Graft polymer long-short brush nanoparticles, and preparation method and application thereof

Abstract

The application discloses a kind of grafting polymer long short brush nanoparticles and its preparation method and application, including the following steps: organic silicon monomer A is obtained by polymerization initiator, initiator and monomer B polymerization reaction, by adjusting the amount of monomer B, polymerization temperature and / or polymerization time, obtain A-b-B-S block copolymer and A-b-B-L block copolymer;Monomer B is selected from including but not limited to styrene, acrylate, methacrylate, vinyl compound;A-b-B-S block polymer, A-b-B-L block polymer and monomer B oligomer are mixed, vacuum annealing, obtain block copolymer self-assembly material, again by hydrolysis crosslinking, post-processing, obtain nanoparticles.The application provides a new method for directly preparing grafting polymer long short brush nanoparticles by block copolymer co-assembly, the preparation process is simple, nanoparticle morphology is controllable, polymer brush polymerization degree and long short brush ratio are controllable.

Description

Technical Field

[0001] This invention relates to a type of grafted polymer long and short brush nanoparticle, its preparation method and application, belonging to the field of nanomaterials. Background Technology

[0002] Filling polymer matrices with nanoparticles can significantly improve certain properties of polymers, such as thermomechanical, optical, and electrical properties. However, due to the thermodynamic incompatibility between inorganic nanoparticles and the polymer matrix, nanoparticles cannot be well dispersed in the polymer matrix, thus forming aggregates and reducing the improvement of polymer properties by nanoparticles. A common method is to graft polymer brushes with the same or similar chemical properties as the matrix onto the surface of nanoparticles to improve the compatibility between nanoparticles and the matrix. Initially, the strategy of grafting polymer single-distribution brushes was used to improve the compatibility between polymer nanoparticles and polymers. However, nanoparticles themselves tend to form clusters of various morphologies, such as beads and sheets [Damien Maillard, Sanat K. Kumar. Nano Lett. 2011, 11, 4569–4573]. This is because the part of the nanoparticle covered by the polymer exhibits wetting with the polymer matrix, while the nanoparticles themselves repel the matrix. The results of theoretical and simulation experiments show that nanoparticles grafted with a large number of short brushes and a small number of long brushes can be better dispersed in the polymer matrix [Tyler B. Martin, Arthi Jayaraman. Macromolecules 2013, 46, 9144-9150]. Brushes grafted near the nanoparticles shield the mutual attraction between particles by aggregating on the surface of the nanoparticles, while brushes grafted far from the nanoparticles can increase the wettability of the grafted layer and the polymer matrix. Experimental results also show that nanoparticles grafted with both long and short brushes are more uniformly dispersed in the polymer matrix than nanoparticles grafted with only long brushes or only short brushes [Ying Li, Peng Tao, Anand Viswanath, Brian C. Benicewicz, Linda S. Schadler. Langmuir 2013, 29, 1211-1220].

[0003] A common method for grafting polymer long and short brushes onto nanoparticles is to first chemically modify the surface of the nanoparticles to introduce functional groups that can initiate monomer polymerization, thereby initiating RAFT polymerization of the monomers to graft short brushes onto the nanoparticles. Then, the RAFT active functional groups are removed, and RAFT active functional groups are introduced again through chemical modification. Finally, monomer polymerization is initiated again to graft long brushes onto the nanoparticles to obtain nanoparticles grafted with long and short brushes. Rungt et al. grafted polystyrene long and short brushes onto SiO2 nanospheres using this method [Atri Rungta, Bharath Natarajan, Tony Neely, Douglas Dukes, Linda S. Schadler, Brian C. Benicewicz. Macromolecules 2012, 45, 9303-9311]. Qiao et al. grafted polymethyl methacrylate (PMMA) long and short brushes onto BaTiO3 nanospheres using this method [Yali Qiao, Xiaodong Yin, Lei Wang, Md. Sayful Islam, Brian C. Benicewicz, Harry J. Ploehn, Chuanbing Tang. Macromolecules 2015, 48, 8998-9006]. While this method successfully prepared nanoparticles grafted with long and short brushes, the synthesis process was cumbersome, and the grafting density of the long and short brushes was uncontrollable. Therefore, a simpler method for preparing polymer-grafted long and short brush nanoparticles is needed. Summary of the Invention

[0004] To address the aforementioned technical problems in the existing technology, this invention provides a method for preparing nanoparticles grafted with polymer long and short brushes, comprising the following steps:

[0005] (1) Monomer A is polymerized to obtain an initiator; said monomer A may be selected from compounds with the structure shown in Formula I:

[0006]

[0007] Among them, R1, R2, and R3 can be the same or different, and R1 can be H, substituted or unsubstituted C. 1-10 The alkyl group, R2, and R3 are independently selected from substituted or unsubstituted C4 groups. 1-16 Alkyl groups; for example, R1 can be selected from H, C 1-10 Alkyl groups, R2, and R3 are independently selected from C1 and C2. 1-8 Alkyl; for example, R1 is selected from H and methyl, R2 is selected from propyl and butyl, and R3 is selected from ethyl and propyl;

[0008] (2) The initiator reacts with monomer B to polymerize, and by adjusting the amount of monomer B, polymerization temperature and / or polymerization time, AbBS block copolymer and AbBL block copolymer are obtained.

