Bottle-brush-shaped polymer filler capable of being dynamically cross-linked as well as preparation method and application of bottle-brush-shaped polymer filler

Abstract

The invention discloses a bottle-brush-shaped polymer filler capable of being dynamically cross-linked as well as a preparation method and application thereof, and belongs to the technical field of polymer glass materials. The molecular structure of the bottle-brush-shaped polymer filler capable of being dynamically cross-linked provided by the invention has a side chain with high grafting density, and a cross-linking site is caught like an octopus to form a multi-arm cross-linked structure, so that the synergistic movement between polymer chain segments is promoted. And secondly, the molecular brush has a rigid structure, and the rigid structure can play a role in strengthening and toughening in a tensile field. The mechanism effectively improves the tensile strength and the elongation at break of the dynamically cross-linkable organic glass, overcomes the defect that a traditional method cannot act on a cross-linked network, provides a new thought and method for development of high-performance reprocessable cross-linked glass, and realizes synergistic improvement of strength and toughness.

Description

Technical Field

[0001] This invention belongs to the field of polymer organic glass material technology, and in particular relates to a dynamically cross-linkable bottle brush-shaped polymer filler, its preparation method and application. Background Technology

[0002] Acrylic glass is an important transparent polymer material, but it has poor creep resistance. To address this issue, cross-linked acrylic glass has been developed, which uses chemical bonding to fix the molecular chains, preventing molecular slippage and significantly improving the performance of acrylic glass. However, a fatal flaw of cross-linked acrylic glass is its inability to be reprocessed, limiting its applications. In recent years, dynamic covalent polymer networks have shown potential for self-healing and recyclability due to their reversibility.

[0003] Strengthening and toughening dynamically crosslinkable acrylic glass is a challenging topic. Existing research mainly focuses on physical doping to strengthen and toughen non-crosslinked acrylic glass. For example, Yamauchi Y et al., in their article "Bottlebrush polymer-reinforced transparent multiphase plastics with enhanced thermal stability. Chem. Commun. 56:(93):14641-44," used molecular brushes as nanofillers to achieve strengthening and toughening through the physical interaction between the molecular brushes and the matrix. However, this filler-based method is mainly based on physical interactions and works on non-crosslinked systems, and is not suitable for strengthening and toughening crosslinked acrylic glass. Summary of the Invention

[0004] The mechanical properties of cross-linked acrylic glass are determined by the cross-linking network. Therefore, the reinforcement and toughening of dynamically cross-linked acrylic glass mainly involves adjusting the network structure. This requires polymerizing relevant toughening fillers within the network and cross-linking them through dynamic bonds to ensure reprocessability. Existing technologies cannot meet these requirements. To address these issues, this invention provides a dynamically cross-linked bottle-brush-shaped polymer filler, its preparation method, and its applications. The dynamically cross-linked bottle-brush-shaped polymer filler provided by this invention has a molecular structure with high grafting density side chains, which, like an octopus, grasp cross-linking sites to form a multi-arm cross-linked structure. Furthermore, the molecular brush itself has a rigid structure, which can play a reinforcing and toughening role under tensile conditions. Experimental results show that the dynamically cross-linked bottle-brush-shaped polymer filler provided by this invention can significantly improve the strength and toughness of cross-linked glass without sacrificing material transparency, providing a new approach and method for the development of high-performance reprocessable cross-linked acrylic glass.

[0005] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a dynamically crosslinkable bottle-brush-shaped polymeric filler, wherein the dynamically crosslinkable bottle-brush-shaped polymeric filler is MBBs (polynorbornene molecular brushes), and its chemical structural formula is: ; Where R is: ; n=40-100, m=10-25.

[0006] The molecular structure of polynorbornene molecular brush has a high grafting density of side chains. The side chain structure is completely matched with the polymethyl methacrylate matrix, exhibiting good molecular-scale compatibility and making it less prone to macroscopic phase separation.

[0007] This invention provides a bottle-brush-like polymer that can be dynamically crosslinked into a crosslinking network. Its molecular structure has side chains with high grafting density, enabling the formation of multi-arm crosslinked structures for reinforcement and toughening. Furthermore, the molecular brush itself possesses a rigid structure, which can contribute to reinforcement and toughening under tensile conditions.

