CN114262401B - Photoinduced reversible solid-liquid conversion azobenzene high polymer material and application thereof in trenchless pipeline repair - Google Patents

Abstract

The invention discloses a photoreversible solid-liquid transition azobenzene polymer material and its application in non-excavation pipeline repair, wherein the photoreversible solid-liquid transition azobenzene polymer material has two types: trans and cis Configuration, shown in following formula I-(E) and following formula I-(Z) respectively:

The polymer of formula I-(E) in trans configuration is solid at room temperature, and the polymer of formula I-(Z) in cis configuration is liquid at room temperature. The azobenzene polymer material of the present invention can be used as a non-excavation pipeline repair lining material, and the pipeline lining layer is obtained by spraying or pouring the azobenzene polymer solution; when the pipeline is damaged, ultraviolet light is applied to the lining layer, Allows lining material to flow to fill cracks for pipeline repair.

Description

A photoreversible solid-liquid transition azobenzene polymer material and its application in trenchless pipelines application in repair

technical field

The invention belongs to the technical field of pipeline repair, and in particular relates to a photoreversible solid-liquid transition azobenzene polymer material and its application in trenchless pipeline repair.

Background technique

In 2020, the length of urban drainage pipelines has exceeded 800,000 kilometers. If the pipelines are used for a long time, they will be damaged such as aging, corrosion, cracks and collapses, and they need to be repaired in time. Pipeline trenchless repair technology refers to the construction of laying, replacing and repairing various underground pipelines under the condition of excavating a very small part of the surface by using various geotechnical drilling equipment and technical means through guided and directional drilling. The new technology will not hinder traffic, destroy vegetation, and will not affect the normal operation of society, so it has high social and economic value.

The existing trenchless pipeline repair technology is a kind of ultraviolet curing pipeline repair technology from Germany, which is the mainstream technology of municipal pipeline trenchless repair. However, after the lining pipe of this repair technology is damaged again, it cannot be repaired again because the traditional cross-linked polymer cannot be melted or dissolved. If you want to stop the water pipe from leaking, you can only flush the lining pipe again or directly excavate and replace the pipe.

Contents of the invention

In view of this, the present invention provides a photoreversible solid-liquid transition azobenzene polymer material and its application in trenchless pipeline repair. The azobenzene macromolecule material of the present invention can change from solid state to liquid state under ultraviolet light for many times, and return to solid state after stopping the light, which meets the requirement of multiple non-excavation repairs of pipelines.

The photoreversible solid-liquid transition azobenzene polymer material of the present invention has two configurations of trans and cis, respectively shown in the following formula I-(E) and the following formula I-(Z):

The trans-configuration formula I-(E) macromolecule is solid at room temperature, and the cis-configuration formula I-(Z) macromolecule is liquid state at room temperature.

The degree of polymerization of the azobenzene polymer material is n=n ₁ +n ₂ , and the range of n is 14-200; the polydispersity index is 1.1-2.

The preparation method of azobenzene polymer material of the present invention comprises the steps:

Step 1: Put the monomer 6-(4-((4-decylphenyl)diazo)phenoxy)hexyl methacrylate, cuprous bromide, and initiator into a pressure-resistant bottle, and then Operate in a glove box, add ligand and anhydrous anisole into the bottle with a syringe, take it out from the glove box after sealing, react at room temperature for 20-320min, overbasic alumina column, then pour it into petroleum ether, pump Filter, dry, dissolve the solid with tetrahydrofuran, and then remove unreacted monomers by multiple precipitations in ether, and dry overnight in vacuum at 45°C to prepare an azobenzene polymer with the structure shown in formula I-(E).

Step 2: Azobenzene polymer I-(E) in trans configuration is converted into azobenzene molecule I-(Z) in cis configuration under 1-100mW/ ^cm2 365nm ultraviolet light irradiation, phase state From solid state to liquid state; cis-configuration azobenzene polymer I-(Z) is placed naturally at room temperature, or converted to trans-configuration azobenzene under 530nm visible light irradiation of 1-100mW/ ^cm2 Polymer I-(E), phase transition from liquid to solid.

Repeating the above step 2, the reversible cycle of solid-liquid transformation can be realized.

In step 1, the structure of the monomer is shown in the following formula II:

The monomer shown in formula II has two configurations: trans and cis. When preparing the trans azobenzene polymer with the structure shown in formula I-(E), as long as the trans configuration in the monomer shown in formula II is guaranteed The content is ≥85%. Under this condition, it can be directly used in the preparation of step 1 azobenzene polymer material.

In step 1, the initiator is 1,8-diacyl bis(2-bromo-2-methylpropionate) octane. Compared with the initiator used for conventional polymerization of azobenzene, this kind of initiator at both ends can increase the polymerization efficiency by at least one time, and is suitable for industrial production.

