High impact fluorine-modified polymethyl methacrylate, its preparation method and application

Abstract

This invention belongs to the field of polymer material preparation technology, and discloses a high-impact fluorinated modified polymethyl methacrylate, its preparation method, and its application. The fluorinated modified polymethyl methacrylate contains a first structural unit as shown in formula (1), a second structural unit as shown in formula (2), and a third structural unit as shown in formula (3). In formula (3), C... n H 2n+1 It is a straight-chain alkyl group, and n is 6-12. This invention introduces two specific functional structural units into the macromolecular chain of polymethyl methacrylate (PMMA) to obtain a novel fluorinated PMMA, which has both high light transmittance and excellent impact resistance and heat resistance.

Description

Technical Field

[0001] This invention belongs to the field of polymer material preparation technology, and relates to the research field of plexiglass. Specifically, this invention relates to a high-impact fluorine-modified polymethyl methacrylate, its preparation method, and its application. Background Technology

[0002] PMMA, as a high-molecular polymer, boasts exceptional transparency, with a light transmittance exceeding that of glass, making it the most transparent polymer material. Optical-grade PMMA, in particular, exhibits superior optical properties and also possesses advantages such as high strength, high toughness, insulation, heat resistance, weather resistance, and ease of processing, while weighing only half that of glass. Therefore, optical-grade PMMA can be used to manufacture a wide range of products, including light guide plates for flat panel displays, optical fiber materials, solar cells, automotive lighting, consumer electronics, and electrical appliances. Driven by the booming development of downstream industries such as flat panel displays, consumer electronics, and solar cells, the demand for optical-grade PMMA in my country continues to grow.

[0003] Due to the relatively short development history of my country's PMMA industry, limited technological and experiential accumulation, coupled with the small scale of many enterprises and insufficient R&D and innovation capabilities, the industry as a whole exhibits a situation of insufficient high-end capacity and overcapacity in low-end products. Demand for high-end products still relies on imports, with optical-grade PMMA being the main imported product. To enhance international competitiveness, improve corporate profitability, and meet downstream market demand, it is urgent to optimize the synthesis process of optical-grade PMMA.

[0004] Optical-grade PMMA products are mostly produced using bulk polymerization, a process that allows for continuous production, high equipment utilization, and eliminates wastewater treatment issues, making it environmentally friendly. Post-polymerization of the colloid is energy-efficient, requiring only the recovery of a small amount of unreacted monomers, perfectly meeting industrial production requirements. After prepolymerization in the polymerization reactor, the PMMA slurry can be directly cast and then polymerized again to produce sheets, rods, pipes, and other products. Alternatively, it can be subjected to high-temperature devolatilization using a screw extruder before extrusion, cutting, and granulation to obtain PMMA molding compound products.

[0005] However, current processes for producing optical-grade PMMA products primarily produce MMA homopolymers, whose macromolecular chains have an amorphous and random microstructure. This results in poor heat resistance and impact strength, limiting their application in high-end materials fields. Furthermore, in the free radical polymerization process for PMMA, the absence of a solvent causes a rapid increase in viscosity after the polymerization reaction reaches a certain point. This severely impacts mass and heat transfer, easily leading to localized overheating and explosive polymerization, increasing operational difficulty and reducing product quality. Therefore, there is an urgent need to develop a process that effectively improves the performance of PMMA products. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a high-impact fluorinated polymethyl methacrylate, its preparation method, and its applications. The present invention introduces two specific functional structural units into the macromolecular chain of polymethyl methacrylate to obtain a novel fluorinated polymethyl methacrylate. This fluorinated polymethyl methacrylate has both high light transmittance and excellent impact resistance and heat resistance.

[0007] To achieve the above-mentioned objectives, a first aspect of the present invention is to provide a fluorinated polymethyl methacrylate containing a first structural unit as shown in formula (1), a second structural unit as shown in formula (2), and a third structural unit as shown in formula (3).

[0008]

[0009] In equation (3), C n H 2n+1 It is a straight-chain alkyl group, and n is 6-12.

[0010] In this invention, C n H 2n+1 It is a straight-chain alkyl group, and n is 6-12, for example, it can be 6, 7, 8, 9, 10, 11, 12.

