CN114133501B - Preparation method of high-water-vapor adsorption polymer ionic gel - Google Patents

Abstract

The invention discloses a method for preparing a polymer ion gel with high water vapor adsorption. By selecting an ionic liquid with high water vapor adsorption capacity and fixing it in a three-dimensional porous network structure of the polymer through in-situ polymerization reaction, the ion gel with high water vapor adsorption capacity is formed. Water vapor adsorption capacity of polymer ion gels. In the present invention, the ionic liquid is adsorbed and saturated first and then fixed in the three-dimensional network structure of the polymer, which avoids the problem of ion gel adsorption saturation leakage, and in the ion gel preparation process, the ionic liquid itself acts as a solvent, reducing the use of chemical reagents . The ion gel can be prepared into blocks, columns or films according to the shape of the mold, and has good flexibility of polymers, and can be widely used in drying, dehumidification, air water collection and other fields.

Description

A kind of preparation method of high water vapor adsorption polymer ion gel

technical field

The invention relates to a method for preparing a high water vapor adsorption polymer ion gel, which belongs to the technical field of drying and dehumidification.

Background technique

Ionic liquids refer to salts that are liquid at or near room temperature and are composed entirely of anions and cations. Due to their good thermal stability, low ignition point, high conductivity, wide electrochemical window and environmental friendliness, ionic liquids have attracted widespread attention in the scientific community and have been applied in the fields of organic synthesis, catalysis, electrochemistry and lubricants. The material formed by immobilizing ionic liquids on a solid substrate is called an ionogel. Ionic gels have the dual characteristics of both ionic liquid and solid matrix, showing good application prospects.

Compared with ionogels with inorganic substances as solid matrix, polymer ionogels exhibit good mechanical properties and flexibility, making them flexible in industrial production. Polymer ion gels not only have good processing properties of polymers, but also can overcome the problems of easy leakage and difficult encapsulation of ionic liquids. At the same time, ionic liquids are used as electrolytes for polymerization reactions, which avoids the poisonous and toxic effects of various organic solvents in traditional gel polymerization reactions. Fire, explosion and other safety hazards caused by flammable and other characteristics.

Although the unique advantages of ionic liquids make them widely used, most of them have extremely strong water absorption, whether they are hydrophilic or hydrophobic. Water vapor is ubiquitous, and ionic liquids can readily absorb water vapor from the atmosphere, even though the presence of trace amounts of water vapor has a strong impact on the measurements of ionic liquid properties. Therefore, this property of ionic liquids has been regarded as a huge disadvantage, and few studies have taken the strong water absorption of ionic liquids as an advantage, and synthesized ionic gels for industrial equipment and systems. Current ion gels are mainly used in electrode materials, catalysis and other fields. Therefore, when selecting ionic liquids and synthesizing ion gels, various methods are used to reduce the water vapor adsorption performance of ion gels, which lacks the water vapor adsorption performance of ionic liquids. option to prepare ionogels with high water vapor adsorption properties.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention provides a method for preparing a high water vapor adsorption polymer ion gel, the purpose of which is to select a high water vapor adsorption ionic liquid, construct a porous network structure through in-situ polymerization, and fix the ionic liquid in Among them, polymer ion gels with high water vapor adsorption are formed.

Technical scheme of the present invention:

A method for preparing high water vapor adsorption polymer ion gel, comprising the following steps:

(1) Place the ionic liquid in a constant temperature and humidity box, set the temperature of the constant temperature and humidity box to be 0-25°C, and the relative humidity to be 80%-90%. Under this condition, the ionic liquid can absorb water vapor to reach saturation. Weigh the mass of the ionic liquid for 1-2 hours to two hours until there is no change in mass for two consecutive times;

(2) Mix the polymer monomer, the saturated ionic liquid obtained in step (1), and the polymerization initiator, stir fully to form a uniform solution, and inject it into a mold of a specific shape, wherein the mass ratio of the initiator is between 0.1% and 1%, the mass ratio of polymer monomer is 40%-60%;

(3) By one of ultraviolet polymerization, microwave polymerization or thermal polymerization, the mixed solution in step (2) undergoes in-situ polymerization reaction to obtain high water vapor adsorption polymer ion gel.

In the present invention, the polymerization reaction methods include three methods: ultraviolet polymerization, microwave polymerization and thermal polymerization.

Among them, the ultraviolet polymerization condition is room temperature, the effective ultraviolet wavelength is 365nm, the power is 8-12W, the ultraviolet light intensity is 200-400mW/cm ² , and the ultraviolet polymerization time is 60-120min; the microwave polymerization condition is that the microwave power is 200-300W, The microwave radiation time is 30-60s, and the microwave radiation program is to start and stop alternately for 1-5s; the thermal polymerization condition is to heat at 60-80°C for 30-60min.

In the present invention, the polymerization initiator includes azobisisobutyronitrile, azobisisoheptanonitrile, N-dimethylaniline and other substances that can promote the corresponding polymerization reaction.

