阅读说明：本技术 一种用于混凝土的复合减水剂的制备方法 (Preparation method of composite water reducing agent for concrete ) 是由 杨雅红 于 2021-11-16 设计创作，主要内容包括：本发明公开了一种用于混凝土的复合减水剂的制备方法,按重量份数计,包括以下成分：马来酸酐甘油磷酸酯30～36份、阳离子聚丙烯酰胺12～16份、烯丙基聚氧乙烯醚10～15份、海藻酸钠12～18份、水20～30份、过硫酸铵6～10份、巯基丙酸5～9份、聚丙烯酸酯8～12份、改性玉米淀粉8～12份、丙烯酸2～5份和抗环血酸2～4份。制备方法包括将马来酸酐甘油磷酸酯、烯丙基聚氧乙烯醚加入到去离子水当中,搅拌,加入过硫酸铵和巯基丙酸,将温度升至70～80℃搅拌反应2～3h,备用；待上述步骤S1中的反应完毕后,将温度将至60～65℃在搅拌过程中滴加丙烯酸和抗坏血酸,滴加完毕后在该温下继续搅拌反应1～1.5h,将阳离子聚丙烯酰胺、海藻酸钠和改性玉米淀粉加入,在该温下搅拌反应40～70min,冷却,得到所述减水剂。(The invention discloses a preparation method of a composite water reducing agent for concrete, which comprises the following components in parts by weight: 30-36 parts of maleic anhydride glycerophosphate, 12-16 parts of cationic polyacrylamide, 10-15 parts of allyl polyoxyethylene ether, 12-18 parts of sodium alginate, 20-30 parts of water, 6-10 parts of ammonium persulfate, 5-9 parts of mercaptopropionic acid, 8-12 parts of polyacrylate, 8-12 parts of modified corn starch, 2-5 parts of acrylic acid and 2-4 parts of ascorbic acid. The preparation method comprises the steps of adding maleic anhydride glycerophosphate and allyl polyoxyethylene ether into deionized water, stirring, adding ammonium persulfate and mercaptopropionic acid, heating to 70-80 ℃, stirring and reacting for 2-3 hours for later use; and (5) after the reaction in the step S1 is finished, dropping acrylic acid and ascorbic acid into the mixture at 60-65 ℃ in the stirring process, continuing stirring and reacting for 1-1.5 h at the temperature after the dropping is finished, adding cationic polyacrylamide, sodium alginate and modified corn starch, stirring and reacting for 40-70 min at the temperature, and cooling to obtain the water reducer.)

1. The preparation method of the composite water reducing agent for concrete is characterized in that the composite water reducing agent comprises the following components in parts by weight: 30-36 parts of maleic anhydride glycerophosphate, 12-16 parts of cationic polyacrylamide, 10-15 parts of allyl polyoxyethylene ether, 12-18 parts of sodium alginate, 20-30 parts of water, 6-10 parts of ammonium persulfate, 5-9 parts of mercaptopropionic acid, 8-12 parts of polyacrylate, 8-12 parts of modified corn starch, 2-5 parts of acrylic acid and 2-4 parts of ascorbic acid;

the preparation method comprises the following steps:

s1: adding maleic anhydride glycerophosphate and allyl polyoxyethylene ether into deionized water, stirring for 0.5-1 h at 130-135 ℃, then adding ammonium persulfate and mercaptopropionic acid, heating to 170-180 ℃, and stirring for reaction for 2-3 h for later use;

s2: and (4) after the reaction in the step S1 is finished, dropping acrylic acid and ascorbic acid into the mixture at a temperature of 160-165 ℃ in a stirring process, continuing stirring and reacting for 1-1.5 h at the temperature after the dropping is finished, then adding cationic polyacrylamide, sodium alginate and modified corn starch, stirring and reacting for 40-70 min at the temperature, and cooling to obtain the water reducer.

2. The preparation method of the composite water reducing agent for concrete according to claim 1, wherein the maleic anhydride glycerophosphate is prepared by the following method:

1) adding maleic anhydride, glycerol and p-toluenesulfonic acid into a four-neck round-bottom flask, heating to 170-180 ℃ in a water bath, and carrying out reflux reaction for 1-2 hours, wherein the molar ratio of the maleic anhydride to the glycerol to the p-toluenesulfonic acid is (1-2) to (3.5-6) to (1.2-3);

2) after the reaction in the step 1) is finished, the temperature is increased to 60-65 ℃, then polyphosphoric acid is added, the reaction is carried out for 1-1.5 h at the temperature, the temperature is reduced to room temperature, and the reaction is continued for 1-2 h at the room temperature, so that the maleic anhydride glycerophosphate is obtained.