[0011] In a preferred embodiment of the fluorinated polymethyl methacrylate according to the present invention, based on 100 wt% of the total weight of the fluorinated polymethyl methacrylate, the content of the first structural unit is 83-95 wt%, the content of the second structural unit is 4.9-16 wt%, and the content of the third structural unit is 0.05-1 wt%; more preferably,

[0012] Based on a total weight of 100 wt% of the fluorinated polymethyl methacrylate, the content of the first structural unit is 84-93 wt%, the content of the second structural unit is 6.8-15.2 wt%, and the content of the third structural unit is 0.2-0.8 wt%.

[0013] As described above, more preferably, based on the total weight of the fluorinated polymethyl methacrylate of 100 wt%, the content of the first structural unit is 84-93 wt%, for example 84 wt%, 86 wt%, 88 wt%, 90 wt%, 92 wt%, 93 wt%, and any two values ​​or any range of any two values.

[0014] As described above, more preferably, based on the total weight of the fluorinated polymethyl methacrylate of 100 wt%, the content of the second structural unit is 6.8-15.2 wt%, for example 6.8 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%, 15.2 wt%, and any two values ​​or any range of any two values.

[0015] As described above, more preferably, based on the total weight of the fluorinated polymethyl methacrylate of 100 wt%, the content of the third structural unit is 0.2-0.8 wt%, for example 0.2 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt%, and any two values ​​or any range of any two values.

[0016] According to a preferred embodiment of the fluorinated polymethyl methacrylate of the present invention, the glass transition temperature of the fluorinated polymethyl methacrylate is 128-156°C, preferably 149-156°C.

[0017] According to a preferred embodiment of the fluorinated polymethyl methacrylate of the present invention, the impact strength of the fluorinated polymethyl methacrylate is 21.7-25.3 KJ / m. 2 The preferred value is 23.8-25.3 KJ / m 2 .

[0018] According to a preferred embodiment of the fluorinated polymethyl methacrylate of the present invention, the weight-average molecular weight of the fluorinated polymethyl methacrylate is 124,000-162,000, preferably 143,000-162,000.

[0019] According to a preferred embodiment of the fluorinated polymethyl methacrylate of the present invention, the PDI of the fluorinated polymethyl methacrylate is 1.44-1.64, preferably 1.44-1.56.

[0020] According to a preferred embodiment of the fluorinated polymethyl methacrylate of the present invention, the haze of the fluorinated polymethyl methacrylate is 0.1%-0.5%, preferably 0.1%-0.2%.

[0021] According to a preferred embodiment of the fluorinated polymethyl methacrylate of the present invention, the light transmittance of the fluorinated polymethyl methacrylate is 92.5%-93%, preferably 92.7%-93%.

[0022] The second aspect of the present invention is to provide a method for preparing the fluorinated polymethyl methacrylate described in the first aspect, comprising, in a protective atmosphere, in the presence of an initiator, a chain transfer agent and a promoter, performing a polymerization reaction on methyl methacrylate, functional monomer I of formula (4) and functional monomer II of formula (5) to obtain the fluorinated polymethyl methacrylate;

[0023]

[0024] In equation (5), C n H 2n+1 It is a straight-chain alkyl group, and n is 6-12.

[0025] In a preferred embodiment of the preparation method according to the present invention, the preparation method includes the following steps:

[0026] Step 1: Mix methyl methacrylate, functional monomer I and functional monomer II to obtain a monomer solution;

[0027] Step 2: Add an accelerator and a chain transfer agent to the monomer solution to obtain a reaction solution;

[0028] Step 3: Under a protective atmosphere, an initiator is added to the reaction solution to carry out the first stage of polymerization reaction, and a prepolymerized adhesive is obtained.

[0029] Step 4: The prepolymerized adhesive solution is subjected to a second-stage polymerization reaction to obtain fluorinated polymethyl methacrylate.

