Semi-interpenetrating network type polyurethane friction material and preparation method thereof

Abstract

The invention discloses a semi-interpenetrating network type polyurethane friction material and a preparation method thereof, and relates to the technical field of polyurethane materials. According to the semi-interpenetrating network type polyurethane friction material, hydrophobic straight-chain polyurethane serves as a matrix, a hydrophilic cross-linked network is constructed in the matrix, and a semi-interpenetrating network structure is formed. According to the semi-interpenetrating network type polyurethane friction material, hydrophobic straight-chain polyurethane serves as a matrix, polyethylene glycol dimethacrylate is introduced into the matrix, free radical polymerization is conducted, a hydrophilic cross-linked network is constructed, and therefore a semi-interpenetrating network structure is formed. Hydrophobic polyurethane is used as a matrix, so that a foundation is provided for stable application of the material in a wading environment; and a hydrophilic cross-linked network can significantly improve the tribological performance of the material under a water lubrication condition.

Description

Technical Field

[0001] This invention relates to the field of polyurethane materials technology, and in particular to a semi-interpenetrating network type polyurethane friction material and its preparation method. Background Technology

[0002] Polyurethane (PU) is a polymer material produced by the addition polymerization reaction of polyisocyanates and polyols. Its molecular structure contains characteristic urethane groups (-NH-COO-). Since its first synthesis by German chemist Otto Bayer in 1937, polyurethane has become one of the most widely used synthetic polymer materials and is hailed as the "fifth largest plastic".

[0003] Polyurethane (PU) possesses excellent molecular designability. As a high-performance polymer material, it boasts strong molecular designability, a wide range of performance tuning capabilities, and excellent mechanical and tribological properties, making it widely used in aerospace, marine, and shipbuilding technologies. However, the increased hydrophobicity of polyurethane significantly reduces its tribological performance under water-lubricated conditions. Summary of the Invention

[0004] To address the technical problem of insufficient hydrophilicity in traditional polyurethane materials, which hinders the rapid formation of an effective water film under water lubrication conditions and results in poor friction performance, this invention provides a semi-interpenetrating network polyurethane friction material and its preparation method. This invention successfully prepares a hydrophilic polyurethane with a semi-interpenetrating network structure through a simple synthesis process, ultimately obtaining a novel polyurethane friction material that exhibits excellent performance in water-lubricated environments.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A semi-interpenetrating network polyurethane friction material is provided, which uses hydrophobic linear polyurethane as a matrix and constructs a hydrophilic cross-linked network in the matrix to form a semi-interpenetrating network structure.

[0007] The hydrophilic crosslinked network is achieved by polymerizing hydrophobic linear polyurethane with polyethylene glycol dimethacrylate.

[0008] The molecular structure of the hydrophobic linear polyurethane is as follows:

[0009] ;

[0010] Where m ranges from 3 to 5, and n ranges from 45 to 50.

[0011] The preparation method of the above-mentioned semi-interpenetrating network polyurethane friction material includes the following steps:

[0012] S1: Add a chain extender to the polyurethane prepolymer and add polyethylene glycol dimethacrylate, and react at a temperature of 70-90℃ for 2-4 hours.

[0013] S2: After the reaction is complete, the mixture obtained from the reaction is molded and dried to obtain a semi-interpenetrating network polyurethane friction material.

[0014] The molar ratio of the chain extender to the diol in the polyurethane prepolymer is 3:1 to 3:2.

[0015] The molar ratio of polyethylene glycol dimethacrylate to the diol in the polyurethane prepolymer is 1:1 to 1:2.

[0016] In step S1, polyethylene glycol dimethacrylate is added before an organic solvent is added.

[0017] Alternatively, a polyethylene glycol dimethacrylate solution can be directly added in step S1; wherein the polyethylene glycol dimethacrylate solution is obtained by dissolving polyethylene glycol dimethacrylate in an organic solvent, and the solid content of the polyethylene glycol dimethacrylate solution is 15%-20%.

[0018] The chain extender is polyetheramine D230, N,N'-di-tert-butylethylenediamine, or 4,4'-diaminodicyclohexylmethane.

[0019] Step S1 is carried out in an N2 atmosphere; the drying process in step S2 is carried out at 40℃-80℃ under vacuum conditions for 24h-72h.

