Fluorine-containing modified organic polysilazane as well as preparation method and application thereof

Abstract

The invention discloses fluorine-containing modified organic polysilazane as well as a preparation method and application thereof. Organic polysilazane and a fluorine-containing alcohol monomer are subjected to alcoholysis reaction to prepare the fluorine-containing modified organic polysilazane. Fluorine-containing modified organic polysilazane and the surface of a base material are combined together through chemical bonds to form a firmly combined protective film, and a fluorine-containing polysilazane coating formed by hydrolysis in air has the effects of hydrophobicity, high and low temperature resistance, scratch resistance, rain prevention, fog prevention and self-cleaning.

Description

Technical Field

[0001] The invention relates to a fluorine-containing modified organic polysilazane, in particular to a fluorine-containing alcohol monomer modified organic polysilazane and a preparation method and application thereof; and belongs to the technical field of polymer preparation. Background Art

[0002] Polysilazane, a polymer whose main chain is composed of Si-N bonds, is an important precursor for preparing Si-C-N ceramics. The bond angle difference between Si and N atoms (Δθ=23°) is smaller than the bond angle difference between Si and O atoms (Δθ=36°), so compared with polysiloxane, it has a smaller tendency to form a ring and is easy to change substituents. In addition, the large number of Si-N bonds in the molecular structure of polysilazane are prone to hydrolysis reactions, and eventually form a stable Si-O-Si structure with -OH on the surface of the substrate, so that the cured polysilazane coating has excellent adhesion to the substrate and has excellent anchoring properties. Therefore, polysilazane, as a ceramic precursor, can be used to construct a coating with excellent heat resistance, chemical corrosion resistance, weather resistance, scratch resistance, transparency and other characteristics, thereby giving the polysilazane coating excellent performance and a longer service life.

[0003] However, most polysilazane molecules only contain a small amount of hydrophobic groups, which cannot meet the coating's requirements for hydrophobic properties. Therefore, it is necessary to modify the polysilazane used as the coating base with a low surface energy substance. Among them, fluorinated organic compounds are widely used in hydrophobic modification.

[0004] At present, there have been studies on the application of hydrophobically modified organopolysilazane in the field of hydrophobic coatings. Chinese invention patent application CN 105385349A discloses a hydrophobic antifouling organopolysilazane coating and a preparation method thereof. The method uses perfluoroalkyl ethyl allyl ether to hydrophobically modify polysilazane through a hydrosilylation reaction, and prepares a hydrophobic self-cleaning coating with good performance. However, the synthesis reaction system of the fluoride perfluoroalkyl ethyl allyl ether used in the method is relatively complex, the product needs to be purified, the process is relatively cumbersome, and the cost of synthesis is high; in addition, the hydrosilylation reaction of perfluoroalkyl ethyl allyl ether and organopolysilazane must be carried out in the presence of a catalyst, and the catalyst remaining in the product is difficult to remove, which will have a certain impact on the performance of the product. Summary of the invention

[0005] The purpose of the present invention is to provide a fluorine-containing modified organic polysilazane and a preparation method thereof. The preparation method is simple, and the coating prepared with the fluorine-containing modified organic polysilazane can be converted into a hydrophobic coating under air conditions, having waterproof and self-cleaning effects.

[0006] To achieve the above object, the present invention provides a fluorine-containing modified organic polysilazane, the structure of which is shown in the following formula:

[0007]

[0008] Wherein, the side groups R1, R2, R3 and R4 on the main chain are organic groups or hydrogen atoms, and the organic groups are straight-chain or branched alkyl, alkenyl, alkynyl or R8 is a straight chain alkylene group containing 1 to 4 carbon atoms, R5, R6 and R7 are straight chain alkyl groups containing 1 to 4 carbon atoms; m is an integer of 6-12, and n is an integer of 1-5.

[0009] The present invention provides a method for preparing the above-mentioned fluorine-containing modified organic polysilazane, comprising: under the protection of an inert gas, subjecting a fluorine-containing alcohol monomer and an organic polysilazane to an alcoholysis reaction in a solvent to prepare the fluorine-containing modified organic polysilazane;

[0010]

[0011] Preferably, the general structural formula of the fluorinated alcohol monomer is wherein m is an integer of 6-12, preferably 6-8; and n is an integer of 1-5, preferably 2-3.

