CN112979905A

CN112979905A - Block polyurethane polymer, polymer modified bentonite admixture thereof, and preparation and application thereof

Info

Publication number: CN112979905A
Application number: CN201911281296.8A
Authority: CN
Inventors: 严涵; 杨勇; 周栋梁; 于诚; 刘金芝; 王秀梅; 黄振; 冉千平
Original assignee: Jiangsu Bote New Materials Co Ltd
Current assignee: Jiangsu Bote New Materials Co Ltd
Priority date: 2019-12-13
Filing date: 2019-12-13
Publication date: 2021-06-18
Anticipated expiration: 2039-12-13
Also published as: CN112979905B

Abstract

The invention discloses a segmented polyurethane polymer, a polymer modified bentonite admixture thereof, a preparation method and application thereof. The polymer modified bentonite is prepared by carrying out aqueous solution intercalation modification on the cationic amphiphilic block polymer and bentonite. Through intercalation modification, the admixture realizes the activity enhancement and the adsorptivity regulation of the clay component and the release control of the polymer component, thereby not influencing the workability of concrete and effectively improving the mechanical property and the chloride ion permeation resistance of the concrete.

Description

Block polyurethane polymer, polymer modified bentonite admixture thereof, and preparation and application thereof

Technical Field

The invention relates to a segmented polyurethane polymer, a polymer modified bentonite admixture thereof, and preparation and application thereof, and belongs to the technical field of building materials.

Technical Field

The admixture is an important component of modern concrete materials, and the admixture is properly introduced into the concrete to replace cement, so that the composition of hydration products can be adjusted, and the microstructure is optimized; moreover, the use of admixtures in place of cement reduces the total amount of cement used in the building material industry, thereby reducing the overall carbon emissions of the building material industry.

Common admixtures at present comprise fly ash, slag, silica fume and the like. However, most of the admixtures are byproducts of the thermal power industry, the steel industry and the electronic industry, the raw materials are limited in source, the yield and the energy production potential are lower than those of cement, and the admixtures are not suitable for use in the future. In this case, the world looks at the clay. The clay is an aluminosilicate material with a two-dimensional lamellar structure on a microscopic scale, has volcanic ash activity after being calcined, and has abundant reserves relative to the admixtures. However, the lamellar structure of clay also makes it possible to perform intercalation reaction with various additives (especially polycarboxylic acid high performance water reducing agent), and some clay (such as bentonite) can absorb water and swell to consume free water, thereby causing a great negative effect on the workability of concrete. How to solve the problem is a key problem of the application of the clay and the derivative materials thereof in the field of cement-based materials.

At present, researches in the field and related fields and industrial workers carry out a lot of researches on clay modification, and the researches find that not only new characteristics can be induced by proper compound intercalation, but also the adsorption activity of the intercalated clay is greatly reduced, and the problem of influencing the workability is greatly relieved. For example, Cesniene (Constr. build. Mater.2018,166:59-71) reports that after a quaternary ammonium salt type small molecule surfactant is inserted into montmorillonite layers, the interlayer spacing is obviously increased, and the modified montmorillonite generates volcanic ash activity. However, the addition of only a small-molecule filler is difficult to cause bridging between hydrated products like a polymer, and the improvement of mechanical properties is limited.

On the polymer side, as a single concrete modification material, modified concrete containing polymer has a long development history, and the development of the modified concrete from early polymer latex modification to the in-situ regulation of microstructure by using polymer is attempted.

However, the aqueous polymer solution or latex used in concrete contains a large amount of ionic groups, and the direct addition of the ionic groups in the mixing stage can generate very obvious negative effects on the cement hydration process, thereby causing the mechanical property problem, which is a big problem which troubles the application of the materials, and the key for solving the problem is how to control the activity of the polymer to slowly release along with the hydration process.

The clay with intercalation affinity provides ideal carrier environment. After the polymer is intercalated into the clay, the advantages of the two materials can be combined, the clay is induced to generate volcanic ash activity, the adsorption of free water and additives is weakened, and the slow release of the polymer is realized, so that the problems are solved.

At present, many patents of polymer intercalated clay are reported in the fields of flame retardant materials, automobile parts and the like. CN101979444B discloses a method for preparing montmorillonite modified by pillaring quaternary phosphonium salt ionic liquid, wherein the interlayer of montmorillonite is pillared and modified by quaternary phosphonium salt and then plastic intercalation is introduced, and the obtained material can be used for heat-resistant and flame-retardant high polymer materials. CN101945933B discloses a telechelic polyester-polycarbonate-organoclay nanocomposite and related methods and articles, which uses telechelic polyester to modify clay, and then compounds it with other high molecular materials, which are used in automobile parts. CN101305043B discloses a nanocomposite composition and a method for preparing the same, which uses a cation-containing random elastic copolymer to modify clay and use it for heat-resistant tire sealing materials.

In the field of building materials, the application of polymer modified clay materials is relatively few, and the polymer and the preparation method disclosed by the patent are difficult to adapt to the special requirements in the field of building materials.

Disclosure of Invention

In order to solve the problem that the existing concrete admixture is difficult to simultaneously consider the working performance and the mechanical property of dispersibility and the like, the invention provides a segmented polyurethane polymer, a polymer modified bentonite admixture thereof, and a preparation method and application thereof. The polymer modified bentonite can effectively improve the mechanical property and the chloride ion permeation resistance of concrete without influencing the workability of the concrete.

