Organosilicon polyurea containing authigenic zwitterions as well as preparation method and application thereof

Abstract

The invention provides organic silicon polyurea containing authigenic zwitterions as well as a preparation method and application of the organic silicon polyurea. The organic silicon polyurea containing the authigenic zwitterions comprises a structural unit derived from a double-end carboxyl functionalized poly authigenic zwitterionic polymer, a structural unit of double-amino-terminated organic silicon and a structural unit of isocyanate. A urea bond and a zwitterionic precursor containing a fluorocarbon group are introduced into organic silicon, the obtained organic silicon polyurea containing authigenic zwitterionic is used as a marine antifouling coating, and the coating is endowed with excellent bonding performance, self-healing performance and static antifouling performance and low simulated barnacle removal strength and water absorption.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials, and more particularly to an organosilicon polyurea containing self-generated zwitterions and a preparation method and application thereof. Background Art

[0002] Silicone antifouling coatings have the advantages of low surface free energy, small surface roughness, low glass transition temperature and low elastic modulus, and are usually used for fouling release coatings. The interface bonding between organisms and the surface of silicone coatings is weak, so the attached organisms can be easily removed by mechanical cleaning or water shear force generated by ship navigation. However, traditional silicone-based antifouling materials have disadvantages such as low mechanical strength, weak adhesion to the substrate, poor static antifouling ability, and lack of self-healing ability. Therefore, their promotion and application are limited.

[0003] At present, many studies have modified it through relevant modification methods. For example, Liu et al. developed a PDMS-based polyurea with a PDMS soft segment and a 1,6-hexanediamine hard segment. The coating has an adhesion strength of up to 2Mpa, which significantly improves the bonding performance of the silicone coating and gives the coating self-healing properties, but it still does not have static antifouling ability. Dundua et al. introduced zwitterionic polymers into the PDMS matrix to improve its static antifouling ability and show low protein adsorption; however, the surface free energy (SFE) of PDMS is low, while the surface free energy (SFE) of zwitterionic polymers is high, resulting in the latter being trapped in the matrix and unable to fully exert its antifouling ability; at the same time, zwitterions increase the hydrophilicity of silicone, affect the swelling rate and modulus of the coating, thereby destroying the dirt release ability of silicone and reducing the mechanical properties; in addition, the incompatibility between highly polar zwitterionic materials and other non-polar building blocks can lead to phase segregation and also damage the mechanical properties.

[0004] Therefore, developing silicone coatings with good adhesion, static antifouling properties, self-healing ability, and low swelling rate is an urgent problem to be solved. Summary of the invention

[0005] To solve the above problems, the present invention provides a silicone polyurea containing self-generated zwitterions and a preparation method thereof. The present invention introduces urea bonds and zwitterion precursors containing fluorocarbon groups into silicone, and the obtained silicone polyurea containing self-generated zwitterions is used as a marine antifouling coating, which gives the coating excellent bonding properties, self-healing properties, static antifouling properties and low water absorption.

[0006] Firstly, one of the objects of the present invention is to provide a silicone polyurea containing self-generated zwitterions.

[0007] Specifically, the organic silicone polyurea containing self-generated zwitterions is derived from a dual-terminal carboxyl-functionalized poly-self-generated zwitterion polymer structural unit, a dual amino-terminated organic silicone structural unit and an isocyanate structural unit.

[0008] The general structural formula of the above-mentioned silicone polyurea is as follows:

[0009]

[0010] In the above general structural formula, the curved part is an alkyl group; the alkyl group is selected from one or a combination of straight chain, branched, and cyclic alkyl groups containing 1 to 20 carbon atoms, preferably one or a combination of straight chain, branched, and cyclic alkyl groups containing 3 to 10 carbon atoms; m=12 to 35, preferably m=25 to 32; n=1 to 5, preferably n=2 to 3; x=1 to 10, preferably x=1 to 5, and more preferably x=1 to 3.

[0011] Preferably, the molecular weight of the silicone polyurea containing self-generated zwitterions is greater than 10000 g·mol -1 ; preferably 12000 to 18000 g·mol -1 .

[0012] Preferably, the weight percentage of the dual-end carboxyl functionalized self-generated zwitterionic polymer in the silicone polyurea containing self-generated zwitterions is 5 to 40%, preferably 10 to 30%, and particularly preferably 15 to 20%.

[0013] It is worth mentioning that the present invention adopts a double-end carboxyl functionalized poly self-generated zwitterionic polymer as a functional monomer, and a double amino-terminated silicone and isocyanate as a matrix monomer, and introduces urea bonds and zwitterionic precursors containing carbon fluoride groups into the silicone. The urea bonds can form a large number of hydrogen bonds to give the silicone coating excellent adhesion properties and at the same time make it have self-healing properties; and the zwitterionic precursors containing carbon fluoride groups have lower surface free energy, can migrate to the surface during the film formation of the coating, and hydrolyze into zwitterions in a seawater environment to improve the static antifouling ability of the coating. At the same time, the zwitterionic precursors located in the coating matrix will not be hydrolyzed, so it will not cause changes in the matrix swelling ratio and modulus caused by traditional zwitterions, so that the coating matrix has a lower water absorption rate.

[0014] Furthermore, the dual-end carboxyl functionalized self-generated zwitterionic polymer is a homopolymer, the middle segment of its molecular chain is a self-generated zwitterionic structural unit containing a carbon fluoride group and a trisulfide carbonyl structural unit, and both ends of the molecular chain are capped by carboxyl groups. Its general structural formula is as follows:

[0015]

[0016] In the above general structural formula, the curved portion is one or a combination of straight-chain or branched alkyl groups containing 1 to 5 carbon atoms, preferably one or a combination of straight-chain or branched alkyl groups containing 2 to 3 carbon atoms, more preferably one or a combination of ethyl, propyl, and isopropyl; n=1 to 5, preferably n=2 to 3.

[0017] It is worth mentioning that the dual-end carboxyl functionalized self-generated zwitterionic homopolymer provided by the present invention can improve the static antifouling performance of the coating while maintaining certain mechanical properties after being introduced into polyurea.

