A fully-polymeric porous solid desiccant and a method of making the same

Abstract

The application belongs to the technical field of dehumidifier, and particularly relates to a full-polymer porous solid dehumidifier and a preparation method thereof. The main raw materials of the full-polymer porous solid dehumidifier include sodium acrylate, acrylic acid, acrylamide and other hydrophilic monomers, polymerizable macromolecular surfactants which can be used as crosslinking agents, initiators and residual water. The full-polymer porous solid dehumidifier provided in the application has the following obvious advantages: 1) high moisture absorption capacity. Under the conditions of 25 DEG C, 90% RH and 70% RH, the equilibrium moisture absorption capacities are 2.16 g / g and 0.8 g / g respectively. 2) fast moisture absorption capacity. Under the condition of 25 DEG C, 90% RH, the moisture absorption capacity in 2 hours is as high as 1.9 g / g. 3) fast regeneration at low temperature. Under the condition of 20% RH, the moisture removal rates at 60 DEG C and 40 DEG C in 30 minutes are as high as 94% and 92% respectively. 4) excellent cyclic use.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of dehumidifier, and particularly relates to a full-polymer porous solid dehumidifier and a preparation method thereof. BACKGROUND

[0002] Because the traditional refrigeration dehumidification technology has the defect of high energy consumption, the dehumidifier has become an important material for controlling air humidity which is widely used at present. According to the difference in physical state, it can be divided into two categories of liquid dehumidifier and solid dehumidifier. Liquid dehumidifier has the problems of difficult handling, leakage risk, secondary pollution caused by gas atomization diffusion, etc., which limits its use in many actual scenes. Solid dehumidifier has the characteristics of relative inertia and stability, and is more suitable for many actual application scenes.

[0003] There are two types of commonly used solid dehumidifiers. One is inorganic porous materials such as silica gel, zeolite and molecular sieve, which are stable in nature, but have low moisture absorption capacity and high regeneration temperature. The other is inorganic hygroscopic salt or its composite material, which is usually lithium chloride or calcium chloride, etc. inorganic salt with strong hygroscopicity or its composite with polymer. They have high moisture absorption capacity and fast moisture absorption rate, but still have potential risks such as diffusion and leakage of water vapor during the dehumidification and regeneration process, which pollutes the environment and corrodes the instruments, which is not conducive to their long-term cyclic use.

[0004] High water absorption resin has the characteristics of relatively high water absorption rate and environmental protection and non-toxic, etc. The porous high water absorption resin and its composite material without inorganic hygroscopic salt have become a new research hotspot in solid hygroscopic materials. Usually, inorganic salts such as sodium bicarbonate (NaHCO3) and ammonium bicarbonate (NH4HCO3) which can easily react to produce gas are used as porogen, and surfactant is used as foam stabilizer. These methods often have the phenomenon of residual decomposition products of porogen and foam stabilizer molecules, which may cause leakage and migration of these residues during later use, affecting the use performance. For example, Alhassan et al. used NaHCO3 as foaming agent, acetic acid or hydrochloric acid as foaming aid, and macromolecular surfactant poloxamer (Pluronic F-127) as foam stabilizer. The obtained porous material has the problem of residual NaHCO3 and Pluronic F-127, which may cause environmental pollution and corrosion of the equipment during the use process. F-127) as a foam stabilizer, a series of zeolite, clay composite porous polymer-based or porous polymer solid desiccants were prepared (Applied Clay Science 2022, 230, 106712; Microporous and Mesoporous Materials 2020, 299, 110106; Microporous and Mesoporous Materials 2022, 342, 112116; Scientific Reports 2022, 12, 5626), which showed a significant decrease in dehumidification efficiency within 10 cycles of moisture absorption-desorption. At the same time, the gas release of the porogen and the gelation of the polymer system are difficult to synchronize, the porogenic effect is not good or difficult to control, and the gas produced pollutes the environment. In addition, most of the current reports also rely on time-consuming and high-energy-consuming freeze-drying drying methods to maintain their porous structure as much as possible, which is not conducive to large-scale industrial production. At the same time, the solid desiccants of the polymer or polymer composite materials reported so far do not contain hygroscopic inorganic salts such as LiCl and CaCl2, etc. Generally, they can maintain good moisture absorption capacity under high humidity (relative humidity ≥ 90%), but when the relative humidity is less than 70%, their moisture absorption capacity decreases sharply, mostly less than 0.4 g / g, and the dehumidification efficiency is greatly reduced. In our previous report, a fast and high moisture absorption capacity composite solid desiccant was prepared by using polyvinyl alcohol 1788 as a foam stabilizer and adding hygroscopic LiCl salt in situ (CN202211436784.3), but there are still potential risks of LiCl salt leakage and migration / leakage of embedded polyvinyl alcohol 1788 during long-term use. SUMMARY

[0005] Therefore, how to prepare a full-polymer solid desiccant that is full-polymer, safe and environmentally friendly, and high-efficiency (high moisture absorption capacity), fast moisture absorption and desorption, and low regeneration temperature is still a research hotspot and challenge.