The segmented polyurethane polymer is a structural sequence formed by two types of units of a cationic chain segment A and a hydrophobic chain segment B alternately, the two ends of the chain segment are of the same unit type, and the two ends of the chain segment are both the cationic chain segment A or both the hydrophobic chain segment B:

the cationic chain segment A consists of hydroxyl quaternary ammonium residues, alkylene and quaternary ammonium salt residues of C2-C16 containing 1-2 quaternary ammonium residues; and the cation chain segment A contains 4-12 quaternary ammonium residues.

Wherein, both ends of the chain segment are hydroxyl quaternary ammonium residues, and both ends of the alkylene are necessarily alternated with the hydroxyl quaternary ammonium residues or the quaternary ammonium salt residues of C2-C16 containing 1-2 quaternary ammonium residues;

the hydrophobic chain segment B consists of isocyanate residue and polyalkyl ether glycol residue; the two are alternately present in a chain segment, and both ends of the chain segment are diisocyanate residues.

The cationic chain segment A and the hydrophobic chain segment B meet the condition that the mass ratio of the single chain segments is 1: 1.6-4.0, and the total mass ratio is 1: 1.2-3.0.

The molecular weight of the block polyurethane polymer is 4000-30000.

The hydroxyl quaternary ammonium residue is a group containing one quaternary ammonium residue and one hydroxyl residue, wherein the hydroxyl group and the quaternary ammonium group are separated by at least 2 carbon atoms, and the hydroxyl quaternary ammonium residue does not contain other hydroxyl quaternary ammonium residues of C4-C10 containing active hydrogen groups and capable of participating in isocyanate addition.

The structural formula of the hydroxyl quaternary ammonium residue is as follows:

wherein R1, R2 and X are such that the residues satisfy the above-mentioned conditions of spacing of the hydroxyl and quaternary ammonium groups residues, and the total number of carbon atoms of the structural unit 1.

The alkylene is C2-C6 alkylene, and the length of the alkylene in the main chain segment is not less than 2 carbon atoms.

The quaternary ammonium salt residue of C2-C16 containing 1-2 quaternary ammonium residues does not contain other active hydrogen-containing groups capable of participating in isocyanate addition,

the structural formula of the quaternary ammonium salt residue containing 1 quaternary ammonium residue and C2-C16 is shown in formula 2; the structural formula of the quaternary ammonium salt residue containing 2 quaternary ammonium residues and C2-C16 is shown in formula 3:

wherein R3-R8 and Y satisfy the above-mentioned restrictions on the number of carbon atoms and groups, and R3-R8 and Y may be bonded to each other to form a ring, as chemically allowed.

Examples of the quaternary ammonium salt residues of C2-C16 containing 1-2 quaternary ammonium residues are as follows (the present invention is not limited to the following structures, and all the structures described above can be satisfied):

the diisocyanate residue has the following structure:

wherein Y is a C2-C20 stable organic structure in aqueous solution, and wherein the two nitrogen atoms are separated by at least 2 carbon atoms.

The structure of the polyalkyl ether glycol residue corresponds to the following structural formula 9:

in the formula, R9 is a linear chain terminal alkylene of C2-C6, R10 is a hydrogen atom or methyl or ethyl; and when R9 is 1, 2-ethylene, R10 can only be methyl or ethyl. p1 is a number of 4 to 40.

The weight average molecular weight of the structural unit B is 800-4000 while satisfying the above description.

The segmented polyurethane polymer is obtained by condensing polyion liquid and polyurethane prepolymer;

the polyion liquid is obtained by reacting dihalogenated hydrocarbon with organic amine and blocking the reaction product by using a hydroxyl tertiary amine blocking agent;

the dihalohydrocarbon H is a C2-C6 halogenated hydrocarbon containing two halogen atoms other than fluorine and having halogen atoms not on the same carbon atom. Examples are: 1, 2-dibromoethane, 1, 4-dibromobutane, 1, 4-dichloro-2-butene.

The organic amine M1 is C2-C10 monobasic organic secondary amine or C6-C16 dibasic organic tertiary amine. M1 has at least two carbon atoms apart from each other amino group and no other active hydrogen-containing groups that can participate in isocyanate addition. Examples are: diethylamine, piperidine, tetramethylethylenediamine, N-dimethylpiperazine.

When the organic amine is secondary amine, the dropping rate and the structure of the dihalohydrocarbon are controlled, and the side reaction of the dihalohydrocarbon and the secondary amine to generate the cyclic quaternary ammonium salt is avoided by slowing down the dropping rate in the time range and avoiding selecting the dihalohydrocarbon with 4-5 carbon atoms separating halogen atoms. Meanwhile, sodium carbonate or potassium carbonate with the molar weight more than 2 times of the theoretically generated hydrogen halide is added in advance as an acid-binding agent before the beginning of the dropwise addition.

The hydroxyl tertiary amine blocking agent M2 is a C4-C10 hydroxyl amine which contains a quaternizable tertiary amino group and a hydroxyl group, wherein the hydroxyl group and the amino group are separated by at least 2 carbon atoms and do not contain other active hydrogen-containing groups capable of participating in isocyanate addition. Examples are: n, N-dimethylethanolamine, N-diethyl-4-hydroxybutylamine, N-hydroxyethylimidazole.

The polyurethane prepolymer is obtained by reacting polyether glycol with isocyanate.