[0018] Furthermore, the dual-end carboxyl functionalized self-generated zwitterionic polymer is derived from fluorocarbon-containing acrylic acid ester compounds and trithiocarbonic acid ester compounds.

[0019] Furthermore, the acrylate compound containing a fluorocarbon group is selected from TCBF, and its chemical name is 2-((3-((2,3,4,5,5,5-hexafluoro-2,4-bis(trifluoromethyl)pentyl)oxy)-3-oxopropyl)(methyl)amino)ethyl acrylate, and its specific structural formula is as follows:

[0020]

[0021] Furthermore, the preparation method of the fluorinated acrylic acid ester compound (TCBF) comprises the following steps:

[0022] Dodecafluoroheptyl acrylate (DFA) and methylaminoethanol are mixed and reacted at low temperature for a period of time, tetrahydrofuran and triethylamine are added, and then a tetrahydrofuran solution of acrylic acid chloride is added dropwise to continue the low temperature reaction to obtain a fluorinated carbon group-containing acrylic acid ester compound (TCBF).

[0023] Furthermore, the general structural formula of trithiocarbonate compounds is as follows:

[0024]

[0025] In the above general structural formula, the curved portion is one or a combination of straight-chain or branched alkyl groups containing 1 to 5 carbon atoms, preferably one or a combination of straight-chain or branched alkyl groups containing 2 to 3 carbon atoms, and more preferably one or a combination of ethyl, propyl, and isopropyl.

[0026] For example, 2,2'-[thiocarbonyl (sulfur)]bis[2-methylpropionic acid] (TSMA) (structural formula I), 2-((((2-carboxyethyl)thio)carbonylthio)thio)-2-methylpropionic acid (structural formula II), 3-(((1-carboxyethyl)thio)carbonylthio)thiopropionic acid (structural formula III), the specific structural formulas are as follows:

[0027]

[0028]

[0029] It is worth mentioning that trithiocarbonate compounds as chain transfer agents can control the reversible addition-fragmentation chain transfer polymerization of acrylate compounds containing carbon fluoride groups.

[0030] In a preferred embodiment of the present invention, the provided dual-end carboxyl functionalized self-generated zwitterionic polymer is obtained by reversible addition-fragmentation chain transfer polymerization of fluorinated acrylic acid ester compounds (TCBF) and trithiocarbonic acid ester compounds (TSMA), and its general structure is as follows:

[0031]

[0032] Furthermore, the degree of polymerization of the dual-end carboxyl functionalized self-generated zwitterionic polymer is 3 to 10, preferably 4 to 6; the number average molecular weight is 1300 to 5500 g.mol -1 , preferably 2300 to 3500 g·mol -1 ; The polydispersity index is 1.15~1.30.

[0033] Furthermore, the diamino-terminated organic silicon is selected from amino-terminated polydimethylsiloxane, and its general structural formula is as follows:

[0034]

[0035] In the above general structural formula, the curved portion is one or a combination of straight-chain or branched alkyl groups containing 1 to 5 carbon atoms, preferably one or a combination of ethyl and propyl groups.

[0036] Preferably, the number average molecular weight of the amino-terminated polydimethylsiloxane is 1500 to 3500 g·mol -1 , preferably 2000 to 2500 g·mol -1 .

[0037] Furthermore, the isocyanate is selected from one or a combination of isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), and dicyclohexylmethane diisocyanate (HMDI).

[0038] Secondly, the second object of the present invention is to provide a method for preparing the organosilicon polyurea containing self-generated zwitterions as one of the objects of the present invention.

[0039] Specifically, the method comprises the following steps:

[0040] Step 1: Under the protection of an inert gas, an acrylic acid ester compound containing a carbon fluoride group and a trithiocarbonate compound are mixed, and a reversible addition-fragmentation chain transfer polymerization reaction is carried out under light initiation to obtain a dual-end carboxyl functionalized self-generated zwitterionic polymer;

[0041] Step 2: dissolving the diamino-terminated organosilicon and the dicarboxyl-functionalized self-generated zwitterionic polymer in a solvent, adding an amide condensation agent for reaction, removing the precipitate, and then adding isocyanate for reaction to obtain organosilicon polyurea containing self-generated zwitterions.

[0042] Furthermore, the method comprises the following steps:

[0043] Step 1: Add fluorinated acrylate compounds, trithiocarbonate compounds, and dioxane filtered through a basic alumina column into a Schlenk tube. Degas the mixture through three "freeze-pump-thaw" cycles, and backfill with nitrogen to normal pressure. Then, place the mixture in a photoreactor to start polymerization under light. After the reaction is completed, precipitate the obtained polymer in n-hexane, and then redissolve it in tetrahydrofuran and repeat it three times. Then, dry it in a vacuum oven to remove the solvent, and obtain a dual-end carboxyl functionalized self-generated zwitterionic polymer.

[0044] Step 2: vacuum dry the diamino-terminated polydimethylsiloxane to remove water, and add it to a three-necked flask equipped with a magnet, a spherical condenser, a constant pressure dropping funnel and a nitrogen protection device. Then, the vacuum-dried double-end carboxyl-functionalized poly self-generated zwitterionic polymer is dissolved in tetrahydrofuran, and an amide condensation agent is added to the flask for pre-activation at room temperature. After the room temperature reaction is complete, the precipitate is removed, and then the isocyanate is dissolved in tetrahydrofuran and added dropwise into the three-necked flask to continue the room temperature reaction. After the reaction is complete, a silicone polyurea solution containing self-generated zwitterions is obtained.

[0045] Furthermore, in step one, the polymerization reaction is carried out in a Schlenk tube; the wavelength of the light is 450 nm; the molar ratio of the fluorocarbon group-containing acrylic acid ester compound to the trithiocarbonate compound is 2.2:1 to 16.5:1, preferably 5.5:1 to 11:1.