In the present invention, the ionic liquid includes 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM BF4), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM BF4), 1-ethyl Ethyl-3-methylimidazole bis-trifluoromethanesulfonimide salt (EMIM TFSI), 1-hexyl-3-methylimidazole bis-trifluoromethanesulfonimide salt (HMIM TFSI), 1-ethyl-3 -Methyl-imidazolium acetate (EMIM Ac), 1-butyl-3-methylimidazole chloride (BMIM Cl), 1-butyl-3-methylimidazole bromide (BMIM Br), iodide 1-Butyl-3-methylimidazole (BMIM I), 1-Butyl-3-methylimidazole trifluoromethanesulfonate (BMIM Otf), 1-Butyl-3-methylimidazole trifluoroacetic acid salt (BMIM TFA), 1-butyl-3-methylimidazolium p-toluenesulfonate (BMIM TOS), 1,3-dimethylimidazolium phosphate (MMIM DMP), 1-butyl -3-methylimidazolium hexafluorophosphate (BMIM PF6), 1-butyl-3-methylimidazolium trifluoromethanesulfonimide salt (BMIM TFSI), 1-ethyl-3-methylimidazolium phosphate Hygroscopic ionic liquids such as diethyl ester salt (EMIM DEP).

In the present invention, polymer monomers include monomers and oligomers, such as styrene, methyl methacrylate, dimethyl siloxane, low molecular polyethylene glycol diacrylate (PEGDA), polyurea, poly Substances that can undergo polymerization reactions such as carbonates, polyesters or polyamides.

In the present invention, the mold used may be in the shape of a cylinder, a cuboid, a film, or the like.

The invention has the beneficial effects of selecting the ionic liquid with high water vapor adsorption capacity and fixing it in the polymer three-dimensional porous network structure through in-situ polymerization to form a polymer ion gel with high water vapor adsorption capacity. In the present invention, the ionic liquid is adsorbed and saturated first and then fixed in the three-dimensional network structure of the polymer, which avoids the problem of ion gel adsorption saturation leakage, and in the ion gel preparation process, the ionic liquid itself acts as a solvent, reducing the use of chemical reagents . The ion gel can be prepared into blocks, columns or films according to the shape of the mold, and has good flexibility of polymers, and can be widely used in drying, dehumidification, air water collection and other fields.

Description of drawings

Figure 1 is a thin film ion gel.

Figure 2 is a scanning electron microscope image of the ion gel.

Figure 3 is the ion gel adsorption isotherm.

Detailed ways

Specific embodiments of the present invention will be described in detail below in conjunction with technical solutions and accompanying drawings.

Example 1

PEGDA oligomer is used for polymerization reaction, EMIM Ac is used as ionic liquid, azobisisobutyronitrile is used as initiator, and high water vapor adsorption polymer ion gel is prepared by thermal polymerization method. The specific steps are as follows:

(1) Weigh 10g of EMIM Ac and place it in a constant temperature and humidity box. Set the temperature of the constant temperature and humidity box at 25°C and the relative humidity at 90%. Measure the mass of the ionic liquid until there is no change in the mass for two consecutive times, and stop the adsorption without any change in the two measured values at the 38th hour and the 40th hour;

(2) Weighing the EMIM Ac mass of adsorption saturation is 20g, and calculating the mass fraction of EMIM Ac in the saturated EMIM Ac is 50%;

(3) PEGDA, step (1) obtained saturated EMIM Ac, and azobisisobutyronitrile are mixed so that the mass ratio of PEGDA, EMIMAc and azobisisobutyronitrile is 60%: 39.5%: 0.5%, fully stirred Make it form a homogeneous solution, the stirring rate is 500r/min, and the stirring time is 30min, and then inject it into a cylindrical mold;

(4) Place the cylindrical mold in an environment of 60° C. and heat for 30 minutes, so that the mixed solution in the cylindrical mold undergoes an in-situ polymerization reaction, and then obtain a high water vapor adsorption polymer ion gel;

(5) Utilize dynamic vapor adsorption instrument, take by weighing 0.1g step (4) gained ion gel, keep adsorption temperature as 25 ℃, test the adsorption capacity of ion gel at 0-90% relative humidity, with relative humidity and adsorption Draw the adsorption isotherm.

As can be seen from Figure 1, the method can prepare a circular film-shaped polymer ion gel;

It can be seen from Figure 2 that the prepared polymer ion gel has a continuous three-dimensional porous cross-linked network structure, which provides sufficient adsorption sites for water vapor adsorption;

It can be seen from Figure 3 that the adsorption isotherm of the prepared polymer ion gel is a type III adsorption isotherm. When the relative humidity is lower than 50%, the adsorption capacity and relative humidity are linearly positively correlated. When the relative humidity is greater than 50%. , the adsorption capacity is positively correlated with the relative humidity exponentially.