The polyether glycol G is a hydrophobic macromolecule which is polymerized by an open-ring oxa-organic cyclic compound and has hydroxyl groups at two ends, and the structure of the polyether glycol G accords with the following general formula 10; examples are: polypropylene oxide, polytetrahydrofuran.

In the above formula, R9, R10 and p1 are as defined in formula 9.

The isocyanate I, is a common commercial diisocyanate, including but not limited to: toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1, 6-hexamethylene diisocyanate, dicyclohexylmethane diisocyanate.

The preparation method of the polyion liquid comprises the following steps: dissolving dihalogenated hydrocarbon H in a solvent S1, then dripping organic amine M1 into the dihalogenated hydrocarbon H at the temperature of 20-60 ℃, continuously dripping for 1-24H, and then continuously reacting for 6-24H at the same temperature to obtain an intermediate solution L1. And then adding a hydroxyl tertiary amine end-capping agent M2, reacting at 30-70 ℃ for 6-18 h, filtering out insoluble residues, and recovering the solvent S1 by reduced pressure distillation to obtain the polyion liquid L2.

The solvent S1 is an aprotic polar, non-aldehyde ketone organic solvent with a boiling point not higher than 120 ℃. The amount of the dihalogenated hydrocarbon is 2.5 to 6 times of the total mass of the dihalogenated hydrocarbon H and the M1.

The molar ratio of the organic amine M1 to the hydroxyl tertiary amine end-capping agent M2 to the dihalohydrocarbon H enables the number of quaternary ammonium groups on the finally obtained polyion liquid L2 to be 4-12 according to the principle of polycondensation reaction, and the number of quaternary ammonium groups is consistent with the number range in the chain segment A. The mass relationships of M1, M2 and H were estimated from the above molar ratios.

The final melting point of the polyionic liquid L2 is not higher than 85 ℃ by proper molecular structure design and adjustment, such as controlling the proportion of rigid structures such as rings, double bonds and the like in a chain segment.

The preparation method of the polyurethane prepolymer comprises the following steps:

firstly, drying polyether glycol G at 100-120 ℃ in vacuum for dewatering, and dewatering isocyanate I by a drying agent after reduced pressure distillation; and then dissolving the I in a solvent S2, adding a catalyst T into the S2 solution of the I under a dry environment protected by nitrogen, then adding G into the solution within 0.5-2 h under stirring, controlling the temperature at 20-60 ℃ in the process, adjusting the temperature to 30-75 ℃, and reacting for 2-8 h to obtain a solution of a polyurethane prepolymer U1.

The solvent S2 is an organic solvent which does not contain active hydrogen capable of reacting with isocyanate, has a boiling point of 120 ℃ or lower, and facilitates the progress of the isocyanate addition reaction. Examples are: acetone, butanone and ethyl acetate.

Solvent S2 needs to be pre-treated with water to ensure that the water content does not affect the polyurethane condensation reaction. The using amount of S2 is 3-6 times of the total mass of polyether glycol G and isocyanate I.

The catalyst T can be any of various known polyurethane condensation catalysts, such as: diethyl piperazine, dibutyl tin dilaurate; dibutyl tin dilaurate is recommended. The dosage of T is 0.05-0.3% of the total mass of G and I.

In the above step, the molar ratio of the polyether glycol G to the isocyanate I is such that the finally obtained polyurethane prepolymer U1 contains 1-4 segments of polyether glycol chain segments based on the principle of polycondensation reaction.

The preparation method of the segmented polyurethane polymer comprises the following steps: adding a certain amount of polyion liquid L2 into a polyurethane prepolymer U1 solution within 0.5-2 h at the temperature of 20-60 ℃, adjusting the temperature to 50-85 ℃, and reacting for 2-8 h to obtain a segmented polyurethane polymer U2 solution.

The mass ratio of the polyion liquid L2 to the polyurethane prepolymer U1 ensures that the generated segmented polyurethane polymer meets the mass ratio relationship between the chain segment A and the chain segment B.

The block polyurethane polymer is used as an intercalation modifier of bentonite.

The polymer modified bentonite admixture is obtained by using the segmented polyurethane polymer intercalation modified bentonite, and the polymer modified bentonite admixture is used as an additive of concrete, so that the concrete mechanical property and the chloride ion permeation resistance can be effectively improved while the concrete workability is not influenced.

In the polymer modified bentonite admixture, the mass ratio of bentonite to the block polyurethane polymer is respectively as follows:

bentonite: 50 to 75 percent

Block polyurethane type polymer: 50 to 25 percent

The bentonite is a clay material with swelling property, and is preferably montmorillonite.

The preparation method of the polymer modified bentonite admixture comprises the following steps: dispersing the segmented polyurethane polymer U2 solution in water, firstly carrying out reduced pressure distillation to recover a solvent S2, and then adding bentonite under stirring at 180-600 rpm; and then, heating to 40-80 ℃, and modifying for 2-12 h at the stirring speed. Then, filtering out the modified bentonite, washing with water, and drying in vacuum at 40-60 ℃ to obtain the polymer modified bentonite admixture C

The dosage of the water used for dispersing the reactant is 5-16 times of the sum of the mass of the segmented polyurethane polymer U2 and the mass of the bentonite.

The polymer modified bentonite material can be used for improving the mechanical and durability properties of silicate cement materials, and is particularly suitable for C30-C60 concrete. The recommended mixing amount is 0.8-3.5% of the total mass of the rubber material.