[0046] Furthermore, in step 2, the molar ratio of the diamino-terminated silicone, the dicarboxyl-functionalized polyzwitterionic polymer, and the isocyanate is 10:0.5-8:0.5-12; preferably 10:1-5:5-9.

[0047] Furthermore, in step 2, the amide condensation agent is selected from a combination of 4-dimethylaminopyridine (DMAP) and N,N'-dicyclohexylcarbocyanine (DCC), and the amount thereof is adjusted according to the amount of raw materials.

[0048] It is worth mentioning that the present invention can prepare different silicone polyureas containing self-generated zwitterions by changing the molecular weight of the bis-amino-terminated polydimethylsiloxane, the degree of polymerization and the content of the dual-terminal carboxyl-functionalized poly self-generated zwitterionic polymer.

[0049] Finally, the third object of the present invention is to provide the application of the silicone polyurea containing self-generated zwitterions as one of the objects of the present invention.

[0050] The organosilicon polyurea containing self-generated zwitterions, which is one of the purposes of the present invention, has good adhesion performance and static antifouling performance to the substrate; at the same time, it has certain self-healing performance and low water absorption rate, and can be used in marine antifouling coatings.

[0051] Furthermore, the method of using the silicone polyurea containing self-generated zwitterions as a coating is as follows:

[0052] The prepared organosilicon polyurea solution or reaction liquid containing self-generated zwitterions is applied to the surface of an object (such as a ship hull), and a coating is obtained after the solvent is removed (such as volatilized or dried).

[0053] Compared with the prior art, the beneficial effects of the present invention are:

[0054] The present invention performs double-end carboxyl functionalization on the self-generated zwitterions containing fluorocarbon groups through RAFT polymerization, and introduces them into the organosilicon polyurea system. The urea bonds can form a large number of hydrogen bonds, which can significantly improve the adhesion of organosilicon on the glass fiber reinforced epoxy resin board, and at the same time make the organosilicon have room temperature self-repairing performance, and the room temperature 24h self-repairing efficiency is between 28 and 40%, while retaining the advantages of low surface free energy of organosilicon, and the simulated barnacle removal strength close to that of unmodified PDMS. Since the introduced self-generated zwitterions containing fluorocarbon groups have low surface free energy, they can migrate to the coating surface during film formation, reducing the proportion trapped in the matrix, and the self-generated zwitterions migrated to the coating surface will be hydrolyzed into zwitterions in seawater, improving the static antifouling ability of the coating, and the self-generated zwitterions located in the matrix will not be hydrolyzed, so it will not cause changes in the swelling ratio and modulus of the matrix, and has a low water absorption rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 The schematic diagram of the reaction for preparing the dual-terminal carboxyl functionalized self-generated zwitterionic polymers of Examples 5 to 7 of the present invention;

[0056] Figure 2 This is a hydrogen nuclear magnetic resonance spectrum of the dual-end carboxyl functionalized self-generated zwitterionic polymer prepared in Example 5 of the present invention;

[0057] Figure 3The hydrogen nuclear magnetic resonance spectra of the dual-end carboxyl functionalized poly self-generated zwitterionic polymer prepared in Example 5 of the present invention before and after hydrolysis;

[0058] Figure 4 The gel permeation test spectra of the dual-end carboxyl functionalized self-generated zwitterionic polymers prepared in Examples 5 to 7 of the present invention;

[0059] Figure 5 This is a flow chart of the reaction for preparing a silicone polyurea containing self-generated zwitterions in Example 8 of the present invention;

[0060] Figure 6 The gel permeation test spectra corresponding to the polymer raw materials, reaction intermediates and products used in preparing the organosilicon polyurea containing self-generated zwitterions in Example 9 of the present invention;

[0061] Figure 7 The stress-strain curves of the silicone polyurea coatings containing self-generated zwitterions prepared in Examples 8 to 11 of the present invention and Comparative Example 1;

[0062] Figure 8 It is a strength diagram of removing simulated barnacles from the organic silicon polyurea coating containing self-generated zwitterions prepared and hydrolyzed in Examples 8 to 11 of the present invention and Comparative Example 1;

[0063] Fig. 9 The water contact angle of the organosilicon polyurea coating containing self-generated zwitterions prepared in Examples 8 to 10 of the present invention in artificial seawater changes with time;

[0064] Fig.10 The infrared comparison diagram of the organosilicon polyurea coating containing self-generated zwitterions prepared in Examples 8 to 10 of the present invention before and after hydrolysis;

[0065] Fig.11 The water absorption rate of the organic silicon polyurea coating containing self-generated zwitterions prepared in Examples 8 to 10 of the present invention after hydrolysis changes with time;

[0066] Fig.12 This is a graph showing the bonding strength of the silicone polyurea coating containing self-generated zwitterions prepared in Examples 8 to 10 of the present invention on a glass fiber reinforced epoxy resin board;

[0067] Fig.13 The stress-strain comparison curves of the organosilicon polyurea coating containing self-generated zwitterions prepared in Examples 8 to 10 of the present invention before and after self-repairing;

[0068] Fig.14 This is a laser confocal scanning micrograph of the organosilicon polyurea coating containing self-generated zwitterions prepared in Examples 8 to 10 of the present invention after hydrolysis;

[0069] Fig.15This is a graph of the relative sedimentation rate of the silicone polyurea coating containing self-generated zwitterions prepared in Examples 8 to 10 of the present invention after hydrolysis. DETAILED DESCRIPTION

[0070] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0071] In the following examples and comparative examples, the raw materials are all from commercially available products, as shown in Table 1:

[0072] Table 1:

[0073]

[0074]

[0075] Example 1

[0076] This example is used to illustrate the preparation of trithiocarbonate compound 2,2'-[thiocarbonyl (sulfur)]bis[2-methylpropionic acid] (TSMA), and the specific preparation method is as follows:

[0077] Under nitrogen environment, carbon disulfide (27.4g, 0.36mol), chloroform (107.5g, 0.9mol), acetone (52.3g, 0.9mol) and tetrabutylammonium hydrogen sulfate (2.41g, 7.1mmol) were mixed with 120ml petroleum ether, added to a 2L round-bottom flask, and cooled with water; sodium hydroxide solution (50%wt) (201.6g, 2.52mol) was added dropwise within 90 minutes, and the temperature was kept below 25°C and stirred overnight; 900ml of water was added to the reaction solution to dissolve the solid, and then 120mL of concentrated hydrochloric acid was added to acidify the aqueous layer, and stirred for 30 minutes under nitrogen purge; the solid product was filtered and thoroughly rinsed with water, dried to constant weight, and 41.3 grams of earthy product were collected.