[0008] Secondly, the present invention provides a method for preparing the above-mentioned dynamically crosslinkable bottle brush-shaped polymer filler, comprising the following steps: adding polynorbornene backbone, polymethyl methacrylate-co-acetoacetic acid ethylene glycol methacrylate and L-ascorbic acid to an organic solvent, mixing well and then performing freeze-thaw cycle degassing, then adding CuSO4·5H2O under a nitrogen atmosphere, thawing the resulting mixture to room temperature and then performing an oil bath reaction, then adding dichloromethane for dilution, filtering, and precipitation to obtain the dynamically crosslinkable bottle brush-shaped polymer filler.

[0009] Furthermore, the mass ratio of the polynorbornene backbone, polymethyl methacrylate-co-acetoacetic acid ethylene glycol methacrylate, L-ascorbic acid, and CuSO4·5H2O is 32:1562:36:10; the oil bath reaction temperature is 50℃ and the time is 2 h.

[0010] Thirdly, the present invention provides an application of the above-mentioned dynamically crosslinkable bottle-brush-shaped polymer filler in the preparation of a molecular brush composite dynamically crosslinkable reinforced and toughened plexiglass material.

[0011] Fourthly, the present invention provides a molecular brush composite dynamically crosslinkable reinforced and toughened plexiglass material, comprising the following raw materials: linear polymethyl methacrylate chains, functional fillers, and amine crosslinking agents; wherein the functional filler is the dynamically crosslinkable bottle brush-shaped polymer filler.

[0012] This invention aims to address the challenge of balancing strength and toughness in existing organic glass-like materials by providing a glass-like material modification technology and material system based on a molecular brush structure composite. By introducing polymer molecular brushes (MBBs) with molecular-scale dispersibility and excellent compatibility into a polymer matrix, the mechanical strength and fracture toughness of the glass-like material are synergistically improved. This overcomes the performance trade-offs and processing limitations faced by traditional inorganic fillers, providing a new approach and method for the development of high-performance, reprocessable cross-linked glasses.

[0013] Furthermore, the mass ratio of the functional filler to the polymethyl methacrylate linear chain is 1:(19-99); the molar ratio of AAEM monomer to amine crosslinker in the polymethyl methacrylate linear chain is 1:0.4-0.6, preferably 1:0.5.

[0014] Furthermore, the polymethacrylate linear chain is selected from PHMA-co-AAEM (polyhexyl methacrylate-co-acetoacetate ethylene glycol methacrylate linear chain) or PMMA-co-AAEM (polymethyl methacrylate-co-acetoacetate ethylene glycol methacrylate linear chain). As an example, this invention mainly demonstrates the effect of PMMA-co-AAEM as a matrix.

[0015] Furthermore, the amine crosslinking agent is selected from TREN (tris(2-aminoethyl)amine).

[0016] TREN has three amine groups, many reactive groups, and NH2 can exchange with the ketone ester groups of AAEM monomers. It has a suitable crosslinking temperature and is inexpensive.

[0017] Fifthly, the present invention provides a method for preparing the molecular brush composite dynamically crosslinkable reinforced and toughened plexiglass material, comprising the following steps: adding polymethyl methacrylate linear chains, functional fillers and amine crosslinking agents to an organic solvent, mixing them evenly, curing them at room temperature, and finally vacuum drying to obtain the molecular brush composite dynamically crosslinkable reinforced and toughened plexiglass material.

[0018] Furthermore, the organic solvent is selected from tetrahydrofuran; the curing temperature is room temperature; and the vacuum drying temperature is 80 °C.

[0019] In preparing the molecular brush composite dynamically crosslinkable reinforced and toughened plexiglass material, this invention uses tetrahydrofuran as a solvent, which has a low boiling point and can evaporate without heating, making the operation safe.

[0020] This invention addresses the performance control problem faced by dynamically crosslinkable acrylic materials by proposing a novel technical route based on molecular brush (MBB) composite modification. This method can improve the strength and toughness of dynamically crosslinkable acrylic materials without sacrificing the transparency and reprocessability of the glass-like materials.

[0021] Compared with the prior art, the present invention has the following advantages and technical effects: The bottle-brush-shaped polymer filler provided by this invention has a molecular structure with high grafting density side chains that, like an octopus, grasp the crosslinking agent to form a multi-arm crosslinking structure, promoting the cooperative movement between polymer chain segments. Secondly, the molecular brush itself has a rigid structure, which can enhance and toughen under tensile conditions. This mechanism effectively improves the tensile strength and elongation at break of acrylic glass materials, overcoming the shortcomings of traditional methods that cannot act on the crosslinking network. It provides new ideas and methods for the development of high-performance reprocessable crosslinked glass, achieving a synergistic improvement in strength and toughness.

