411-2008 Determination of Indentation Hardness (Shore Hardness) of Plastics and Hard Rubber Using a Hardness Tester, and GJB 1251A Specification for Cast Aviation Acrylic Glass, the basic physical properties were tested and characterized, and the results are shown in Table 1. The results show that, compared with the control group, Examples 1-5 exhibited better consistency in tensile strength, tensile modulus of elasticity, impact strength, tensile fracture strain, flexural modulus of elasticity, flexural strength, and hardness, while the resistance to exudation and heat distortion temperature were significantly improved. Specifically, the evaluation process for anti-precipitation ability involved immersion in MMA solvent for 48 hours, followed by UV-Vis spectral characterization of the solvent. The characteristic peaks of the MMA solution spectra at different concentrations of the corresponding photosensitive color-changing compound were compared to determine the presence and amount of precipitation. Furthermore, this application conducted stability analysis on the tensile strength, tensile modulus of elasticity, flexural strength, and flexural modulus of elasticity in the data. The coefficients of variation were all less than 2%, indicating minimal data fluctuation. Therefore, compared to the control group, Examples 1-5 did not show statistically significant changes in physical and mechanical properties, indicating good consistency in performance, while the anti-precipitation ability and heat distortion temperature were significantly improved. All the above indicators of Examples 1-5 and the control group meet the technical requirements of "GJB 1251A Casting Aviation Acrylic Glass Specification," meaning they fall within the application scope of aviation acrylic glass. Additionally, after irradiating the test samples with a UV light source for 30 seconds and then turning off the UV light source, a rapid color change occurred. Meanwhile, the control group showed a corresponding color change, but in the anti-precipitation ability test, the control group showed precipitation, while Examples 1-5 showed no precipitation, indicating that the implementation effect of the technical solution of this application is quite ideal, giving aviation plexiglass a stable and reliable light-response color-changing function.

[0175] Table 1. Statistics of Basic Physical Properties

[0176] Note: a The impact strength is the unnotched impact strength of a simply supported beam. Examples 1, 2, 3, 4, and 5 correspond to Example 1, Example 2, Example 3, Example 4, and Example 5, respectively. The above embodiments are merely illustrative of the principles and effects of this application and are not intended to limit this application. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this application. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this application should still be covered by the claims of this application.

Claims

1. A photosensitive color-changing aviation acrylic glass, characterized in that, The product comprises a PMMA matrix and a photoresponsive color-changing compound, wherein the photoresponsive color-changing compound is dispersed in the PMMA matrix by chemical bonding, and the chemical bonding includes at least one of the following: The photoresponsive color-changing compound is dispersed in the PMMA matrix in a chemically bonded manner through a ring-opening reaction with a functional compound; The photoresponsive color-changing compound is dispersed in the PMMA matrix in a chemically bonded manner by copolymerization of unsaturated units with monomers that form PMMA.

2. The photosensitive color-changing aviation organic glass according to claim 1, characterized in that, The mass percentage of the photoresponsive color-changing compound is ≤30%, and the mass percentage of the PMMA matrix is ​​≥60%.

3. The photosensitive color-changing aviation organic glass according to claim 1, characterized in that, The photoresponsive color-changing compound includes at least one selected from photoresponsive color-changing compounds having epoxy groups and photoresponsive color-changing compounds having tertiary amine groups; the functional compound includes at least one selected from a first functional compound and a second functional compound; wherein, The photoresponsive color-changing compound having an epoxy group unit undergoes a ring-opening reaction with the first functional compound through the epoxy group unit, and the photoresponsive color-changing compound having a tertiary amine group unit undergoes a ring-opening reaction with the second functional compound through the tertiary amine group unit.

4. The photosensitive color-changing aviation organic glass according to claim 1, characterized in that, The first functional compound is a compound containing a maleimide group, and the second functional compound is an unsaturated compound containing an epoxy group.