[0078] The product was further purified by stirring in toluene / acetone (v / v=4 / 1) to obtain a yellow crystalline solid product.

[0079] Example 2

[0080] This example is used to illustrate the preparation of the trithiocarbonate compound 2-((((2-carboxyethyl)sulfur)carbonylsulfuryl)sulfur)-2-methylpropionic acid. The specific preparation method is as follows:

[0081] 3-Mercaptopropionic acid (10.6 g, 0.1 mol), deionized water (100 mL) and 50 wt% NaOH solution (16.0 g, 0.2 mol) were added to a 250 mL round-bottom flask equipped with a magnetic stirring bar. After stirring for 0.5 h, carbon disulfide (6.0 mL, 0.1 mol) was added dropwise, and the resulting yellow solution was stirred at 25 ° C overnight. Chloroform (29.9 g, 0.25 mol) and acetone (16.8 g, 0.3 mol) were then added, and 50 wt% NaOH solution (60.0 g, 0.75 mol) was added dropwise, and a small amount of tetrabutylammonium hydrogen sulfate was added to help phase transfer, and the mixture was stirred at 25 ° C overnight. After the reaction was completed, the mixture was acidified with concentrated hydrochloric acid, and then the product was filtered to obtain a precipitate, washed with deionized water, and then dried in a vacuum drying oven at 60 ° C to constant weight. Recrystallization in acetone gave a pure product.

[0082] Example 3

[0083] This example is used to illustrate the preparation of the trithiocarbonate compound 3-(((1-carboxyethyl)thio)carbonylthio)thiopropionic acid. The specific preparation method is as follows:

[0084] 3-Mercaptopropionic acid (10.6 g, 0.1 mol), deionized water (100 mL) and 50 wt% NaOH solution (16.0 g, 0.2 mol) were added to a 250 mL round-bottom flask equipped with a magnetic stirring bar. After stirring for 0.5 h, carbon disulfide (6.0 mL, 0.1 mol) was added dropwise, and the resulting yellow solution was stirred overnight at 25 ° C. Subsequently, 2-bromopropionic acid (15.3 g, 0.1 mol) was added dropwise to the yellow solution, and the mixture was stirred overnight at 25 ° C. Concentrated hydrochloric acid was added to acidify the reaction mixture, and the product was filtered to obtain a precipitate, which was washed with deionized water and then dried in a vacuum drying oven at 60 ° C to constant weight to obtain a pure product.

[0085] Example 4

[0086] This example is used to illustrate the preparation of 2-((3-((2,3,4,5,5,5-hexafluoro-2,4-bis(trifluoromethyl)pentyl)oxy)-3-oxopropyl)(methyl)amino)ethyl acrylate (TCBF), a fluorinated acrylate compound. The specific preparation method is as follows:

[0087] Under ice-water bath conditions, 10.0 g of dodecafluoroheptyl acrylate (DFA) was added to a 100 mL three-necked flask equipped with a constant pressure dropping funnel and a magnet, and then 1.94 g of methylaminoethanol was added to react for 3 hours; 45 mL of tetrahydrofuran (THF) and 2.62 g of triethylamine (TEA) were added to the reaction solution, and under ice-water bath conditions, 2.36 g of acrylic acid chloride dissolved in 15 ml of THF was added to the constant pressure dropping funnel dropwise into the round-bottom flask and continued to react for 3 hours; the white precipitate was removed by filtration, the solvent was removed by rotary evaporation, the obtained liquid was dissolved in ethyl acetate, and extracted three times with a saturated sodium chloride solution; the extracted liquid was dried over anhydrous sodium sulfate, filtered, rotary evaporated, and dried in a vacuum oven at 60°C for 24 hours to obtain a transparent oily product.

[0088] Example 5

[0089] This example is used to illustrate the preparation of a dual-end carboxyl functionalized self-generated zwitterionic polymer, and the specific preparation method is as follows:

[0090] 13.5mmol TCBF monomer, 2.44mmol TSMA, and 14ml dioxane filtered through an alkaline alumina column were added to a Schlenk tube. It was frozen with liquid nitrogen, degassed through three "freeze-pump-thaw" cycles, and backfilled with nitrogen to normal pressure, and then placed in a photoreactor and polymerized at a wavelength of 450nm for 8h. After the reaction, the resulting polymer was precipitated in n-hexane and then redissolved in tetrahydrofuran, and the unreacted monomers were removed by repeating three times. After that, the solvent was removed by drying at 60°C in a vacuum oven for 24h to obtain a dual-end carboxyl functionalized poly self-generated zwitterionic polymer (PTCBF), and the degree of polymerization DP=5 was calculated based on the nuclear magnetic resonance hydrogen spectrum.

[0091] Figure 1 A schematic diagram of the reaction in this example is shown.

[0092] Figure 2 The hydrogen nuclear magnetic resonance spectrum of the dual-end carboxyl functionalized self-generated zwitterionic polymer prepared in this example is shown.

[0093] Figure 3 The hydrogen nuclear magnetic resonance spectra of the dual-end carboxyl functionalized poly self-generated zwitterionic polymer prepared in this example before and after hydrolysis are shown.

[0094] Depend on Figure 2 It can be seen that the present invention prepares a dual-end carboxyl functionalized poly self-generated zwitterionic polymer (PTCBF).

[0095] Depend on Figure 3It can be seen that peaks h and g disappeared after hydrolysis, indicating that the ester bond connected to the carbon fluoride group was successfully hydrolyzed to generate zwitterions; while peak b did not disappear, indicating that the ester bond far away from the carbon fluoride group was not hydrolyzed, further proving that zwitterions can be generated.

