阅读说明：本技术 一种poss结构封端的聚羧酸减水剂及其制备方法 (POSS structure-terminated polycarboxylate superplasticizer and preparation method thereof ) 是由 郑春扬 王学川 钱珊珊 卢通 赵旭 彭荩影 屈浩杰 于鹏程 于 2021-01-21 设计创作，主要内容包括：本发明公开了一种POSS结构封端的聚羧酸减水剂及其制备方法,该减水剂为梳形结构,主链为羧基阴离子基团组成,侧链由甲基封端聚乙二醇和POSS结构封端的聚乙二醇组成；其制备方法将POSS结构封端的烷撑聚氧乙烯醚线性大分子E、甲氧基封端的烷撑聚氧乙烯醚线性大分子F与聚丙烯酸S在催化剂A作用下进行酯化接枝反应,并将生成物稀释成40%质量份数的水溶液,水溶液即为POSS结构封端的聚羧酸减水剂。本发明制备的POSS结构封端的聚羧酸减水剂能提供更强的空间位阻效应,从而获得较传统聚羧酸减水剂更高的减水能力和降粘效果；此外POSS结构具有较大的空间尺寸,能有效抑制聚羧酸减水剂聚乙二醇侧链在泥土中的插层吸附。(The invention discloses a POSS structure-terminated polycarboxylate water reducer and a preparation method thereof, wherein the water reducer is of a comb-shaped structure, a main chain is composed of carboxyl anion groups, and a side chain is composed of methyl-terminated polyethylene glycol and POSS structure-terminated polyethylene glycol; the preparation method comprises the steps of carrying out esterification grafting reaction on an alkylene polyoxyethylene ether linear macromolecule E terminated by a POSS structure, an alkylene polyoxyethylene ether linear macromolecule F terminated by a methoxyl group and polyacrylic acid S under the action of a catalyst A, and diluting a product into 40% aqueous solution in parts by mass, wherein the aqueous solution is the polycarboxylic acid water reducing agent terminated by the POSS structure. The prepared POSS structure-terminated polycarboxylate superplasticizer can provide stronger steric hindrance effect, thereby obtaining higher water reducing capacity and viscosity reduction effect than the traditional polycarboxylate superplasticizer; in addition, the POSS structure has larger space size, and can effectively inhibit the intercalation adsorption of the polyethylene glycol side chain of the polycarboxylate superplasticizer in soil.)

1. The POSS structure-terminated polycarboxylate superplasticizer is characterized in that: the poly carboxylic acid water reducing agent with the POSS structure end capping is in a comb-shaped structure, the main chain is composed of carboxyl anion groups, and the side chain is composed of methyl end capping polyethylene glycol and POSS structure end capping polyethylene glycol according to a preset molar ratio; the molecular formula is shown as the following formula (I):

（Ⅰ）

in the formula (I), R is one of methyl, ethyl, propyl, isopropyl, phenyl, cyclohexyl, butyl, isobutyl, n-pentyl, 2-methylbutyl, 2-dimethylpropyl, hexyl, 2-methylpentyl, 3-methylpentyl, 2-dimethylbutyl and 2, 3-dimethylbutyl; r1 is H atom or methyl; q is one of-CH 2O-, -CH2CH 2O-and-CH 2CH2CH 2O-; a. b, c, m and n are integers; wherein a (b + c) = 1-10, b: c = 0.5-2.0, m = 10-135, and n = 22-113.

2. The POSS structure-terminated polycarboxylate water reducer according to claim 1, characterized in that: the number average molecular weight of the POSS structure-terminated polycarboxylate superplasticizer is 10000-100000.