[0009] The monomer B may be selected from compounds including but not limited to styrene, acrylate, methacrylate, and vinyl compounds, and the monomer B does not contain acidic groups or acid-crosslinkable groups; for example, the monomer B is not vinylpyridine, butyl acrylate, n-octyl methacrylate, etc.; for example, the monomer B is selected from methyl methacrylate and / or styrene;

[0010] (3) The AbBS block polymer, AbBL block polymer and monomer B oligomer are mixed and vacuum annealed to obtain a block copolymer self-assembled material.

[0011] (4) The block copolymer self-assembled material is hydrolyzed, cross-linked, and post-treated to obtain the grafted polymer long and short brush nanoparticles.

[0012] According to an embodiment of the present invention, the preparation process of the initiator includes:

[0013] The initiator was obtained by mixing cumyl dithiobenzoate, azobisisobutyronitrile and monomer A and then performing a polymerization reaction.

[0014] Preferably, the temperature of the polymerization reaction can be 50°C to 100°C, for example, 60°C to 90°C, such as 60°C, 75°C or 90°C; preferably, the time of the polymerization reaction can be 1 to 72 hours, for example, 5 to 18 hours.

[0015] Preferably, the molar ratio of monomer A, cumyl dithiobenzoate, and azobisisobutyronitrile can be (20-1000):1:(0.05-5), for example (30-600):1:(0.5-1), with example molar ratios of 50:1:0.2, 100:1:0.3, 200:1:0.2, 500:1:0.3, or 600:1:0.5;

[0016] Preferably, the polymerization reaction is carried out in an inert atmosphere, such as in a nitrogen atmosphere.

[0017] According to an embodiment of the present invention, the number-average molecular weight of the initiator is (10-100)×10 3 g / mol, for example (30-60)×10 3 g / mol, for example 40 × 10 g / mol 3 g / mol, 43×10 3 g / mol, 45×10 3g / mol, 50×10 3 g / mol, 60×10 3 g / mol.

[0018] According to an embodiment of the present invention, the number-average molecular weight of the AbBS block copolymer is less than that of the AbBL block copolymer.

[0019] According to an embodiment of the present invention, the number-average molecular weight of the AbBS block copolymer is (10-100)×10⁻⁶. 3 g / mol, for example (30-90)×10 3 g / mol, for example 20 × 10 3 g / mol, 40×10 3 g / mol, 50×10 3 g / mol, 60×10 3 g / mol, 70×10 3 g / mol, 78×10 3 g / mol, 80×10 3 g / mol, 88×10 3 g / mol.

[0020] According to an embodiment of the present invention, the number-average molecular weight of the AbBL block copolymer is (100-300)×10⁻⁶. 3 g / mol, for example (130-180)×10 3 g / mol, for example 110 × 10 3 g / mol, 120×10 3 g / mol, 130×10 3 g / mol, 150×10 3 g / mol, 155×10 3 g / mol, 160×10 3 g / mol, 180×10 3 g / mol.

[0021] According to an embodiment of the present invention, the temperature of the polymerization reaction in step (2) is 40 to 150°C, for example 60 to 140°C, and exemplarily 60°C or 90°C.

[0022] According to an embodiment of the present invention, the polymerization reaction time in step (2) is 1 to 60 hours, for example 5 to 30 hours, and exemplary times are 10 hours, 15 hours, 16 hours, 17 hours, and 20 hours.

[0023] According to an embodiment of the present invention, the molar ratio of the initiator to monomer B in step (2) can be 1:(10 - 20000), for example, 1:(3500 - 16000), and exemplary values are 1:2000, 1:3000, 1:4500, 1:5000, 1:6780, 1:8500, 1:9580, 1:10800, 1:12000, 1:15600.

[0024] According to an embodiment of the present invention, the polymerization reaction in step (2) is carried out in an inert atmosphere, for example, in a nitrogen atmosphere.

[0025] According to an embodiment of the present invention, the number average molecular weight of the oligomer of monomer B is (1 - 10)×10 3 g / mol, for example, (2 - 10)×10 3 g / mol, and exemplary values are 2.5×10 3 g / mol, 4×10 3 g / mol, 5.6×10 3 g / mol, 7.2×10 3 g / mol, 9.2×10 3 g / mol.

[0026] According to an embodiment of the present invention, the preparation process of the oligomer of monomer B includes: mixing cumyl dithiobenzoate, azobisisobutyronitrile and monomer B, and obtaining the oligomer of monomer B after a polymerization reaction;

[0027] Preferably, the molar ratio of monomer B, cumyl dithiobenzoate and azobisisobutyronitrile is (10 - 8000):1:(0.05 - 4), for example, 120:1:0.2, 100:1:0.2;

[0028] Preferably, the temperature of the polymerization reaction is 40 - 150 °C, for example, 50 - 120 °C, and an exemplary value is 60 °C;

[0029] Preferably, the time of the polymerization reaction is 1 - 60 hours, for example, 5 - 30 hours, and exemplary values are 10 hours, 15 hours, 16 hours, 17 hours, 18 hours, 20 hours;

[0030] Preferably, the polymerization reaction is carried out in an inert atmosphere, for example, in a nitrogen atmosphere.