[0096] Example 6

[0097] This example is used to illustrate the preparation of a dual-end carboxyl functionalized self-generated zwitterionic polymer, and the specific preparation method is as follows:

[0098] 13.5mmol TCBF monomer, 1.22mmol TSMA, and 14ml dioxane filtered through a basic alumina column were added to a Schlenk tube. It was frozen with liquid nitrogen, degassed through three "freeze-pump-thaw" cycles, and backfilled with nitrogen to normal pressure, and then placed in a photoreactor and polymerized at a wavelength of 450nm for 8h. After the reaction, the resulting polymer was precipitated in n-hexane and then redissolved in tetrahydrofuran, and the unreacted monomers were removed three times. After that, the solvent was removed by drying at 60°C in a vacuum oven for 24h to obtain a dual-end carboxyl functionalized poly self-generated zwitterionic polymer (PTCBF) (DP=10).

[0099] Example 7

[0100] This example is used to illustrate the preparation of a dual-end carboxyl functionalized self-generated zwitterionic polymer, and the specific preparation method is as follows:

[0101] 13.5mmol TCBF monomer, 6.1mmol TSMA, and 14ml dioxane filtered through a basic alumina column were added to a Schlenk tube. It was frozen with liquid nitrogen, degassed through three "freeze-pump-thaw" cycles, and backfilled with nitrogen to normal pressure, and then placed in a photoreactor and polymerized at a wavelength of 450nm for 8h. After the reaction, the resulting polymer was precipitated in n-hexane and then redissolved in tetrahydrofuran, and the unreacted monomers were removed three times. After that, the solvent was removed at 60°C in a vacuum oven to obtain a dual-end carboxyl functionalized poly self-generated zwitterionic polymer (PTCBF) (DP=2).

[0102] Figure 4 The gel permeation chromatograms of the dual-end carboxyl functionalized self-generated zwitterionic polymer PTCBF prepared in Examples 5 to 7 are shown.

[0103] Depend on Figure 4 The molecular weight and dispersion index of the polymers provided in Examples 5 to 7 were obtained, as shown in Table 2.

[0104] Table 2:

[0105] Example Mn (calculated by GPC) PDI 5 <![CDATA[2940g·mol -1 ]]> 1.295 6 <![CDATA[5000g·mol -1 ]]> 1.294 7 <![CDATA[1650g·mol -1 ]]> 1.17

[0106] It can be seen from Table 2 that with the increase of feed ratio, the molecular weight increases, proving that PTCBF is obtained; at the same time, with the increase of feed ratio, the GPC peak position shifts to the left and has a lower polydispersity index, proving that with the increase of feed ratio, the degree of polymerization increases, and proving that the reaction is a reversible addition-fragmentation chain transfer polymerization.

[0107] Example 8

[0108] This example is used to illustrate the preparation of a silicone polyurea coating containing self-generated zwitterions. The specific preparation method is as follows:

[0109] 0.832 mmol ART-PDMS (Mn = 2500 g.mol -1 ) was dried under vacuum at 110°C for 2h, and then added to a 100mL three-necked flask with a magnet, a spherical condenser, a constant pressure dropping funnel and a nitrogen protection device. 0.087mmol of PTCBF (DP=5) prepared in Example 5 was dissolved in 5ml of tetrahydrofuran, and 0.017mmol of DMAP and 0.182mmol of DCC were added. After pre-activation at 25°C for 0.5h, the mixture was added to the flask. After the reaction was maintained at 25°C for 3h, the precipitate was removed. Then, 0.819mmol of isophorone diisocyanate (IPDI) was dissolved in 5ml of tetrahydrofuran and added dropwise to the three-necked flask to continue the reaction at 25°C for 3h. After the reaction was completed, the reaction solution was poured into a polytetrafluoroethylene mold, first placed at room temperature for 12h, and then cured in a vacuum oven at 60°C for 24h to obtain a coating named PTCBF-PU2500-5-10 with a molecular weight of 15600g·mol -1 .

[0110] In the above coating, the mass fraction of the dual-terminal carboxyl functionalized self-generated zwitterionic polymer is 10%wt.

[0111] Figure 5 A flow chart showing the reaction process of this example is shown.

[0112] Example 9

[0113] This example is used to illustrate the preparation of a silicone polyurea coating containing self-generated zwitterions. The specific preparation method is as follows:

[0114] 0.748 mmol ART-PDMS (Mn = 2500 g.mol -1) was dried under vacuum at 110°C for 2h, and then added to a 100mL three-necked flask with a magnet, a spherical condenser, a constant pressure dropping funnel and a nitrogen protection device. 0.175mmol of PTCBF (DP=5) prepared in Example 5 was dissolved in 5ml of tetrahydrofuran, and 0.035mmol of DMAP and 0.367mmol of DCC were added. After pre-activation at 25°C for 0.5h, it was added to the flask. After keeping the temperature at 25°C for 3h, the precipitate was removed. Then, 0.630mmol of isophorone diisocyanate (IPDI) was dissolved in 5ml of tetrahydrofuran and added dropwise to the three-necked flask to continue to react at 25°C for 3h. After the reaction was completed, the reaction solution was poured into a polytetrafluoroethylene mold, first placed at room temperature for 12h, and then cured in a vacuum oven at 60°C for 24h to obtain a coating named PTCBF-PU2500-5-20 with a molecular weight of 15400g·mol -1 .

[0115] In the above coating, the mass fraction of the dual-end carboxyl functionalized self-generated zwitterionic polymer is 20 wt%.

[0116] Figure 6 The gel permeation test spectra of the polymer raw materials, intermediates and products used in the preparation of the silicone polyurea containing self-generated zwitterions in this embodiment are shown.

[0117] Depend on Figure 6 It can be seen that the GPC peak positions corresponding to the intermediates and the final products produced during the preparation process are shifted to the left compared to the GPC peak positions of the raw materials, proving that the molecular weight of the intermediates and the final products increases, indicating that the reaction has occurred successfully.