3. A preparation method of a POSS structure-terminated polycarboxylate water reducer is used for preparing the POSS structure-terminated polycarboxylate water reducer as claimed in any one of claims 1 to 2, and is characterized in that: the POSS structure end-capped alkylene polyoxyethylene ether linear macromolecule E and the methoxy end-capped alkylene polyoxyethyleneThe linear macromolecule F of the vinyl ether and polyacrylic acid S are subjected to esterification grafting reaction under the action of a catalyst A, and N is introduced in the reaction process₂Taking away generated water, reacting at 100-200 ℃ for 4h, cooling to room temperature, and diluting the product into 40% aqueous solution in parts by mass; the water solution is a POSS structure terminated polycarboxylate superplasticizer; the catalyst A is one of concentrated sulfuric acid, concentrated phosphoric acid, p-toluenesulfonic acid, p-hydroxybenzene sulfonic acid, concentrated hydrochloric acid, concentrated nitric acid, sodium bisulfite, sodium metabisulfite, phosphotungstic acid, tetrabutyl titanate and 4-dimethylaminopyridine.

4. The preparation method of the POSS structure-terminated polycarboxylate superplasticizer according to claim 3, is characterized by comprising the following steps: the catalyst A is concentrated sulfuric acid.

5. The preparation method of the POSS structure-terminated polycarboxylate superplasticizer according to claim 3, is characterized by comprising the following steps: the POSS structure-terminated alkylene polyoxyethylene ether linear macromolecule E is prepared by substituting octahydro silsesquioxane POSS and terminal alkenyl alkylene polyoxyethylene ether under the action of Karstedt catalyst.

6. The preparation method of the POSS structure-terminated polycarboxylate superplasticizer according to claim 3, is characterized by comprising the following steps: the methoxy-terminated alkylene polyoxyethylene ether linear macromolecule F is obtained by ring-opening polymerization of ethylene oxide when methanol is used as an initiator, and the number average molecular weight of the methoxy-terminated alkylene polyoxyethylene ether linear macromolecule F is 500-6000.

7. The preparation method of the POSS structure-terminated polycarboxylate superplasticizer according to claim 3, is characterized by comprising the following steps: the polyacrylic acid S is an oligomer obtained by free radical polymerization of acrylic acid, and the number average molecular weight of the oligomer is 1000-8000.

8. The preparation method of the POSS structure-terminated polycarboxylate superplasticizer according to claim 5, is characterized in that: the mono-hydrogen substituted octa-silsesquioxane POSS is prepared from trichlorosilane with a molar ratio of 1:7HSiCl₃And trichloroalkylsilane RSiCl₃Hydrolyzing in a mixed solution of ethanol and water, and distilling under reduced pressure to remove generated HCl and redundant solvent to obtain purified monohydrogen-substituted octasilsesquioxane POSS; the molecular formula of the mono-hydrogen substituted octa-silsesquioxane POSS is shown as a formula (II):

（Ⅱ）

in the formula (II), R is one of methyl, ethyl, propyl, isopropyl, phenyl, cyclohexyl, butyl, isobutyl, n-pentyl, 2-methylbutyl, 2-dimethylpropyl, hexyl, 2-methylpentyl, 3-methylpentyl, 2-dimethylbutyl and 2, 3-dimethylbutyl.

9. The preparation method of the POSS structure-terminated polycarboxylate superplasticizer according to claim 5, is characterized in that: the terminal alkylene polyoxyethylene ether is obtained by ring-opening polymerization of terminal alkylene alcohol serving as an initiator and ethylene oxide, and the number average molecular weight of the terminal alkylene polyoxyethylene ether is 1000-5000; the molecular formula of the terminal alkylene polyoxyethylene ether is shown as the formula (III):

（Ⅲ）

in the formula (III), R₁Is H atom or methyl; q is-CH₂O-、-CH₂CH₂O-、-CH₂CH₂CH₂CH₂O-, or one of the above.

Technical Field

The invention relates to the technical field of building materials, in particular to a POSS structure-terminated polycarboxylate superplasticizer and a preparation method thereof.

Background

In order to improve the fluidity of concrete mixtures and keep certain plasticizing performance to meet cast-in-place requirements when the water consumption is low, the water reducing agent becomes an indispensable component of the concrete mixtures, wherein the polycarboxylic acid water reducing agent is widely used for various concrete mixtures due to the characteristics of high water reducing rate, low shrinkage, economy, environmental protection and the like. With the continuous development of high-performance concrete, concrete mixtures are required to have good plasticizing performance at a lower water consumption, so that a polycarboxylic acid water reducing agent is required to have higher dispersing capacity; in addition, with the increasing exhaustion of natural resources, the concrete mixture begins to adopt artificial sandstone in a large area, so that the raw materials such as sandstone contain a small amount of stone powder and mud powder, but the polyethylene glycol side chain of the polycarboxylic acid water reducing agent is easy to perform intercalation adsorption in soil, and the use effect of the polycarboxylic acid water reducing agent is greatly weakened.