3. The method for preparing the composite water reducing agent for concrete according to claim 2, wherein the molar ratio of polyphosphoric acid to maleic anhydride is (1.3-2.2): (1-2).

4. The preparation method of the composite water reducing agent for concrete according to claim 2, characterized in that the cationic polyacrylamide has a molecular weight of 900-1200 ten thousand.

5. The preparation method of the composite water reducing agent for concrete according to claim 1, wherein the modified corn starch is prepared by the following method:

adding corn starch into deionized water, stirring for 5-8 min, adding lithium magnesium silicate and magnesium humate, continuously stirring for 10-20 min, transferring to a high-pressure reaction kettle, reacting for 3-5 h at 90-105 ℃, cooling, filtering, and drying under vacuum conditions to obtain the modified corn starch.

6. The preparation method of the composite water reducing agent for concrete according to claim 5, wherein the mass ratio of the corn starch, the lithium magnesium silicate and the magnesium humate is (4-7): (1.2-1.5): (0.8-1.1).

Technical Field

The invention belongs to the technical field of concrete admixtures, and particularly relates to a preparation method of a composite water reducing agent for concrete.

Background

The concrete water reducing agent is an additive which can reduce the water consumption for mixing and improve the strength of concrete under the conditions of unchanged concrete workability and cement consumption; the flocculation structure of cement particles is hindered or destroyed through surface active action, complexation, electrostatic repulsive force or three-dimensional repulsive force, and the like, so that the workability and strength of concrete can be ensured while the cement consumption is saved. Concrete admixture, referred to as admixture for short, is a substance added to improve the performance of concrete before or during the mixing process of mixing the concrete. The admixture can effectively improve the performance of concrete and has good economic benefit, so the admixture is widely applied in many countries, and the application in engineering is more and more emphasized, thus becoming an indispensable material in concrete. The water reducing agent is the most important additive in concrete, and can reduce the water consumption for mixing and improve the strength of the concrete under the condition of unchanged concrete workability and cement consumption; or the cement consumption is saved under the condition of unchanged workability and strength. For example, a patent document CN108503256A discloses an adaptive comprehensive polycarboxylic acid water reducing agent, which comprises the following components: 15-30 parts of a mud-resistant polycarboxylic acid water reducing agent, 8-30 parts of a slump-retaining polycarboxylic acid water reducing agent, 10-34 parts of a water-reducing polycarboxylic acid water reducing agent, 7-28 parts of a polycarboxylic acid solution, 5-16 parts of lignosulfonate and 10-40 parts of water.

Disclosure of Invention

The invention aims to provide a preparation method of a composite water reducing agent for concrete, which comprises the following components in parts by weight: 30-36 parts of maleic anhydride glycerophosphate, 12-16 parts of cationic polyacrylamide, 10-15 parts of allyl polyoxyethylene ether, 12-18 parts of sodium alginate, 20-30 parts of water, 6-10 parts of ammonium persulfate, 5-9 parts of mercaptopropionic acid, 8-12 parts of polyacrylate, 8-12 parts of modified corn starch, 2-5 parts of acrylic acid and 2-4 parts of ascorbic acid.

The preparation method comprises the following steps:

s1: adding maleic anhydride glycerophosphate and allyl polyoxyethylene ether into deionized water, stirring for 0.5-1 h at 130-135 ℃, then adding ammonium persulfate and mercaptopropionic acid, heating to 170-180 ℃, and stirring for reaction for 2-3 h for later use.

S2: and (4) after the reaction in the step S1 is finished, dropping acrylic acid and ascorbic acid into the mixture at a temperature of 160-165 ℃ in a stirring process, continuing stirring and reacting for 1-1.5 h at the temperature after the dropping is finished, then adding cationic polyacrylamide, sodium alginate and modified corn starch, stirring and reacting for 40-70 min at the temperature, and cooling to obtain the water reducer.

Preferably, the maleic anhydride glycerol phosphate is prepared by the following method:

1) adding maleic anhydride, glycerol and p-toluenesulfonic acid into a four-neck round-bottom flask, heating in a water bath to 170-180 ℃, and performing reflux reaction for 1-2 hours, wherein the molar ratio of the maleic anhydride to the glycerol to the p-toluenesulfonic acid is (1-2) to (3.5-6) to (1.2-3).

