Organic silicon modified polyurea material for fluid interface drag reduction as well as preparation method and application of organic silicon modified polyurea material

Abstract

The invention discloses an organic silicon modified polyurea material for fluid interface drag reduction and a preparation method and application thereof, and the preparation method of the organic silicon modified polyurea material comprises the following steps: reacting polypropylene glycol, hydroxyl-terminated polydimethylsiloxane and excessive isophorone diisocyanate in the presence of a catalyst to generate a polyurethane prepolymer with an NCO-terminated group; the preparation method comprises the following steps: reacting diethyl maleate with 4, 4 '-diaminocyclohexylmethane to generate polyaspartic acid ester; the prepolymer and polyaspartic acid ester are mixed and cured to form the organic silicon modified polyurea elastomer. The chemical bonding type organic silicon modified polyurea material provided by the invention has the advantages of low surface energy, high wear resistance and long-acting drag reduction performance, solves the problems of poor weather resistance, insufficient hydrophobicity and the like of traditional polyurea, and avoids the phase separation defect of physical blending.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a silicone-modified polyurea material for fluid interface drag reduction, a preparation method and application thereof. BACKGROUND

[0002] Drag reduction technology aims to reduce the resistance of an object moving in a fluid (such as a liquid or gas) or to reduce the energy loss of a fluid flowing in a pipeline, and has extremely important application value and significant economic benefits in many fields. For example, in the field of ship transportation, reducing the frictional resistance of the ship body can greatly reduce fuel consumption and greenhouse gas emissions; in the field of oil and gas transportation, reducing the flow resistance of fluid in the pipeline can effectively improve the transportation efficiency and reduce the energy consumption of pumping; in the fields of aerospace, medical devices (such as microfluidic devices), underwater equipment, etc., high-efficiency drag reduction technology is also crucial.

[0003] At present, one of the main technical approaches to achieve fluid interface drag reduction is to construct a coating with low surface energy and flexible characteristics.

[0004] Polyurea materials are widely used in protective coatings, waterproof engineering, etc. due to their excellent mechanical properties (high wear resistance, high impact resistance, high elasticity), excellent adhesion, rapid curing, good chemical corrosion resistance, and strong designability. In theory, polyurea has the potential to be used as a durable drag reduction coating matrix. However, the surface energy of conventional polyurea materials is relatively high, and its inherent hydrophobicity is not enough to achieve high-efficiency fluid drag reduction. Silicone materials, on the other hand, have extremely low surface energy, excellent flexibility and low-temperature flexibility, but their mechanical properties are extremely poor.

[0005] In view of the advantages and disadvantages of polyurea and silicone, silicone is introduced into the polyurea system for modification in order to obtain a composite material that combines the advantages of both, thereby achieving efficient and durable fluid drag reduction.

[0006] However, there are many challenges in realizing effective silicone-modified polyurea in the prior art: compatibility problem: there is a significant difference in polarity and solubility parameter between silicone (non-polar) and most polyurea components (polar), resulting in poor compatibility between the two, which easily leads to macroscopic or microscopic phase separation. This not only affects the modification effect, but also may cause loss of mechanical properties of the material and even processing difficulties. Reactivity and interface bonding: how to achieve effective chemical bonding between the silicone component and the polyurea matrix instead of simple physical blending is the key to improving the modification effect and material stability.

[0007] Therefore, although the organosilicon modified polyurea has great application potential, the prior art still generally faces key problems such as poor compatibility, serious phase separation, low chemical bonding efficiency, difficulty in designing a structure of a modifier to balance various performances, complex process, and difficulty in significantly improving weather resistance and hydrophobicity while maintaining excellent mechanical strength. Developing a new type of organosilicon modified polyurea technology or material can effectively overcome the above defects, and has important practical significance and urgent market demand. SUMMARY

[0008] In view of the above technical problems existing in the prior art, the purpose of the present application is to provide an organosilicon modified polyurea material for fluid interface drag reduction and a preparation method and application thereof. The present application provides a chemical bonding type organosilicon modified polyurea material, which has low surface energy, high wear resistance and long-acting drag reduction performance, solves the problems of poor weather resistance and insufficient hydrophobicity of traditional polyurea, and avoids the phase separation defect of physical blending.