[0006] In view of this, the present application develops a new type of efficient, fast and low-temperature regenerated all-polymer solid dehumidifier. For the first time, under the conditions of nitrogen atmosphere and the presence of self-made polymerizable macromolecular surfactant, a porous superabsorbent polymer hydrogel is prepared by simple aqueous solution radical copolymerization. After the polymerization reaction, the product is obtained by shearing, drying in a common air oven, which is an efficient and fast porous all-polymer solid dehumidifier. It needs to be particularly pointed out that, unlike previous reports: 1) Here, nitrogen is not only used as a protective gas for radical polymerization, but also creatively used to replace traditional NaHCO3 or low-boiling-point organic solvents as a green and environmentally friendly foaming agent; 2) The polymerizable macromolecular surfactant is used instead of traditional foam stabilizer and crosslinking agent, which can not only stabilize the foam generated by nitrogen, but also act as an in-situ crosslinking agent to stabilize the porous structure of the gel after foaming system gelation. The covalent bond is connected to the three-dimensional network of the polymer, and there is no residual problem of foaming agent and foam stabilizer. Moreover, it can endow the obtained porous gel with excellent mechanical properties; 3) Because the obtained porous gel has excellent mechanical properties, it can be directly dried in a blast oven without time-consuming and energy-consuming freeze-drying, and still maintain its excellent porous structure; 4) The whole preparation process is green and environmentally friendly, without pollution and waste, and easy to mass industrial production.

[0007] The polymerizable macromolecular surfactant is used as a foam stabilizer and a macromolecular crosslinking agent, and a porous all-polymer dehumidifier is prepared by simple aqueous solution radical copolymerization under the condition of nitrogen bubbling.

[0008] The present application provides a preparation method of an all-polymer porous solid dehumidifier, comprising the following steps:

[0009] S1: Dissolve poloxamer F127, isocyanate acrylate, polymerization inhibitor and catalyst in an organic solvent, heat and react to obtain a polymerizable macromolecular surfactant which can be used as a free radical polymerization crosslinking agent;

[0010] S2: Under inert atmosphere, stir the polymerizable macromolecular surfactant, aqueous solution containing hydrophilic polymer monomer and initiator to generate bubbles, and obtain a mixed solution; the hydrophilic polymer monomer is one or more of acrylic acid, sodium acrylate, acrylamide and 2-acrylamide-2-methylpropane sulfonic acid hydrophilic monomer;

[0011] S3: Heat the mixed solution to react, stop stirring and pass inert gas after gelation, continue to stand for a certain time to obtain a product;

[0012] S4: Cut the product into small pieces, dry to obtain the all-polymer porous solid dehumidifier.

[0013] Preferably, in the step S1, the polymerization inhibitor is p-hydroxyanisole.

[0014] Preferably, in the step S1, the catalyst is dibutyltin dilaurate.

[0015] Preferably, in the step S1, the organic solvent is 1,2-dichloroethane.

[0016] Preferably, the mass ratio of the poloxamer F127, isocyanate acrylate and polymerization inhibitor is 10-50:1-5:0.1-0.5.

[0017] Preferably, in the step S1, the temperature of the heating reaction is 50-70℃, and the time is 1-5h.

[0018] Preferably, in the step S1, after the heating reaction, the product is precipitated with diethyl ether, centrifuged, and vacuum dried to obtain the polymerizable macromolecular surfactant.

[0019] Further, the temperature of the vacuum drying is room temperature (25±5℃), and the time is 2-10h.

[0020] Preferably, in the step S2, the inert atmosphere is nitrogen or argon.

[0021] In some embodiments, the macromolecular surfactant with foam stabilizer function that can be radically polymerized is used as a crosslinking agent in the reaction.

[0022] Preferably, in the step S2, the initiator is ammonium persulfate or potassium persulfate.