[0030] According to a preferred embodiment of the preparation method of fluorine-modified polymethyl methacrylate of the present invention,

[0031] Step 1 also includes a step of cooling methyl methacrylate, preferably with the methyl methacrylate at a temperature of 0-10°C before mixing with functional monomer I and functional monomer II; and / or,

[0032] In step 3, the conditions for the first stage of polymerization reaction include: a temperature of 100-140°C and / or a time of 10-40 minutes.

[0033] In a preferred embodiment of the method for preparing fluorinated polymethyl methacrylate according to the present invention, in step 4, the conditions for the polymerization reaction in the second stage include: a temperature of 180-270°C and / or a time of 40-100 minutes; more preferably, the polymerization reaction in the second stage is carried out in an extruder, preferably including front extrusion, middle extrusion and final extrusion; more preferably, the temperature of the front extrusion is 180-220°C, the temperature of the middle extrusion is 200-250°C, the temperature of the final extrusion is 230-270°C, and / or the residence time of the colloid in the extruder is 40-100 minutes.

[0034] In a preferred embodiment of the preparation method of fluorinated polymethyl methacrylate according to the present invention, the preparation method further includes granulation, cooling and drying of the obtained fluorinated polymethyl methacrylate after the second stage polymerization reaction.

[0035] In a more preferred embodiment of the present invention, the preparation method includes the following steps:

[0036] Step 1: Methyl methacrylate purified by vacuum distillation is cooled to 0-10℃ and metered into a specially designed polymerization reactor by a pump. Functional monomer I and functional monomer II are added to the polymerization reactor and stirred thoroughly to dissolve them completely.

[0037] Step 2: Add chain transfer agent and accelerator to the polymerization reactor, stir to dissolve, and make it a stable solution;

[0038] Step 3: After blowing nitrogen gas into the polymerization reactor for 30 minutes, add the initiator, stir to mix it evenly, heat the polymerization reactor to 100-140℃, and react for 10-40 minutes.

[0039] Step 4: Extrude the prepolymerized adhesive from the bottom of the polymerization reactor and send it to the screw devouring extruder. The temperature of the front section of the extruder is 180-220℃, the temperature of the middle section is 200-250℃, and the temperature of the last section is 230-270℃. The reaction time of the colloid in the extruder is 40-100 minutes.

[0040] Step 5: Start the cutting head at the front of the extruder to granulate, cool and dry to obtain high-impact polymethyl methacrylate molding compound.

[0041] Preferably, based on the above technical solution, in step 1, a specially designed polymerization reactor is equipped with a high-torque stirring paddle to enhance mass and heat transfer, prevent coking and yellowing, and ensure smooth material discharge; at the same time, a gas phase condenser is installed at the top of the polymerization reactor to achieve precise temperature control of bulk polymerization.

[0042] Preferably, based on the above technical solution, in step 4, a devolatilization port is provided at the upper end of the end extruder, where unreacted monomers are removed at high temperature, condensed, and then recycled.

[0043] In a preferred embodiment of the preparation method of fluorinated polymethyl methacrylate according to the present invention, based on a total weight of methyl methacrylate, functional monomer I, and functional monomer II of 100 wt%, the amount of methyl methacrylate is 83-95 wt%, the content of functional monomer I is 4.9-16 wt%, and the content of functional monomer II is 0.05-1 wt%; more preferably,

[0044] Based on a total weight of 100 wt% for methyl methacrylate, functional monomer I, and functional monomer II, the amount of methyl methacrylate used is 84-93 wt%, for example, 84 wt%, 86 wt%, 88 wt%, 90 wt%, 92 wt%, 93 wt%, or any two values ​​or any range of any two values; the amount of functional monomer I used is 6.8-15.2 wt%, for example, 6.8 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%, 15.2 wt%, or any two values ​​or any range of any two values; the amount of functional monomer II used is 0.2-0.8 wt%, for example, 0.2 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt%, or any two values ​​or any range of any two values.

[0045] According to the present invention, the chain transfer agent can be selected from a wide range. In a preferred embodiment of the present invention, the chain transfer agent is C. 10 -C 18 The alkyl thiols are preferably at least one of hexadecyl thiols, tetradecyl thiols, tert-tetradecyl thiols, dodecyl thiols, and tert-dodecyl thiols.