5. A method for manufacturing photosensitive color-changing aviation acrylic glass, characterized in that, Includes the following steps: S1: Provide MMA monomers and prepolymerize the MMA monomers to obtain a matrix material; S2: Prepare a homogeneous mixture, the homogeneous mixture comprising the matrix material, an initiator, and at least one of the following components: a photoresponsive color-changing compound that undergoes a ring-opening reaction with a functional compound; a photoresponsive color-changing compound having unsaturated units; S3: The homogeneous mixture is cured to disperse the photoresponsive color-changing compound in the PMMA matrix through at least one of the following chemical bonding methods: the photoresponsive color-changing compound is dispersed in the PMMA matrix through a ring-opening reaction with the functional compound, thereby chemically bonding the photoresponsive color-changing compound in the PMMA matrix; the photoresponsive color-changing compound is dispersed in the PMMA matrix through a copolymerization reaction between unsaturated units and MMA monomers in the matrix material, thereby obtaining the photoresponsive color-changing aviation acrylic glass.

6. The method for manufacturing photosensitive color-changing aviation acrylic glass according to claim 5, characterized in that, In step S1, the prepolymerization of the MMA monomer to obtain the matrix material includes at least one of the following: A photoresponsive color-changing compound having epoxy groups, an initiator, and the MMA monomer are mixed and polymerized to form a precursor mixture containing the polymerization precursor, thereby obtaining the matrix material. A photoresponsive color-changing compound having tertiary amine units, an initiator, and the MMA monomer are mixed and polymerized to form a precursor mixture containing the polymerization precursor, thereby obtaining the matrix material. The photoresponsive color-changing compound with unsaturated units, the initiator, and the MMA monomer are mixed and then subjected to a polymerization reaction to form a precursor mixture containing the polymerization precursor, so as to obtain the matrix material. The ratio of the amount of at least one of the photoresponsive color-changing compounds having epoxy groups, the photoresponsive color-changing compounds having tertiary amino groups, and the photoresponsive color-changing compounds having unsaturated groups to the amount of the MMA monomer is less than or equal to 1:

10.

7. The method for manufacturing photoresponsive color-changing aviation acrylic glass according to claim 5, characterized in that, In the homogeneous mixture, at least one of the photoresponsive color-changing compound that undergoes a ring-opening reaction with the functional compound and the photoresponsive color-changing compound having unsaturated units, is present in a mass ratio of (5 ~ 30): (60 ~ 90) to the matrix material. The molar ratio of the functional compound to the photoresponsive color-changing compound that undergoes a ring-opening reaction with the functional compound is 2:1 to 1:

2. The initiator has a mass percentage of ≤0.6% in the homogeneous mixture.

8. The method for manufacturing photosensitive color-changing aviation acrylic glass according to claim 5, characterized in that, The photoresponsive color-changing compound that undergoes a ring-opening reaction with the functional compound includes at least one of a photoresponsive color-changing compound having an epoxy group and a photoresponsive color-changing compound having a tertiary amine group, wherein the functional compound includes at least one of a first functional compound and a second functional compound; wherein, The photoresponsive color-changing compound having an epoxy group unit undergoes a ring-opening reaction with the first functional compound, and the photoresponsive color-changing compound having a tertiary amine group unit undergoes a ring-opening reaction with the second functional compound.

9. The method for manufacturing photosensitive color-changing aviation acrylic glass according to claim 5, characterized in that, The step of curing the homogeneous mixture includes: a water bath at 35-65°C for 12-120 h, followed by a forced-air bath at 105-135°C for 10-80 h.

10. The method for manufacturing photosensitive color-changing aviation acrylic glass according to claim 5, characterized in that, It also includes the step of modifying and preparing a photoresponsive color-changing compound, wherein the step of modifying and preparing a photoresponsive color-changing compound includes: Prepare an organic solution of the initial compound that exhibits photoresponsive color-changing function; The modified molecule is added to the organic solution, and the reaction is carried out under heat. After the reaction is completed, the mixture is washed, separated and purified to obtain a photosensitive color-changing compound with an epoxy group, a photosensitive color-changing compound with a tertiary amine group, or a photosensitive color-changing compound with an unsaturated group.

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