In order to improve the water reducing rate and the plasticizing time of polycarboxylic acid, the prior art Chinese patent publication numbers are as follows: CN107245131A, invention name: a preparation method of an amino polyether end group silanization polycarboxylate water reducer discloses a preparation method of an amino polyether end group silanization polycarboxylate water reducer. Compared with the common polycarboxylic acid water reducing agent, the polycarboxylic acid water reducing agent prepared by the method has better dispersing ability and slump retaining ability. The prior art Chinese patent publication numbers are: CN110760037A, invention name: an amino acid modified mud-resistant polycarboxylate superplasticizer and a preparation method thereof are disclosed, and the amino acid modified mud-resistant polycarboxylate superplasticizer is prepared by polymerizing amino acid modified unsaturated acid ester, unsaturated macromonomer and acrylic acid through free radicals. The water reducing agent effectively inhibits the surface adsorption and intercalation adsorption of clay to the polycarboxylic acid water reducing agent by utilizing the electrostatic repulsion, the nonpolar structure and the terminal steric hindrance. The prior art Chinese patent publication numbers are: CN107200819A, invention name: a synthetic method of silicon-containing polycarboxylate superplasticizer discloses a synthetic method of silicon-containing polycarboxylate superplasticizer, which is mainly prepared by carrying out free radical copolymerization reaction on organosilicon-terminated vinyl polyethylene glycol and acrylic acid or methacrylic acid; the side chain has certain adsorption capacity, so that the nano-silver nanoparticle has higher dispersibility. The prior art Chinese patent publication numbers are: CN108623745A, invention name: a benzene ring and a phosphate group structure are introduced at the tail end of a branched chain of the polycarboxylate superplasticizer, the benzene ring enhances the steric hindrance effect of the polycarboxylate superplasticizer, and the phosphate group structure provides an electrostatic repulsion effect, so that the prepared polycarboxylate superplasticizer has higher water reducing rate. In the prior art, proper modification is carried out on the side chain of the polycarboxylate superplasticizer, so that the steric hindrance effect of the polycarboxylate superplasticizer is favorably improved, and the intercalation adsorption of the polycarboxylate superplasticizer in soil can be effectively inhibited by introducing the rigid hydrophobic group.

Disclosure of Invention

1. The technical problem to be solved is as follows:

aiming at the technical problems, the invention provides the POSS structure-terminated polycarboxylate water reducer and the preparation method thereof, which can further improve the steric hindrance effect of the polycarboxylate water reducer and greatly inhibit the intercalation of polyethylene glycol side chains in soil. According to the method, POSS groups with certain spatial sizes are adopted to modify the side chains, and the POSS structure is positioned at the tail end of polyethylene glycol, so that the hydrophilicity of the polycarboxylic acid water reducing agent is not influenced, and meanwhile, the larger steric hindrance is provided; meanwhile, the POSS structure is larger than the interlayer spacing of clay in three-dimensional size, so that the probability of side chain intercalation adsorption in the clay is greatly reduced, and the effective utilization rate of the polycarboxylate superplasticizer is improved.

2. The technical scheme is as follows:

the POSS structure-terminated polycarboxylate superplasticizer is characterized in that: the poly carboxylic acid water reducing agent with the POSS structure end capping is in a comb-shaped structure, the main chain is composed of carboxyl anion groups, and the side chain is composed of methyl end capping polyethylene glycol and POSS structure end capping polyethylene glycol according to a preset molar ratio; the molecular formula is shown as the following formula (I):

（Ⅰ）

in the formula (I), R is one of methyl, ethyl, propyl, isopropyl, phenyl, cyclohexyl, butyl, isobutyl, n-pentyl, 2-methylbutyl, 2-dimethylpropyl, hexyl, 2-methylpentyl, 3-methylpentyl, 2-dimethylbutyl and 2, 3-dimethylbutyl; r1 is H atom or methyl; q is one of-CH 2O-, -CH2CH 2O-and-CH 2CH2CH 2O-; a. b, c, m and n are integers; wherein a (b + c) = 1-10, b: c = 0.5-2.0, m = 10-135, and n = 22-113.