The polymer modified bentonite material is a block polymer in a microstructure, and cations among bentonite layers are replaced by ion exchange so as to be inserted among the layers. Microscopically, the cationic segment a of the block polymer is bonded to the aluminosilicate lamellae of the bentonite by electrostatic interaction; the hydrophobic chain segment B is adsorbed between the cationic chain segments of the upper and lower two sheets through hydrophobic effect to form a shape similar to that of the cationic chain segment: a sandwich structure of cationic segments of the polymer of the previous layer-aluminosilicate sheet layer-cationic segments-hydrophobic segments-cationic segments-next aluminosilicate sheet layer.

The interlayer structure is formed, so that on one hand, the distance between aluminosilicate sheets of the bentonite is increased, and the components of the slurry pore solution can be favorably deeply reacted, so that the bentonite in the material can generate the pozzolanic activity. After the clay is filled by the polymer intercalation, no space is left for obviously adsorbing the free water and the water reducing agent, so that the negative influence of the clay on the early working performance of the cement-based material is greatly reduced.

On the other hand, the interlayer structure enables the polymer to be fixed between the bentonite sheets before the bentonite sheets are decomposed by the volcanic ash reaction in the early stage of cement hydration, so that the slow release of the polymer is realized, and the negative influence of the common water-soluble polymer on the early stage hydration of the cement-based material is avoided. Along with the gradual decomposition of the bentonite sheet layer, the polymer is released and filled in C-S-H generated by hydration to directly form an organic-inorganic composite microstructure, so that the mechanical property of the cement-based material can be improved from a microscopic level, and meanwhile, the release of the polymer increases the viscosity temperature of the pore solution, so that harmful substances are more difficult to permeate.

Under the synergy of the volcanic ash activity effect of the inorganic component and the slow-release microstructure optimization effect of the organic component of the polymer modified bentonite material, the polymer modified bentonite material can effectively improve the mechanical property and durability of the portland cement-based material. Meanwhile, the production process basically has no three wastes, the solvent and the auxiliary reagent can be recycled, the conditions are relatively mild, and the method is convenient for large-scale industrialization.

Detailed Description

The following examples further illustrate specific embodiments of the present invention, but the materials and methods encompassed by the present invention should not be limited to the following examples, and equivalent changes or modifications made to the method according to the present invention should be within the scope of the present invention.

Because the present invention involves many reagents and process steps, embodiments will be explained in stages to better understand the basic principles of the present invention for the reader and the user in practice.

First, the synthesis method of polyion liquid will be explained, and the structural formula of the main organic raw materials used at this stage is shown in the following table:

TABLE 1 reaction raw materials used in Synthesis examples of polyionic liquids

Examples 1 to 1

212 parts by mass of 1, 3-dibromopropane was dissolved in 833 parts by mass of acetonitrile, 191 parts by mass of sodium carbonate was added, 65.7 parts by mass of diethylamine was dropped thereto at 25 ℃ for 24 hours, and then the reaction was continued at the same temperature for 16 hours to obtain an intermediate solution L1-1. Then, 26.7 parts by mass of dimethylethanolamine was added, reaction was carried out at 30 ℃ for 18 hours, then insoluble residues were filtered off, and acetonitrile was recovered by distillation under reduced pressure to obtain polyion liquid L2-1.

Examples 1 to 2

146.4 parts by mass of 1, 6-dibromohexane was dissolved in 725 parts of acetonitrile, 112 parts by mass of potassium carbonate was added, 34.8 parts by mass of morpholine was added dropwise thereto at 30 ℃ for 18 hours, and then the reaction was continued at the same temperature for 24 hours to obtain an intermediate solution L1-2. Then, 44.8 parts by mass of hydroxyethyl imidazole was added thereto, and the mixture was reacted at 40 ℃ for 12 hours, and then insoluble residues were filtered off, and acetonitrile was recovered by distillation under reduced pressure to obtain polyion liquid L2-2.

Examples 1 to 3

59.4 parts by mass of 1, 2-dichloroethane was dissolved in 446 parts by mass of tetrahydrofuran, and then 114 parts by mass of tetraethyl 1, 6-hexanediamine was added dropwise thereto at 50 ℃ for 2 hours, followed by further reaction at the same temperature for 12 hours to obtain an intermediate solution L1-3. Then, 23.4 parts of diethylethanolamine was added to the reaction mixture to react at 60 ℃ for 8 hours, and then insoluble residue was filtered off, and tetrahydrofuran was recovered by distillation under reduced pressure to obtain polyion liquid L2-3.

Examples 1 to 4

103.7 parts by mass of 1, 4-dibromobutane was dissolved in 794 parts by mass of dioxane, and then 36.5 parts by mass of N, N' -dimethylpiperazine was added dropwise thereto at 60 ℃ for 1 hour, followed by continuing the reaction at the same temperature for 6 hours to obtain an intermediate solution L1-4. Then, 28.5 parts by mass of dimethylethanolamine was added, reaction was carried out at 70 ℃ for 6 hours, then insoluble residue was filtered off, and dioxane was recovered by distillation under reduced pressure to obtain polyion liquid L2-4.

The following examples, which are examples of the synthesis of U1 polyurethane prepolymers, show the structure and material parameters of U1 as follows:

TABLE 2 types and parameters of raw materials used in the example of polyurethane prepolymer Synthesis

Example 2-1

Firstly, polypropylene glycol-600 is dried in vacuum to remove water, and toluene diisocyanate is distilled under reduced pressure and then is removed with a drying agent. Then, 121.8 parts by mass of toluene diisocyanate was dissolved in 1000 parts by mass of acetone, 0.17 part by mass of dibutyltin dilaurate was added to the solution under a dry atmosphere protected by nitrogen, and 210 parts by mass of polypropylene glycol-600 was added within 0.5 hour with stirring, while controlling the temperature at 20 ℃ and then adjusting the temperature to 30 ℃ for reaction for 8 hours, to obtain a solution of a polyurethane prepolymer U1-1.