[0031] According to an embodiment of the present invention, the molar ratio of the A-b-B-S block copolymer to the A-b-B-L block copolymer is denoted as A, where 0 < A ≤ 20, for example, A = 9:1, 8:2, 5:5, 2:8 or 1:9.

[0032] According to an embodiment of the present invention, the ratio of the mass of the oligomer of monomer B to the total mass of the AbBS block copolymer and the AbBL block copolymer is in the range of (0 to 10):1, and the mass of the oligomer of monomer B is not zero; for example, the ratio range is 2.5 to 5.7:1 or 2.2 to 6.7:1, with examples being 1.6:1, 1.8:1, 2.5:1, 2.7:1, 3.2:1, 3.6:1, 4.5:1, and 5.5:1.

[0033] According to an embodiment of the present invention, after the above polymerization reaction is completed, the reaction product is purified and vacuum dried. For example, the vacuum drying temperature can be 25-90°C, specifically 40°C, 50°C, or 80°C. The vacuum drying time does not exceed 96 hours, for example, 10-60 hours, specifically 24 hours, 36 hours, or 48 hours.

[0034] According to an embodiment of the present invention, the vacuum annealing temperature can be 90-200℃, for example 100-150℃, with exemplary values ​​of 105℃, 125℃, and 130℃. The vacuum annealing time does not exceed 192 hours, with exemplary values ​​of 48 hours and 100 hours.

[0035] According to an embodiment of the present invention, the hydrolytic crosslinking is carried out in a hydrochloric acid atmosphere, a dilute acid or alkaline solution, causing the siloxane groups in the block copolymer self-assembled material to undergo hydrolytic crosslinking; for example, in a dilute hydrochloric acid or sodium hydroxide aqueous solution.

[0036] According to an embodiment of the present invention, the temperature of the hydrolysis-crosslinking reaction can be 20°C to 80°C, and the time can be 8 to 75 hours, for example, hydrolysis-crosslinking reaction at 20°C for 16 hours, hydrolysis-crosslinking reaction at 25°C for 12 hours, hydrolysis-crosslinking reaction at 30°C for 25 hours, hydrolysis-crosslinking reaction at 40°C for 48 hours, or hydrolysis-crosslinking reaction at 60°C for 6 hours.

[0037] According to an embodiment of the present invention, the post-processing in step 4) includes the removal of oligomers of monomer B.

[0038] According to an exemplary embodiment of the present invention, the method for preparing the grafted polymer long and short brush nanoparticles includes the following steps:

[0039] (1) Isopropylbenzene dithiobenzoate, azobisisobutyronitrile and methacryloyloxypropyltriethoxysilane are mixed and polymerized to obtain polymethacryloyloxypropyltriethoxysilane, which is the initiator.

[0040] (2) The initiator undergoes a polymerization reaction with styrene, and by adjusting the amount of styrene, the polymerization temperature, and / or the polymerization time, a poly(methacryloyloxypropyl)triethoxysilane-b-polystyrene-S block copolymer and a poly(methacryloyloxypropyl)triethoxysilane-b-polystyrene-L block copolymer are obtained;

[0041] (3) The poly(methacryloyloxypropyl)triethoxysilane-b-polystyrene-S block copolymer, the poly(methacryloyloxypropyl)triethoxysilane-b-polystyrene-L block copolymer, and the polystyrene oligomer are mixed and vacuum annealed to obtain a block copolymer self-assembled material;

[0042] The molar ratio of the poly(methacryloyloxypropyl)triethoxysilane-b-polystyrene-S block copolymer to the poly(methacryloyloxypropyl)triethoxysilane-b-polystyrene-L block copolymer is denoted as A1, where 0 < A1 ≤ 20, for example, 9:1, 8:2, 5:5, 2:8, 1:9;

[0043] The ratio of the mass of the polystyrene oligomer to the total mass of the poly(methacryloyloxypropyl)triethoxysilane-b-polystyrene-L block copolymer and the poly(methacryloyloxypropyl)triethoxysilane-b-polystyrene-S block copolymer is (0 - 10):1, and the mass of the polystyrene oligomer is not zero; for example, 2.5 - 5.7:1, 1.6:1, 2.7:1, 3.2:1, or 4.5:1;

[0044] (4) The block copolymer self-assembled material is subjected to hydrolysis crosslinking and post-treatment to obtain the nanoparticles of the graft polymer long and short brushes.