Further, the number average molecular weight of the POSS structure-terminated polycarboxylate superplasticizer is 10000-100000.

A preparation method of a POSS structure-terminated polycarboxylate superplasticizer is characterized by comprising the following steps: carrying out esterification grafting reaction on an alkylene polyoxyethylene ether linear macromolecule E terminated by a POSS structure, an alkylene polyoxyethylene ether linear macromolecule F terminated by a methoxyl group and polyacrylic acid S under the action of a catalyst A, and introducing N in the reaction process₂Taking away generated water, reacting at 100-200 ℃ for 4h, cooling to room temperature, and diluting the product into 40% aqueous solution in parts by mass; the water solution is a POSS structure terminated polycarboxylate superplasticizer; the catalyst A is one of concentrated sulfuric acid, concentrated phosphoric acid, p-toluenesulfonic acid, p-hydroxybenzene sulfonic acid, concentrated hydrochloric acid, concentrated nitric acid, sodium bisulfite, sodium metabisulfite, phosphotungstic acid, tetrabutyl titanate and 4-dimethylaminopyridine.

Further, the catalyst A is concentrated sulfuric acid.

Further, the POSS structure-terminated alkylene polyoxyethylene ether linear macromolecule E is prepared by substituting octahydro silsesquioxane POSS and terminal alkenyl alkylene polyoxyethylene ether under the action of Karstedt catalyst.

Further, the methoxy-terminated alkylene polyoxyethylene ether linear macromolecule F is obtained by ring-opening polymerization of ethylene oxide when methanol is used as an initiator, and the number average molecular weight of the methoxy-terminated alkylene polyoxyethylene ether linear macromolecule F is 500-6000.

Further, the polyacrylic acid S is an oligomer obtained by radical polymerization of acrylic acid, and has a number average molecular weight of 1000 to 8000.

Further, the monohydrogen-substituted octasilsesquioxane POSS is prepared from trichlorosilane HSiCl in a molar ratio of 1:7₃And trichloroalkylsilane RSiCl₃Hydrolyzing in a mixed solution of ethanol and water, and distilling under reduced pressure to remove generated HCl and redundant solvent to obtain purified monohydrogen-substituted octasilsesquioxane POSS; the molecular formula of the mono-hydrogen substituted octa-silsesquioxane POSS is shown as a formula (II):

（Ⅱ）

in the formula (II), R is one of methyl, ethyl, propyl, isopropyl, phenyl, cyclohexyl, butyl, isobutyl, n-pentyl, 2-methylbutyl, 2-dimethylpropyl, hexyl, 2-methylpentyl, 3-methylpentyl, 2-dimethylbutyl and 2, 3-dimethylbutyl.

Further, the terminal alkenyl alkylene polyoxyethylene ether is obtained by ring-opening polymerization of terminal alkenyl alcohol serving as an initiator and ethylene oxide, and the number average molecular weight of the terminal alkenyl alkylene polyoxyethylene ether is 1000-5000; the molecular formula of the terminal alkylene polyoxyethylene ether is shown as the formula (III):

（Ⅲ）

in the formula (III), R₁Is a H atom orA methyl group; q is-CH₂O-、-CH₂CH₂O-、-CH₂CH₂CH₂CH₂O-, or one of the above.

3. Has the advantages that:

(1) according to the invention, the POSS structure-terminated alkylene polyoxyethylene ether is adopted to partially replace a polyethylene glycol side chain of the polycarboxylate superplasticizer, so that the side chain has higher rigidity, the steric effect of the polycarboxylate superplasticizer is improved, and the POSS structure-terminated polycarboxylate superplasticizer has higher dispersibility.