Example 2

Polymerization occurs with dimethylsiloxane, EMIM DEP is used as ionic liquid, and N-dimethylaniline is used as initiator to prepare high water vapor adsorption polymer ion gel by microwave polymerization. The specific steps are as follows:

(1) Weigh 20g of EMIM DEP and place it in a constant temperature and humidity box. Set the temperature of the constant temperature and humidity box to 20°C and the relative humidity to 80%. Measure the quality of the ionic liquid until there is no change in the mass for two consecutive times, and there is no change in the two measured values at the 31st hour and the 32nd hour, and the adsorption is stopped;

(2) Weigh the mass of EMIM DEP saturated with adsorption to be 39g, and calculate the mass fraction of EMIM DEP in the saturated EMIM DEP to be 51.28%;

(3) Dimethylsiloxane, step (1) gained saturated EMIM DEP, and azobisisobutyronitrile are mixed so that the mass ratio of dimethylsiloxane, EMIM DEP and N-dimethylaniline is 50%: 49%: 1%, fully stirred to make it form a homogeneous solution, the stirring speed is 400r/min, and the stirring time is 60min, then inject in the cylindrical mould;

(4) Place the cylindrical mold in the microwave generator, the microwave power is 300W, the microwave radiation time is 40s, and the microwave radiation program is to start and stop each 5s alternately, so that the mixed solution in the cylindrical mold In-situ polymerization occurs, and high water vapor adsorption polymer ion gels are obtained;

(5) Utilize dynamic steam adsorption instrument, take by weighing 0.13g step (4) gained ion gel, keep adsorption temperature as 25 ℃, test the adsorption capacity of ion gel at 0-90% relative humidity, with relative humidity and adsorption Draw the adsorption isotherm.

Claims (7)

1. A preparation method of a high-water vapor adsorption polymer ionic gel comprises the following steps:

(1) Placing the ionic liquid in a constant temperature and humidity box, setting the temperature of the constant temperature and humidity box at 0-25 ℃ and the relative humidity at 80-90%, and enabling the ionic liquid to adsorb water vapor to be saturated under the condition;

(2) Mixing a polymer monomer, the saturated ionic liquid obtained in the step (1) and a polymerization initiator, fully stirring to form a uniform solution, injecting the uniform solution into a mold, wherein the mass ratio of the initiator in the uniform solution is 0.1-1%, the mass ratio of the polymer monomer is 40-60%, and the balance is the saturated ionic liquid;

(3) Carrying out in-situ polymerization reaction on the mixed solution in the step (2) to obtain high-water-vapor adsorption polymer ionic gel;

the polymerization reaction mode in the step (3) comprises one or more than two of ultraviolet polymerization, microwave polymerization and thermal polymerization;

the ultraviolet polymerization condition is room temperature, the effective ultraviolet wavelength is 365nm, the power is 8-12W, the ultraviolet light intensity is 200-400mW/cm 2, and the ultraviolet polymerization time is 60-120min; the microwave polymerization conditions are that the microwave power is 200-300W, the microwave radiation time is 30-60s, and the microwave radiation program is that starting and stopping are alternately carried out by 1-5 s; the thermal polymerization condition is heating at 60-80 deg.C for 30-60min.

2. The method according to claim 1, wherein the determination criterion for the ionic liquid to adsorb water vapor under such conditions is that the mass of the ionic liquid is weighed every 1 to 2 hours until the mass of the ionic liquid is unchanged by two successive weighing.

3. The method according to claim 1, wherein the polymerization initiator comprises one or both of azobisisobutyronitrile and azobisisoheptonitrile.

4. The production method according to claim 1, the ionic liquid comprises one or more of 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM BF 4), 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM BF 4), 1-ethyl-3-methylimidazolium bistrifluoromethylsulfonyl imide salt (EMIM TFSI), 1-hexyl-3-methylimidazolium bistrifluoromethylsulfonyl imide salt (HMIM TFSI), 1-ethyl-3-methyl-imidazolium acetate (EMIM Ac), 1-butyl-3-methylimidazole chloride (BMIM Cl), 1-butyl-3-methylimidazole bromide (BMIM Br), 1-butyl-3-methylimidazole iodide (BMIM I), 1-butyl-3-methylimidazolium trifluoromethanesulfonate (BMIM Otf), 1-butyl-3-methylimidazolium trifluoroacetate (BMIM TFA), 1-butyl-3-methylimidazolium p-methylbenzenesulfonate (BMTOSI), 1,3-dimethylimidazole phosphate dimethyl ester salt (BMM DMP), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM TFPF), 1-butyl-3-methylimidazolium 6-methyl-methylsulfonyl imide salt (EMIM PF), and 1-ethyl-3-methylimidazolium disulfonate (EMIM TFSI).

5. The method according to claim 1, wherein the polymer monomer comprises one or more of a monomer and an oligomer.

6. The method of claim 5, wherein the polymer monomer comprises one or more of styrene, methyl methacrylate, dimethyl siloxane, low molecular weight polyethylene glycol diacrylate (PEGDA), polyurea, polycarbonate, polyester, or polyamide.

7. The method according to claim 1, wherein the mold is one or more of a cylindrical shape, a rectangular parallelepiped shape, and a film shape.

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