[0046] According to the present invention, the amount of chain transfer agent can be selected within a wide range. In a preferred embodiment of the present invention, the amount of chain transfer agent is 0.1%-0.4% of the total weight of methyl methacrylate, functional monomer I and functional monomer II.

[0047] In a preferred embodiment of the present invention, the accelerator is 1-(2-fluorophenyl)-2-thiourea.

[0048] The accelerator is a compound represented by formula (6):

[0049]

[0050] According to the present invention, the amount of the accelerator can be selected within a wide range. In a preferred embodiment of the present invention, the amount of the accelerator is 0.05%-0.1% of the total weight of methyl methacrylate, functional monomer I and functional monomer II.

[0051] According to the present invention, the initiator can be selected from a wide range. In a preferred embodiment of the present invention, the initiator is at least one selected from azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, azobisisobutyramidine hydrochloride, benzoyl peroxide, tert-butyl peroxide, and dicumyl peroxide.

[0052] According to the present invention, the amount of the initiator can be selected within a wide range. In a preferred embodiment of the present invention, the amount of the initiator is 0.1%-1% of the total weight of methyl methacrylate, functional monomer I and functional monomer II.

[0053] According to the present invention, the protective atmosphere includes, but is not limited to, nitrogen and / or inert gases.

[0054] A third aspect of the present invention is to provide an application of fluorinated polymethyl methacrylate prepared by the method described in the first aspect or the method described in the second aspect in liquid crystal materials, optical materials, aerospace materials, building materials, medical materials or agricultural materials.

[0055] Through the above technical solution, the fluorinated polymethyl methacrylate of the present invention contains a first structural unit as shown in formula (1), a second structural unit as shown in formula (2), and a third structural unit as shown in formula (3).

[0056]

[0057] In equation (3), C n H 2n+1 It is a straight-chain alkyl group, and n is 6-12. This invention introduces two specific functional structural units into the macromolecular chain of polymethyl methacrylate (PMMA) to obtain a novel fluorinated PMMA, which has both high light transmittance and excellent impact resistance and heat resistance.

[0058] The fluorine-modified polymethyl methacrylate and its preparation method described in this invention have the following advantages and effects in terms of structure and performance compared with the prior art:

[0059] This invention introduces a polymerizable trifluoromethyl functional monomer I and a functional monomer II containing a long-chain alkyl structure into the macromolecular structure of polymethyl methacrylate (PMMA). Simultaneously, a fluorophenylthiourea polymerization accelerator is introduced into the bulk polymerization system. This enhances the activity of the two functional monomers in free bulk polymerization and improves the randomness of the three structural units in the macromolecular chain. Therefore, while maintaining the high light transmittance of PMMA, the impact resistance and heat resistance of the polymer product are further improved. The preparation method of this invention introduces a chain transfer agent into the bulk polymerization system, reducing the probability of disproportionation termination and contributing to improved thermal stability of the copolymer. Furthermore, the introduction of bis(trifluoromethyl) groups into the first structural unit of the polymer macromolecular chain significantly enhances intermolecular and chain-to-molecule interactions, resulting in higher thermal decomposition temperatures and impact resistance, thereby broadening the application areas of PMMA products.

[0060] This invention employs a copolymerization method to improve the overall performance of plexiglass. Specifically, it uses methyl methacrylate (MMA) to copolymerize with two specific functional monomers mentioned above, introducing these two specific functional monomers into the macromolecular chain of MMA. This results in plexiglass not only possessing excellent light transmittance, but more importantly, outstanding impact resistance and temperature resistance. It also improves the temperature resistance and thermal decomposition temperature of plexiglass, thus broadening the application fields of MMA products. Detailed Implementation

[0061] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0062] The following are some specific embodiments.

[0063] The molecular weight and molecular weight distribution (PDI) of the polymer were measured by gel permeation chromatography (PL-gPC20); the glass transition temperature (Tg) of the polymer was tested by differential scanning calorimetry (DSC8500); the water absorption rate of the sample was determined according to ISO 62-2008 Determination of water absorption of plastics; the transmittance and haze of the polymer were determined according to national standard gB / T2410; and the impact strength of the polymer was tested according to ISO 179-1-2010.