2) After the reaction in the step 1) is finished, the temperature is increased to 60-65 ℃, then polyphosphoric acid is added, the reaction is carried out for 1-1.5 h at the temperature, the temperature is reduced to room temperature, and the reaction is continued for 1-2 h at the room temperature to obtain the maleic anhydride glycerophosphate.

More preferably, the molar ratio of the polyphosphoric acid to the maleic anhydride is (1.3-2.2): (1-2).

Preferably, the cationic polyacrylamide has a molecular weight of 900 to 1200 ten thousand.

Preferably, the modified corn starch is prepared by the following method:

adding corn starch into deionized water, stirring for 5-8 min, adding lithium magnesium silicate and magnesium humate, continuously stirring for 10-20 min, transferring to a high-pressure reaction kettle, reacting for 3-5 h at 90-105 ℃, cooling, filtering, and drying under vacuum conditions to obtain the modified corn starch.

More preferably, the mass ratio of the corn starch, the lithium magnesium silicate and the magnesium humate is (4-7): (1.2-1.5): 0.8-1.1).

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, the prepared composite water reducing agent has higher water reducing rate, lower water content and bleeding rate, and has better compression strength ratio and shrinkage ratio compared with a common water reducing agent, and the comprehensive performance of the composite water reducing agent is more excellent compared with the common water reducing agent.

Detailed Description

The following embodiments of the present invention are described in detail, and the embodiments are implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, it should be noted that, for those skilled in the art, a plurality of modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Example 1

A preparation method of a composite water reducing agent for concrete specifically comprises the following steps:

the paint comprises the following components in parts by weight: 30 parts of maleic anhydride glycerophosphate, 12 parts of cationic polyacrylamide, 10 parts of allyl polyoxyethylene ether, 12 parts of sodium alginate, 20 parts of water, 6 parts of ammonium persulfate, 5 parts of mercaptopropionic acid, 8 parts of polyacrylate, 8 parts of modified corn starch, 2 parts of acrylic acid and 2 parts of ascorbic acid.

The maleic anhydride glycerol phosphate is prepared by the following method:

1) adding maleic anhydride, glycerol and p-toluenesulfonic acid into a four-neck round-bottom flask, heating in a water bath to 170 ℃, and carrying out reflux reaction for 1h, wherein the molar ratio of the maleic anhydride to the glycerol to the p-toluenesulfonic acid is 1:3.5: 1.2.

2) After the reaction in the step 1) is finished, the temperature is increased to 60 ℃, then polyphosphoric acid is added, the reaction is carried out for 1-1.5 h at the temperature, the temperature is reduced to room temperature, and the reaction is continued for 1h at the room temperature to obtain maleic anhydride glycerophosphate; wherein the molar ratio of polyphosphoric acid to maleic anhydride is 1.3: 1.

The modified corn starch is prepared by the following method:

adding corn starch into deionized water, stirring for 5min, adding lithium magnesium silicate and magnesium humate, stirring for 10min, transferring to a high-pressure reaction kettle, reacting at 90 ℃ for 3h, cooling, filtering, and drying under vacuum condition to obtain modified corn starch, wherein the mass ratio of the corn starch to the lithium magnesium silicate to the magnesium humate is 4:1.2: 0.8.

The preparation method comprises the following steps:

s1: adding maleic anhydride glycerophosphate and allyl polyoxyethylene ether into deionized water, stirring for 0.5h at 130 ℃, then adding ammonium persulfate and mercaptopropionic acid, heating to 170 ℃, and stirring for reaction for 2h for later use.

S2: and (4) after the reaction in the step S1 is finished, dropping acrylic acid and ascorbic acid into the temperature of 160 ℃ in the stirring process, continuing stirring and reacting for 1h at the temperature after the dropping is finished, then adding cationic polyacrylamide, sodium alginate and modified corn starch, stirring and reacting for 40min at the temperature, and cooling to obtain the water reducer.

Example 2

A preparation method of a composite water reducing agent for concrete specifically comprises the following steps:

the paint comprises the following components in parts by weight: 36 parts of maleic anhydride glycerophosphate, 16 parts of cationic polyacrylamide, 15 parts of allyl polyoxyethylene ether, 18 parts of sodium alginate, 30 parts of water, 6-10 parts of ammonium persulfate, 9 parts of mercaptopropionic acid, 12 parts of polyacrylate, 12 parts of modified corn starch, 5 parts of acrylic acid and 4 parts of ascorbic acid.

The maleic anhydride glycerol phosphate is prepared by the following method:

1) adding maleic anhydride, glycerol and p-toluenesulfonic acid into a four-neck round-bottom flask, heating in a water bath to 180 ℃, and carrying out reflux reaction for 2 hours, wherein the molar ratio of the maleic anhydride to the glycerol to the p-toluenesulfonic acid is 2:6: 3.