[0023] Preferably, in the step S3, the temperature of the heating reaction is 50-90℃, and the time is 1-5h.

[0024] Preferably, in the step S4, the temperature of the drying is 60-100℃, and the time is 2-10h.

[0025] Further, in the step S4, after drying, the product is crushed to 12-20 mesh to obtain the all-polymer porous solid desiccant.

[0026] Specifically, the preparation method of the all-polymer porous solid desiccant comprises the following steps:

[0027] (1) A sodium hydroxide solution is prepared, and a certain amount of acrylic acid is added dropwise into the sodium hydroxide solution under ice water bath stirring to obtain a sodium acrylate solution or a mixed solution of sodium acrylate and acrylic acid;

[0028] (2) Acrylamide is added to the above solution to obtain a mixed solution, and the mixed solution is placed in an open reactor;

[0029] (3) under stirring, nitrogen is bubbled for 15 minutes to 1 hour to remove oxygen in the reaction system;

[0030] (4) initiator is added;

[0031] (5) polymerizable macromolecular surfactant is added;

[0032] (6) nitrogen is continuously bubbled and the reaction solution is stirred to generate a large amount of foam in the solution, forming a stable foam system;

[0033] (7) the temperature is increased to make the reaction solution polymerize, obtaining a full-polymer porous solid desiccant.

[0034] The application further provides a full-polymer porous solid desiccant prepared by the preparation method.

[0035] Preferably, the raw materials include the following components by weight: 10-80 parts of sodium acrylate, 0-20 parts of acrylic acid, 0-15 parts of acrylamide, 1-10 parts of polymerizable macromolecular surfactant, 1-5 parts of initiator and an appropriate amount of water.

[0036] Compared with the prior art, the technical scheme of the application has the following advantages:

[0037] The full-polymer porous solid desiccant provided by the application has a high moisture absorption capacity, a fast moisture absorption-desorption capacity, a low regeneration temperature, can be quickly recycled without mass loss, is environmentally friendly and non-toxic, and has no moisture absorption material leakage problem.

[0038] The preparation method of the full-polymer porous solid desiccant provided by the application is a new method for preparing a porous polymer under environmentally friendly conditions by using a polymerizable macromolecular surfactant as a foam stabilizer and a macromolecular crosslinking agent. The method has high poration efficiency and solves the problem of invalid foam generation caused by the addition of a porogen too early or too late in the traditional method. The foam stabilizer also simultaneously acts as a crosslinking agent to participate in the polymerization reaction, solving the potential risk of reducing the dehumidification efficiency caused by the migration and leakage of the traditional foam stabilizer physically embedded in the solid desiccant after the polymerization reaction. The application uses a nitrogen gas used for free radical polymerization as an environmentally friendly inert protective gas to simultaneously act as a foaming agent, solving the environmental pollution problems caused by the decomposition and residue of a traditional inorganic foaming agent (NaHCO3 or NH4HCO3, etc.) or the release of a pollution gas (ammonia or carbon dioxide) or the volatilization of a low-boiling-point organic solvent porogen. Meanwhile, the macromolecular crosslinking agent also plays a role in regulating the polymer network, endowing the obtained porous gel and solid desiccant with excellent mechanical properties, facilitating storage, use and transportation in various occasions. The preparation method is simple, environmentally friendly, has no byproduct residue, does not require a complex post-treatment step and is easy to mass industrialized production. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The hygroscopic performance test results of Example 1 and three comparative examples under the condition of 25℃ and 70% RH are shown in the figure.

[0040] Figure 2 The hygroscopic performance test results of Example 1 and three comparative examples under the condition of 25℃ and 90% RH are shown in the figure.

[0041] Figure 3 The hygroscopic performance test results of Example 1 under different temperature and humidity conditions are shown in the figure.

[0042] Figure 4 The hygroscopic performance test results of Example 1 are shown in the figure. DETAILED DESCRIPTION

[0043] The application will be further described below in conjunction with the drawings and specific examples, so that those skilled in the art can better understand the application and implement it, but the examples are not limiting to the application.

[0044] There are two types of commonly used solid dehumidifiers. One type is inorganic porous materials such as silica gel, zeolite and molecular sieve, which are stable in nature but have low hygroscopic capacity. The other type is salt-based composite materials, usually strong hygroscopic inorganic salts such as lithium chloride or calcium chloride, which are combined with superabsorbent resin. They have high hygroscopic capacity and fast hygroscopic rate, but there is a risk of water vapor diffusion and leakage during the dehumidification and regeneration process. At the same time, the regeneration temperature of this type of dehumidifier is high (usually above 100℃), which is not conducive to their cyclic use.