[0045] According to an exemplary embodiment of the present invention, the method for preparing the nanoparticles of the graft polymer long and short brushes comprises the following steps:

[0046] (1) Cumyl dithiobenzoate, azobisisobutyronitrile, and methacryloyloxypropyltriethoxysilane are mixed and, after a polymerization reaction, poly(methacryloyloxypropyl)triethoxysilane, i.e., the initiator, is obtained;

[0047] (2) The initiator undergoes a polymerization reaction with methyl methacrylate, and by adjusting the amount of methyl methacrylate, the polymerization temperature, and / or the polymerization time, a poly(methacryloyloxypropyl)triethoxysilane-b-poly(methyl methacrylate)-S block copolymer and a poly(methacryloyloxypropyl)triethoxysilane-b-poly(methyl methacrylate)-L block copolymer are obtained;

[0048] (3) Mix the poly (methacryloyloxypropyltriethoxysilane)-b-poly (methyl methacrylate)-S block copolymer, poly (methacryloyloxypropyltriethoxysilane)-b-poly (methyl methacrylate)-L block copolymer and poly (methyl methacrylate) oligomer, and perform vacuum annealing to obtain a block copolymer self-assembled material;

[0049] The molar ratio of the poly (methacryloyloxypropyltriethoxysilane)-b-poly (methyl methacrylate)-S to the poly (methacryloyloxypropyltriethoxysilane)-b-poly (methyl methacrylate)-L is A2, where 0 < A2 ≤ 20, for example, 9:1, 8:2, 5:5, 2:8, 1:9;

[0050] The ratio of the mass of the poly (methyl methacrylate) oligomer to the total mass of the poly (methacryloyloxypropyltriethoxysilane)-b-poly (methyl methacrylate)-L block copolymer and the poly (methacryloyloxypropyltriethoxysilane)-b-poly (methyl methacrylate)-S block copolymer is (0 - 10):1, and the mass of the poly (methyl methacrylate) oligomer is not zero, for example, 2.2 - 6.7:1, 1.8:1, 2.5:1, 3.6:1 or 5.5:1;

[0051] (4) Hydrolyze and crosslink the block copolymer self-assembled material, and perform post-treatment to obtain the nanoparticles of the graft polymer long and short brushes.

[0052] The present invention also provides the nanoparticles prepared by the above method.

[0053] According to the embodiments of the present invention, the morphology of the nanoparticles can be spherical, columnar, coexistence of sheet and column, etc.

[0054] According to the embodiments of the present invention, the nanoparticles can be SiO2 nanoparticles with coexistence of sheet and column grafted with polystyrene (PS) long and short brushes, spherical SiO2 nanoparticles grafted with PS long and short brushes, columnar SiO2 nanoparticles grafted with poly (methyl methacrylate) (PMMA) long and short brushes, and spherical SiO2 nanoparticles grafted with PMMA long and short brushes.

[0055] According to the embodiments of the present invention, the SiO2 nanoparticles with coexistence of sheet and column grafted with polystyrene (PS) long and short brushes have a morphology substantially as Figure 2 shown.

[0056] According to the embodiments of the present invention, the spherical SiO2 nanoparticles grafted with PS long and short brushes have a morphology substantially as Figure 3 shown.

[0057] According to the embodiments of the present invention, the columnar SiO2 nanoparticles grafted with poly (methyl methacrylate) (PMMA) long and short brushes have a morphology substantially as Figure 4 The shape shown.

[0058] According to an embodiment of the present invention, the spherical SiO2 nanoparticles grafted with PMMA long and short brushes have essentially the following properties: Figure 5 The shape shown.

[0059] The present invention also provides the application of the above method in the preparation of nanoparticles with controllable morphology.

[0060] According to an embodiment of the present invention, the morphology of the nanoparticles can be spherical, columnar, or a combination of lamellae and columns.

[0061] For example, the method is used in the preparation of SiO2 nanoparticles with coexisting sheets and columns grafted with long and short polystyrene (PS) brushes, spherical SiO2 nanoparticles grafted with long and short PS brushes, columnar SiO2 nanoparticles grafted with long and short polymethyl methacrylate (PMMA) brushes, and spherical SiO2 nanoparticles grafted with long and short PMMA brushes.

[0062] The grafted polymer long and short brush nanoparticles provided by this invention can be used as nanofillers.

[0063] The beneficial effects of this invention are:

[0064] This invention provides a method for preparing and applying nanoparticles grafted with polymer long and short brushes. By using AbB block copolymer co-assembly, nanoparticles with different morphologies of grafted long and short brushes can be directly prepared, which not only simplifies the preparation process but also yields more nanoparticles with controllable morphology.

[0065] (1) This invention provides a new method for directly preparing grafted polymer long and short brush nanoparticles by block copolymer co-assembly. The preparation process is simple, the morphology of the nanoparticles is controllable, and the degree of polymerization of the polymer brush and the ratio of long and short brushes are controllable.

[0066] (2) By changing the ratio of block copolymer and homopolymer, the present invention can prepare grafted polymer length brush nanoparticles with different morphologies.

[0067] (3) By changing the molecular weight of the block copolymer, the present invention can change the length of the long and short brushes of the nanoparticles, and prepare nanoparticles of arbitrary length and short brushes.

[0068] (4) By changing the ratio of the two block copolymers, the present invention can prepare nanoparticles with different ratios of long and short brushes. Attached Figure Description

[0069] Figure 1This is a schematic diagram of the molecular structure of polymethacryloyloxypropyltriethoxysilane-b-polystyrene block copolymer and polymethacryloyloxypropyltriethoxysilane-b-polymethyl methacrylate block copolymer prepared by RAFT polymerization.