[0064] In the following examples, the mass content of methyl methacrylate, functional monomer I, and functional monomer II within parentheses refers to the percentage of methyl methacrylate, functional monomer I, and functional monomer II based on the total mass of all monomers being 100%.

[0065] In the following embodiments, functional unit I is as shown in formula (4), and functional unit II is as shown in formula (5);

[0066]

[0067] In equation (5), C n H 2n+1 It is a straight-chain alkyl group, and n is described in the corresponding examples.

[0068] Example 1

[0069] 1. The purified methyl methacrylate was cooled to 0°C, and then 605.9g (83.0% by mass) was metered into a special polymerization reactor by a pump. 116.8g (16.0% by mass) of functional monomer I and 7.3g (1.0% by mass) of functional monomer II (n=6) were added to the polymerization reactor and stirred thoroughly to dissolve them completely and form a homogeneous solution.

[0070] 2. Add 0.73g of tert-dodecyl mercaptan and 0.365g of 1-(2-fluorophenyl)-2-thiourea to the above polymerization reactor, stir to dissolve, and make it into a stable and homogeneous solution;

[0071] 3. After purging nitrogen gas into the polymerization reactor for 30 minutes, add 0.73g of dimethyl azobisisobutyrate, stir to mix evenly, heat the polymerization reactor to 100℃ to initiate polymerization, and turn on the high torque stirrer to react for 40 minutes.

[0072] 4. The prepolymerized adhesive liquid in the above polymerization reactor is extruded from the bottom of the reactor and sent to the screw devouring extruder. The temperature of the front section of the extruder is 220℃, the temperature of the middle section is 250℃, and the temperature of the last section is 270℃. The residence time of the adhesive in the extruder is 40 minutes.

[0073] 5. Start the cutting head at the front end of the extruder to granulate, and then vacuum dry at 110℃ to constant weight to obtain polymethyl methacrylate copolymer molding compound. The performance test results are shown in Table 1.

[0074] Example 2

[0075] 1. Cool the purified methyl methacrylate to 5°C, then meter 675.25g (92.5% by mass) into a specially designed polymerization reactor using a pump. Add 51.1g (7.0% by mass) of functional monomer I and 3.65g (0.5% by mass) of functional monomer II (n=8) to the polymerization reactor and stir thoroughly to dissolve them completely, forming a homogeneous solution.

[0076] 2. Add 2.19g dodecyl mercaptan and 0.657g 1-(2-fluorophenyl)-2-thiourea to the above polymerization reactor, stir to dissolve, and make it into a stable and homogeneous solution;

[0077] 3. After purging nitrogen gas into the polymerization reactor for 30 minutes, add 5.11g of benzoyl peroxide, stir to mix evenly, heat the polymerization reactor to 130℃ to initiate polymerization, and turn on the high torque stirrer to react for 30 minutes.

[0078] 4. The prepolymerized adhesive liquid in the above polymerization reactor is extruded from the bottom of the reactor and sent to the screw devouring extruder. The temperature of the front section of the extruder is 190℃, the temperature of the middle section is 220℃, and the temperature of the last section is 250℃. The residence time of the adhesive in the extruder is 60 minutes.

[0079] 5. Start the cutting head at the front end of the extruder to granulate, and then vacuum dry at 110℃ to constant weight to obtain polymethyl methacrylate copolymer molding compound. The performance test results are shown in Table 1.

[0080] Example 3

[0081] 1. The purified methyl methacrylate was cooled to 0°C, and then 640.94g (87.8% by mass) was metered into a special polymerization reactor by a pump. 87.6g (12% by mass) of functional monomer I and 1.46g (0.2% by mass) of functional monomer II (n=8) were added to the polymerization reactor and stirred thoroughly to dissolve them completely and form a homogeneous solution.

[0082] 2. Add 1.825g dodecyl mercaptan and 0.438g 1-(2-fluorophenyl)-2-thiourea to the above polymerization reactor, stir to dissolve, and make it into a stable and homogeneous solution;

[0083] 3. After purging nitrogen gas into the polymerization reactor for 30 minutes, add 3.65g of benzoyl peroxide, stir to mix evenly, heat the polymerization reactor to 110℃ to initiate polymerization, and turn on the high torque stirrer to react for 20 minutes.