[0020] The polyurethane prepolymer is prepared through the following steps:

[0021] S0: Polyester or polyether polyol and diisocyanate are mixed in an organic solvent to form a mixture, then a catalyst is added, and the mixture is reacted at 40-80℃ for 2-5 hours to obtain polyurethane prepolymer.

[0022] The molar ratio of polyester or polyether polyol to diisocyanate is 1:2 to 1:4.

[0023] The catalysts are amine catalysts and organometallic catalysts.

[0024] The beneficial effects of this invention are as follows:

[0025] (1) The semi-interpenetrating network polyurethane friction material of the present invention uses hydrophobic linear polyurethane as the matrix, and constructs a hydrophilic crosslinked network by introducing polyethylene glycol dimethacrylate into it and carrying out free radical polymerization, thereby forming a semi-interpenetrating network structure. The hydrophobic polyurethane as the matrix provides a basis for the stable application of the material in water-related environments; while the hydrophilic crosslinked network can significantly improve the tribological properties of the material under water lubrication conditions.

[0026] (2) The semi-interpenetrating network polyurethane friction material of the present invention has a structural design that combines a hydrophobic matrix and a hydrophilic network, which enables polyurethane to maintain underwater structural stability while having excellent lubrication properties, and is especially suitable for tribological applications in marine engineering, ship equipment and other fields. Attached Figure Description

[0027] Figure 1 The images show the contact angles of water with semi-interpenetrating network polyurethane friction materials prepared in Examples 1 to 4 and comparative examples of the present invention.

[0028] Figure 2 The figures show the contact angle test results of water for the semi-interpenetrating network polyurethane friction materials prepared in Examples 1 to 4 and the comparative examples of the present invention.

[0029] Figure 3 The friction coefficient curves of the semi-interpenetrating network polyurethane friction materials prepared in Examples 1 to 4 and the comparative examples of the present invention under the conditions of 66 N and 0.54 m / s are shown.

[0030] Figure 4 The graph shows the average friction coefficient test results of the semi-interpenetrating network polyurethane friction materials prepared in Examples 1 to 4 and the comparative examples of the present invention under the conditions of 66 N and 0.54 m / s. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0032] The preparation method of the semi-interpenetrating network polyurethane friction material of the present invention is as follows:

[0033] First, select polyester or polyether polyol (molecular weight range: 1000-3000) and place it in a three-necked flask. Stir and dry it under oil bath conditions at 100-150℃ and N2 atmosphere.

[0034] Next, after the polyester or polyether polyol cools to 60-100℃, add an equivalent amount of diisocyanate (selectable types: hexamethylene diisocyanate (HDI) / isophorone diisocyanate (IPDI) / diphenylmethane diisocyanate (MDI) / hexamethylene diisocyanate (HDI)), with a molar ratio of polyester or polyether polyol to diisocyanate of 1:2 to 1:4; and measure a certain amount of organic solvent (selectable solvents: N,N-dimethylformamide (DMF) / N,N-dimethylacetamide (DMAc) / tetrahydrofuran (THF)), mix them and add them to the reaction flask, so that the solid content is maintained at 10%-30%. A catalyst (selectable catalysts include amine catalysts and organometallic catalysts) accounting for 0.2%-0.5% of the total system mass fraction is added dropwise. Amine catalysts are generally tertiary amine salts, such as N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, triethylamine, N,N-dimethylbenzylamine, etc.; organometallic catalysts include dibutyltin dilaurate, stannous isooctanoate, zinc isooctanoate, bismuth isooctanoate, etc.) is added dropwise at a temperature of 40-80℃ under a N2 atmosphere for 2-5 hours to obtain a polyurethane prepolymer.

[0035] Add an appropriate amount of diamine chain extender or diol chain extender (molar ratio with diol is 3:1 to 3:2) (polyetheramine D230, N,N'-di-tert-butylethylenediamine, 4,4'-diaminodicyclohexylmethane) to the polyurethane prepolymer to carry out the first step of chain extension reaction; at the same time, add polyethylene glycol dimethacrylate (molar ratio with diol is 1:1 to 1:2), the reaction temperature is 70-90℃, and the reaction is carried out under N2 atmosphere for 2h-4h.