(2) The POSS structure at the tail end of the side chain of the prepared POSS structure-terminated polycarboxylate superplasticizer has a large three-dimensional size, is difficult to intercalate between layers of soil, and has excellent mud-resistant and plastic-retaining properties.

(3) The prepared POSS structure-terminated polycarboxylate water reducer can be compounded with small materials such as an early strength agent, a retarder, a viscosity regulator, a bubble regulator and the like for use, and can be used as a functional polycarboxylate water reducer after being compounded.

Detailed Description

The POSS structure-terminated polycarboxylate superplasticizer is characterized in that: the poly carboxylic acid water reducing agent with the POSS structure end capping is in a comb-shaped structure, the main chain is composed of carboxyl anion groups, and the side chain is composed of methyl end capping polyethylene glycol and POSS structure end capping polyethylene glycol according to a preset molar ratio; the molecular formula is shown as the following formula (I):

（Ⅰ）

in the formula (I), R is one of methyl, ethyl, propyl, isopropyl, phenyl, cyclohexyl, butyl, isobutyl, n-pentyl, 2-methylbutyl, 2-dimethylpropyl, hexyl, 2-methylpentyl, 3-methylpentyl, 2-dimethylbutyl and 2, 3-dimethylbutyl; r1 is H atom or methyl; q is one of-CH 2O-, -CH2CH 2O-and-CH 2CH2CH 2O-; a. b, c, m and n are integers; wherein a (b + c) = 1-10, b: c = 0.5-2.0, m = 10-135, and n = 22-113.

Further, the number average molecular weight of the POSS structure-terminated polycarboxylate superplasticizer is 10000-100000.

A preparation method of a POSS structure-terminated polycarboxylate superplasticizer is characterized by comprising the following steps: carrying out esterification grafting reaction on an alkylene polyoxyethylene ether linear macromolecule E terminated by a POSS structure, an alkylene polyoxyethylene ether linear macromolecule F terminated by a methoxyl group and polyacrylic acid S under the action of a catalyst A, and introducing N in the reaction process₂Taking away generated water, reacting at 100-200 ℃ for 4h, cooling to room temperature, and diluting the product into 40% aqueous solution in parts by mass; the water solution is a POSS structure terminated polycarboxylate superplasticizer; the catalyst A is one of concentrated sulfuric acid, concentrated phosphoric acid, p-toluenesulfonic acid, p-hydroxybenzene sulfonic acid, concentrated hydrochloric acid, concentrated nitric acid, sodium bisulfite, sodium metabisulfite, phosphotungstic acid, tetrabutyl titanate and 4-dimethylaminopyridine.

Further, the catalyst A is concentrated sulfuric acid.

Further, the POSS structure-terminated alkylene polyoxyethylene ether linear macromolecule E is prepared by substituting octahydro silsesquioxane POSS and terminal alkenyl alkylene polyoxyethylene ether under the action of Karstedt catalyst.

Further, the methoxy-terminated alkylene polyoxyethylene ether linear macromolecule F is obtained by ring-opening polymerization of ethylene oxide when methanol is used as an initiator, and the number average molecular weight of the methoxy-terminated alkylene polyoxyethylene ether linear macromolecule F is 500-6000.

Further, the polyacrylic acid S is an oligomer obtained by radical polymerization of acrylic acid, and has a number average molecular weight of 1000 to 8000.

Further, the monohydrogen-substituted octasilsesquioxane POSS is prepared from trichlorosilane HSiCl in a molar ratio of 1:7₃And trichloroalkylsilane RSiCl₃Hydrolyzing in a mixed solution of ethanol and water, and distilling under reduced pressure to remove generated HCl and redundant solvent to obtain purified monohydrogen-substituted octasilsesquioxane POSS; the molecular formula of the mono-hydrogen substituted octa-silsesquioxane POSS is shown as a formula (II):

（Ⅱ）

in the formula (II), R is one of methyl, ethyl, propyl, isopropyl, phenyl, cyclohexyl, butyl, isobutyl, n-pentyl, 2-methylbutyl, 2-dimethylpropyl, hexyl, 2-methylpentyl, 3-methylpentyl, 2-dimethylbutyl and 2, 3-dimethylbutyl.