[0009] The technical scheme adopted by the present application is as follows:

[0010] A preparation method of an organosilicon modified polyurea material for fluid interface drag reduction, comprising the following steps:

[0011] Step 1: polypropylene glycol, hydroxyl-terminated polydimethylsiloxane and excess isophorone diisocyanate are reacted in the presence of a catalyst to generate a polyurethane prepolymer with terminal NCO groups;

[0012] Step 2: maleic acid diethyl ester is reacted with 4,4'-diaminocyclohexyl methane to generate polyaspartic acid ester, and the reaction formula is as follows:

[0013]

[0014] Step 3: the prepolymer in step 1 is mixed and cured with the polyaspartic acid ester in step 2, the NCO groups in the prepolymer are reacted with the secondary amine groups in the polyaspartic acid ester molecules to form an organosilicon modified polyurea elastomer, and the preparation is completed.

[0015] Further, in step 1, the catalyst is dibutyltin dilaurate, the reaction is carried out under stirring in a N2 atmosphere, the reaction temperature is 75-85 DEG C, and the reaction time is 2-5 h.

[0016] Further, in step 1, the molar ratio of polypropylene glycol to hydroxyl-terminated polydimethylsiloxane is 2-9:1, preferably 2.3-4:1; the molar amount of isophorone diisocyanate is 2.2-3 times, preferably 2.4-2.5 times, of the total molar amount of polypropylene glycol and hydroxyl-terminated polydimethylsiloxane.

[0017] Further, in step 1, the mass ratio of the catalyst to the total amount of substance of polypropylene glycol and hydroxyl-terminated polydimethylsiloxane is 1 g: 150-300 mmol.

[0018] Further, the reaction process in step 2 is: slowly dropwise adding diethyl maleate into 4,4'-diaminocyclohexyl methane at a temperature of 40-50 DEG C, under N2 atmosphere and stirring, after the addition is completed, the temperature is raised to 75-85 DEG C, and stirring is carried out for 20-30 h.

[0019] Further, the molar ratio of diethyl maleate to 4,4'-diaminocyclohexyl methane is 1.8-2.5:1, preferably 2:1.

[0020] Further, in step 3, the molar ratio of the NCO group content in the prepolymer to polyaspartic acid ester is 1.8-2.4:1, preferably 2:1. Since one molecule of polyaspartic acid ester contains two -NH- groups, the molar ratio of the NCO group in the prepolymer to the -NH- group in the polyaspartic acid ester molecule is 0.9-1.2:1, preferably 1:1.

[0021] As can be seen from the reaction formula in step 2, polyaspartic acid ester is formed by the reaction of one molecule of 4,4'-diaminocyclohexyl methane and two molecules of diethyl maleate, and the molecular weight of polyaspartic acid ester can be calculated to be 554.

[0022] Further, in step 3, the mixing and curing process is: first mixing and stirring for 5-20 min, and then curing at room temperature for 20-30 h.

[0023] The application also provides the application of the organic silicon modified polyurea material in a drag reduction coating.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] The application successfully combines the low surface energy advantage of organic silicon and the high mechanical performance and high durability advantage of polyurea at the molecular level, creating a new composite material with hydrophobic characteristics, excellent mechanical strength, excellent wear resistance and adhesion, long-term stable drag reduction effect. It effectively overcomes the performance short board of existing single material or simply physically modified polyurea in drag reduction applications (such as poor mechanical performance, insufficient wear resistance, short-term hydrophobicity, and modification of bulk properties), and provides a high-performance and high-reliability material solution for fluid drag reduction requirements in the fields of ships, pipeline transportation, underwater equipment, etc. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is the contact angle comparison result of the organic silicon modified polyurea material coating prepared under different molar ratios of polypropylene glycol and hydroxyl silicone oil in Example 1-Example 2.

[0027] Figure 2 Figure 1 is a stress-strain curve comparison result of the coating of the silicone-modified polyurea material prepared in Example 1-Example 2 under different molar ratios of polypropylene glycol and hydroxyl silicone oil.

[0028] Figure 3 Figure 1 is a drag reduction test result of the coating of the silicone-modified polyurea material prepared in Example 1.

[0029] Figure 4 Figure 1 is a drag reduction test result of the coating of the silicone-modified polyurea material prepared in Example 3, in which the polypropylene glycol has a molecular weight of 4000. DETAILED DESCRIPTION

[0030] The application will be further described in conjunction with specific examples, but the scope of protection of the application is not limited thereto.

[0031] In the embodiments of the application, the polypropylene glycol with a molecular weight of 1000, 2000 and 4000 is purchased from Shanghai Maikelin Biochemical Technology Co., Ltd.