[0022] The preparation method of the molecular brush composite dynamically cross-linkable reinforced and toughened plexiglass material used in this invention is simple, controllable, and universal. It is compatible with blending processes, requires no additional complex equipment or high energy consumption, and is applicable to a variety of general-purpose glass systems. It has good versatility and industrialization prospects. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 Synthetic route diagram for polynorbornene molecular brush; Figure 2 The proton NMR spectrum of the polynorbornene molecular brush prepared in Example 1 ( 1 HNMR); Figure 3 The images show gel permeation chromatograms of the unreacted mixture before the click reaction and the mixture of MBBs and anisole after the click reaction in Example 1. Figure 4 Tensile stress-strain curves of dumbbell-shaped splines obtained by injection molding of PMMA-vitrimer prepared in Comparative Example 1, PMMA-5wt%MBBs-vitrimer prepared in Example 1, and PMMA-1wt%MBBs-vitrimer prepared in Example 2 were obtained. Figure 5Frequency scan of PMMA-vitrimer prepared for Comparative Example 1; Figure 6 Frequency scan of PMMA-5wt%MBBs-vitrimer prepared in Example 1; Figure 7 The frequency scan diagram of PMMA-1wt%MBBs-vitrimer prepared in Example 2. Detailed Implementation

[0025] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0026] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0027] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0028] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0029] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0030] The room temperature in this invention refers to 25±2℃.

[0031] Unless otherwise specified, all materials used in this invention are commercially available products.

[0032] This invention prepares polymethyl methacrylate-co-acetoacetic acid ethylene glycol methacrylate according to the method provided in the article Catalyst-Free Vitrimers from VinylPolymers by Smerlin et al.

[0033] Example 1: Preparation of polynorbornene molecular brush S1. PNB-3N3 (polynorbornene backbone, 32.65 mg), ay-PMMA-co-AAEM (polymethyl methacrylate-co-acetoacetic acid methacrylate, 1.562 g), L-ascorbic acid (36.68 mg), anisole (0.1 mL), and N,N-dimethylformamide (10.0 mL) were uniformly mixed. After the mixture was deoxygenated through three cycles of freezing-vacuuming-thawing, CuSO4·5H2O (10.41 mg) was rapidly added to the frozen reaction mixture in the last cycle under a nitrogen atmosphere. After thawing the resulting mixture to room temperature, it was reacted in an oil bath at 50 °C for 2 hours. The polymer solution was obtained by exposing it to air to terminate the reaction. The polymer solution was diluted with dichloromethane (dichloromethane:polymer solution = 15:1, v / v), filtered through neutral alumina (200-300 mesh), and precipitated three times with icy diethyl ether to obtain purified MBBs (polynorbornene molecular brushes). S2. Weigh 1.9 g of polymethyl methacrylate-co-acetoacetic acid ethylene glycol methacrylate, 237.6 mg of tris(2-aminoethyl)amine, and 100 mg of the polynorbornene molecular brush prepared in S1. Add the above raw materials to tetrahydrofuran (10 mL), mix well, and transfer to a glass mold. The molar ratio of AAEM monomer to amine crosslinking agent in the linear chain of polymethyl methacrylate is 1:0.5. Volatilize the tetrahydrofuran at room temperature for 3 days, and then dry the product in a vacuum at 80 °C for 24 h. A dynamically crosslinkable reinforced and toughened plexiglass material with molecular brush composite is prepared, denoted as PMMA-5wt%MBBs-vitrimer.

[0034] The synthetic route of polynorbornene molecular brush in this invention is as follows: Figure 1 As shown, n is 48 and m is 12.

[0035] The proton NMR spectrum of the polynorbornene molecular brush prepared in this embodiment (… 1 HNMR) such as Figure 2 As shown. By Figure 2The spectral analysis shows that the characteristic peaks of polynorbornene and polymethyl methacrylate-co-acetoacetic acid ethylene glycol methacrylate are present, confirming that the two have successfully achieved a click reaction, that is, the azide group and alkynyl group of the main chain undergo a click reaction, and R replaces the azide.