[0118] Example 10

[0119] This example is used to illustrate the preparation of a silicone polyurea coating containing self-generated zwitterions. The specific preparation method is as follows:

[0120] 0.664 mmol ART-PDMS (Mn = 2500 g.mol -1) was dried under vacuum at 110°C for 2h, and then added to a 100mL three-necked flask with a magnet, a spherical condenser, a constant pressure dropping funnel and a nitrogen protection device. 0.262mmol of PTCBF (DP=5) prepared in Example 5 was dissolved in 5ml of tetrahydrofuran, and 0.052mmol of DMAP and 0.550mmol of DCC were added. After pre-activation at 25°C for 0.5h, the mixture was added to the flask. After the reaction was maintained at 25°C for 3h, the precipitate was removed. Then, 0.442mmol of isophorone diisocyanate (IPDI) was dissolved in 5ml of tetrahydrofuran and added dropwise to the three-necked flask. The reaction was continued at 25°C for 3h. After the reaction was completed, the reaction solution was poured into a polytetrafluoroethylene mold, first placed at room temperature for 12h, and then cured in a vacuum oven at 60°C for 24h to obtain a coating named PTCBF-PU2500-5-30 with a molecular weight of 15800g·mol -1 .

[0121] In the above coating, the mass fraction of the dual-end carboxyl functionalized self-generated zwitterionic polymer is 30%wt.

[0122] Embodiment 11

[0123] This example is used to illustrate the preparation of a silicone polyurea coating containing self-generated zwitterions. The specific preparation method is as follows:

[0124] 0.433 mmol ART-PDMS (Mn = 2500 g.mol -1 ) was dried under vacuum at 110°C for 2h, and then added to a 100mL three-necked flask with a magnet, a spherical condenser, a constant pressure dropping funnel and a nitrogen protection device. 0.092mmol of PTCBF (DP=10) prepared in Example 6 was dissolved in 10ml of tetrahydrofuran, and 0.018mmol of DMAP and 0.193mmol of DCC were added. After pre-activation at 25°C for 0.5h, the mixture was added to the flask. The reaction was maintained at 25°C for 3h and the precipitate was removed. Then, 0.375mmol of isophorone diisocyanate (IPDI) was dissolved in 10ml of tetrahydrofuran and added dropwise to the three-necked flask. The reaction was continued at 25°C for 3h. After the reaction was completed, the reaction solution was poured into a polytetrafluoroethylene mold, first placed at room temperature for 12h, and then cured in a vacuum oven at 60°C for 24h to obtain a coating named PTCBF-PU2500-10-20.

[0125] In the above coating, the mass fraction of the dual-end carboxyl functionalized self-generated zwitterionic polymer is 20 wt%.

[0126] Comparative Example 1

[0127] This example is used to illustrate the preparation of a silicone polyurea coating containing self-generated zwitterions. The specific preparation method is as follows:

[0128] 1.66 mmol ART-PDMS (Mn = 1000 g.mol -1 ) was dried under vacuum at 110°C for 2h, and then added to a 100mL three-necked flask with a magnet, a spherical condenser, a constant pressure dropping funnel and a nitrogen protection device. 0.175mmol of PTCBF (DP=5) prepared in Example 5 was dissolved in 5ml of tetrahydrofuran, and 0.035mmol of DMAP and 0.367mmol of DCC were added. After pre-activation at 25°C for 0.5h, the mixture was added to the flask. The reaction was maintained at 25°C for 3h and the precipitate was removed. Then 1.633mmol of isophorone diisocyanate (IPDI) was dissolved in 5ml of tetrahydrofuran and added dropwise to the three-necked flask. The reaction was continued at 25°C for 3 hours. After the reaction was completed, the reaction solution was poured into a polytetrafluoroethylene mold, first placed at room temperature for 12h, and then cured in a vacuum oven at 60°C for 24h to obtain a coating named PTCBF-PU1000-5-20.

[0129] In the above coating, the mass fraction of the dual-terminal carboxyl functionalized self-generated zwitterionic polymer is 20%wt.

[0130] Comparative Example 2

[0131] This example is used to illustrate the preparation of a silicone polyurea coating containing self-generated zwitterions. The specific preparation method is as follows:

[0132] 0.764 mmol ART-PDMS (Mn = 2500 g.mol -1 ) was dried under vacuum at 110°C for 2h, and then added to a 100mL three-necked flask with a spherical condenser, a constant pressure dropping funnel and a nitrogen protection device. 0.381mmol of PTCBF (DP=2) prepared in Example 7 was dissolved in 5ml of tetrahydrofuran, and 0.076mmol of DMAP and 0.800mmol of DCC were added. After pre-activation at 25°C for 0.5h, the mixture was added to the flask. The reaction was maintained at 25°C for 3h and the precipitate was removed. Then, 0.421mmol of 1-isophorone diisocyanate (IPDI) was dissolved in 5ml of tetrahydrofuran and added dropwise to the three-necked flask. The reaction was continued at 25°C for 3h. After the reaction was completed, the reaction solution was poured into a polytetrafluoroethylene mold, first placed at room temperature for 12h, and then cured in a vacuum oven at 60°C for 24h to obtain a coating named PTCBF-PU2500-2-20.

[0133] In the above coating, the mass fraction of the dual-end carboxyl functionalized self-generated zwitterionic polymer is 20 wt%.

[0134] Figure 7The stress-strain curves of the silicone polyurea coatings containing self-generated zwitterions prepared in Examples 8 to 11 and Comparative Example 1 are shown.