[0070] Figure 2 This is a transmission electron microscope image of SiO2 nanoparticles with coexisting grafted PS long and short brushes prepared by the assembly-crosslinking method in Example 1 of the present invention, dispersed in tetrahydrofuran.

[0071] Figure 3 This is a transmission electron microscope image of spherical SiO2 nanoparticles grafted with PS long and short brushes, prepared by the assembly-crosslinking method in Example 2 of the present invention, dispersed in tetrahydrofuran.

[0072] Figure 4 This is a transmission electron microscope image of columnar SiO2 nanoparticles grafted with PMMA long and short brushes, prepared by the assembly-crosslinking method in Example 3 of the present invention, dispersed in tetrahydrofuran.

[0073] Figure 5 This is a transmission electron microscope image of spherical SiO2 nanoparticles grafted with PMMA long and short brushes, prepared by the assembly-crosslinking method in Example 4 of the present invention, dispersed in tetrahydrofuran. Detailed Implementation

[0074] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0075] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0076] Example 1: SiO2 nanoparticles grafted onto PS long and short brush plates coexisting.

[0077] 1) Add methacryloyloxypropyltriethoxysilane (30.0 g, 0.1 mol) and cumyl dithiobenzoate (0.141 g, 5.2 × 10⁻⁶ mol) to a Schlenk flask. -1 mmol) and azobisisobutyronitrile (17.0 mg, 1.0 × 10⁻⁶ ... -1 The product was reacted with mmol) and then reacted at 60°C for 16 hours under sealed conditions. After purification, the product was vacuum dried at 50°C to obtain a viscous liquid, which is the macromolecular initiator polymethacryloyloxypropyltriethoxysilane (PTEPM). 43k );

[0078] 2) Add the above-mentioned polymethacryloyloxypropyltriethoxysilane (1.0 g, 2.3 × 10⁻⁶) to a Schlenk flask. - 2 0.139 mol) of polymethacryloyloxypropyltriethoxysilane-b-polystyrene block copolymer (PTEPM) was reacted with styrene (14.5 g, 0.139 mol) under sealed conditions at 90 °C for 16 hours. The product was purified and dried under vacuum at 50 °C to obtain a powdered solid. 43k -PS 88k );

[0079] 3) Add 1.0 g of the polymethacryloyloxypropyltriethoxysilane (2.3 × 10⁻⁶ g) prepared in step 1) to the Schlenk flask. -2 0.233 mol) of polymethacryloyloxypropyltriethoxysilane-b-polystyrene block copolymer (PTEPM) was reacted with styrene (24.2 g, 0.233 mol) at 90 °C for 16 hours under sealed conditions. The product was purified and dried under vacuum at 50 °C to obtain a powdered solid. 43k -PS 155k );

[0080] 4) Styrene (60.0 g, 0.577 mol), cumyl dithiobenzoate (1.57 g, 5.77 mmol), and azobisisobutyronitrile (0.189 g, 1.15 mmol) were added to a Schlenk flask. The mixture was reacted at 90 °C for 18 h under sealed conditions. After purification, the product was vacuum dried at 60 °C for 24 h to obtain a light red powder solid. The obtained product is low-polymer polystyrene (PS). 7.2k ).

[0081] 5) Add the PTEPM prepared in step 2) to the round-bottom flask. 43k -PS 88k 0.662g, PTEPM prepared in step 3) 43k -PS 155k 1g, PS prepared in step 4) 7.2k 0.338g was added to tetrahydrofuran and stirred to form a solution. The solvent was evaporated at room temperature to obtain a solid material. After vacuum annealing at 120℃ for 2 days, a block copolymer self-assembled material with a regular micro-column phase separation structure was obtained.

[0082] 6) The above co-assembled material was placed in a hydrochloric acid atmosphere at room temperature for 24 hours for hydrolysis and crosslinking to obtain crosslinked and cured co-assembled material. The co-assembled material was then post-treated to remove low-polymerization degree polystyrene to obtain purified SiO2 nanoparticles (Lam+Cyl-Bimo-PS) with grafted PS long and short brushes coexisting on the sheets and columns. 5S5L ).

[0083] Polymethacryloyloxypropyltriethoxysilane-b-polystyrene block copolymer has the following properties: Figure 1 The structure shown in PTEPM-PS. Lam+Cyl-Bimo-PS 5S5L It was dispersed in tetrahydrofuran, dried, and then observed under a transmission microscope (TEM). Figure 2 The TEM image shows that the SiO2 nanoparticles grafted with PS long and short brushes exhibit a morphology of lamellar and columnar coexistence.