[0032] The hydroxyl-terminated polydimethylsiloxane, i.e. hydroxyl silicone oil, has a molecular weight of 2000 and is purchased from Shenzhen Silicone Home Chemical Center.

[0033] In the application, the content of NCO groups in the silicone-modified isocyanate prepolymer is tested by using the acetone-di-n-butylamine titration method.

[0034] Example 1:

[0035] The method for forming the silicone-modified polyaspartic ester polyurea coating according to the application comprises the following steps:

[0036] Step 1, preparation of the silicone-modified isocyanate prepolymer: 9 mmol of polypropylene glycol (with a molecular weight of 2000) is mixed with 1 mmol of hydroxyl silicone oil (with a molecular weight of 2000, purchased from Shenzhen Silicone Home Chemical Center), and water is removed by vacuumizing and treating at 105°C for two hours. Then 24.2 mmol of isophorone diisocyanate is added, 0.05 g of dibutyltin dilaurate is added dropwise, and the reaction is carried out at 80°C under N2 protection for 3 h, with stirring throughout.

[0037] Step 2, preparation of the polyaspartic ester: 0.2 mol of diethyl maleate is slowly added dropwise to 0.1 mol of 4,4'-diaminocyclohexyl methane at 45°C under N2 protection and stirring. After the addition is completed, the temperature is raised to 80°C, and the reaction is carried out for 24 h.

[0038] Step three, preparation of silicone-modified polyurea material: the NCO group content in the prepolymer of step one is mixed with the polyaspartic acid ester of step two at a molar ratio of 2:1 for ten minutes, then brushed on an iron plate, and cured at room temperature for 24 h to obtain a silicone-modified polyurea material coating on the iron plate.

[0039] Example 2

[0040] Example 2 The experimental steps of Example 1 are repeated, with the only difference being that the molar ratio of polypropylene glycol to hydroxyl silicone oil in Example 2 is changed from 9:1 to 10:0, 8:2, and 7:3, respectively, while the total molar amount of both polypropylene glycol and hydroxyl silicone oil remains unchanged at 10 mmol, and the remaining conditions remain unchanged.

[0041] Example 1 and Example 2 The silicone-modified polyurea material coatings formed under different molar ratios of polypropylene glycol to hydroxyl silicone oil in Example 1 and Example 2 are tested for performance, and the results are shown in Table 1.

[0042] Table 1 Comparison of mechanical properties and adhesion of silicone-modified polyurea material coatings

[0043]

[0044] The contact angles of the silicone-modified polyurea material coatings prepared under different molar ratios of polypropylene glycol to hydroxyl silicone oil in Example 1-Example 2 are shown in Table 1. Figure 1 As can be seen from Table 1, the addition of hydroxyl silicone oil improves the hydrophobicity of the coating, but as the proportion of hydroxyl silicone oil increases, the contact angle slowly decreases. Figure 1

[0045] The stress-strain curves of the silicone-modified polyurea material coatings prepared under different molar ratios of polypropylene glycol to hydroxyl silicone oil in Example 1-Example 2 are shown in Table 1. Figure 2 As can be seen from Table 1, the addition of hydroxyl silicone oil improves the mechanical properties, and both the tensile strength and elongation at break are improved, as the proportion of hydroxyl silicone oil increases, the elongation at break decreases, and the tensile strength increases. Figure 2

[0046] The drag reduction test results of the silicone-modified polyurea material coating prepared in Example 1 are shown in Table 1. Figure 3

[0047] Example 3

[0048] Compared with Example 1, the formation method of the silicone-modified polyurea coating in Example 3 is basically the same as that in Example 1, with only two differences:

[0049] 1) In Example 3, no hydroxyl silicone oil is added in the preparation of the prepolymer in step one;

[0050] ​​​2) The molecular weight of the polypropylene glycol used in Example 3 is 1000, 2000 or 4000, and the rest of the conditions remain unchanged.

[0051] The mechanical properties and adhesion of the silicone-modified polyurea material coating prepared in Example 3 under different molecular weights of polypropylene glycol are compared in Table 2.

[0052] Table 2

[0053]

[0054] The drag reduction test results of the silicone-modified polyurea material coating prepared in Example 3 with polypropylene glycol of 4000 molecular weight are shown in Table 2. Figure 4

[0055] Figure 3 Figure 4 The conditions for the drag reduction test in Examples 1-3 are as follows: the test sample is fixed on a rotating disc and immersed in a water flow, and the rotating disc drives the test sample to rotate under the action of a frequency modulation motor, thereby realizing the rotation of the test sample at different speeds in the water flow, and the drag reduction rate results at different speeds are tested.