Examples 2 to 2

Firstly, polypropylene glycol-800 is dried in vacuum to remove water, and diphenylmethane diisocyanate is distilled under reduced pressure and then is removed with a drying agent. Then, 112.5 parts by mass of diphenylmethane diisocyanate was dissolved in 2400 parts by mass of methyl ethyl ketone, 0.41 part by mass of dibutyltin dilaurate was added to the solution under a dry atmosphere protected by nitrogen, and then 240 parts by mass of polypropylene glycol-800 was added within 2 hours with stirring, while controlling the temperature at 60 ℃ and then adjusting the temperature to 65 ℃ for reaction for 4 hours, to obtain a solution of a polyurethane prepolymer U1-2.

Examples 2 to 3

Firstly, polypropylene glycol-2200 is dried in vacuum to remove water, isophorone diisocyanate is distilled under reduced pressure and then is removed with drying agent. Then, 53.3 parts by mass of isophorone diisocyanate was dissolved in 1300 parts by mass of dioxane, 0.95 part by mass of dibutyltin dilaurate was added to the solution under a dry atmosphere protected by nitrogen, and then 264 parts by mass of polypropylene glycol-2200 was added within 1 hour with stirring, while controlling the temperature at 40 ℃ and then adjusting the temperature to 75 ℃, followed by reaction for 2 hours, to obtain a solution of a polyurethane prepolymer U1-3.

Examples 2 to 4

Firstly, polytetrahydrofuran-750 is dried in vacuum to remove water, hexamethylene diisocyanate is distilled under reduced pressure, and then water is removed by a drying agent. Then, 100.8 parts by mass of hexamethylene diisocyanate was dissolved in 1800 parts by mass of acetone, 0.69 part by mass of dibutyltin dilaurate was added to the solution in a dry environment protected by nitrogen, 360 parts by mass of polytetrahydrofuran-750 was added within 1.5 hours while stirring, the temperature was controlled at 50 ℃ in the process, and then the reaction was carried out at the same temperature for 6 hours to obtain a solution of a polyurethane prepolymer U1-4.

Next, the procedure of synthesizing a polyurethane block polymer and modifying bentonite using the above examples will be explained.

Example 3-1

114.8 parts by mass of L2-4 is added into a U1-1 solution containing 142.2 parts by mass of U1-1 within 2 hours at the temperature of 20 ℃, and then the temperature is adjusted to 50 ℃ to react for 4 hours, so that a solution of cationic block polyurethane U2-1 is obtained.

After 51.4 parts by mass of the U2-1 solution was dispersed in 1050 parts by mass of water, the solvent was recovered by distillation under reduced pressure, and then 154.2 parts by mass of montmorillonite was added under stirring at 180 rpm; thereafter, the temperature was raised to 60 ℃ and the modification was carried out for 2 hours at the aforementioned stirring rate. Then filtering out the modified montmorillonite, washing with water, and vacuum drying at 50 ℃ to obtain the modified montmorillonite C-1.

Examples 3 to 2

At 20 ℃, 137.8 parts by mass of L2-4 is added into a U1-1 solution containing 199.1 parts by mass of U1-1 within 2 hours, then the temperature is adjusted to 50 ℃, and the reaction is carried out for 8 hours, so as to obtain a solution of cationic block polyurethane U2-2.

After 67.4 parts by mass of the U2-2 solution was dispersed in 1950 parts by mass of water, the solvent was recovered by distillation under reduced pressure, and then 125.1 parts by mass of montmorillonite was added under stirring at 240 rpm; thereafter, the temperature was raised to 50 ℃ and the modification was carried out for 4 hours at the aforementioned stirring rate. Then filtering out the modified montmorillonite, washing with water, and vacuum drying at 50 ℃ to obtain the modified montmorillonite C-2.

Examples 3 to 3

138.8 parts by mass of L2-3 is added into U1-4 solution containing 230.4 parts by mass of U1-4 within 0.5h at 60 ℃, and then the temperature is adjusted to 60 ℃ for reaction for 4h, so as to obtain the solution of cationic block polyurethane U2-3.

Dispersing 73.8 parts by mass of U2-3 solution in 2100 parts by mass of water, distilling under reduced pressure to recover the solvent, and then adding 137.1 parts by mass of montmorillonite under stirring at 240 rpm; thereafter, the temperature was raised to 50 ℃ and the modification was carried out for 4 hours at the aforementioned stirring rate. Then filtering out the modified montmorillonite, washing with water, and vacuum drying at 50 ℃ to obtain the modified montmorillonite C-3.

Examples 3 to 4

At 60 ℃, 138.8 parts by mass of L2-3 is added into a U1-4 solution containing 288 parts by mass of U1-4 within 0.5h, then the temperature is adjusted to 80 ℃, and the reaction is carried out for 4h, thus obtaining a solution of cationic block polyurethane U2-4.