Further, the terminal alkenyl alkylene polyoxyethylene ether is obtained by ring-opening polymerization of terminal alkenyl alcohol serving as an initiator and ethylene oxide, and the number average molecular weight of the terminal alkenyl alkylene polyoxyethylene ether is 1000-5000; the molecular formula of the terminal alkylene polyoxyethylene ether is shown as the formula (III):

（Ⅲ）

in the formula (III), R₁Is H atom or methyl; q is-CH₂O-、-CH₂CH₂O-、-CH₂CH₂CH₂CH₂O-, or one of the above.

The poly carboxylic acid water reducing agent with the POSS structure end capping prepared by the method comprises the following three steps:

the method comprises the following steps: preparation of monohydrogen-substituted octasilsesquioxane (POSS): trichlorosilane (HSiCl) with a molar ratio of 1:7₃) And trichloroalkylsilanes (RSiCl)₃) Hydrolyzing in 20-80% ethanol water solution for 12-72 h, and distilling under reduced pressure to remove generated HCl and redundant solvent to obtain monohydrogen substituted octasilsesquioxane (POSS), wherein the molecular formula is shown as the following formula (II):

。

step two: preparing an POSS structure end-capped alkylene polyoxyethylene ether linear macromolecule E: and (2) carrying out addition reaction on the monohydrogen substituted octasilsesquioxane (POSS) prepared in the step one and terminal alkylene polyoxyethylene ether under the action of a Karstedt catalyst, wherein the reaction temperature is 60-100 ℃, and the reaction time is 4-8 h to obtain the POSS structure-terminated alkylene polyoxyethylene ether linear macromolecule E.

The terminal alkylene polyoxyethylene ether is obtained by ring-opening polymerization of terminal alkylene alcohol serving as an initiator and ethylene oxide, the number average molecular weight of the terminal alkylene polyoxyethylene ether is 1000-5000, and the molecular formula of the terminal alkylene polyoxyethylene ether is as follows:

wherein R is₁Is H atom or methyl; q is-CH₂O-、-CH₂CH₂O-、-CH₂CH₂CH₂CH₂O-one of them.

Step three: preparing a POSS structure-terminated polycarboxylate superplasticizer: carrying out esterification grafting reaction on the POSS structure-terminated alkylene polyoxyethylene ether linear macromolecule E, the methoxy-terminated alkylene polyoxyethylene ether linear macromolecule F and polyacrylic acid S prepared in the step two under the action of a catalyst A, and introducing N in the reaction process₂Taking away generated water, reacting at 100-200 ℃ for 4h, cooling to room temperature, and diluting to obtain 40% aqueous solution in parts by mass, wherein the molecular structure of the POSS structure-terminated polycarboxylate superplasticizer is shown in formula (III).

The methoxy-terminated alkylene polyoxyethylene ether linear macromolecule F is obtained by ring-opening polymerization of ethylene oxide when methanol is used as an initiator, and the number average molecular weight of the methoxy-terminated alkylene polyoxyethylene ether linear macromolecule F is 500-6000.

The polyacrylic acid S is an oligomer obtained by free radical polymerization of acrylic acid, and the number average molecular weight of the oligomer is 1000-8000.

The catalyst A is one of concentrated sulfuric acid, concentrated phosphoric acid, p-toluenesulfonic acid, p-hydroxybenzene sulfonic acid, concentrated hydrochloric acid, concentrated nitric acid, sodium bisulfite, sodium metabisulfite, phosphotungstic acid, tetrabutyl titanate and 4-dimethylaminopyridine, and preferably concentrated sulfuric acid.