The initiator 1,8-diacyl bis(2-bromo-2-methylpropionate) octane is prepared by a method comprising the following steps:

Dissolve 1,8-octanediol (1.65g, 11.3mmol) in dichloromethane solvent, then add triethylamine (8.2mL, 58.9mmol) to it, stir well, and cool to below 5°C in an ice-water bath ; Add dropwise 2-bromoisobutyryl bromide (7ml, 56.5mmol) in the system at a speed of 3s/ drop, white smoke is produced during the dropwise addition process, and the temperature rises slightly; after dropwise addition, seal with parafilm bottle mouth, continue overnight stirring reaction for 12h; after the reaction is completed, extract three times with dichloromethane (lower layer) and saturated aqueous solution of sodium chloride, collect the organic phase, dry over anhydrous sodium sulfate to remove water, filter, and remove the solvent by rotary evaporation at 40°C. Silica gel column, the eluent is petroleum ether: dichloromethane 100:0-4:1 (v/v), vacuum dried at 45°C for 4h to obtain 1.8g initiator.

The invention obtains an azobenzene polymer material with photoreversible solid-liquid transition characteristics at room temperature through an ATRP polymerization method, and can be used as a non-excavation pipeline repair lining material. Specifically, the inner lining layer of the pipeline is obtained by spraying or pouring the azobenzene polymer solution. When the pipeline is damaged, applying ultraviolet light to the lining layer can make the lining material flow to fill the cracks and realize pipeline repair.

The thickness of the inner lining layer is 0.1-1 mm.

The organic solvent of the azobenzene polymer solution can be any one of chloroform, tetrahydrofuran, anisole or dioxane.

The concentration of the azobenzene polymer solution is 20-50wt%.

In the azobenzene macromolecule solution, because the azobenzene macromolecule I-(Z) of the cis configuration has fluidity, it may be washed away by the liquid in the pipeline, and the azobenzene macromolecule of the trans configuration The I-(E) content needs to exceed 80%. After the solvent volatilizes, an inner lining layer with better mechanical properties can be formed to protect the pipeline.

Compared with the existing lining materials for trenchless pipeline repair, the present invention has the following advantages:

The photo-liquefied inner lining material for non-excavation pipeline repair of the present invention has a linear structure, which can be heated above the melting point to make it flow, and can also undergo photo-induced solid-liquid transformation by utilizing photo-induced cis-trans isomerism. Once the pipeline is damaged, the azobenzene polymer can be made to flow through heating or light, so as to realize multiple non-excavation repairs of the pipeline. Moreover, due to the fluidity of the cis-azobenzene polymer material, under the action of pressure and gravity, the cis-azobenzene polymer can be sucked into the crack by capillary force to completely fill the entire crack and achieve better Repair effect.

Description of drawings

Figure 1 shows the H NMR spectra of polymerized monomers.

Figure 2 shows the H NMR spectrum of the azobenzene polymer.

Fig. 3 shows the photomicrograph (scale bar is 50 μm) of liquefaction of trans-azobenzene solid sample under the irradiation of ultraviolet light (365nm LED light source).

Fig. 4 shows the computerized tomography results (the scale is 6 mm) of the PVC-U pipe coated with azobenzene polymer before and after repair.

detailed description

In order to further illustrate the present invention, the synthesis method of the azobenzene polymer material with photoreversible solid-liquid transition characteristics provided by the present invention and its application as a pipeline repair lining will be described in detail below in conjunction with examples.

The 4-n-decylaniline used in the following examples was purchased from TCL, concentrated hydrochloric acid, tetrahydrofuran, sodium nitrite, phenol, sodium hydroxide, sodium bicarbonate, anhydrous potassium carbonate, anhydrous sodium sulfate, chloroform and methanol were purchased from Sinopharm, petroleum ether and methylene chloride were purchased from Cologne Chemicals, 6-chloro-1-hexanol was purchased from Anaiji, and methacryloyl chloride was purchased from McLean.

Embodiment 1: the synthesis of polymerization monomer

1. 4-n-decylaniline (10g, 42.8mmol) was added to a mixed solution of dilute hydrochloric acid (11.0ml, ρ=1.18g/ml, 128.8mmol) and tetrahydrofuran (40ml), then placed in an ice-water bath. After stirring evenly, an aqueous solution of sodium nitrite (2.950 g, 42.8 mmol) was slowly added thereto, and mixed for 20 min. Phenol (4.6 mL, 1.071 g/ml, 49.5 mmol) was dissolved in an aqueous solution of sodium hydroxide (1.7 g, 43.0 mmol) and potassium carbonate (6.0 g, 43.4 mmol), and stirred for 20 min. The mixed solution containing 4-n-decylaniline was slowly added dropwise to the mixed solution containing phenol to react, the solution gradually changed from yellow to brown, and stirred at room temperature for 4 h. Neutralize to pH=6 with dilute hydrochloric acid, filter with suction, and wash with water three times to obtain a yellow-brown solid. Vacuum-dried at 45°C overnight, thermally recrystallized from petroleum ether, filtered, and vacuum-dried again to obtain 13.8 g of the product. Yield: 95%.

