Method For Preparing Self-Cleaning Anti-Icing Coating Based On Brushlike Organosilicone

Abstract

The present disclosure relates to a method for preparing a self-cleaning anti-icing coating based on brushlike organosilicon. In this method, a brushlike organosilicon-modified polyurethane coating is prepared by subjecting a thiolactone, a diamine compound and monovinyl-terminated polydimethylsiloxane to a simple multi-component click reaction to obtain a dihydroxy-terminated block, and introducing the dihydroxy-terminated block into a polyurethane matrix.

Claims

1. A method for preparing a self-cleaning anti-icing coating based on brushlike organosilicon, comprising the following steps: step 1, preparing a modified thiolactone: under nitrogen, mixing a solvent A, a thiolactone, a mercaptoalcohol and a base catalyst A in sequence to obtain a first mixture, and subjecting the first mixture to a thiol-ene addition reaction at ambient temperature for 1-3 h to obtain the modified thiolactone, wherein a molar ratio of the thiolactone to the mercaptoalcohol is 1:1; step 2, preparing a siloxane block: sequentially adding the modified thiolactone, a diamine and a siloxane into a reactor to obtain a second mixture, and subjecting the second mixture to an amino nucleophilic ring opening reaction and a thiol click reaction of thiolactone for 6-24 h to obtain the siloxane block, wherein a molar ratio of the modified thiolactone to the diamine to the siloxane is 2:1:2; step 3: preparing a polyurethane matrix: under nitrogen, sequentially adding the solvent A, the siloxane block, a diol, a diisocyanate, a catalyst B and a chain extender into a reactor, and reacting at a temperature of 50-80° C. for 3-12 h to obtain a polyurethane matrix, wherein a molar ratio of the diisocyanate to a mixture of the diol and the siloxane block to the chain extender is in a range of (2-4):1:(1-3), a molar ratio of the diol to the siloxane block in the mixture of the diol and the siloxane block is in a range of 1:(0.01-0.2), and the solvent A accounts for 30%-80% of the total mass of the solvent A, the siloxane block, the diol, the diisocyanate, the catalyst B and the chain extender; and step 4: preparing a brushlike self-cleaning anti-icing coating: dissolving the polyurethane matrix in the solvent A to obtain a mixed solution with a concentration of 10%-50%, laying the mixed solution on a substrate by using a tape casting method, placing the substrate in a drying oven and heating for 18-36 h in a gradient heating manner from 50° C. to 120° C. by using an annealing method, and subjecting the substrate after heating to a vacuum drying at 60-80° C. for 6-24 h to remove remaining solvent to obtain the brushlike self-cleaning anti-icing coating.

2. The method of claim 1, wherein the thiolactone is acrylamide thiolactone.

3. The method of claim 1, wherein the mercaptoalcohol is selected from the group consisting of 3-mercapto-1-propanol, 2-mercaptoethanol and 6-mercapto-1-hexanol.

4. The method of claim 1, wherein the base catalyst A comprises at least one selected from the group consisting of triethylamine, dimethylphenylphosphine and a tributylphosphine basic compound.

5. The method of claim 1, wherein the siloxane is monovinyl-terminated polydimethylsiloxane.

6. The method of claim 1, wherein the solvent A comprises at least one selected from the group consisting of tetrahydrofuran, dioxane and n-butyl acetate.

7. The method of claim 1, wherein the diamine comprises at least one selected from the group consisting of polyetheramine D 400, polyetheramine D 2000 and hexamethylene diamine.

8. The method of claim 1, wherein the catalyst B comprises at least one selected from the group consisting of triethylamine, dibutyltin dilaurate and triethylenediamine basic compound.

9. The method of claim 1, wherein the diisocyanate comprises at least one selected from the group consisting of toluene diisocyanate, isophorone diisocyanate, methylenediphenyl diisocyanate, dicyclohexylmethane diisocyanate, hexamethylene diisocyanate and lysinediisocyanate.

10. The method of claim 1, wherein the chain extender is a diol chain extender selected from the group consisting of ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, 1,4-cyclohexanediol, hydrogenated bisphenol A, terephthalyl alcohol, hydroquinone bis-β-hydroxyethyl ether and resorcinol hydroxy ether.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a schematic diagram of an ice adhesion test device;

[0028] FIG. 2A shows a sample at the start of the surface self-cleaning performance test of Example 3;

[0029] FIG. 2B shows a sample during the surface self-cleaning performance test of Example 3;

[0030] FIG. 2C shows a sample at the end of the surface self-cleaning performance test of Example 3.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0031] The present disclosure is further described with reference to examples and accompanying drawings.