[0036] It should be noted that the anisole added in this embodiment does not participate in the reaction. The purpose of adding anisole is to monitor the grafting rate of the reaction later by gel permeation chromatography. After uniformly mixing PNB-3N3, ay-PMMA-co-AAEM, L-ascorbic acid, anisole, and N,N-dimethylformamide, 40 μl of the unreacted mixture was taken for later use; after the reaction was completed, 40 μl of the reacted mixture was taken for gel permeation chromatography. Figure 3 The images show gel permeation chromatograms of the unreacted mixture before and after the click reaction in Example 1; from Figure 3 It can be seen that before the click reaction, the sample contained alkynyl polymethyl methacrylate side chains, polynorbornene backbone, and anisole, respectively. After the click reaction, a new peak shifted to the left appeared; this peak is the molecular brush peak. The alkynyl polymethyl methacrylate side chains decreased, and the polynorbornene backbone almost disappeared, confirming the successful synthesis of the polynorbornene molecular brush.

[0037] Example 2 S1. Same as Example 1; S2. Weigh 1.98 g of polymethyl methacrylate-co-acetoacetic acid ethylene glycol methacrylate, 237.6 mg of tris(2-aminoethyl)amine, and 0.02 g of the polynorbornene molecular brush prepared in S1. Add the above raw materials to tetrahydrofuran (10 mL), mix well, and transfer to a glass mold. The molar ratio of AAEM monomer to amine crosslinking agent in the linear chain of polymethyl methacrylate is 1:0.5. Volatilize the tetrahydrofuran at room temperature for 3 days, and then dry the product in a vacuum at 80 °C for 24 h. A dynamically crosslinkable reinforced and toughened plexiglass material with molecular brush composite is prepared, denoted as PMMA-1wt%MBBs-vitrimer.

[0038] Comparative Example 1 This comparative example prepares a glass-like material (PMMA-vitrimer).

[0039] Weigh out 2 g of polymethyl methacrylate-co-acetoacetic acid ethylene glycol methacrylate and 237.6 mg of tris(2-aminoethyl)amine, add them to 10 mL of tetrahydrofuran, mix well, transfer to a glass mold, and evaporate the tetrahydrofuran at room temperature for 3 days. Then dry the product in a vacuum at 80 °C for 24 h to obtain PMMA-vitrimer.

[0040] Performance testing 1. Mechanical property testing The PMMA-vitrimer prepared in Comparative Example 1, the PMMA-5wt%MBBs-vitrimer prepared in Example 1, and the PMMA-1wt%MBBs-vitrimer prepared in Example 2 were all injection molded to obtain dumbbell-shaped specimens, and then their mechanical properties were tested.

[0041] The specific mechanical property testing method is as follows: Dumbbell-shaped specimens were subjected to tensile testing at 10 mm / min on a universal tensile testing machine at room temperature. Each specimen underwent at least three individual tensile tests, and the results are as follows: Figure 4 The tensile stress-strain curves (based on test data from three parallel specimens) of dumbbell-shaped specimens obtained by injection molding of PMMA-vitrimer prepared in Comparative Example 1, PMMA-5wt%MBBs-vitrimer prepared in Example 1, and PMMA-1wt%MBBs-vitrimer prepared in Example 2 are shown.

[0042] Depend on Figure 4 It can be seen that, compared with the PMMA-vitrimer in Comparative Example 1, the PMMA-MBBs-vitrimer in Examples 1 and 2 showed significant improvements in fracture strength and elongation at break, indicating that the addition of molecular brushes significantly improved the strength and toughness of dynamically crosslinkable plexiglass. Figure 4 As can be seen from the entire curve, from the starting point to the fracture point, Example 1 (PMMA-5wt%MBBs-vitrimer) exhibits the highest fracture strength and elongation at break, and its stress-strain curve encloses the largest area, indicating that the strength and toughness of the material improve with increasing molecular brush content. This demonstrates that the molecular brush composite dynamically crosslinkable reinforced and toughened organic glass material prepared in this invention can simultaneously improve the strength and toughness of crosslinkable glass materials, achieving simultaneous optimization of the strength and toughness of crosslinkable glass materials.

[0043] 2. The PMMA-vitrimer prepared in Comparative Example 1, the PMMA-5wt%MBBs-vitrimer prepared in Example 1, and the PMMA-1wt%MBBs-vitrimer prepared in Example 2 were all hot-pressed to obtain discs with a diameter of 8 mm. The discs were then tested using an Anton Paar MCR 302e rheometer in dynamic frequency scanning mode, with an 8 mm parallel plate used for measurement. The frequency range was 100-0.1 rad / s, and the test temperature was 150-180 °C.