[0135] Depend on Figure 7 It can be seen that the coatings prepared in Examples 8 to 11 and Comparative Example 1 have good mechanical properties. However, the silicone polyurea containing self-generated zwitterions prepared in Comparative Example 2 cannot form a film due to its low mechanical strength and cannot be used as a coating. When preparing the silicone polyurea containing self-generated zwitterions in Comparative Example 2, PTCBF (DP=2) prepared in Example 7 was used to modify the polyurea. Due to its low degree of polymerization and low molecular weight, when the content of PTCBF in the polyurea reaches 20%wt, a large amount of PTCBF is required. The mechanical strength of the polyurea coating mainly depends on the hydrogen bonds formed by the urea bonds. The increase in the amount of PTCBF will react with more amino groups to form amide bonds, reducing the content of urea bonds. Therefore, its mechanical strength is low and it cannot form a film as a coating.

[0136] Figure 8 The strength of removing simulated barnacles on the silicone polyurea coating containing self-generated zwitterions prepared and hydrolyzed in Examples 8 to 11 and Comparative Example 1 is shown.

[0137] Depend on Figure 8 It can be seen that the coating prepared in comparative example 1 requires the highest strength to remove simulated barnacles, and the coating prepared in example 10 requires a strength of 0.25Mpa to remove simulated barnacles, which is very close to 0.2Mpa of PDMS. This is because the ART-PDMS used in comparative example 1 has a lower molecular weight and will form more urea bonds. Urea bonds, as polar groups, will increase the surface free energy of the coating and form hydrogen bonds with the surface of the simulated barnacles to increase the removal strength. The strength required to remove simulated barnacles from the coatings prepared in examples 8 to 10 gradually decreases. This is because the content of PTCBF in the coatings of examples 8 to 10 increases successively, replacing part of the urea bonds with amide bonds, reducing the content of urea bonds, reducing the surface free energy of the coating, and forming fewer hydrogen bonds, which is beneficial to the removal of simulated barnacles. At the same time, the increase in PTCBF content will also reduce the elastic modulus of the coating surface (caused by Figure 7 It can be seen that a lower surface elastic modulus is more conducive to the removal of simulated barnacles; and the strength required for the coating prepared in Example 11 to remove simulated barnacles is higher than that in Example 9. This is because the PTCBF used in Example 11 has a high degree of polymerization, which will produce more obvious microphase separation when forming the coating, resulting in an increase in surface roughness. The increase in surface roughness is not conducive to the removal of simulated barnacles, so the removal strength of the simulated barnacles is slightly increased.

[0138] Fig. 9 The graphs showing the change of water contact angles of the organosilicon polyurea coatings containing self-generated zwitterions prepared in Examples 8 to 10 in artificial seawater over time are shown.

[0139] Depend on Fig. 9 It can be seen that the water contact angle of the coating prepared in Examples 8 to 10 in artificial seawater gradually decreases and tends to be stable after 3 days, proving that the self-generated zwitterions in the coating are successfully hydrolyzed to produce zwitterions, and are completely hydrolyzed after 3 days. In addition, as the content of PTCBF in Examples 8 to 10 increases, the hydrolysis angle decreases more significantly. However, even the water contact angle of Example 10 after complete hydrolysis is greater than 100°, proving that it has a lower surface free energy and is more conducive to the release of contamination.

[0140] Fig.10 The infrared contrast images of the organosilicon polyurea coating containing self-generated zwitterions prepared in Examples 8 to 10 before and after hydrolysis are shown.

[0141] Depend on Fig.10 It can be seen that after the hydrolysis of the organosilicon polyurea coatings prepared in Examples 8 to 10, the -1 The peak intensity at 1560 cm-1 decreased, proving the hydrolysis of the ester bond. The peak intensity decreased more significantly with the increase of PTCBF content. -1 The increase in peak intensity at COO - The generation of zwitterions, and with the increase of PTCBF content, the peak intensity increases more significantly. The generated zwitterions can improve the static antifouling ability of the coating.

[0142] Fig.11 The water absorption curves of the organic silicon polyurea coatings containing self-generated zwitterions prepared in Examples 8 to 10 after hydrolysis are shown as a function of time.

[0143] Depend on Fig.11 It can be seen that the water absorption rate of the coatings prepared in Examples 8 to 10 after hydrolysis tends to be stable after 4 days, and even the water absorption rate of the coating containing 30wt% PTCBF is not high, only 10%. This is because the water absorption rate of the coating after hydrolysis is related to the PTCBF content. The zwitterions produced after the hydrolysis of PTCBF have strong hydration. Therefore, with the increase of PTCBF content, the water absorption rate of the coating gradually increases. However, since most of the zwitterions are on the surface of the coating, the self-generated zwitterions in the matrix will not be hydrolyzed, so it will not cause the matrix to swell, which can effectively prevent the problem of serious water absorption and keep the water absorption rate of the coating low.

[0144] Fig.12 The graphs show the bonding strength of the silicone polyurea coatings containing self-generated zwitterions prepared in Examples 8 to 10 on the glass fiber reinforced epoxy resin board.

[0145] Depend on Fig.12It can be seen that the bonding strength of the coatings prepared in Examples 8 to 10 on the glass fiber reinforced epoxy resin board is greater than 1 MPa, and can be used as antifouling coatings. The urea bonds in the coatings prepared in Examples 8 to 10 interact with the epoxy resin board to improve the bonding strength of the coatings, so that the coatings meet the requirements of marine antifouling coatings.

[0146] Fig.13 The stress-strain curves of the organosilicon polyurea coatings containing self-generated zwitterions prepared in Examples 8 to 10 before and after self-repair are shown.

[0147] Depend on Fig.13 It can be seen that the coatings prepared in Examples 8 to 10 have certain room temperature self-healing properties. On the one hand, the coatings introduce zwitterionic precursors containing carbon fluoride groups, which make the coatings have a lower elastic modulus, and the chain segments are more easily migrated at room temperature, so that the coatings have better self-healing ability at room temperature; on the other hand, the coatings have an appropriate amount of urea bonds, which can reconstruct sufficient hydrogen bonds for self-healing, so that the coatings maintain good self-healing properties.

[0148] The self-repairing efficiency of the coatings prepared in Examples 8 to 10 after 24 hours is shown in Table 3, where self-repairing efficiency = (fracture strength of the strip after self-repairing / fracture strength of the original strip)*100%.