[0084] 4. The prepolymerized adhesive liquid in the above polymerization reactor is extruded from the bottom of the reactor and sent to the screw devouring extruder. The temperature of the front section of the extruder is 210℃, the temperature of the middle section is 240℃, and the temperature of the last section is 260℃. The residence time of the adhesive in the extruder is 50 minutes.

[0085] 5. Start the cutting head at the front end of the extruder to granulate, and then vacuum dry at 110℃ to constant weight to obtain polymethyl methacrylate copolymer molding compound. The performance test results are shown in Table 1.

[0086] Example 4

[0087] 1. The purified methyl methacrylate was cooled to 10°C, and then 614.66g (84.2% by mass) was metered into a special polymerization reactor by a pump. 109.5g (15% by mass) of functional monomer I and 5.84g (0.8% by mass) of functional monomer II (n=8) were added to the polymerization reactor and stirred thoroughly to dissolve them completely and form a homogeneous solution.

[0088] 2. Add 2.409g of dodecyl mercaptan and 0.511g of 1-(2-fluorophenyl)-2-thiourea to the above polymerization reactor, stir to dissolve, and make it into a stable and homogeneous solution;

[0089] 3. After purging nitrogen gas into the polymerization reactor for 30 minutes, add 2.92g of azobisisobutyronitrile, stir to mix evenly, heat the polymerization reactor to 120℃ to initiate polymerization, and turn on the high torque stirrer to react for 20 minutes.

[0090] 4. The prepolymerized adhesive liquid in the above polymerization reactor is extruded from the bottom of the reactor and sent to the screw devouring extruder. The temperature of the front section of the extruder is 200℃, the temperature of the middle section is 220℃, and the temperature of the last section is 240℃. The residence time of the adhesive in the extruder is 80 minutes.

[0091] 5. Start the cutting head at the front end of the extruder to granulate, and then vacuum dry at 110℃ to constant weight to obtain polymethyl methacrylate copolymer molding compound. The performance test results are shown in Table 1.

[0092] Example 5

[0093] 1. The purified methyl methacrylate was cooled to 5°C, and then 693.062g (94.94% by mass) was metered into a special polymerization reactor by a pump. 36.5g (5% by mass) of functional monomer I and 0.438g (0.6% by mass) of functional monomer II (n=12) were added to the polymerization reactor and stirred thoroughly to dissolve them completely and form a homogeneous solution.

[0094] 2. Add 2.92g of n-octyl mercaptan and 7.3g of 1-(2-fluorophenyl)-2-thiourea to the above polymerization reactor, stir to dissolve, and make it into a stable and homogeneous solution;

[0095] 3. After purging nitrogen gas into the polymerization reactor for 30 minutes, add 7.3g of tert-butyl peroxide, stir to mix evenly, heat the polymerization reactor to 140℃ to initiate polymerization, and turn on the high torque stirrer to react for 10 minutes.

[0096] 4. The prepolymerized adhesive liquid in the above polymerization reactor is extruded from the bottom of the reactor and sent to the screw devouring extruder. The temperature of the front section of the extruder is 180℃, the temperature of the middle section is 200℃, and the temperature of the last section is 230℃. The residence time of the adhesive in the extruder is 100 minutes.

[0097] 5. Start the cutting head at the front end of the extruder to granulate, and then vacuum dry at 110℃ to constant weight to obtain polymethyl methacrylate copolymer molding compound. The performance test results are shown in Table 1.

[0098] Comparative Example 1

[0099] Polymethyl methacrylate copolymer molding compound was prepared according to the method of Example 3, except that the accelerator was replaced with o-tolylthiourea.

[0100] Comparative Example 2

[0101] The polymer was prepared according to the method of Example 3, except that styrene was used instead of functional monomer I in Example 3.

[0102] Comparative Example 3

[0103] The polymer was prepared according to the method of Example 3, except that only functional monomer I was added, and functional monomer II was not added.

[0104] Comparative Example 4

[0105] The polymer was prepared according to the method of Example 3, except that only functional monomer II was added, and functional monomer I was not added.