[0045] Therefore, how to prepare a dehumidifier with fast dehumidification rate and low regeneration temperature has become a hot research topic. Superabsorbent resin has become a commonly used water absorption matrix in salt-based composite hygroscopic materials due to its high water absorption. In order to obtain an environmentally friendly and non-toxic dehumidifier with low regeneration temperature, the present application attempts to use pure polymer as a dehumidifier without adding any hygroscopic salt, and at the same time, in order to improve its hygroscopic performance. The present application adopts the method of preparing porous resin to increase its contact area with water vapor and improve its hygroscopic capacity and hygroscopic and dehumidification rate.

[0046] In view of this, the present application develops a new porogenic method, i.e. using polymerizable macromolecular surfactant as foam stabilizer and macromolecular crosslinking agent, under the condition of nitrogen bubbling, to prepare all-polymer porous solid dehumidifier in a green and environmentally friendly way.

[0047] In the first aspect, the present application provides a polymerizable macromolecular surfactant, the raw materials for preparing the polymerizable macromolecular surfactant include poloxamer F127, isocyanate acrylate, polymerization inhibitor, catalyst and the balance of solvent.

[0048] The pore-forming method provided by the present application uses polymerizable macromolecular surfactants as foam stabilizers and cross-linking agents, and the polymerization is completed to covalently bond into the polymer network, without residual pore-forming agents.

[0049] The all-polymer porous solid dehumidifier provided by the present application has faster and stronger dehumidification capacity, lower regeneration temperature, fast recycling without mass loss, environmental protection, and no dehumidification material leakage.

[0050] In some embodiments, the all-polymer porous solid dehumidifier is a porous polymer that does not contain any inorganic dehumidification salt and other auxiliary agents, and only increases the dehumidification area through the porous structure to increase the dehumidification capacity and rate.

[0051] In some embodiments, the polymer resin can be a homopolymer or copolymer of one or more monomers commonly used to prepare superabsorbent resin, such as acrylic acid, sodium acrylate, and acrylamide or 2-acrylamide-2-methylpropane sulfonic acid.

[0052] It can be understood that the polymerizable macromolecular surfactant has a large molecular weight, can participate in the reaction as a foam stabilizer and a cross-linking agent during the polymerization process, has no residue, and the macromolecular cross-linking agent makes the mesh structure of the polymer large and easy to accommodate more water. The use of the porous all-polymer dehumidifier has the advantages of high dehumidification capacity, fast dehumidification rate, environmental protection, no toxicity, low regeneration temperature, and reusability.

[0053] In some embodiments, the shape of the composite solid dehumidifier includes at least one of granular, sheet, powder, and block shapes. Preferably, the shape of the composite solid dehumidifier is granular.

[0054] In some embodiments, the particle size of the composite solid dehumidifier is ≤4 mesh, and the composite solid dehumidifier with a suitable particle size can improve its dehumidification performance. Preferably, the particle size of the composite solid dehumidifier is 4 mesh-20 mesh, and more preferably, the particle size of the composite solid dehumidifier is 12-20 mesh.

[0055] In a second aspect, the present application also provides a preparation method of a polymerizable macromolecular surfactant, which specifically comprises:

[0056] Step (1), obtaining a reaction solution by mixing poloxamer F127, isocyanate acrylate, a polymerization inhibitor, and a catalyst in a solvent;

[0057] Step (2), heating the mixed solution for reaction;

[0058] Step (3), precipitating the product with diethyl ether, removing the diethyl ether by centrifugation, and vacuum drying at room temperature.

[0059] In another aspect, the application also provides a preparation method of a full-polymer porous solid desiccant, i.e. using the prepared macromolecular surfactant as a porogen to prepare a porous polymer, specifically comprising:

[0060] Step (4), preparing a sodium hydroxide solution, and adding a certain amount of acrylic acid into the sodium hydroxide solution under stirring in an ice water bath to obtain a solution of sodium acrylate and acrylic acid;

[0061] Step (5), adding acrylamide into the solution of sodium acrylate and acrylic acid to obtain a mixed solution, and placing the mixed solution in an open reactor;

[0062] Step (6), placing the polymerizable macromolecular surfactant and ammonium persulfate in a constant pressure dropping funnel;

[0063] Step (7), removing oxygen in the open reactor and the constant pressure dropping funnel by nitrogen;

[0064] Step (8), opening the constant pressure dropping funnel, and mixing the reaction solution with the polymerizable macromolecular surfactant and the initiator;

[0065] Step (9), continuously passing nitrogen and stirring the reaction solution to generate a large amount of bubbles in the solution;

[0066] Step (10), increasing the temperature to 60°C to polymerize the reaction solution;

[0067] Step (11), taking out the product, cutting it into pieces, and drying at 80°C.