[0056] Example 4

[0057] Step 1: 10 mmol of polypropylene glycol is removed of water under vacuum at 105°C for two hours. Then 24.2 mmol of isophorone diisocyanate is added, 0.05 g of dibutyltin dilaurate is added dropwise, and the reaction is carried out at 80°C under N2 protection for 3 h, with stirring throughout.

[0058] Step 2: The preparation of polyaspartic acid ester is repeated in Example 1.

[0059] Step 3: Preparation of silicone-modified polyurea material: the NCO group content in the prepolymer of Step 1 is mixed with the polyaspartic acid ester of Step 2 at a molar ratio of 2:1, then 1 wt% of dimethyl silicone oil is added to the mixture, and the mixture is stirred for ten minutes, then brushed on an iron plate and cured at room temperature for 24 h to obtain a silicone-modified polyurea material coating on the iron plate.

[0060] The mechanical properties, adhesion and contact angle of the silicone-modified polyurea material coating prepared in Example 4 are shown in Table 3.

[0061] Table 3

[0062]

[0063] The content described in the specification is only a list of forms of the inventive concept, and the protection scope of the present application should not be considered to be limited to the specific forms stated in the examples.​​

Claims

1. A method for preparing organosilicon-modified polyurea materials for fluid interface drag reduction, characterized in that... Includes the following steps: Step 1: Polypropylene glycol, hydroxyl-terminated polydimethylsiloxane and excess isophorone diisocyanate react in the presence of a catalyst to generate a polyurethane prepolymer with NCO-terminated groups; Step 2: Diethyl maleate reacts with 4,4'-diaminocyclohexylmethane to generate polyaspartic acid ester; Step 3: The prepolymer described in Step 1 is mixed with the polyaspartic acid ester described in Step 2 and cured to form an organosilicon-modified polyurea elastomer, thus completing the preparation.

2. The method for preparing an organosilicon-modified polyurea material for fluid interface drag reduction as described in claim 1, characterized in that... In step 1, the catalyst is dibutyltin dilaurate, the reaction is carried out under N2 atmosphere with stirring, the reaction temperature is 75-85℃, and the reaction time is 2-5h.

3. The method for preparing an organosilicon-modified polyurea material for fluid interface drag reduction as described in claim 2, characterized in that... The molar ratio of polypropylene glycol to hydroxyl-terminated polydimethylsiloxane is 2-9:1, preferably 2.3-4:1; the molar amount of isophorone diisocyanate is 2.2-3 times the total molar amount of polypropylene glycol and hydroxyl-terminated polydimethylsiloxane, preferably 2.4-2.5 times.

4. The method for preparing an organosilicon-modified polyurea material for fluid interface drag reduction as described in claim 2, characterized in that... The mass ratio of the catalyst to the total mass of polypropylene glycol and hydroxyl-terminated polydimethylsiloxane is 1g:150-300mmol.

5. The method for preparing an organosilicon-modified polyurea material for fluid interface drag reduction as described in claim 1, characterized in that... The reaction process described in step 2 is as follows: under the conditions of 40-50℃ temperature, N2 atmosphere and stirring, diethyl maleate is slowly added dropwise to 4,4'-diaminocyclohexylmethane. After the addition is completed, the temperature is raised to 75-85℃ and the reaction is stirred for 20-30 hours.

6. The method for preparing an organosilicon-modified polyurea material for fluid interface drag reduction as described in claim 1, characterized in that... The molar ratio of diethyl maleate to 4,4'-diaminocyclohexylmethane is 1.8-2.5:1, preferably 2:

1.

7. The method for preparing an organosilicon-modified polyurea material for fluid interface drag reduction as described in claim 1, characterized in that... In step 3, the molar ratio of NCO group content in the prepolymer to polyaspartic acid ester is 1.8-2.4:1, preferably 2:

1.

8. The method for preparing an organosilicon-modified polyurea material for fluid interface drag reduction as described in claim 1, characterized in that... In step 3, the mixing and curing process is as follows: first mix and stir for 5-20 minutes, then cure at room temperature for 20-30 hours.

9. An organosilicon-modified polyurea material for fluid interface drag reduction prepared by the method described in any one of claims 1-8.

10. The application of the organosilicon-modified polyurea material as described in claim 9 in drag-reducing coatings.

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