[0036] After the reaction is complete, the mixture is poured into a mold and dried under vacuum at 40℃-80℃ for 24h-72h to remove residual solvent, thus obtaining a polyurethane elastomer film.

[0037] Example 1:

[0038] (1) Weigh 2 mmol of polytetrahydrofuran ether diol (PTMG, Mn=2000) and add it to a three-necked flask. Heat to 120°C and mechanically stir for 2 hours to dry.

[0039] (2) When the temperature drops to 70℃, add 4 mmol of hexamethylene diisocyanate (HDI) and 30 ml of N,N-dimethylformamide (DMF), then add 100 μL of dibutyltin dilaurate catalyst and react for 3 h;

[0040] (3) Then add 1 mmol of polyetheramine D230, then add 0.5 mmol of polyethylene glycol dimethacrylate, and add 20 ml of solvent DMF. React at 90 °C for 3 h.

[0041] (4) Pour the mixture into an 80°C vacuum drying oven containing the mold and cure for 24 hours to obtain a polyurethane film material. The entire reaction was carried out under a nitrogen atmosphere. The product of Example 1 was named InPU. 0.5 .

[0042] Example 2:

[0043] (1) The steps 1-2 of Example 1 are basically the same;

[0044] (2) Then add 1 mmol of polyetheramine D230, then add 1 mmol of polyethylene glycol dimethacrylate, and add 20 ml of solvent DMF. React at 90 °C for 3 h.

[0045] (3) Pour the mixture into an 80°C vacuum drying oven containing the mold and cure for 24 hours to obtain a polyurethane film material. The entire reaction was carried out under a nitrogen atmosphere. The product of Example 2 was named InPU1.

[0046] Example 3:

[0047] (1) The steps 1-2 of Example 1 are basically the same;

[0048] (2) Add 1 mmol of polyetheramine D230, then add 1.5 mmol of polyethylene glycol dimethacrylate, and add 20 ml of solvent DMF. React at 90 °C for 3 h.

[0049] (3) Pour the mixture into an 80°C vacuum drying oven containing the mold and cure for 24 hours to obtain a polyurethane film material. The entire reaction was carried out under a nitrogen atmosphere. The product of Example 3 was named InPU. 1.5 .

[0050] Example 4:

[0051] (1) The steps 1-2 of Example 1 are basically the same;

[0052] (2) Then add 1 mmol of polyetheramine D230, then add 2 mmol of polyethylene glycol dimethacrylate, and add 20 ml of solvent DMF. React at 90°C for 3 h.

[0053] (3) Pour the mixture into an 80°C vacuum drying oven containing the mold and cure for 24 hours to obtain a polyurethane film material. The entire reaction was carried out under a nitrogen atmosphere. The product of Example 4 was named InPU2.

[0054] Comparative Example 1:

[0055] (1) The steps 1-2 of Example 1 are basically the same;

[0056] (2) Then add 1 mmol of polyetheramine D230 and 20 ml of solvent DMF, and react at 90 °C for 3 h;

[0057] (3) Pour the mixture into an 80°C vacuum drying oven containing the mold and cure for 24 hours to obtain a polyurethane film material. The entire reaction was carried out under a nitrogen atmosphere. Comparative Example 1 was named PU.

[0058] Performance testing:

[0059] To evaluate the differences in the hydrophilicity of polyurethane materials, the contact angles of Examples 1-4 and Comparative Example 1 with water were tested; tribological tests were performed on Examples 1-4 and Comparative Example 1 using a high-speed ring-block friction tester under conditions of 66 N and 0.54 m / s.

[0060] Experimental results:

[0061] To evaluate the mechanical and tribological properties of the polyurethane material, tests were conducted on Examples 1-4 and Comparative Example 1, and the results are as follows: Figures 1 to 4 As shown.

[0062] The contact angle images of the products and water in Examples 1-4 and Comparative Example 1 are shown below. Figure 1 As shown, the contact angle test results of the products of Examples 1-4 and Comparative Example 1 are as follows: Figure 2 As shown, by Figure 1 and Figure 2 It is known that introducing the polyethylene glycol dimethacrylate crosslinking network into the polyurethane chain greatly improves the hydrophilicity of polyurethane, with the lowest contact angle with water reaching 32.4°, which is much lower than the contact angle between PU and water (82.6°).