Specific example 1:

adding 50 percent by mass of B into a reaction vessel with a stirring deviceAnd (2) 500 parts of alcohol aqueous solution, adding 13.55 parts by mass of trichlorosilane and 104.65 parts by mass of trichloromethylsilane into a reaction vessel, starting stirring, reacting at normal temperature for 18 hours, and distilling under reduced pressure to remove HCl and a solvent generated in and out of the reaction. 200 parts of isobutylene alkylene polyoxyethylene ether with the number average molecular weight of 2000, 2 parts of Karstedt catalyst are added into a reaction vessel, the reaction is carried out for 5 hours at 80 ℃ to obtain POSS structure-terminated alkylene polyoxyethylene ether linear macromolecule E1, then 60 parts of methoxy-terminated alkylene polyoxyethylene ether (F1) with the average molecular weight of 1000, 64.8 parts of polyacrylic acid (S1) with the average molecular weight of 3000 and 0.3 part of concentrated sulfuric acid are added into the reaction vessel, and N is introduced into the reaction vessel₂Carrying water, controlling the reaction temperature to be 150 ℃, cooling to room temperature after reacting for 4h, and diluting the water solution to be 40% aqueous solution by mass, so as to obtain 934.5 parts aqueous solution which is the target POSS structure terminated polycarboxylate superplasticizer, and the structural formula is as follows:

in the formula: a: b: c =7.4:1.0: 0.6.

Specific example 2:

adding 500 parts by mass of 60% ethanol aqueous solution into a reaction vessel with a stirring device, adding 13.55 parts by mass of trichlorosilane and 148.05 parts by mass of trichlorophenylsilane into the reaction vessel, starting stirring, reacting at normal temperature for 18h, and carrying out reduced pressure distillation to remove HCl and a solvent generated in the reaction. 100 parts of isobutylene alkylene polyoxyethylene ether with the number average molecular weight of 1000 is added into a reaction vessel, 2 parts of Karstedt catalyst is added, the reaction is carried out for 5 hours at 60 ℃ to obtain POSS structure-terminated alkylene polyoxyethylene ether linear macromolecule E2, then 50 parts of methoxy-terminated alkylene polyoxyethylene ether (F2) with the average molecular weight of 1000, 32.4 parts of polyacrylic acid (S2) with the average molecular weight of 4000 and 0.3 part of concentrated sulfuric acid are added into the reaction vessel, and N is introduced into the reaction vessel₂Carrying water, controlling the reaction temperature at 150 ℃, reacting for 4 hours, cooling to room temperature, and diluting into 40% aqueous solution by mass694.75 parts of aqueous solution is obtained, namely the target POSS structure-terminated polycarboxylate superplasticizer, and the structural formula is as follows:

in the formula: a: b: c =3.5:1.0: 0.5.

Specific example 3: adding 500 parts by mass of 60% ethanol aqueous solution into a reaction vessel with a stirring device, adding 13.55 parts by mass of trichlorosilane and 152.25 parts by mass of trichlorocyclohexylsilane into the reaction vessel, starting stirring, reacting at normal temperature for 18h, and carrying out reduced pressure distillation to remove HCl and a solvent generated in the reaction. Adding 100 parts of isopentene alkylene polyoxyethylene ether with the number average molecular weight of 1000 into a reaction vessel, adding 1.5 parts of Karstedt catalyst, reacting for 4 hours at 60 ℃ to obtain POSS structure-terminated alkylene polyoxyethylene ether linear macromolecule E3, then adding 80 parts of methoxy-terminated alkylene polyoxyethylene ether (F3) with the average molecular weight of 1500 by mass, 69.12 parts of polyacrylic acid (S3) with the average molecular weight of 4500 by mass and 0.4 part of p-toluenesulfonic acid by mass into the reaction vessel, introducing N₂Carrying water, controlling the reaction temperature to 160 ℃, cooling to room temperature after reacting for 4 hours, and diluting the water solution into water solution with the mass fraction of 40%, so as to obtain 864.85 parts of water solution, namely the target POSS structure terminated polycarboxylate superplasticizer, wherein the structural formula is as follows:

in the formula: a: b: c =8.0:1.0: 0.5.