[0084] Example 2: Spherical SiO2 nanoparticles grafted with PS long and short brushes

[0085] 1) Add methacryloyloxypropyltriethoxysilane (30.0 g, 0.1 mol) and cumyl dithiobenzoate (0.141 g, 5.2 × 10⁻⁶ mol) to a Schlenk flask. -1 mmol) and azobisisobutyronitrile (17.0 mg, 1.0 × 10⁻⁶ ... -1 The product was reacted with mmol) and then reacted at 60°C for 16 hours under sealed conditions. After purification, the product was vacuum dried at 50°C to obtain a viscous liquid, which is the macromolecular initiator polymethacryloyloxypropyltriethoxysilane (PTEPM). 43k );

[0086] 2) Add the above-mentioned polymethacryloyloxypropyltriethoxysilane (1.0 g, 2.3 × 10⁻⁶) to a Schlenk flask. - 2 0.139 mol) of polymethacryloyloxypropyltriethoxysilane-b-polystyrene block copolymer (PTEPM) was reacted with styrene (14.5 g, 0.139 mol) under sealed conditions at 90 °C for 16 hours. The product was purified and dried under vacuum at 50 °C to obtain a powdered solid. 43k -PS 88k );

[0087] 3) Add 1.0 g of the polymethacryloyloxypropyltriethoxysilane (2.3 × 10⁻⁶ g) prepared in step 1) to the Schlenk flask. -2 0.233 mol) of polymethacryloyloxypropyltriethoxysilane-b-polystyrene block copolymer (PTEPM) was reacted with styrene (24.2 g, 0.233 mol) at 90 °C for 16 hours under sealed conditions. The product was purified and dried under vacuum at 50 °C to obtain a powdered solid. 43k -PS 155k );

[0088] 4) Styrene (60.0 g, 0.577 mol), cumyl dithiobenzoate (1.57 g, 5.77 mmol), and azobisisobutyronitrile (0.189 g, 1.15 mmol) were added to a Schlenk flask. The mixture was reacted at 90 °C for 18 h under sealed conditions. After purification, the product was vacuum dried at 60 °C for 24 h to obtain a light red powder solid. The obtained product is low-polymer polystyrene (PS). 7.2k ).

[0089] 5) Add the PTEPM prepared in step 2) to the round-bottom flask. 43k -PS 88k 0.662g, PTEPM prepared in step 3) 43k -PS 155k 1g, PS prepared in step 4) 7.2k 2.682g was added, and then tetrahydrofuran was added and stirred to form a solution. The solvent was evaporated at room temperature to obtain a solid material. After vacuum annealing at 120℃ for 2 days, a block copolymer self-assembled material with a regular micro-column phase separation structure was obtained.

[0090] 6) The above-mentioned co-assembled material was placed in a hydrochloric acid atmosphere at room temperature for 18 hours for hydrolysis and crosslinking to obtain a crosslinked and cured co-assembled material. The co-assembled material was then post-treated to remove low-polymerization degree polystyrene to obtain purified spherical SiO2 nanoparticles (Sph-Bimo-PS) grafted with PS long and short brushes. 5S5L ).

[0091] Sph-Bimo-PS 5S5L It was dispersed in tetrahydrofuran, dried, and then observed under a transmission microscope (TEM). Figure 3 The TEM image shows that the SiO2 nanoparticles grafted with PS long and short brushes exhibit a spherical morphology.

[0092] Example 3: Columnar SiO2 nanoparticles grafted with PMMA long and short brushes

[0093] 1) Add 20.0 g of methacryloyloxypropyltriethoxysilane (6.9 × 10⁻⁶) to a Schlenk flask. -2 mol), cumyl dithiobenzoate (0.094 g, 3.4 × 10⁻⁶ ... -1 mmol) and azobisisobutyronitrile (11 mg, 6.9 × 10⁻⁶ ... -2 The product was reacted at 60°C for 15 hours under sealed conditions. After purification, the product was vacuum dried at 50°C to obtain a viscous liquid, which was the macromolecular initiator polymethacryloyloxypropyltriethoxysilane (PTEPM). 43k );

[0094] 2) Add the above-mentioned polymethacryloyloxypropyltriethoxysilane (2.0 g, 4.7 × 10⁻⁶) to a Schlenk flask. - 2 0.242 mol) of polymethacryloxypropyltriethoxysilane-b-polymethyl methacrylate block copolymer (PTEPM) was reacted with methyl methacrylate (24.23 g, 0.242 mol) at 60 °C for 17 hours under sealed conditions. The product was purified and dried under vacuum at 50 °C to obtain a powdered solid, which is polymethacryloxypropyltriethoxysilane-b-polymethyl methacrylate block copolymer (PTEPM). 43k PMMA 78k );

[0095] 3) Add 1.0 g of the polymethacryloyloxypropyltriethoxysilane (2.3 × 10⁻⁶ g) prepared in step 1) to the Schlenk flask. -2 0.280 mol) of polymethacryloxypropyltriethoxysilane-b-polymethyl methacrylate block copolymer (PTEPM) was reacted with methyl methacrylate (27.96 g, 0.280 mol) at 60 °C for 17 hours under sealed conditions. The product was purified and dried under vacuum at 50 °C to obtain a powdered solid. 43k PMMA 180k );

[0096] 4) Methyl methacrylate (100.0 g, 1.0 mol), cumyl dithiobenzoate (2.72 g, 0.01 mol), and azobisisobutyronitrile (0.328 g, 2.0 mmol) were added to a Schlenk flask. The mixture was reacted at 60 °C for 18 h under sealed conditions. After purification, the product was vacuum dried at 50 °C for 24 h to obtain a light red powder solid. The obtained product is low-polymerization degree polymethyl methacrylate (PMMA). 7.5k ).