2. Weigh the product 4-(4-decylphenylazo)phenol (13.5g, 39.8mmol) in step 1 and dissolve it in 300ml N,N-dimethylformamide, add potassium carbonate (6.0g, 43.4mmol), stirred for 20min. Add 6-chloro-1-hexanol (8ml, ρ=1.024g/ml, 60.0mmol) and several grains of potassium iodide to it, and react at 110°C for 22h. After cooling, it was extracted with ethyl acetate and aqueous sodium bicarbonate solution, and the organic phase was separated, dried over anhydrous sodium sulfate, filtered, and ethyl acetate was removed by rotary evaporation at 45°C to obtain a crude product. The crude product was recrystallized twice using dichloromethane and petroleum ether as good and poor solvents, respectively. Drying under vacuum at 45°C overnight gave 17.0 g of product. Yield: 90%.

3. Weigh the product 6-(4-((4-decylphenylazo)phenoxy)hexan-1-ol (10.2g, 23.1mmol), triethylamine (3.6ml, ρ =0.73g/ml, 25.5mmol) and 150mL dichloromethane join in the 250mL one-necked flask, place in ice-water bath.After stirring evenly, through the dropping funnel, with the speed of 3～4 seconds/drop, add formazan wherein A mixed solution of acryloyl chloride (2.7mL, ρ=1.1g/ml, 28.5mmol) and 30mL of dichloromethane. Overnight reaction for 14h, all the raw materials on the spot plate were reacted. Under the condition of stirring, sodium bicarbonate was added to the solution to saturate Neutralize the remaining methacryloyl chloride with aqueous solution, and then extract three times with dichloromethane. Separate the organic phase, dry it with anhydrous sodium sulfate, filter, and remove the solvent by rotary evaporation. Then recrystallize twice with tetrahydrofuran and methanol, and filter with suction , dried overnight at 40° C. under vacuum to obtain 9.6 g of polymerized monomers, yield: 80%.

Figure 1 shows the H NMR spectra of the prepared polymerized monomers.

Embodiment 2: Polymerization of azobenzene macromolecule

Dissolve 1,8-octanediol (1.65g, 11.3mmol) in 80mml of dichloromethane solvent, then add triethylamine (8.2mL, 58.9mmol) to it, stir well, and cool to 5°C in an ice-water bath Below; through the dropping funnel, add 2-bromoisobutyryl bromide (7ml, 56.5mmol) in this solution with the speed of 3s/ drops, white mist is produced in the dropping process, and temperature rises slightly. After the dropwise addition, seal the mouth of the bottle with parafilm and continue to stir overnight for 12h. Extract three times with dichloromethane (lower layer) and saturated aqueous sodium chloride, and collect the organic phase. Dry with anhydrous sodium sulfate to remove water, filter, and remove solvent by rotary evaporation at 40°C. Pass through a silica gel column, and the eluent is petroleum ether:dichloromethane 100:0-4:1. Vacuum-dry at 45°C for 4 hours to obtain 1.8g of initiator.

Take the monomer 6-(4-((4-decylphenyl)azo)phenoxy)hexyl methacrylate (2.000g, 4mmol), cuprous bromide (38.0mg, 26.4 μmol), double-ended initiator 1,8-diacylbis(2-bromo-2-methylpropionate) octane (57.2mg, 128.8μmol) were put into a 15mL thick-walled pressure-resistant bottle, and then To operate in the box, add the ligand PMDETA (110 μl, 529.0 μmol) to the bottle with a microsyringe, then add 4 mL of anhydrous anisole, seal it and take it out of the glove box. Stir in a water bath at 31°C for 40 minutes, and the monomer conversion rate is 51.7%. After passing through a basic alumina column, pour it into petroleum ether, filter it with suction, and dry it. The solid was dissolved in tetrahydrofuran, and unreacted monomers were removed by precipitation in ether, and dried under vacuum at 45°C overnight to obtain the polymer shown in formula II-(E). Polymer _Mn = 15K, PDI = 1.18 as determined by GPC. Figure 2 shows the H NMR spectrum of the prepared azobenzene polymer.

Example 3: Photo-induced solid-liquid transition of azobenzene polymers at the micron scale

At room temperature, take a small amount of azobenzene polymer (embodiment 2) solid sample on a smooth and clean glass slide, place the glass slide on the stage of the microscope, and use 365nm (5.5mW/cm ² ) ultraviolet light The surface of the solid sample is irradiated to cause photoisomerization, and after 15 minutes of irradiation, a complete solid-liquid transition is achieved. Figure 3 shows the liquefaction of trans solid samples under UV light irradiation.