[0044] Figure 5 Frequency scan of PMMA-vitrimer prepared for Comparative Example 1; Figure 6Frequency scan of PMMA-5wt%MBBs-vitrimer prepared in Example 1; Figure 7 The above are frequency scans of PMMA-1wt%MBBs-vitrimer prepared in Example 2. The black horizontal lines in the three graphs represent the storage modulus of the fully cross-linked material, calculated based on the affine network model theory. The specific calculation method is as follows: G... affine =ρRT / M c M c The molecular weight is expressed as a unit of crosslinking degree. In this invention, polymer M... c =400g / mol, G can be calculated. affine =8.8×10 6 Pa, from Figure 5 The data shows a discrepancy between the platform modulus and the theoretical modulus of a fully cross-linked network, indicating numerous defects and the inability to achieve complete cross-linking. The strength and toughness of the sample can still be improved. Figure 6 and Figure 7 As can be seen, with the addition of the molecular brush, this octopus-like multi-arm structure can entangle most of the cross-linking sites, thus increasing the plateau modulus. From Figure 6 As can be seen, the plateau modulus of Example 1 (PMMA-5wt%MBBs-vitrimer) is basically on par with the theoretical maximum modulus, indicating that the network has been fully cross-linked. The improved toughness of the sample demonstrates that the molecular brush composite dynamically cross-linkable reinforced and toughened plexiglass material provided by this invention can simultaneously improve the strength and toughness of dynamically cross-linkable plexiglass materials.

[0045] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A dynamically cross-linkable bottle-brush shaped polymer filler, characterized in that, The dynamically cross-linkable bottle-brush-shaped polymer filler is a polynorbornene molecular brush, and its chemical structural formula is: ； Where R is: ; n=40-100, m=10-25, x=50-100.

2. A method for preparing the dynamically crosslinkable bottle-brush-shaped polymer filler according to claim 1, characterized in that, The process includes the following steps: adding polynorbornene backbone, polymethyl methacrylate-co-acetoacetic acid ethylene glycol methacrylate and L-ascorbic acid to an organic solvent, mixing well, and then performing freeze-thaw cycle degassing. CuSO4·5H2O is then added under a nitrogen atmosphere. The resulting mixture is thawed to room temperature and then reacted in an oil bath. Dichloromethane is then added for dilution, filtration, and precipitation to obtain the dynamically crosslinkable bottle brush-shaped polymer filler.

3. The method for preparing the dynamically crosslinkable bottle-brush-shaped polymer filler according to claim 2, characterized in that, The mass ratio of the polynorbornene backbone, polymethyl methacrylate-co-acetoacetic acid ethylene glycol methacrylate, L-ascorbic acid, and CuSO4·5H2O is 32:1562:36:10; the oil bath reaction is carried out at a temperature of 50 °C for 2 h.

4. The application of the dynamically crosslinkable bottle brush-shaped polymer filler as described in claim 1 in the preparation of a molecular brush composite dynamically crosslinkable reinforced and toughened plexiglass material.

5. A molecular brush composite dynamically cross-linkable reinforced and toughened plexiglass material, characterized in that, It includes the following raw materials: linear polymethyl methacrylate, functional filler and amine crosslinking agent; the functional filler is the dynamically crosslinkable bottle brush polymer filler as described in claim 1.

6. The molecular brush composite dynamically cross-linkable reinforced and toughened plexiglass material according to claim 5, characterized in that, The mass ratio of the functional filler to the polymethyl methacrylate linear chain is 1:(19-99); the molar ratio of AAEM monomer to amine crosslinker in the polymethyl methacrylate linear chain is 1:0.4-0.

6.

7. The molecular brush composite dynamically cross-linkable reinforced and toughened plexiglass material according to claim 6, characterized in that, The polymethacrylate linear chain is selected from polyhexyl methacrylate-co-acetoacetate ethylene glycol methacrylate linear chain or polymethyl methacrylate-co-acetoacetate ethylene glycol methacrylate linear chain.

8. The molecular brush composite dynamically cross-linkable reinforced and toughened plexiglass material according to claim 6, characterized in that, The amine crosslinking agent is selected from tris(2-aminoethyl)amine.

9. A method for preparing a dynamically cross-linkable reinforced and toughened plexiglass material composited with molecular brushes as described in any one of claims 5-8, characterized in that, The process includes the following steps: adding the polymethyl methacrylate linear chain, functional filler, and amine crosslinking agent to an organic solvent, mixing them evenly, curing them at room temperature, and finally vacuum drying them to prepare the molecular brush composite dynamically crosslinkable reinforced and toughened plexiglass material.

10. The preparation method according to claim 9, characterized in that, The organic solvent is selected from tetrahydrofuran; the curing temperature is room temperature; and the vacuum drying temperature is 80 °C.

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