[0097] 5) Add the PTEPM prepared in step 2) to the round-bottom flask. 43k PMMA 78k 0.543g, PTEPM prepared in step 3) 43k -PS 180k 1g, PMMA prepared in step 4) 7.5k 0.457g was added to tetrahydrofuran and stirred to form a solution. The solvent was evaporated at room temperature to obtain a solid material. After vacuum annealing at 120℃ for 2 days, a block copolymer self-assembled material with a regular micro-column phase separation structure was obtained.

[0098] 6) The above co-assembled materials were placed in a hydrochloric acid atmosphere at room temperature for 24 hours for hydrolysis and crosslinking to obtain crosslinked and cured co-assembled materials. The co-assembled materials were then post-treated to remove low-polymerization degree polymethyl methacrylate to obtain purified columnar SiO2 nanoparticles (Cyl-Bimo-PMMA) grafted with long and short brushes. 5S5L ).

[0099] Polymethacryloyloxypropyltriethoxysilane-b-polymethyl methacrylate block copolymer has the following properties: Figure 1 The structure shown in PTEPM-PMMA. Cyl-Bimo-PMMA. 5S5 Dispersed in tetrahydrofuran and dried, the SiO2 nanoparticles grafted with PMMA long and short brushes were observed by transmission electron microscopy (TEM). TEM showed that the SiO2 nanoparticles were columnar in shape.

[0100] Example 4: Spherical SiO2 nanoparticles grafted with PMMA long and short brushes

[0101] 1) Add 20.0 g of methacryloyloxypropyltriethoxysilane (6.9 × 10⁻⁶) to a Schlenk flask. -2 mol), cumyl dithiobenzoate (0.094 g, 3.4 × 10⁻⁶ ... -1 mmol) and azobisisobutyronitrile (11 mg, 6.9 × 10⁻⁶ ... -2 The product was reacted at 60°C for 15 hours under sealed conditions. After purification, the product was vacuum dried at 50°C to obtain a viscous liquid, which was the macromolecular initiator polymethacryloyloxypropyltriethoxysilane (PTEPM). 43k );

[0102] 2) Add the above-mentioned polymethacryloyloxypropyltriethoxysilane (2.0 g, 4.7 × 10⁻⁶) to a Schlenk flask. - 2 0.242 mol) of polymethacryloxypropyltriethoxysilane-b-polymethyl methacrylate block copolymer (PTEPM) was reacted with methyl methacrylate (24.23 g, 0.242 mol) at 60 °C for 17 hours under sealed conditions. The product was purified and dried under vacuum at 50 °C to obtain a powdered solid, which is polymethacryloxypropyltriethoxysilane-b-polymethyl methacrylate block copolymer (PTEPM). 43k PMMA 78k );

[0103] 3) Add 1.0 g of the polymethacryloyloxypropyltriethoxysilane (2.3 × 10⁻⁶ g) prepared in step 1) to the Schlenk flask. -20.280 mol) of polymethacryloxypropyltriethoxysilane-b-polymethyl methacrylate block copolymer (PTEPM) was reacted with methyl methacrylate (27.96 g, 0.280 mol) at 60 °C for 17 hours under sealed conditions. The product was purified and dried under vacuum at 50 °C to obtain a powdered solid. 43k PMMA 180k );

[0104] 4) Methyl methacrylate (100.0 g, 1.0 mol), cumyl dithiobenzoate (2.72 g, 0.01 mol), and azobisisobutyronitrile (0.328 g, 2.0 mmol) were added to a Schlenk flask. The mixture was reacted at 60 °C for 18 h under sealed conditions. After purification, the product was dried under vacuum at 50 °C for 24 h to obtain a light red powder solid. The obtained product is low-polymer polystyrene (PMMA). 7.5k ).

[0105] 5) Add the PTEPM prepared in step 2) to the round-bottom flask. 43k PMMA 78k 0.543g, PTEPM prepared in step 3) 43k -PS 180k 1g, PMMA prepared in step 4) 7.5k 2.313g was added, and then tetrahydrofuran was added and stirred to form a solution. The solvent was evaporated at room temperature to obtain a solid material. After vacuum annealing at 120℃ for 2 days, a block copolymer self-assembled material 1 with a regular micro-columnar phase separation structure was obtained.

[0106] 6) Add the PTEPM prepared in step 2) to the round-bottom flask. 43k PMMA 78k 0.868g, PTEPM prepared in step 3) 43k -PS 180k 0.4g, PMMA prepared in step 4) 7.5k 2.588g was added, and then tetrahydrofuran was added and stirred to form a solution. The solvent was evaporated at room temperature to obtain a solid material. After vacuum annealing at 120℃ for 2 days, a block copolymer self-assembled material 2 with a regular micro-column phase separation structure was obtained.