Example 1

[0032] Under nitrogen, 5.0 mL of dioxane, 0.10 mmol of acrylamide thiolactone, 0.10 mmol of 3-mercapto-1-propanol and 0.50 mL of triethylamine were respectively added into a reactor to obtain a first mixture, and the first mixture was subjected to a thiol-ene addition reaction at ambient temperature for 1 h, obtaining a modified thiolactone. 0.05 mmol of a diamine and 0.10 mmol of a siloxane were sequentially added in the reactor to obtain a second mixture, and the second mixture was sequentially subjected to an amino nucleophilic ring opening reaction and a thiol click reaction of thiolactone for 6 h, obtaining a siloxane block. Under nitrogen, 12 mmol of PTMEG, 6 mmol of IPDI, 50 μL of DBTDL and 6 mmol of BDO (dissolved in 5 mL of DOX) were sequentially added into a reactor and reacted at a temperature of 60° C. for 4 h, obtaining a resin matrix. 1 g of the resin matrix was taken and dissolved in 3 mL of DOX, obtaining a solution with a concentration of 25%. The solution was laid on a substrate by using a tape casting method, and the substrate was placed in a drying oven and heated for 18 h in a gradient heating manner from 50° C. to 120° C. by using an annealing method, and then subjected to a vacuum drying at a temperature of 60° C. for 6 h to remove remaining solvent, obtaining a brushlike self-cleaning anti-icing coating with a smooth and flat surface. The coating has a tensile strength of 6.5 MPa, a water contact angle of 93° determined by a contact angle experiment, and a delayed icing time of 5 min.

[0033] Ice adhesion test: An ice adhesion test device used mainly includes a cooling plate 1, a dynamometer (SUNDOO, SH-50N) comprising a force transducer 2 and a force probe 3, a plastic cuvette 4 (1*1*4.5 cm.sup.3), and a motion stage 5. Firstly, a sample 6 to be tested was fixed on the cooling plate 1, a thermocouple was fixed at the bottom of the sample 6 to determine the test temperature, the cuvette 4 containing 1.5 mL of deionized water was put upside down on the surface of the sample 6 (icicle cross-sectional area A.sub.ice=1*1 cm.sup.2=1 cm.sup.2), the whole test device was placed at a temperature of −12° C. for 6 h to ensure that the water frozen (with a cooling plate temperature of −12° C., an ambient temperature of 15° C., and a humidity of 50%) to an icicle, and the icicle was pushed horizontally by the force probe 3 vertical thereto at a constant speed of 2 mm/s. A maximum force (F.sub.max) of the force probe 3 pushing the icicle is recorded as a force for removing ice from the surface of the sample, and the ice adhesion (τ.sub.ice) could be calculated by using the formula τ.sub.ice=F.sub.max/A.sub.ice. The foregoing process was repeated at least three times to ensure its repeatability.

[0034] According to the test, the sample has an F.sub.max of 4.60 N, and a τ.sub.ice of 46.0 kPa.

Example 2

[0035] Under nitrogen, 5.0 mL of dioxane, 0.20 mmol of acrylamide thiolactone, 0.20 mmol of 3-mercapto-1-propanol and 1.0 mL of triethylamine were respectively added into a reactor to obtain a first mixture, and the first mixture was subjected to a thiol-ene addition reaction at ambient temperature for 3 h, obtaining a modified thiolactone. 0.10 mmol of a diamine and 0.20 mmol of a siloxane were sequentially added in the reactor to obtain a second mixture, and the second mixture was sequentially subjected to an amino nucleophilic ring opening reaction and a thiol click reaction of thiolactone for 18 h, obtaining a siloxane block. Under nitrogen, 8.0 mmol of PTMEG, 2.0 mmol of IPDI, 150 μL of DBTDL and 6.0 mmol of BDO (dissolved in 5 mL of DOX) were sequentially added into a reactor and reacted at a temperature of 80° C. for 6 h, obtaining a resin matrix. 1 g of the resin matrix was taken and dissolved in 4 mL of DOX, obtaining a solution with a concentration of 20%. The solution was laid on a substrate by using a tape casting method, and the substrate was placed in a drying oven and heated for 24 h in a gradient heating manner from 50° C. to 120° C. by using an annealing method, and then subjected to a vacuum drying at a temperature of 60° C. for 8 h to remove remaining solvent, obtaining a brushlike self-cleaning anti-icing coating with a smooth and flat surface. The coating has a tensile strength of 18 MPa, a water contact angle of 990 determined by a contact angle experiment, and a delayed icing time of 7 min.