[0068] In the above scheme, an inert gas such as nitrogen commonly used in free radical polymerization is used as a protective gas and a foaming agent, and the polymerizable macromolecular surfactant is used as a foam stabilizer and a macromolecular crosslinking agent to prepare a porous polymer under environmentally friendly conditions. This method has high porogen efficiency and solves the problem of ineffective foam generation caused by the addition of the porogen too early or too late in the traditional method. The foam stabilizer also simultaneously acts as a crosslinking agent to participate in the polymerization reaction, solving the problems of environmental pollution caused by the decomposition and residue of traditional inorganic foaming agents or the release of contaminated gases, or the volatilization of low-boiling-point organic porogens, and the residue of ordinary foam stabilizers. Moreover, the full-polymer porous solid desiccant is a new environmentally friendly high-performance solid desiccant. Compared with common inorganic porous desiccants, it has a high moisture absorption capacity and a comparable moisture absorption rate; compared with solid desiccants containing moisture absorption salts, it has the advantages of being environmentally friendly, non-toxic, non-corrosive, stable in properties, low in regeneration temperature, and recyclable.

[0069] The technical solutions of the application will be described in detail below in combination with specific embodiments:

[0070] The polymerization inhibitor in step (1) is p-hydroxyanisole, the catalyst is dibutyltin dilaurate, and the solvent is 1,2-dichloroethane.

[0071] The components include 10-50% poloxamer F127, 1-5% isocyanate acrylate ethyl ester, 0.1-0.5% p-hydroxyanisole, a catalyst amount of dibutyltin dilaurate, and the rest solvent.

[0072] The reaction temperature in step (2) is 70°C, and the reaction time is 5h.

[0073] The amount of diethyl ether in step (3) is usually 10 times the amount of the mixed solution, and the vacuum drying time is usually 24h.

[0074] The ice water bath stirring in step (4) is conducive to preventing the volatilization of acrylic acid and the increase of the neutralization reaction temperature leading to the self-polymerization of monomers. The raw materials include 5-30% sodium hydroxide, 10-50% acrylic acid, and the rest water.

[0075] The raw materials in step (5) include 0-20% acrylamide, 1-10% polymerizable macromolecular surfactant solution, 0.1-3% ammonium persulfate, and the rest water.

[0076] In step (6), the polymerizable macromolecular surfactant is placed in a constant pressure dropping funnel to prevent the generation of bubbles during the nitrogen blowing process.

[0077] The application also provides a dehumidifying agent, which includes the above-mentioned all-polymer porous solid dehumidifying agent.

[0078] The all-polymer porous solid dehumidifying agent of the application is further described below in combination with specific examples and comparative examples, but the application is not limited to the following examples. All raw materials of the application are not particularly limited in purity, and the application preferably uses conventional purity in the field of dehumidifying materials or the purity required in the corresponding application field.

[0079] To further illustrate the application, the all-polymer porous solid dehumidifying agent and the preparation method thereof provided by the application are described in detail in combination with the following examples, but it should be understood that these examples are based on the technical scheme of the application, and detailed implementation modes and specific operation processes are given, which are only for further illustrating the features and advantages of the application, and are not a limitation on the claims of the application, and the protection scope of the application is not limited to the following examples.