[0063] The tribological properties of the products from Examples 1-4 and the Comparative Example were tested using a high-speed ring-block friction testing machine. The friction coefficient curves of the products from Examples 1-4 and Comparative Example 1 are shown below. Figure 3 As shown, the average coefficient of friction of the products of Examples 1-4 and Comparative Example 1 is as follows: Figure 4 As shown. By Figure 3 and Figure 4 It is evident that the hydrophilic semi-interpenetrating network structure of polyurethane material provided by this invention maintains a low coefficient of friction and exhibits excellent tribological properties.

[0064] In summary, the polyurethane prepared by this invention has excellent hydrophilic and tribological properties, and is expected to be used in marine, shipbuilding and other fields.

[0065] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention. The above embodiments are provided only for the purpose of describing the present invention and are not intended to limit the present invention. Parts not described in detail in this specification are well-known in the art and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims. All equivalent substitutions and modifications made without departing from the spirit and principle of the present invention should be covered within the scope of the present invention.

Claims

1. A semi-interpenetrating network type polyurethane friction material, characterized in that, The semi-interpenetrating network polyurethane friction material uses hydrophobic linear polyurethane as the matrix, and constructs a hydrophilic cross-linked network in the matrix to form a semi-interpenetrating network structure.

2. The semi-interpenetrating network polyurethane friction material according to claim 1, characterized in that, The hydrophilic crosslinked network is achieved by polymerizing hydrophobic linear polyurethane with polyethylene glycol dimethacrylate.

3. The semi-interpenetrating network polyurethane friction material according to claim 2, characterized in that, The molecular structure of the hydrophobic linear polyurethane is as follows: ； Where m ranges from 3 to 5, and n ranges from 45 to 50.

4. The method for preparing the semi-interpenetrating network polyurethane friction material according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1: Add a chain extender to the polyurethane prepolymer and add polyethylene glycol dimethacrylate, and react at a temperature of 70-90℃ for 2-4 hours. S2: After the reaction is complete, the mixture obtained from the reaction is molded and dried to obtain a semi-interpenetrating network polyurethane friction material.

5. The method for preparing the semi-interpenetrating network polyurethane friction material according to claim 4, characterized in that, The molar ratio of the chain extender to the diol in the polyurethane prepolymer is 3:1 to 3:

2.

6. The method for preparing the semi-interpenetrating network polyurethane friction material according to claim 4, characterized in that, The molar ratio of polyethylene glycol dimethacrylate to the diol in the polyurethane prepolymer is 1:1 to 1:

2.

7. The method for preparing the semi-interpenetrating network polyurethane friction material according to claim 4, characterized in that, In step S1, polyethylene glycol dimethacrylate is added first, followed by the addition of an organic solvent; Alternatively, a polyethylene glycol dimethacrylate solution can be directly added in step S1; wherein the polyethylene glycol dimethacrylate solution is obtained by dissolving polyethylene glycol dimethacrylate in an organic solvent, and the solid content of the polyethylene glycol dimethacrylate solution is 15%-20%.

8. The method for preparing the semi-interpenetrating network polyurethane friction material according to claim 4, characterized in that, The chain extender is polyetheramine D230, N,N'-di-tert-butylethylenediamine, or 4,4'-diaminodicyclohexylmethane.

9. The method for preparing the semi-interpenetrating network polyurethane friction material according to claim 4, characterized in that, Step S1 is carried out in an N2 atmosphere; the drying process in step S2 is carried out at 40℃-80℃ under vacuum conditions for 24h-72h.

10. The method for preparing a semi-interpenetrating network polyurethane friction material according to any one of claims 4 to 9, characterized in that, The polyurethane prepolymer is prepared by the following steps: S0: Polyester or polyether polyol and diisocyanate are mixed in an organic solvent to form a mixture, then a catalyst is added, and the mixture is reacted at 40-80℃ for 2-5 hours to obtain polyurethane prepolymer. The molar ratio of polyester or polyether polyol to diisocyanate is 1:2 to 1:

4. The catalysts are amine catalysts and organometallic catalysts.

Images