[0036] Ice adhesion test: An ice adhesion test device used mainly includes a cooling plate 1, a dynamometer (SUNDOO, SH-50N) comprising a force transducer 2 and a force probe 3, a plastic cuvette 4 (1*1*4.5 cm.sup.3), and a motion stage 5. Firstly, a sample 6 to be tested was fixed on the cooling plate 1, a thermocouple was fixed at the bottom of the sample 6 to determine the test temperature, the cuvette 4 containing 1.5 mL of deionized water was put upside down on the surface of the sample 6 (icicle cross-sectional area A.sub.ice=1*1 cm.sup.2=1 cm.sup.2), the whole test device was placed at a temperature of −12° C. for 6 h to ensure that the water frozen (with a cooling plate 1 temperature of −12° C., an ambient temperature of 15° C., and a humidity of 50%) to an icicle, and the icicle was pushed horizontally by the force probe 3 vertical thereto at a constant speed of 2 mm/s. A maximum force (F.sub.max) of the force probe 3 pushing the icicle is recorded as a force for removing ice from the surface of the sample, and the ice adhesion (τ.sub.ice) could be calculated by using the formula τ.sub.ice=F.sub.max/A.sub.ice. The foregoing process was repeated at least three times to ensure its repeatability.

[0037] According to the test, the sample has an F.sub.max of 1.94N, and a τ.sub.ice of 19.4 kPa.

Example 3

[0038] Under nitrogen, 5.0 mL of dioxane, 0.10 mmol of acrylamide thiolactone, 0.10 mmol of 3-mercapto-1-propanol and 0.50 mL of triethylamine were respectively added into a reactor to obtain a first mixture, and the first mixture was subjected to a thiol-ene addition reaction at ambient temperature for 1 h, obtaining a modified thiolactone. 0.05 mmol of a diamine and 0.10 mmol of a siloxane were sequentially added in the reactor to obtain a second mixture, and the second mixture was sequentially subjected to an amino nucleophilic ring opening reaction and a thiol click reaction of thiolactone for 6 h, obtaining a siloxane block. Under nitrogen, 16 mmol of PTMEG, 4 mmol of IPDI, 50 μL of DBTDL and 12 mmol of BDO (dissolved in 5 mL of DOX) were sequentially added into a reactor and reacted at a temperature of 70° C. for 10 h, obtaining a resin matrix. 1 g of the resin matrix was taken and dissolved in 2 mL of DOX, obtaining a solution with a concentration of 33%. The solution was laid on a substrate by using a tape casting method, and the substrate was placed in a drying oven and heated for 18 h in a gradient heating manner from 50° C. to 120° C. by using an annealing method, and then subjected to a vacuum drying at a temperature of 60° C. for 12 h to remove remaining solvent, obtaining a brushlike self-cleaning anti-icing coating with a smooth and flat surface. The coating has a tensile strength of 32.95 MPa, a water contact angle of 95.870 determined by a contact angle experiment, and a delayed icing time of 7 min.

[0039] Ice adhesion test: An ice adhesion test device used mainly includes a cooling plate 1, a dynamometer (SUNDOO, SH-50N) comprising a force transducer 2 and a force probe 3, a plastic cuvette 4 (1*1*4.5 cm.sup.3), and a motion stage 5. Firstly a sample 6 to be tested was fixed on the cooling plate, a thermocouple was fixed at the bottom of the sample 6 to determine the test temperature, the cuvette 4 containing 1.5 mL of deionized water was put upside down on the surface of the sample 6 (icicle cross-sectional area A.sub.ice=1*1 cm.sup.2=1 cm.sup.2), the whole test device was placed at a temperature of −12° C. for 6 h to ensure that the water frozen (with a cooling plate 1 temperature of −12° C., an ambient temperature of 15° C., and a humidity of 50%) to an icicle, and the icicle was pushed horizontally by the force probe 3 vertical thereto at a constant speed of 2 mm/s. A maximum force (F.sub.max) of the force probe 3 pushing the icicle is recorded as a force for removing ice from the surface of the sample, and the ice adhesion (τ.sub.ice) could be calculated by using the formula τ.sub.ice=F.sub.max/A.sub.ice. The foregoing process was repeated at least three times to ensure its repeatability.

[0040] According to the test, the sample has an F.sub.max of 2.02N, and a τ.sub.ice of 20.2 kPa.