Specific example 4: adding 500 parts by mass of 60% ethanol aqueous solution into a reaction vessel with a stirring device, adding 13.55 parts by mass of trichlorosilane and 114.45 parts by mass of trichloroethylsilane into the reaction vessel, starting stirring, reacting at normal temperature for 20 hours, and carrying out reduced pressure distillation to remove HCl and solvent generated in the reaction. Adding isopentene alkylene polyoxyethylene ether 150 with the number average molecular weight of 1500 into a reaction containerAdding 3 parts of Karstedt catalyst, reacting for 4 hours at 80 ℃ to obtain POSS structure-terminated alkylene polyoxyethylene ether linear macromolecule E4, adding 250 parts of methoxy-terminated alkylene polyoxyethylene ether (F4) with the average molecular weight of 2500 by mass, 115.2 parts of polyacrylic acid (S4) with the average molecular weight of 3500 by mass and 0.6 part of p-toluenesulfonic acid by mass into a reaction vessel, and introducing N₂Carrying water, controlling the reaction temperature to be 180 ℃, cooling to room temperature after reacting for 4h, and diluting the water solution into water solution with the mass fraction of 40%, so as to obtain 1433.75 parts of water solution, namely the target POSS structure terminated polycarboxylate superplasticizer, wherein the structural formula is as follows:

in the formula: a: b: c =14:1.0: 1.0.

Specific example 5: adding 500 parts by mass of 50% ethanol aqueous solution into a reaction vessel with a stirring device, adding 13.55 parts by mass of trichlorosilane and 124.25 parts by mass of trichloroisopropylsilane into the reaction vessel, starting stirring, reacting at normal temperature for 20 hours, and carrying out reduced pressure distillation to remove HCl and a solvent generated in the reaction. Adding 200 parts of allyl alkylene polyoxyethylene ether with the number average molecular weight of 2000, adding 3 parts of Karstedt catalyst, reacting for 4 hours at 70 ℃ to obtain POSS structure-terminated alkylene polyoxyethylene ether linear macromolecule E5, then adding 100 parts of methoxy-terminated alkylene polyoxyethylene ether (F5) with the average molecular weight of 4000, 54 parts of polyacrylic acid (S5) with the average molecular weight of 6000 and 0.6 part of p-toluenesulfonic acid into the reaction vessel, introducing N₂Carrying water, controlling the reaction temperature to be 180 ℃, cooling to room temperature after reacting for 4h, and diluting the water solution into water solution with the mass fraction of 40%, so as to obtain 1058.625 parts of water solution, namely the target POSS structure terminated polycarboxylate superplasticizer, wherein the structural formula is as follows:

in the formula: a: b: c =6.25:1.0: 0.25.

Testing the dispersion performance of the product, namely the concrete mixture in each specific embodiment;

and (3) performing a concrete mixture performance test by referring to GB/T8076-2012 concrete admixture, and comparing the initial slump and the expansion degree of the concrete mixture and the 1h slump and the expansion degree under the condition of the same mixing amount of the polycarboxylic acid water reducing agent so as to evaluate the dispersing capacity of the water reducing agent to the concrete mixture. The control group 1 and the control group 2 are all commercially available polycarboxylic acid water reducing agents. A reference cement (P. I.42.5) was selected for the experiment.

As can be seen from Table 1, the POSS structure-terminated polycarboxylate water reducer prepared by the invention has higher initial dispersing capacity and shows better initial fluidity than the polyethylene glycol side chain polycarboxylate water reducers on the market; the concrete mixture has less fluidity loss after 1 hour, has better plastic-retaining effect and is more beneficial to site construction.

The product of each specific example, namely the soil resistance test:

and (3) performing a concrete mixture performance test by referring to GB/T8076-2012 concrete admixture, and comparing the initial slump and the expansion degree of the concrete mixture and the 1h slump and the expansion degree under the condition of the same mixing amount of the polycarboxylic acid water reducing agent so as to evaluate the dispersing capacity of the water reducing agent to the concrete mixture. The control group 1 and the control group 2 are all commercially available polycarboxylic acid water reducing agents. The test was carried out using reference cement (P. I.42.5) +3% montmorillonite.

As can be seen from Table 2, the POSS structure-terminated polycarboxylate superplasticizer prepared by the invention has obviously reduced sensitivity to montmorillonite, so that the concrete mixture has better initial fluidity and fluidity retention capability.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.