[0012] Preferably, the structural formula of the organopolysilazane is The side groups R1, R2, R3 and R4 on the main chain are organic groups or hydrogen atoms; the organic groups are straight-chain or branched alkyl, alkenyl, alkynyl or R8 is a straight chain alkylene group containing 1 to 4 carbon atoms, and R5, R6 and R7 are straight chain alkyl groups containing 1 to 4 carbon atoms.

[0013] Preferably, the inert gas is nitrogen or argon.

[0014] Preferably, the solvent is at least one of tetrahydrofuran, toluene, xylene, ethylbenzene, n-hexane, n-octane, n-decane, cyclohexane, ethyl acetate, butyl acetate, tert-butyl acetate, ethyl ether, n-butyl ether, petroleum ether, acetone, methyl butyl ketone and ethyl butyl ketone, or a combination thereof.

[0015] Preferably, the mass ratio of the fluorine-containing alcohol monomer to the organopolysilazane is 1:1 to 1:100, preferably 1:1 to 1:40.

[0016] Preferably, the amount of the solvent used is 3 to 20 times, preferably 3 to 10 times, the total mass of the fluorinated alcohol monomer and the organopolysilazane.

[0017] Preferably, the alcoholysis reaction temperature is 20-60°C, preferably 30-50°C.

[0018] Preferably, the alcoholysis reaction time is 2 to 12 hours, preferably 6 to 10 hours.

[0019] Preferably, after the alcoholysis reaction, the solvent is removed by vacuum evaporation at 40-90°C.

[0020] In addition, the present invention provides a hydrophobic coating comprising the above-mentioned fluorine-containing modified organic polysilazane.

[0021] Preferably, the solvent is further included, and the solvent is at least one of tetrahydrofuran, toluene, xylene, ethylbenzene, n-hexane, n-octane, n-decane, cyclohexane, ethyl acetate, butyl acetate, tert-butyl acetate, ethyl ether, n-butyl ether, petroleum ether, acetone, methyl butyl ketone and ethyl butyl ketone, or a combination thereof.

[0022] Preferably, in the hydrophobic coating, the concentration of the fluorine-modified organopolysilazane is 1 to 60 wt %, preferably 10 to 40 wt %.

[0023] Finally, the present invention provides a stable and durable hydrophobic coating and a method for preparing the same, which is obtained by coating the hydrophobic coating on the surface of a substrate and then curing the coating.

[0024] Preferably, coating is performed by drop casting, dipping, spraying, spin coating, scraping, roller coating or brushing, preferably spraying.

[0025] Preferably, the substrate is one of an inorganic non-metallic material, a metal material, a polymer material and a composite material having a one-dimensional, two-dimensional or three-dimensional structure, preferably glass.

[0026] Preferably, curing refers to curing at a temperature of 60 to 200° C. for 0.5 to 5 hours, preferably at a temperature of 80 to 120° C. for 1 to 3 hours.

[0027] Preferably, the water contact angle of the hydrophobic coating is 103° to 108°.

[0028] In summary, the synthesis method of the fluorine-modified organic polysilicon nitrogen silicon disclosed in the present invention and the method of using the same as a durable hydrophobic coating on the surface of a substrate have four characteristics:

[0029] (1) Fluorinated modified organopolysilazane imparts good bonding strength between polymer coatings and substrates such as glass, overcoming the common limitation of low surface energy coatings in terms of poor adhesion to substrate materials, making fluorinated polysilazane a durable hydrophobic agent;

[0030] (2) Fluorine-modified organic polysilazane is converted into a polysiloxane structure under the action of air moisture, forming a uniform and dense semi-inorganic coating while maintaining good interfacial bonding strength, breaking through the problem that low surface energy coatings are difficult to infiltrate and spread on high-polarity glass surfaces;

[0031] (3) Compared with the common hydrosilylation reaction, the modification reaction adopted in the present invention does not require the use of catalysts and other auxiliary agents, the reaction can still be carried out under mild and simple reaction conditions, and the product does not require post-treatment, which greatly improves the production efficiency;

[0032] (4) The conventional method of using multi-component blending to compromise and resolve the contradiction between substrate wettability and coating hydrophobicity is abandoned, and the precursor technology is used to achieve the unity of the two; the modified organic polysilazane in the present invention has a wide range of applicability and is suitable for various substrate surfaces, such as glass, plastic, metal and ceramic. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The infrared spectrum (FT-IR) of the perfluorooctyl propanol modified organopolysilazane prepared in Example 1 and its reactants, namely perfluorooctyl propanol (PFOP) and organopolysilazane (OPSZ).