[0080] Example 1

[0081] The poloxamer F127, isocyanate acrylate ethyl, p-hydroxyanisole and p-dibutyltin dilaurate were dissolved in 1,2-dichloroethane, heated at 60°C for 3h, precipitated with ether, centrifuged, and vacuum dried at 25°C for 6h to obtain the polymerizable macromolecular surfactant;

[0082] Dissolve 6.40g sodium hydroxide in 15mL water, cool to room temperature; add 14.40g acrylic acid and 20mL water to an open reaction bottle, put into a magnetic sonicator, and stir to mix the solution on a magnetic stirrer;

[0083] Slowly drop the prepared acrylic acid solution into a certain amount of sodium hydroxide solution under ice water bath conditions, and finally make the neutralization degree of acrylic acid 80%;

[0084] Dissolve 2.0g acrylamide in the above solution;

[0085] Mix 7.50g, 10wt.% polymerizable macromolecular surfactant solution and 1.00g, 10wt.% ammonium persulfate solution, and place them in a constant pressure dropping funnel; combine the constant pressure dropping funnel with the open reactor, seal the reaction device, and pass nitrogen for 1h to remove oxygen in the reaction solution;

[0086] Put the whole device in a 60°C oil bath, open the piston of the constant pressure dropping funnel, and make the polymerizable surfactant and initiator enter the monomer solution, stir quickly and continue to pass nitrogen to produce a large amount of foam in the solution, and the polymerization reaction occurs after about 20min;

[0087] Take out the above product, cut it into small pieces, dry at 100°C, then crush it with a crusher, and sieve to obtain 12-20 mesh granular resin.

[0088] Example 2

[0089] The poloxamer F127, isocyanate acrylate ethyl, p-hydroxyanisole and p-dibutyltin dilaurate were dissolved in 1,2-dichloroethane, heated at 50°C for 1h, precipitated with ether, centrifuged, and vacuum dried at 20-30°C for 2h to obtain the polymerizable macromolecular surfactant;

[0090] Dissolve 6.40g sodium hydroxide in 15mL water, cool to room temperature in an open reactor; mix 14.40g acrylic acid and 20mL water evenly;

[0091] Slowly drop the prepared acrylic acid solution into a certain amount of sodium hydroxide solution under ice water bath conditions, and finally make the neutralization degree of acrylic acid 80%;

[0092] Dissolve 2.0g acrylamide in the above solution;

[0093] A 7.50 g, 10 wt.% aqueous solution of the polymerizable macromolecular surfactant and 1.00 g of a 10 wt.% potassium persulfate solution were mixed and placed in a constant pressure dropping funnel; the constant pressure dropping funnel was combined with the open reactor, the reaction apparatus was sealed, and nitrogen was bubbled through for 1 h to remove oxygen from the reaction solution;

[0094] The entire apparatus was placed in a 50°C oil bath, the piston of the constant pressure dropping funnel was opened, and the polymerizable surfactant and initiator were allowed to enter the monomer solution, rapid stirring was performed and nitrogen was continuously bubbled through, which caused a large amount of foam to be generated in the solution, and the polymerization reaction occurred after about 20 min for 1 h;

[0095] The product was removed, cut into pieces, dried at 60°C for 2 h, and then ground using a pulverizer and sieved to obtain a 12-mesh granular resin.

[0096] Example 3

[0097] Poloxamer F127, isocyanate acrylate, p-hydroxyanisole, and dibutyltin dilaurate were dissolved in 1,2-dichloroethane, heated at 70°C for 5 h, precipitated using diethyl ether, centrifuged, and vacuum dried at 20-30°C for 10 h to obtain a polymerizable macromolecular surfactant;

[0098] 6.40 g of sodium hydroxide was dissolved in 15 mL of water, and the solution was cooled to room temperature in an open reactor; 14.40 g of acrylic acid and 20 mL of water were mixed uniformly;

[0099] The previously prepared acrylic acid solution was slowly added dropwise to a certain amount of sodium hydroxide solution under the condition of an ice water bath, and the neutralization degree of the acrylic acid was finally 80%;

[0100] 2.0 g of acrylamide was dissolved in the above solution;

[0101] A 7.50 g, 10 wt.% aqueous solution of the polymerizable macromolecular surfactant and 1.00 g of a 10 wt.% potassium persulfate solution were mixed and placed in a constant pressure dropping funnel; the constant pressure dropping funnel was combined with the open reactor, the reaction apparatus was sealed, and nitrogen was bubbled through for 1 h to remove oxygen from the reaction solution;

[0102] The entire apparatus was placed in a 90°C oil bath, the piston of the constant pressure dropping funnel was opened, and the polymerizable surfactant and initiator were allowed to enter the monomer solution, rapid stirring was performed and nitrogen was continuously bubbled through, which caused a large amount of foam to be generated in the solution, and the polymerization reaction occurred after about 20 min for 5 h;

[0103] The product was removed, cut into pieces, dried at 100°C for 10 h, and then ground using a pulverizer and sieved to obtain a 20-mesh granular resin.