2) After the reaction in the step 1) is finished, the temperature is increased to 65 ℃, then polyphosphoric acid is added, the reaction is carried out at the temperature for 1.5h, the temperature is reduced to room temperature, and the reaction is continued for 2h at the room temperature to obtain maleic anhydride glycerophosphate; wherein the molar ratio of polyphosphoric acid to maleic anhydride is 2.2: 2.

The modified corn starch is prepared by the following method:

adding corn starch into deionized water, stirring for 8min, adding lithium magnesium silicate and magnesium humate, stirring for 20min, transferring to a high-pressure reaction kettle, reacting at 105 ℃ for 5h, cooling, filtering, and drying under vacuum condition to obtain modified corn starch, wherein the mass ratio of the corn starch to the lithium magnesium silicate to the magnesium humate is 7:1.5: 1.1.

The preparation method comprises the following steps:

s1: adding maleic anhydride glycerophosphate and allyl polyoxyethylene ether into deionized water, stirring at 135 ℃ for 1h, then adding ammonium persulfate and mercaptopropionic acid, heating to 180 ℃, and stirring for reaction for 3h for later use.

S2: and (4) after the reaction in the step S1 is finished, dropping acrylic acid and ascorbic acid into the temperature of 165 ℃ in the stirring process, continuing stirring and reacting for 1.5h at the temperature after the dropping is finished, then adding cationic polyacrylamide, sodium alginate and modified corn starch, stirring and reacting for 70min at the temperature, and cooling to obtain the water reducer.

Example 3

A preparation method of a composite water reducing agent for concrete specifically comprises the following steps:

the paint comprises the following components in parts by weight: 34 parts of maleic anhydride glycerophosphate, 14 parts of cationic polyacrylamide, 12 parts of allyl polyoxyethylene ether, 16 parts of sodium alginate, 25 parts of water, 8 parts of ammonium persulfate, 7 parts of mercaptopropionic acid, 10 parts of polyacrylate, 10 parts of modified corn starch, 4 parts of acrylic acid and 3 parts of ascorbic acid.

The maleic anhydride glycerol phosphate is prepared by the following method:

1) adding maleic anhydride, glycerol and p-toluenesulfonic acid into a four-neck round-bottom flask, heating in a water bath to 175 ℃, and carrying out reflux reaction for 1.5h, wherein the molar ratio of the maleic anhydride to the glycerol to the p-toluenesulfonic acid is 1.6:4.8: 2.6.

2) After the reaction in the step 1) is finished, the temperature is increased to 62 ℃, then polyphosphoric acid is added, the reaction is carried out for 1-1.5 h at the temperature, the temperature is reduced to room temperature, and the reaction is continued for 1.5h at the room temperature to obtain maleic anhydride glycerophosphate; wherein the molar ratio of polyphosphoric acid to maleic anhydride is 1.8: 1.6.

The modified corn starch is prepared by the following method:

adding corn starch into deionized water, stirring for 6min, adding lithium magnesium silicate and magnesium humate, stirring for 15min, transferring to a high-pressure reaction kettle, reacting at 100 ℃ for 4h, cooling, filtering, and drying under vacuum condition to obtain modified corn starch, wherein the mass ratio of the corn starch to the lithium magnesium silicate to the magnesium humate is 6:1.4: 0.9.

The preparation method comprises the following steps:

s1: adding maleic anhydride glycerophosphate and allyl polyoxyethylene ether into deionized water, stirring for 0.8h at 132 ℃, then adding ammonium persulfate and mercaptopropionic acid, heating to 175 ℃, and stirring for reaction for 2.5h for later use.

S2: and (4) after the reaction in the step S1 is finished, dropping acrylic acid and ascorbic acid into the temperature of 162 ℃ in the stirring process, continuing stirring and reacting for 1.2h at the temperature after the dropping is finished, then adding cationic polyacrylamide, sodium alginate and modified corn starch, stirring and reacting for 60min at the temperature, and cooling to obtain the water reducer.

Comparative example 1

Some common type of water reducer is purchased commercially.

Examples of the experiments

The water reducing agents prepared in examples 1 to 3 were mixed into concrete, and then the following main performance tests were performed, the test results of which are shown in table 1 below,

table 1. test results:

as can be seen from the above table 1, the composite water reducing agent prepared in the embodiments 1 to 3 of the present invention has more excellent comprehensive properties in various properties compared with the common water reducing agent in the comparative example 1.