[0034] Figure 2 The hydrogen nuclear magnetic resonance spectrum (HNMR) of the perfluorooctyl propanol modified organopolysilazane and its reactants, namely perfluorooctyl propanol (PFOP) and organopolysilazane (OPSZ) prepared in Example 1 1 H-NMR) chart.

[0035] Figure 3 This is a thermogravimetric analysis diagram of the perfluorooctylpropanol-modified organopolysilazane coating constructed on the surface of a glass substrate in Example 2.

[0036] Figure 4 This is a picture of a water droplet in contact with a glass surface when measuring the water contact angle of the perfluorooctyl propanol-modified organopolysilazane coating constructed on the surface of a glass substrate in Example 2.

[0037] Figure 5 Photographs of a water droplet in contact with a glass surface obtained to measure the water contact angle of an unmodified organopolysilazane coating.

[0038] Figure 6 This is a picture of a water drop in contact with a glass surface when measuring the water contact angle on a blank glass surface.

[0039] Figure 7 This is a picture of a water droplet in contact with a glass surface when measuring the water contact angle of the perfluorohexylethanol-modified organopolysilazane coating constructed on the surface of a glass substrate in Example 4. DETAILED DESCRIPTION

[0040] The following are embodiments of the present invention, but the present invention is not limited to the following embodiments. Any non-substantial improvements made by adopting the concept and technical solution of the present invention, or directly applying the technology of the present invention without improvement, are within the scope of the claims of the present invention.

[0041] The present invention provides a method for preparing the above-mentioned fluorine-containing modified organic polysilazane, the method comprising the following steps:

[0042] (1) Under the protection of an inert gas, adding a fluorinated alcohol monomer and an organopolysilazane into a solvent and stirring the mixture uniformly;

[0043] (2) After alcoholysis reaction at a temperature of 20 to 60° C. for 2 to 12 hours, the solvent in the reaction system is removed by vacuum evaporation to obtain a fluorine-containing modified organopolysilazane.

[0044] The alcoholysis reaction for preparing the fluorine-containing modified organopolysilazane is shown in reaction formula (1):

[0045]

[0046] Example 1 Preparation of Perfluorooctylpropanol Modified Organopolysilazane

[0047] In a pre-dried 25mL Schlenk reaction tube, ventilate 3 times to remove air and moisture in the bottle, add 2.00g of organopolysilazane (OPSZ) and 15.0mL of solvent THF in sequence under nitrogen protection, and stir evenly at 600r / min; then add 0.8g of perfluorooctyl propanol (PFOP), insert a nitrogen balloon at the bottle mouth for protection, heat to 50°C, and react the reaction system at 50°C under stirring for 10h, then stop heating and terminate the reaction. The solvent in the reaction system is removed by rotary evaporation to obtain translucent liquid perfluorooctyl propanol modified organopolysilazane OPSZ-PFOP-40%.

[0048] The structure of the organic polysilazane used in this embodiment is:

[0049]

[0050] Figure 1 This is the infrared spectrum (FT-IR) of the perfluorooctyl propanol modified organopolysilazane and its reactants, namely perfluorooctyl propanol (PFOP) and organopolysilazane (OPSZ) prepared in Example 1. The υ(NH) stretching vibration peak corresponds to 3383 cm -1 , υ(CH) stretching vibration peak corresponds to 2961cm -1 ,υ(Si-H) stretching vibration peak corresponds to 2120cm -1 , the δ(Si-CH3) bending vibration absorption peak corresponds to 1251cm -1 ,δ(NH) bending vibration absorption peak corresponds to 1161cm -1 ,υ(Si-N) stretching vibration peak corresponds to 890cm -1The υ(OH) stretching vibration peak of PFOP corresponds to 3322 cm -1 , but it did not appear in the infrared absorption spectrum of OPSZ-PFOP-40%, indicating that the PFOP involved in the reaction has completely participated in the reaction. At the same time, it was observed that OPSZ-PFOP-40% -1 The υ(CF) stretching vibration peak also appeared at , proving that the modified OPSZ was successful.