[0106] Table 1

[0107]

[0108]

[0109] As can be seen from the experimental results recorded in Table 1, compared with Comparative Examples 1-4, Examples 1-5 of the present invention not only improved the light transmittance of polymethyl methacrylate, but also improved the impact resistance and heat resistance of polymethyl methacrylate, achieving unexpected technical effects and showing significant progress.

[0110] It should be noted that the embodiments described above are only for explaining the present invention and do not constitute any limitation on the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory terms, not limiting terms. Modifications can be made to the present invention within the scope of the claims, and revisions can be made to the present invention without departing from the scope and spirit of the present invention. Although the present invention described herein relates to specific methods, materials, and embodiments, it does not mean that the present invention is limited to the specific examples disclosed herein; on the contrary, the present invention can be extended to all other methods and applications with the same function.

[0111] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0112] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0113] The endpoints and any values ​​of the ranges disclosed in this application are not limited to the precise ranges or values; such ranges or values ​​should be understood to include values ​​close to them. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. In principle, various technical solutions can be combined with each other to obtain new technical solutions, which should also be considered as specifically disclosed herein.

[0114] In the context of this specification, except where expressly stated otherwise, any matters or issues not mentioned shall apply directly to those known in the art without any modification.

[0115] Furthermore, any implementation described herein can be freely combined with one or more other implementations described herein, and the resulting technical solutions or technical ideas shall be regarded as part of the original disclosure or original record of the present invention, and should not be regarded as new content not disclosed or anticipated herein, unless those skilled in the art consider the combination to be obviously unreasonable.

Claims

1. A fluorinated polymethyl methacrylate comprising a first structural unit as shown in formula (1), a second structural unit as shown in formula (2), and a third structural unit as shown in formula (3), Equation (1); Equation (2); Equation (3), in Equation (3), C n H 2n+1 It is a straight-chain alkyl group, and n is 6-12; Based on a total weight of 100wt% of the fluorinated polymethyl methacrylate, the content of the first structural unit is 83-95wt%, the content of the second structural unit is 4.9-16wt%, and the content of the third structural unit is 0.05-1wt%.

2. The fluorinated polymethyl methacrylate according to claim 1, characterized in that: Based on a total weight of 100wt% of the fluorinated polymethyl methacrylate, the content of the first structural unit is 84-93wt%, the content of the second structural unit is 6.8-15.2wt%, and the content of the third structural unit is 0.2-0.8wt%.

3. The fluorinated polymethyl methacrylate according to claim 1 or 2, characterized in that: The glass transition temperature of the fluorinated polymethyl methacrylate is 128-156℃; and / or, The fluorinated modified polymethyl methacrylate has an impact strength of 21.7-25.3 KJ / m. 2 ; and / or, The fluorinated modified polymethyl methacrylate has a weight-average molecular weight of 124,000-162,000; and / or, The PDI of the fluorinated polymethyl methacrylate is 1.44-1.64; and / or, The haze of the fluorinated polymethyl methacrylate is 0.1%-0.5%; and / or, The light transmittance of the fluorinated polymethyl methacrylate is 92.5%-93%.

4. The fluorinated polymethyl methacrylate according to claim 1 or 2, characterized in that: The glass transition temperature of the fluorinated polymethyl methacrylate is 149-156℃; and / or, The fluorine-modified polymethyl methacrylate has an impact strength of 23.8-25.3 KJ / m. 2 ; and / or, The fluorinated polymethyl methacrylate has a weight-average molecular weight of 143,000-162,000; and / or, The PDI of the fluorinated polymethyl methacrylate is 1.44-1.56; and / or, The haze of the fluorinated polymethyl methacrylate is 0.1%-0.2%; and / or, The light transmittance of the fluorinated polymethyl methacrylate is 92.7%-93%.