[0149] Table 3:

[0150] Example Self-healing efficiency 8 28％ 9 36％ 10 30％

[0151] Fig.14 Laser confocal scanning micrographs showing the sedimentation of Pseudomonas aeruginosa onto the PDMS coating and the silicone polyurea coating containing self-generated zwitterions prepared in Examples 8-10.

[0152] Fig.15 The relative sedimentation rate of Pseudomonas aeruginosa on the PDMS coating and the organic silicon urea coating containing self-generated zwitterions prepared in Examples 8 to 10 is shown.

[0153] Depend on Fig.14 and 15 It can be seen that the coatings prepared in Examples 8 to 10 have strong hydration due to the presence of zwitterions, and can form a hydration layer on the surface of the coating to hinder the adhesion of bacteria, so they have excellent antibacterial adhesion properties. After the coatings prepared in Examples 8 to 10 are hydrolyzed, the presence of zwitterions significantly improves the antibacterial adhesion properties, and the antibacterial adhesion properties are enhanced with the increase of PTCBF content. Among them, Examples 9 and 10 can reach 92% and 93% antibacterial adhesion rates respectively, have excellent antibacterial adhesion properties, and have good static antifouling ability.

[0154] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A silicone polyurea containing self-generated zwitterions, comprising structural units derived from a dual-terminal carboxyl-functionalized poly self-generated zwitterion polymer, structural units of a diamino-terminated silicone and isocyanate structural units.

2. The organosilicon polyurea containing self-generated zwitterions according to claim 1, characterized in that: The general structural formula of the organic silicon polyurea containing self-generated zwitterions is as follows: Among them, the curved part represents the alkyl group; Preferably, the alkyl group is selected from one or a combination of linear, branched, and cyclic alkyl groups containing 1 to 20 carbon atoms; More preferably, the alkyl group is selected from one or a combination of linear, branched, and cyclic alkyl groups containing 3 to 10 carbon atoms; and / or, m = 12 to 35, preferably m = 25 to 32; and / or, n = 1 to 5, preferably n = 2 to 3; and / or, x=1-10, preferably x=1-5, more preferably x=1-3.

3. The organosilicon polyurea containing self-generated zwitterions according to claim 1, characterized in that: The molecular weight of the organic silicon polyurea containing self-generated zwitterions is greater than 10000 g·mol -1 ; preferably 12000 to 18000 g·mol -1 and / or, The weight percentage of the dual-end carboxyl functionalized self-generated zwitterionic polymer in the self-generated zwitterion-containing silicone polyurea is 5 to 40%, preferably 10 to 30%, and particularly preferably 15 to 20%.

4. The organosilicon polyurea containing self-generated zwitterions according to claim 1, characterized in that: The dual-end carboxyl functionalized self-generated zwitterionic polymer is a homopolymer, the middle segment of its molecular chain is a self-generated zwitterionic structural unit containing a carbon fluoride group and a trisulfide carbonyl structural unit, and both ends of the molecular chain are capped by carboxyl groups. Its general structural formula is as follows: The curved portion is one or a combination of straight-chain or branched alkyl groups containing 1 to 5 carbon atoms, preferably one or a combination of straight-chain or branched alkyl groups containing 2 to 3 carbon atoms; and / or, n=1-5, preferably n=2-3.

5. The organosilicon polyurea containing self-generated zwitterions according to claim 4, characterized in that: The dual-end carboxyl functionalized self-generated zwitterionic polymer is derived from fluorinated acrylate compounds and trithiocarbonate compounds; The acrylate compound containing a fluorocarbon group is selected from TCBF, and its structural formula is as follows: and / or, The general structural formula of the trithiocarbonate compound is as follows: In the general structural formula of the trithiocarbonate compound, the curved portion is one or a combination of straight-chain or branched alkyl groups containing 1 to 5 carbon atoms, preferably one or a combination of straight-chain or branched alkyl groups containing 2 to 3 carbon atoms, and more preferably one or a combination of ethyl, propyl, and isopropyl.

6. The organosilicon polyurea containing self-generated zwitterions according to claim 4, characterized in that: The dual-end carboxyl functionalized self-generated zwitterionic polymer has a degree of polymerization of 3 to 10, preferably 4 to 6; and a number average molecular weight of 1800 to 5500 g.mol -1 , preferably 2300 to 3500 g·mol -1 ; The polydispersity index is 1.15~1.

30.

7. The organosilicon polyurea containing self-generated zwitterions according to claim 1, characterized in that: The diamino-terminated organic silicon is selected from amino-terminated polydimethylsiloxane, and its general structural formula is as follows: The curved portion is one or a combination of straight-chain or branched alkyl groups containing 1 to 5 carbon atoms, preferably one or a combination of ethyl and propyl groups; Preferably, the number average molecular weight of the amino-terminated polydimethylsiloxane is 1500 to 3500 g·mol -1 , preferably 2000 to 2500 g·mol -1 .

8. The organosilicon polyurea containing self-generated zwitterions according to claim 1, characterized in that: The isocyanate is selected from one or a combination of isophorone diisocyanate, hexamethylene diisocyanate and dicyclohexylmethane diisocyanate.

9. The method for preparing the organosilicon polyurea containing self-generated zwitterions according to any one of claims 1 to 8, comprising the following steps: Step 1: Under the protection of an inert gas, an acrylic acid ester compound containing a carbon fluoride group and a trithiocarbonate compound are mixed, and a reversible addition-fragmentation chain transfer polymerization reaction is carried out under light initiation to obtain a dual-end carboxyl functionalized self-generated zwitterionic polymer; Step 2: dissolving the diamino-terminated organosilicon and the double-terminal carboxyl-functionalized poly spontaneous zwitterionic polymer in a solvent, adding an amide condensation agent to react, removing the precipitate, and then adding isocyanate to react to obtain the organosilicon polyurea containing spontaneous zwitterions.

10. Use of the organosilicon polyurea containing self-generated zwitterions according to any one of claims 1 to 8, wherein the polymer is used in marine antifouling coatings.

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