[0051] Figure 2 The hydrogen nuclear magnetic resonance spectrum (HNMR) of the perfluorooctyl propanol modified organopolysilazane and its reactants, namely perfluorooctyl propanol (PFOP) and organopolysilazane (OPSZ) prepared in Example 1 1 H-NMR) graph. 1 H-NMR spectrum shows that in OPSZ-PFOP-40% 1 In the H-NMR spectrum, there is no proton peak at 4.03-4.08ppm belonging to -OH in the PFOP molecule, which indicates that the hydroxyl group in the PFOP molecule has completely participated in the reaction and disappeared. 1 In the H-NMR spectrum, there is also a C H 2-O(δ=3.74), C H 2-CF2(δ=2.18), CH2-C H 2 (δ=1.85), proving that the OPSZ modification was successful.

[0052] Example 2 Application of perfluorooctyl propanol modified organopolysilazane

[0053] 0.05 g of the perfluorooctyl propanol modified organopolysilazane OPSZ-PFOP-40% prepared in Example 1 was dissolved in 1 mL of ethyl acetate solvent and mixed evenly to obtain an OPSZ-PFOP-40% solution with a mass fraction of 4.8 wt%; then, glass (Glass) and tinplate (SPTE) were used as substrates, and the prepared OPSZ-PFOP-40% solution was coated on the surface of the substrate by spraying technology, and thermally cured at 120°C for 2 hours to obtain perfluorooctyl propanol modified organopolysilazane OPSZ-PFOP-40% coatings constructed on the surfaces of different substrates, which were respectively recorded as OPSZ-PFOP-40%@Glass and OPSZ-PFOP-40%@SPTE.

[0054] Figure 3This is the thermogravimetric analysis of the OPSZ-PFOP-40%@Glass coating constructed on the surface of the glass substrate in Example 2. From the thermogravimetric TGA curve, the thermal weight loss of the thermally cured OPSZ-PFOP-40% before 363°C mainly comes from the release of NH3 and H2 during the thermal curing process; the thermal cross-linking reaction is below 350°C; the organic to inorganic conversion occurs between 350 and 790°C, and then the thermogravimetric curve tends to be flat, and the ceramic pyrolysis yield at 790°C is 65.3%.

[0055] Figure 5 , Figure 6 and Figure 7 The pictures of water droplets contacting different surfaces are obtained when measuring the water contact angle of the OPSZ-PFOP-40%@Glass coating constructed on the glass surface used as the substrate in Example 2, the unmodified organopolysilazane OPSZ@Glass coating and the blank glass surface as the control. Figure 7 According to the test results, the water contact angle of the blank glass surface is only 45.2°, which is a hydrophilic surface; Figure 5 OPSZ-PFOP-40%@Glass coating constructed on glass substrate and Figure 6 The water contact angles on the surface of the unmodified organopolysilazane OPSZ@Glass coating were 106.1° and 95.6°, respectively, both showing hydrophobicity, and the hydrophobicity of the OPSZ-PFOP-40%@Glass coating was more significant.

[0056] Example 3 Preparation of Perfluorohexylethanol Modified Organopolysilazane

[0057] In a pre-dried 25mL Schlenk reaction tube, ventilate 3 times to remove air and moisture in the bottle, add 2.00g of organopolysilazane (OPSZ) and 15.0mL of solvent THF in sequence under nitrogen protection, and stir evenly at 600r / min; then add 0.6g of perfluorohexylethanol (PFHE), insert a nitrogen balloon at the bottle mouth for protection, heat to 50°C, and react the reaction system at 50°C with stirring for 10h, then stop heating and terminate the reaction. The solvent in the reaction system is removed by rotary evaporation to obtain translucent liquid perfluorohexylethanol modified organopolysilazane OPSZ-PFHE-30%.