5. A method for preparing fluorinated polymethyl methacrylate according to any one of claims 1-4, comprising, in a protective atmosphere, in the presence of an initiator, a chain transfer agent and a promoter, performing a polymerization reaction on methyl methacrylate, functional monomer I of formula (4) and functional monomer II of formula (5) to obtain the fluorinated polymethyl methacrylate; Equation (4); Equation (5), C in Equation (5) n H 2n+1 It is a straight-chain alkyl group, and n is 6-12; Based on a total weight of 100wt% for methyl methacrylate, functional monomer I, and functional monomer II, the amount of methyl methacrylate used is 83-95wt%, the content of functional monomer I is 4.9-16wt%, and the content of functional monomer II is 0.05-1wt%.

6. The preparation method according to claim 5, characterized in that... Includes the following steps: Step 1: Mix methyl methacrylate, functional monomer I and functional monomer II to obtain a monomer solution; Step 2: Add an accelerator and a chain transfer agent to the monomer solution to obtain a reaction solution; Step 3: Under a protective atmosphere, an initiator is added to the reaction solution to carry out the first stage of polymerization reaction, and a prepolymerized adhesive is obtained. Step 4: The prepolymerized adhesive solution is subjected to a second-stage polymerization reaction to obtain fluorinated polymethyl methacrylate.

7. The preparation method according to claim 6, characterized in that: Step 1 also includes a step of cooling methyl methacrylate; and / or, In step 3, the conditions for the first stage of polymerization reaction include: a temperature of 100-140°C and / or a time of 10-40 minutes.

8. The preparation method according to claim 6, characterized in that: In step 1, the temperature of methyl methacrylate before mixing with functional monomer I and functional monomer II is 0-10℃.

9. The preparation method according to claim 6, characterized in that: In step 4, the conditions for the second stage of polymerization reaction include: a temperature of 180-270°C and / or a time of 40-100 minutes.

10. The preparation method according to claim 9, characterized in that: The second stage of polymerization is carried out in an extruder.

11. The preparation method according to claim 10, characterized in that: The polymerization reaction in the second stage includes front-end extrusion, middle-end extrusion, and back-end extrusion.

12. The preparation method according to claim 11, characterized in that: The extrusion temperature is 180-220℃ for the first stage, 200-250℃ for the middle stage, and 230-270℃ for the last stage, and / or the residence time of the colloid in the extruder is 40-100 minutes.

13. The preparation method according to claim 6, characterized in that: The preparation method further includes granulating, cooling and drying the obtained fluorinated polymethyl methacrylate after the second-stage polymerization reaction.

14. The preparation method according to any one of claims 5-13, characterized in that: Based on a total weight of 100wt% for methyl methacrylate, functional monomer I, and functional monomer II, the amount of methyl methacrylate is 84-93wt%, the amount of functional monomer I is 6.8-15.2wt%, and the amount of functional monomer II is 0.2-0.8wt%.

15. The preparation method according to any one of claims 5-13, characterized in that: The chain transfer agent is C. 10 -C 18 Alkyl thiols; and / or, The chain transfer agent is used in an amount of 0.1%-0.4% of the total weight of methyl methacrylate, functional monomer I, and functional monomer II; and / or, The accelerator is 1-(2-fluorophenyl)-2-thiourea; and / or, the amount of the accelerator is 0.05%-0.1% of the total weight of methyl methacrylate, functional monomer I and functional monomer II.

16. The preparation method according to any one of claims 5-13, characterized in that: The chain transfer agent is at least one of hexadecyl mercaptan, tetradecyl mercaptan, tert-tetradecyl mercaptan, dodecyl mercaptan, and tert-dodecyl mercaptan.

17. The preparation method according to any one of claims 5-13, characterized in that: The initiator is at least one selected from azobisisobutyronitrile, azobisisoheptanenitrile, dimethyl azobisisobutyrate, azobisisobutyramidine hydrochloride, benzoyl peroxide, tert-butyl peroxide, and dicumyl peroxide; and / or, The amount of the initiator is 0.1%-1% of the total weight of methyl methacrylate, functional monomer I, and functional monomer II; And / or, the protective atmosphere is nitrogen and / or an inert gas.

18. The application of the fluorinated polymethyl methacrylate according to any one of claims 1-4 or the fluorinated polymethyl methacrylate prepared by the preparation method according to any one of claims 5-17 in liquid crystal materials, optical materials, aerospace materials, building materials, medical materials or agricultural materials.

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