[0104] Comparative Example 1

[0105] The preparation method of the polymerizable macromolecular surfactant in the comparative example is the same as that in Example 1.

[0106] Dissolve 6.40 g of sodium hydroxide in 15 mL of water, and cool to room temperature in an open reactor; uniformly mix 14.40 g of acrylic acid and 20 mL of water;

[0107] Slowly drop the prepared acrylic acid solution into a certain amount of sodium hydroxide solution under the condition of an ice water bath, and finally make the neutralization degree of acrylic acid 80%;

[0108] Dissolve 2.00 g of acrylamide in the above solution;

[0109] Mix 7.50 g of a 10 wt.% poloxamer F127 solution, 0.01 g of N,N-methylenebisacrylamide, and 1.00 g of a 10 wt.% ammonium persulfate solution, and place in a constant pressure dropping funnel; combine the constant pressure dropping funnel with the open reactor, seal the reaction device, and pass nitrogen gas for 1 h to remove oxygen in the reaction solution;

[0110] Place the entire device in a 60°C oil bath, open the piston of the constant pressure dropping funnel, and make the polymerizable surfactant and initiator enter the monomer solution, quickly stir, and continuously pass nitrogen gas to generate a large amount of foam in the solution, and the polymerization reaction occurs after about 20 min;

[0111] Take out the above product, cut it into pieces, dry at 100°C, and then crush with a crusher and sieve to obtain a 12-20 mesh granular resin.

[0112] Comparative Example 2

[0113] Dissolve 6.40 g of sodium hydroxide in 15 mL of water, and cool to room temperature in an open reactor; uniformly mix 14.40 g of acrylic acid and 20 mL of water;

[0114] Slowly drop the prepared acrylic acid solution into a certain amount of sodium hydroxide solution under the condition of an ice water bath, and finally make the neutralization degree of acrylic acid 80%;

[0115] Dissolve 2.00 g of acrylamide in the above solution;

[0116] Mix 7.50 g of a 10 wt.% polymerizable macromolecular surfactant solution and 1.00 g of a 10 wt.% ammonium persulfate solution, and place in a constant pressure dropping funnel; combine the constant pressure dropping funnel with the open reactor, seal the reaction device, and pass nitrogen gas for 1 h to remove oxygen in the reaction solution;

[0117] The whole device was placed in a 60°C oil bath, the piston of the constant pressure dropping funnel was opened, the crosslinking agent and initiator were allowed to enter the monomer solution, and nitrogen was continuously passed, and the polymerization reaction occurred after about 20 minutes;

[0118] The product was removed, cut into pieces, dried at 100°C, and then crushed with a pulverizer and sieved to obtain a 12-20 mesh granular resin.

[0119] Comparative Example 3

[0120] 6.40 g of sodium hydroxide was dissolved in 15 mL of water, and the solution was cooled to room temperature in an open reactor; 14.40 g of acrylic acid and 20 mL of water were mixed uniformly;

[0121] The previously prepared acrylic acid solution was slowly added to a certain amount of sodium hydroxide solution under the condition of an ice water bath, and the neutralization degree of the acrylic acid was finally 80%;

[0122] 2.00 g of acrylamide was dissolved in the above solution;

[0123] 7.5 mL of water, 0.01 g of N,N-methylenebisacrylamide, and 1.00 g of a 10 wt.% ammonium persulfate solution were mixed and placed in a constant pressure dropping funnel; the constant pressure dropping funnel was combined with the open reactor, the reaction device was sealed, and nitrogen was passed for 1 h to remove oxygen in the reaction liquid;

[0124] The whole device was placed in a 60°C oil bath, the piston of the constant pressure dropping funnel was opened, the crosslinking agent and initiator were allowed to enter the monomer solution, and nitrogen was continuously passed, and the polymerization reaction occurred after about 20 minutes;

[0125] The product was removed, cut into pieces, dried at 100°C, and then crushed with a pulverizer and sieved to obtain a 12-20 mesh granular resin.