Dispersing 106.7 parts by mass of U2-4 solution in 3400 parts by mass of water, distilling under reduced pressure to recover the solvent, and then adding 106.7 parts by mass of montmorillonite under stirring at 600 rpm; then, the temperature was raised to 80 ℃ and the mixture was modified at the above stirring rate for 10 hours. Then filtering out the modified montmorillonite, washing with water, and vacuum drying at 60 ℃ to obtain the modified montmorillonite C-4.

Examples 3 to 5

At 40 ℃, 103.7 parts by mass of L2-2 is added into a U1-2 solution containing 282 parts by mass of U1-2 within 1h, then the temperature is adjusted to 60 ℃, and the reaction is carried out for 6h, thus obtaining a solution of cationic block polyurethane U2-5.

Dispersing 69.4 parts by mass of U2-5 solution in 1900 parts by mass of water, distilling under reduced pressure to recover the solvent, and adding 162.0 parts by mass of montmorillonite while stirring at 240 rpm; then, the temperature was raised to 40 ℃ and the mixture was modified at the above stirring rate for 12 hours. Then filtering out the modified montmorillonite, washing with water, and vacuum drying at 50 ℃ to obtain the modified montmorillonite C-5.

Examples 3 to 6

113 parts by mass of L2-1 was added to 264.4 parts by mass of U1-3 solution of U1-3 over 1 hour at 40 ℃ and then the temperature was adjusted to 85 ℃ to react for 2 hours to obtain a solution of cationic block polyurethane U2-6.

Dispersing 75.5 parts by mass of U2-6 solution in 2250 parts by mass of water, distilling under reduced pressure to recover the solvent, and then adding 113.2 parts by mass of montmorillonite while stirring at 360 rpm; then, the temperature was raised to 60 ℃ and the mixture was modified at the above stirring rate for 6 hours. Then filtering out the modified montmorillonite, washing with water, and vacuum drying at 50 ℃ to obtain the modified montmorillonite C-6.

Examples 3 to 7

135.6 parts by mass of L2-1 was added to a solution of U1-2 containing 293.8 parts by mass of U1-2 over 1 hour at 40 ℃ and then the temperature was adjusted to 70 ℃ to react for 4 hours to obtain a solution of cationic block polyurethane U2-7.

After 85.9 parts by mass of the U2-7 solution was dispersed in 2500 parts by mass of water, the solvent was recovered by distillation under reduced pressure, and then 128.8 parts by mass of montmorillonite was added under stirring at 480 rpm; then, the temperature was raised to 60 ℃ and the mixture was modified at the above stirring rate for 6 hours. Then filtering out the modified montmorillonite, washing with water, and vacuum drying at 40 ℃ to obtain the modified montmorillonite C-7.

Examples 3 to 8

123.4 parts by mass of L2-3 is added into a U1-2 solution containing 235 parts by mass of U1-2 within 1 hour at the temperature of 50 ℃, and then the temperature is adjusted to 70 ℃ to react for 4 hours, so as to obtain a solution of cationic block polyurethane U2-8.

After 89.6 parts by mass of the U2-8 solution was dispersed in 2400 parts by mass of water, the solvent was recovered by distillation under reduced pressure, and then 109.5 parts by mass of montmorillonite was added under agitation at 480 rpm; thereafter, the temperature was raised to 70 ℃ and the modification was carried out for 8 hours at the aforementioned stirring rate. Then filtering out the modified montmorillonite, washing with water, and vacuum drying at 40 ℃ to obtain the modified montmorillonite C-8.

Application example

Next, the concrete was modified in the above examples to verify its performance characteristics and benefits, except that unmodified montmorillonite, calcined clay, and polymer components U2-4 and U2-7 in the typical samples of the examples were used as a comparison.

The specification and the flow of the test material are based on GB 8076-. The amount of the organic control group is subtracted from the polymer component ratio in the corresponding examples, and the mass of the organic control group is taken into account in the water phase.

The cement used in the test was P I42.5.5 benchmark cement. Slump of all samples is adjusted to 20 +/-1 cm by using a water reducing agent, and the water reducing agent is a PCA-I type high-performance water reducing agent of Jiangsu Subot New materials GmbH.

TABLE 3 mixing ratio of concrete used in concrete test (unit kg/m3)

TABLE 4 consumption of water reducer and 28d C resistance of examples and control modified concrete

As can be seen from the above table, at the same slump temperature, compared with the control group, each example has no influence on the amount and gas content of the water reducing agent, and the consumption of the water reducing agent is remarkably increased by the montmorillonite and the calcined clay, especially by the montmorillonite. Meanwhile, if only the polymer is added by neglecting the clay component, although the consumption of the water reducing agent is slightly reduced, the gas content of the concrete is obviously increased due to the micelle forming property of the block polymer.

In the aspect of strong temperature, compared with a blank group with 28d, the strong temperature of each group doped in the embodiment is obviously improved to 11.0-22.7%. The montmorillonite group has no obvious change in the strong temperature, and the calcined clay group is only slightly improved under the doping amount. Compared with two inorganic control materials, the temperature of the polymer directly doped in the high-strength material is greatly reduced, on one hand, the high-strength material is the reason that the polymer is adsorbed on the surfaces of cement particles and hydration products in the early stage of hydration, so that the early-stage hydration reaction is prevented from being carried out, and the generation of a basic microstructure is prevented; on the other hand, the high air entrainment caused by the polymer also causes a significant reduction in mechanical properties.