[0058] The structure of the organopolysilazane used in this embodiment is:

[0059]

[0060] Example 4 Application of perfluorohexylethanol modified organopolysilazane

[0061] 0.05 g of the perfluorohexylethanol modified organopolysilazane OPSZ-PFHE-30% prepared in Example 3 was dissolved in 1 mL of ethyl acetate solvent and mixed evenly to obtain an OPSZ-PFHE-30% solution with a mass fraction of 4.8 wt%; then, glass (Glass) and tinplate (SPTE) were used as substrates, and the prepared OPSZ-PFHE-30% solution was coated on the surface of the substrate by spraying technology, and thermally cured at 120°C for 2 hours to obtain perfluorohexylethanol modified organopolysilazane OPSZ-PFHE-30% coatings constructed on the surfaces of different substrates, which were respectively recorded as OPSZ-PFHE-30%@Glass and OPSZ-PFHE-30%@SPTE.

[0062] Figure 7 This is a picture of a water droplet in contact with the coating surface when measuring the water contact angle of the OPSZ-PFHE-30%@Glass coating constructed on the glass surface used as a substrate in Example 4. Figure 6 According to the test results, the water contact angle of the blank glass surface is only 45.2°, which is a hydrophilic surface; Figure 7 OPSZ-PFHE-30%@Glass coating constructed on glass substrate and Figure 5 The water contact angles on the surfaces of the unmodified organopolysilazane OPSZ@Glass coatings were 104.6° and 95.6°, respectively, both showing hydrophobicity, and the OPSZ-PFHE-30%@Glass coating was more hydrophobic.

Claims

1. A fluorine-containing modified organopolysilazane, characterized in that: The structure is shown below: The side groups R1, R2, R3 and R4 on the main chain are organic groups or hydrogen atoms, wherein the organic groups are straight-chain or branched alkyl, alkenyl, alkynyl or R8 is a straight chain alkylene group containing 1 to 4 carbon atoms, R5, R6 and R7 are straight chain alkyl groups containing 1 to 4 carbon atoms; m is an integer of 6-12, and n is an integer of 1-5.

2. The method for preparing the fluorine-containing modified organopolysilazane according to claim 1, characterized in that: include: Under the protection of an inert gas, a fluorine-containing alcohol monomer and an organic polysilazane are subjected to an alcoholysis reaction in a solvent to prepare a fluorine-containing modified organic polysilazane.

3. The method according to claim 2, characterized in that Fluorinated alcohol monomers In the formula (a), m is an integer of 6-12, preferably 6-8; n is an integer of 1-5, preferably 2-3.

4. The method according to claim 2, characterized in that Organic polysilazane In the embodiment, the side groups R1, R2, R3 and R4 on the main chain are organic groups or hydrogen atoms; wherein the organic group is a straight or branched alkyl, alkenyl, alkynyl or R8 is a straight chain alkylene group containing 1 to 4 carbon atoms, and R5, R6 and R7 are straight chain alkyl groups containing 1 to 4 carbon atoms.

5. The method according to claim 2, characterized in that The mass ratio of the fluorine-containing alcohol monomer to the organopolysilazane is 1:1 to 1:100, preferably 1:1 to 1:

40.

6. The method according to claim 2, characterized in that The alcoholysis reaction temperature is 20 to 60° C., preferably 30 to 50° C.; the alcoholysis reaction time is 2 to 12 hours, preferably 6 to 10 hours.

7. A hydrophobic coating, characterized in that: It comprises the fluorine-containing modified organopolysilazane as claimed in claim 1.

8. The hydrophobic coating according to claim 7, characterized in that The invention also comprises a solvent, which is at least one of tetrahydrofuran, toluene, xylene, ethylbenzene, n-hexane, n-octane, n-decane, cyclohexane, ethyl acetate, butyl acetate, tert-butyl acetate, ethyl ether, n-butyl ether, petroleum ether, acetone, methyl butyl ketone and ethyl butyl ketone, or a combination thereof.

9. The hydrophobic coating according to claim 7, characterized in that In the hydrophobic coating, the concentration of the fluorine-containing modified organopolysilazane is 1 to 60 wt %, preferably 10 to 40 wt %.

10. A stable and durable hydrophobic coating, obtained by curing the hydrophobic coating as claimed in any one of claims 7 to 9 after coating on the surface of a substrate.

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