[0126] Effect evaluation

[0127] Test method: hygroscopic capacity and dehumidification rate test of dehumidifier

[0128] The 12-20 mesh granular dehumidifier to be tested was uniformly placed in a stainless steel mesh sieve, and the stainless steel mesh sieve was placed in a constant temperature and humidity chamber, and appropriate temperature and humidity were set. The weight difference at different times was accurately weighed with a balance to obtain the hygroscopic capacity. The hygroscopic capacity was divided by the weight of the material itself to obtain the hygroscopic rate. The dehumidifier after hygroscopic equilibrium under the condition of 25°C and 90% RH was uniformly placed in a stainless steel mesh sieve, and the stainless steel mesh sieve was placed in a constant temperature and humidity chamber, and appropriate temperature and 20% RH humidity were set. The weight difference at different times was accurately weighed with a balance to obtain the dehumidification amount. The dehumidification amount was divided by the saturated hygroscopic capacity of the material to obtain the dehumidification rate.

[0129] The all-polymer porous solid desiccant prepared in Example 1 and Comparative Examples 1 to 3 were subjected to the above tests respectively, and the test results are as follows:

[0130] Table 1. Test data of moisture absorption performance of all-polymer porous solid desiccant under conditions of 25℃ / 70%RH and 25℃ / 90%RH.

[0131]

[0132] Table 2. Test data on the moisture absorption performance of all-polymer solid desiccant under different temperature and humidity conditions.

[0133]

[0134]

[0135] Table 3. Dehydration rate test data of all-polymer solid desiccant under different temperature conditions.

[0136]

[0137] According to Table 1 and Figure 1 , 2 The results show that the porous all-polymer desiccant prepared using nitrogen as a foaming agent and polymerizable macromolecular surfactants as foam stabilizers and crosslinking agents has a faster moisture absorption rate and a higher moisture absorption capacity.

[0138] According to Table 2 and Figure 3 The results show that Example 1 has a certain degree of moisture absorption effect under different temperatures and humidity levels. As the temperature increases, the moisture absorption capacity decreases at the same humidity.

[0139] As shown in Table 3, Example 1 can remove almost all the water inside even when dehumidifying at a low temperature, demonstrating excellent low-temperature rapid regeneration capabilities.

[0140] Figure 4 The results of the moisture absorption performance test for Example 1 are as follows: moisture absorption for 2 hours at 25°C and 90% RH, followed by desiccation for 30 minutes at 60°C and 20% RH, repeated 20 times. Figure 4 The results show that after 20 cycles, the moisture absorption performance of Example 1 remained almost unchanged, demonstrating excellent reusability.

[0141] Obviously, the above embodiments are merely example for clearly illustrating, and are not limitation to the embodiments. For ordinary skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, all the embodiments need not and can not be exhausted. The obvious changes or variations derived therefrom are still within the scope of the present invention.

Claims

1. A method for preparing a fully-polymeric porous solid desiccant, characterized by, The method comprises the following steps: S1: dissolving poloxamer F127, isocyanate acrylate, polymerization inhibitor and catalyst in an organic solvent, heating and reacting to obtain a polymerizable macromolecular surfactant which can be used as a free radical polymerization crosslinking agent; in the step S1, the polymerization inhibitor is p-hydroxyanisole, and the catalyst is dibutyltin dilaurate; S2: under an inert atmosphere, stirring the polymerizable macromolecular surfactant, an aqueous solution containing hydrophilic polymer monomers and an initiator to generate bubbles to obtain a mixed solution; the hydrophilic polymer monomers are one or more of acrylic acid, sodium acrylate, acrylamide and 2-acrylamide-2-methylpropane sulfonic acid; S3: heating and reacting the mixed solution, stopping stirring and inert gas supply after the solution is gelled, and standing and reacting to obtain a product; S4: cutting and drying the product to obtain the all-polymer porous solid dehumidifier; the mass ratio of poloxamer F127, isocyanate acrylate and polymerization inhibitor is 10-50:1-5:0.1-0.5; in the step S1, the heating and reaction temperature is 50-70℃, and the time is 1-5 h; in the step S2, the initiator is ammonium persulfate or potassium persulfate; in the step S3, the heating and reaction temperature is 50-90℃, and the time is 1-5 h.

2. The production method according to claim 1, wherein In the step S1, after heating and reaction, the product is precipitated with diethyl ether, centrifuged and vacuum dried to obtain the polymerizable macromolecular surfactant.

3. An all-polymer porous solid dehumidifier prepared by the preparation method of any one of claims 1-2.

4. The all-polymeric porous solid desiccant of claim 3, wherein, The raw materials comprise the following components by weight: 10-80 parts of sodium acrylate, 0-20 parts of acrylic acid, 0-15 parts of acrylamide, 1-10 parts of polymerizable macromolecular surfactant, 1-5 parts of initiator and water.

Images