[0107] 7) The co-assembled materials 1 and 2 were placed in a hydrochloric acid atmosphere at room temperature for 24 hours for hydrolysis and crosslinking to obtain crosslinked and cured co-assembled materials a and b. Co-assembled materials a and b were then post-treated to remove low-polymerization degree polymethyl methacrylate to obtain purified spherical SiO2 nanoparticles (Sph-Bimo-PMMA) grafted with long and short brushes. 8S2L ), Spherical SiO2 nanoparticles grafted with PMMA long and short brushes (Sph-Bimo-PMMA)5S5L ).

[0108] Sph-Bimo-PMMA 8S2L Sph-Bimo-PMMA 5S5L They were dispersed separately in tetrahydrofuran, dried, and observed under a transmission microscope (TEM). Figure 5 In the middle, 'a' represents Sph-Bimo-PMMA. 8S2L Topographical diagram, Figure 5 b represents Sph-Bimo-PMMA 5S5L The morphology image shows that the SiO2 nanoparticles grafted with PMMA long and short brushes exhibit a spherical morphology, as revealed by TEM.

[0109] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a graft polymer long-short brush nanoparticle, characterized by, The preparation method comprises the following steps: (1) mixing cumene dithiobenzoate, azobisisobutyronitrile and monomer A, obtaining initiator after polymerization reaction, the number average molecular weight of the initiator is (30-60) x 10 3 g / mol; the monomer A is selected from the compound with the structure shown in formula I: Formula I Wherein, R1 is selected from H, methyl, R2 is selected from propylene, butylene, and R3 is selected from ethyl, propyl; (2) the initiator is polymerized with monomer B, by adjusting the amount of monomer B, polymerization temperature and / or polymerization time, to obtain A- b -B-S block copolymer and A- b -B-L block copolymer; said A- b the number average molecular weight of said A- b the number average molecular weight of said A- The A- b The number average molecular weight of the A-B-S block copolymer is (10-100) x 10 3 g / mol; said A- b The number average molecular weight of the A-B-L block copolymer is (100-300) x 10 3 g / mol; The A- b The molar ratio of the A- B-S block copolymer to the A- b The molar ratio of the A- B-L block copolymer is denoted as A, 0 < A < 20. The monomer B is selected from methyl methacrylate and / or styrene; (3) the A- b -B-S block polymer, A- b -B-L block polymer and an oligomer of monomer B are mixed, vacuum annealed to obtain a block copolymer self-assembly material; The preparation process of the oligomer of the monomer B comprises the following steps: mixing cumene dithiobenzoate, azobisisobutyronitrile and the monomer B, and obtaining the oligomer of the monomer B through polymerization reaction; The molar ratio of the monomer B, cumene dithiobenzoate and azobisisobutyronitrile is (10-8000):1:(0.05-4); The number average molecular weight of the oligomer of monomer B is (1-10) x 10 3 g / mol; The mass of the oligomer of monomer B is related to that of A- b -BS block copolymer and A- b -The ratio of the total mass of the BL block copolymer is in the range of (0~10):1, and the mass of the oligomer of monomer B is not zero; (4) The block copolymer self-assembly material is hydrolyzed, cross-linked, and post-treated to obtain the grafted polymer long-short brush nanoparticles; The morphology of the nanoparticles is spherical, columnar or sheet-columnar coexistence.

2. The production method according to claim 1, characterized by, The monomer A is methacryloxypropyl triethoxysilane.

3. The production method according to claim 1, characterized by, The A- b The number average molecular weight of the A-B-S block copolymer is (30-90) x 10 3 g / mol. The A- b The number average molecular weight of the A-B-L block copolymer is (130-180) x 10 3 g / mol.

4. The method of claim 1, wherein, The temperature of the polymerization reaction in step (2) is 40-150 DEG C, and the polymerization reaction time is 1-60 hours; And / or, the molar ratio of the initiator to the monomer B in step (2) is 1:(10-20000).

5. The preparation method according to claim 1, characterized in that, A=9:1, 8:2, 5:5, 2:8 or 1:9; The ratio of the mass of the oligomers of monomer B to the total mass of the A- b -B-S block copolymer to the total mass of the A- b The ratio of the mass of the oligomers of monomer B to the total mass of the A- 6. The method of claim 1, wherein, The temperature of the vacuum annealing is 90-200 DEG C, and the time of the vacuum annealing is not more than 192 hours; The hydrolysis cross-linking is carried out in a hydrochloric acid atmosphere, a dilute acid or an alkali solution; Step 4) The post-treatment comprises removing the oligomer of the monomer B.

7. Nanoparticles prepared by the method of any one of claims 1-6; The morphology of the nanoparticles is spherical, columnar or sheet-columnar coexistence.

8. The nanoparticle of claim 7, wherein, The nanoparticles are sheet-columnar coexistence SiO2 nanoparticles grafted with polystyrene long-short brush, spherical SiO2 nanoparticles grafted with PS long-short brush, columnar SiO2 nanoparticles grafted with polymethyl methacrylate long-short brush, and spherical SiO2 nanoparticles grafted with PMMA long-short brush.

9. Application of the method of any one of claims 1-6 in the preparation of nanoparticles with controllable morphology, wherein the morphology of the nanoparticles is spherical, columnar or sheet-columnar coexistence.

10. Application of the nanoparticles of claim 7 or 8 as nanofillers.

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