Example 4: Repair result of PVC-U pipe lined with azobenzene polymer

At room temperature, 800mg of azobenzene macromolecule (Example 2) was dissolved in 4ml of tetrahydrofuran, configured into a solution with a mass fraction of 23wt%, and spin-coated on a PVC-U tube with an inner diameter of 28mm and a length of 10cm . After standing at room temperature for 2 hours, put it into a vacuum oven at 45°C to dry overnight. Use a CNC machine tool to penetrate the PVC-U pipe (the crack is 12mm long and 0.5mm wide), and then irradiate the inside of the PVC-U pipe with a 365nm (8mW/cm ² ) ultraviolet lamp to make the azobenzene polymer lining occur. After photoisomerization and fluidity, the cracks were repaired after about 4 hours. Fig. 4 shows the computerized tomography results before and after the repair of the PVC-U pipe coated with azobenzene polymer (the scale bar is 6mm).

It can be seen from the above examples that the azobenzene polymer provided by the present invention has high synthesis efficiency and excellent photoreversible solid-liquid transition characteristics, and can be used for repairing pipelines.

The descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principles of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims (7)

1. A photoreversible solid-liquid transition azobenzene polymer material, characterized in that: The photoreversible solid-liquid transition azobenzene polymer material has two configurations of trans and cis, respectively shown in the following formula I-(E) and the following formula I-(Z):

The formula I-(E) macromolecule of the trans configuration is solid at room temperature, and the formula I-(Z) macromolecule of the cis configuration is liquid at room temperature; The degree of polymerization of the azobenzene polymer material is n=n ₁ +n ₂ , and the range of n is 14-200; the polydispersity index is 1.1-2; The photoreversible solid-liquid transition azobenzene polymer material is prepared by a method comprising the following steps: Step 1: Put the monomer 6-(4-((4-decylphenyl)diazo)phenoxy)hexyl methacrylate, cuprous bromide, and initiator into a pressure-resistant bottle, and then Operate in a glove box, add ligand and anhydrous anisole into the bottle with a syringe, take it out from the glove box after sealing, react at room temperature for 20-320min, overbasic alumina column, then pour it into petroleum ether, pump Filter, dry, dissolve solid with tetrahydrofuran, then remove unreacted monomer by repeated precipitation in ether, dry in vacuo, prepare the azobenzene macromolecule of structure as shown in formula I-(E); Step 2: Azobenzene polymer I-(E) in trans configuration is converted into azobenzene molecule I-(Z) in cis configuration under 1-100mW/ ^cm2 365nm ultraviolet light irradiation, phase state From solid state to liquid state; cis-configuration azobenzene polymer I-(Z) is placed naturally at room temperature, or converted to trans-configuration azobenzene under 530nm visible light irradiation of 1-100mW/ ^cm2 Polymer I-(E), the phase state changes from liquid to solid; In step 1, the structure of the monomer is shown in the following formula II:

In step 1, the initiator is 1,8-diacyl bis(2-bromo-2-methylpropionate) octane. 2. The photoreversible solid-liquid transition azobenzene macromolecule material according to claim 1, characterized in that said initiator 1,8-diacyl bis(2-bromo-2-methylpropionate) octane Alkane is prepared by a method comprising the following steps: Dissolve 1,8-octanediol in dichloromethane solvent, then add triethylamine to it, stir evenly, cool to below 5°C in an ice-water bath; add 2-bromoisobutyryl bromide dropwise to the system , during the dropwise addition, white smoke was produced, and the temperature rose slightly; after the dropwise addition was completed, the bottle mouth was sealed, and the stirring reaction was continued for 12 hours; after the reaction was completed, the initiator was separated and purified. 3. an application of the photoreversible solid-liquid transition azobenzene polymer material according to claim 1, characterized in that: The azobenzene polymer material is used as a lining material for non-excavation pipeline repair, and the pipeline lining layer is obtained by spraying or pouring the azobenzene polymer solution; when the pipeline is damaged, ultraviolet light is applied to the lining layer, which can Allows lining material to flow to fill cracks, enabling pipeline repair. 4. The application according to claim 3, characterized in that: The thickness of the inner lining layer is 0.1-1 mm. 5. The application according to claim 3, characterized in that: The organic solvent of the azobenzene polymer solution can be any one of chloroform, tetrahydrofuran, anisole or dioxane. 6. The application according to claim 3 or 5, characterized in that: The concentration of the azobenzene polymer solution is 20-50wt%. 7. The application according to claim 3, characterized in that: In the azobenzene polymer solution, the content of trans-configuration azobenzene polymer I-(E) is more than or equal to 80 wt%.

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