The performance of each example and comparative example was evaluated mainly in terms of durability by chloride ion permeation test

TABLE 5 chloride ion diffusion coefficient and permeation pressure resistance of each example and comparative modified concrete

As can be seen from the above table, the diffusion coefficient of chloride ions of the concrete doped with the concrete of the embodiment is reduced by about 45-60% compared with the standard. While the diffusion coefficient and the contrast ratio of the montmorillonite-doped group are only slightly reduced. Although the diffusion coefficient of chloride ions is reduced, the reduction rate of the directly doped polymer group is far less than that of each example, which is probably caused by that the directly doped polymer is greatly embedded in early hydration and the microstructure is reduced at the temperature of densification ℃ after the hydration is hindered. This demonstrates that a more significant increase in chloride ion permeability can be achieved over a single component via a synergistic effect of the pozzolanic activity of the admixture bentonite component and the slow release microstructural modification of the polymeric component.

In conclusion, the admixture disclosed by the invention obviously improves the mechanical property and impermeability of concrete, and the efficiency of the admixture is obviously superior to that of a pure clay material or a pure polymer, so that the preparation method disclosed by the invention is proved to be beneficial.

Claims

1. A segmented polyurethane polymer is characterized in that the segmented polyurethane polymer is a structural sequence formed by two types of units of a cationic chain segment A and a hydrophobic chain segment B alternately, the two ends of the chain segment are of the same unit type, and the two ends of the chain segment are both the cationic chain segment A or both the hydrophobic chain segment B;

the cationic chain segment A is composed of hydroxyl quaternary ammonium residues, alkylene and quaternary ammonium salt residues of C2-C16 containing 1-2 quaternary ammonium residues, and the cationic chain segment A contains 4-12 quaternary ammonium residues; two ends of the cation chain segment A are hydroxyl quaternary amine residues, and two ends of the alkylene group are alternately connected with the hydroxyl quaternary amine residues or quaternary ammonium salt residues of C2-C16 containing 1-2 quaternary ammonium residues;

the hydroxyl quaternary ammonium residue is a group containing a quaternary ammonium residue and a hydroxyl residue, the hydroxyl and the quaternary ammonium group are separated by at least 2 carbon atoms, and in addition, the hydroxyl quaternary ammonium residue does not contain other hydroxyl quaternary ammonium residues which contain active hydrogen groups and are C4-C10 and can participate in isocyanate addition;

the alkylene group is C2-C6 alkylene group, and the length of the alkylene group in the main chain segment is not less than 2 carbon atoms;

the quaternary ammonium salt residues of C2-C16 containing 1-2 quaternary ammonium residues do not contain other active hydrogen-containing groups capable of participating in isocyanate addition;

the hydrophobic chain segment B consists of isocyanate residue and polyalkyl ether glycol residue; the two are alternately arranged in a chain segment, and both ends of the chain segment are isocyanate residues; the weight average molecular weight of the hydrophobic chain segment B is 800-4000;

2. The block polyurethane polymer according to claim 1, wherein the weight average molecular weight is 4000 to 30000.

3. The block-type polyurethane polymer according to claim 1, wherein the hydroxy quaternary ammonium residue has the following structural formula:

wherein the structures of R1, R2 and X are such that the residue is such that the hydroxyl and quaternary ammonium groups are separated by at least 2 carbon atoms and that in addition to this, no other hydroxyl quaternary ammonium residues of C4-C10 containing active hydrogen groups are involved in the isocyanate addition.

4. The block polyurethane polymer according to claim 1, wherein the quaternary ammonium salt residue of C2-C16 containing 1 quaternary ammonium residue has a structural formula shown in formula 2; the structural formula of the quaternary ammonium salt residue containing 2 quaternary ammonium residues and C2-C16 is shown in formula 3:

in the formula, R3-R8 and Y enable the two formulas to meet the carbon number and group limitation conditions, and meanwhile, under the chemically allowable premise, R3-R4 can be connected with each other to form a ring assembly structure, and R5-R8 can also be connected with each other and form a ring assembly structure with Y.

5. The block-type polyurethane polymer according to claim 1, wherein the diisocyanate residue has the following structure:

wherein Z is C2-C20, and is a stable organic structure in aqueous solution, and two nitrogen atoms in the formula are separated by at least 2 carbon atoms.

6. The block-type polyurethane polymer of claim 1 wherein the structure of the polyalkyl ether diol residue corresponds to structural formula 9:

in the formula, R9 is a linear chain terminal alkylene of C2-C6, R10 is a hydrogen atom or methyl or ethyl; and when R9 is 1, 2-ethylene, R10 can only be methyl or ethyl; p1 is a number of 4 to 40.

7. The process for the preparation of a segmented polyurethane polymer as claimed in any one of claims 1 to 5, wherein the segmented polyurethane polymer is obtained by condensation of a polyionic liquid with a polyurethane prepolymer;

the dihalohydrocarbon H is a C2-C6 halogenated hydrocarbon containing two halogen atoms except fluorine, and the halogen atoms are not on the same carbon atom;

the organic amine M1 is a C2-C10 monobasic organic secondary amine or C6-C16 dibasic organic tertiary amine; m1 has at least two carbon atoms separating the amino groups and no other active hydrogen-containing groups that can participate in isocyanate addition;

the hydroxyl tertiary amine blocking agent M2 is C4-C10 hydroxylamine containing an active hydrogen group and capable of participating in isocyanate addition, wherein the hydroxyl tertiary amine blocking agent M2 contains a quaternizable tertiary amino group and a hydroxyl group, and the hydroxyl group and the amino group are separated by at least 2 carbon atoms;

examples are: n, N-dimethylethanolamine, N-diethyl-4-hydroxybutylamine, N-hydroxyethylimidazole;

the polyurethane prepolymer is obtained by reacting polyether glycol G with isocyanate;

the polyether glycol G is a hydrophobic macromolecule which is polymerized by ring-opening oxygen heterocyclic compounds and has hydroxyl groups at two ends.

8. The method according to claim 6, wherein the dihalohydrocarbon is selected from 1, 2-dibromoethane, 1, 4-dibromobutane or 1, 4-dichloro-2-butene.

9. The method according to claim 6, wherein said organic amine is selected from diethylamine, piperidine, tetramethylethylenediamine, N, N-dimethylpiperazine.

10. The process according to claim 6, characterized in that the isocyanate I is selected from toluene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, 1, 6-hexamethylene diisocyanate or dicyclohexylmethane diisocyanate.

11. The process of claim 6, wherein the polyether glycol G has a structure according to the following formula:

in the formula, the linear chain end alkylene of C2-C6, R10 is hydrogen atom or methyl, ethyl; and when R9 is 1, 2-ethylene, R10 can only be methyl or ethyl; p1 is a number of 4 to 40.

12. The method of claim 10, wherein the polyether glycol G is selected from polypropylene oxide or polytetrahydrofuran.

13. The method according to claim 6, wherein the polyionic liquid is prepared by: dissolving dihalogenated hydrocarbon H in a solvent S1, then, dropwise adding organic amine M1 into the dihalogenated hydrocarbon H at the temperature of 20-60 ℃, continuously dropwise adding for 1-24H, and then, continuously reacting for 6-24H at the same temperature to obtain an intermediate solution L1; then, adding a hydroxyl tertiary amine end-capping agent M2, reacting at 30-70 ℃ for 6-18 h, filtering out insoluble residues, and recovering a solvent S1 by reduced pressure distillation to obtain a polyion liquid L2;

the solvent S1 is an aprotic polar, non-aldehyde ketone organic solvent with the boiling point not higher than 120 ℃;

the amount of the dihalogenated hydrocarbon is 2.5 to 6 times of the total mass of the dihalogenated hydrocarbon H and the M1.

14. The method of claim 6, wherein the polyurethane prepolymer is prepared by the following method:

firstly, drying polyether glycol G at 100-120 ℃ in vacuum for dewatering, and dewatering isocyanate I by a drying agent after reduced pressure distillation; then, dissolving the I in a solvent S2, adding a catalyst T into the S2 solution of the I under a dry environment protected by nitrogen, then adding G into the solution within 0.5-2 h under stirring, controlling the temperature at 20-60 ℃ in the process, adjusting the temperature to 30-75 ℃, and reacting for 2-8 h to obtain a solution of a polyurethane prepolymer U1;

the solvent S2 is an organic solvent which does not contain active hydrogen capable of reacting with isocyanate, has a boiling point below 120 ℃ and is beneficial to the isocyanate addition reaction;

the solvent S2 needs to be subjected to water removal pretreatment to ensure that the water content in the solvent does not influence the polyurethane condensation reaction; the using amount of S2 is 3-6 times of the total mass of polyether glycol G and isocyanate I;

the dosage of the catalyst T is 0.05-0.3% of the total mass of G and I;

15. The process according to claim 14, characterized in that the solvent S2 is selected from acetone, butanone, ethyl acetate.

16. The process of claim 14 wherein the catalyst T is dibutyl tin dilaurate or diethyl piperazine.

17. The process according to claim 6, characterized in that the block polyurethane polymer is prepared by a process comprising: adding a certain amount of polyion liquid L2 into a polyurethane prepolymer U1 solution within 0.5-2 h at the temperature of 20-60 ℃, adjusting the temperature to 50-85 ℃, and reacting for 2-8 h to obtain a segmented polyurethane polymer U2 solution.

18. Use of a segmented polyurethane polymer as claimed in any one of claims 1 to 5 as an intercalation modifier for bentonite.

19. The use according to claim 18, wherein a polymer modified bentonite admixture is obtained using the block polyurethane polymer intercalated modified bentonite.

20. The polymer modified bentonite admixture is characterized in that in the polymer modified bentonite admixture, the mass ratio of bentonite to the mass ratio of the block polyurethane type polymer are respectively as follows:

bentonite: 50 to 75 percent of the total weight of the steel,

block polyurethane type polymer: 50 to 25 percent.

21. The polymer modified bentonite admixture of claim 19 wherein the bentonite is montmorillonite.

22. A method of preparing a polymer modified bentonite admixture according to claim 18 or 19, comprising the steps of:

dispersing the segmented polyurethane polymer U2 solution in water, then firstly carrying out reduced pressure distillation to recover the solvent, and then adding bentonite under stirring at 180-600 rpm; then, heating to 40-80 ℃, and modifying for 2-12 h at the stirring speed;

then, filtering out the modified bentonite, washing with water, and drying in vacuum at 40-60 ℃ to obtain the polymer modified bentonite admixture C;

the amount of the water is 5-16 times of the sum of the mass of the segmented polyurethane polymer U2 and the mass of the bentonite.

23. Use of a polymer modified bentonite admixture according to claim 19 as an additive in concrete.

24. Use according to claim 23, for the improvement of mechanical and durability properties of portland cement-based materials.

25. The use of claim 24, wherein the admixture is 0.8-3.5% of the total mass of the cementitious material, for C30-C60 concrete.