Synthesis method of polycarboxylic acid high-performance water reducing agent of star-like structure

Abstract

The invention discloses a synthesis method of a polycarboxylic acid high-performance water reducing agent of a star-like structure, belonging to the field of a water reducing agent. According to the synthesis method, polybasic alcohol, (methyl) acrylic acid, a polyethylene glycol compound and the like are used as esterification raw materials, and the polycarboxylic acid high-performance water reducing agent of the star-like structure is prepared through a sequential esterification and polymerization method, i.e., the (methyl) acrylic acid and the polybasic alcohol are used as reactants, a star-like polymerizable active end is prepared through esterification reaction under the action of a catalyst, and then the polycarboxylic acid high-performance water reducing agent is prepared from the star-like polymerizable active end and esterification macromolecule, a molecular weight regulator and an unsaturated carboxylic acid monomer under the action of an initiator through free radical polymerization reaction. The synthesis method has the advantages of simplicity, easiness in control, high polymerization degree, low cost, no pollution, capability of realizing the polycarboxylic acid high-performance water reducing agent of the star-like structure connected with a plurality of polycarboxylic acid molecules, and more superior cement paste fluidity and holding capacity, good cement adaptability and concrete application performance compared with the conventional linear and comb-shaped polycarboxylic acid water reducing agent in the case of normal and low added amount.

Description

technical field

[0001] The invention relates to the technical field of a polycarboxylic acid high-performance water reducer for cement concrete, in particular to a polyhydric alcohol and acrylic monomer first esterified to form an active core and then combined with (meth)acrylic acid polyethylene glycol A specific preparation method for copolymerizing ester macromonomers into a star-shaped structure polycarboxylic acid high-performance water reducer. Background technique

[0002] With the continuous increase of the amount of concrete and cement, and the continuous development to the direction of high workability, high strength, and no pollution, concrete and cement admixtures have become one of its important components. The emergence of polycarboxylic acid-based high-performance water-reducing agents has solved the problems of low water-reducing rate and retardation of ordinary lignosulfonate-based water-reducing agents, and made up for the environmental pollution and rapid ...

Examples

Embodiment 1

[0030] First, 9.11g of sorbitol was added to the reactor, the temperature was raised to 40°C, 1.8g of phenothiazine, 36.03g of acrylic acid, and 4.51g of phosphoric acid were added to the reactor in turn, and the stirring time between each addition was 20 minutes, and the temperature was raised to Add 13.54g cyclohexane at 80°C, continue to heat up to 100°C for esterification reaction, separate the water obtained during the reaction, and remove the water-carrying agent by vacuuming after 10 hours of reaction to obtain the first step of esterification Reaction product: Take 50g of methoxypolyethylene glycol (molecular weight = 2500) into the reactor, raise the temperature to 50°C, add 0.36g of phenothiazine, 7.21g of acrylic acid, and 5g of phosphoric acid into the reactor in sequence, and add each time Stir at intervals of 20 minutes, add 17.16g of toluene when the temperature rises to 80°C, continue to heat up to 105°C for esterification reaction, and separate the water obtain...

Embodiment 2

[0032] After the polycarboxylate superplasticizer with a concentration of 20% obtained in Example 1 was stored at 6°C for 20 days, its implementation effect was measured.

Embodiment 3

[0034] First, add 18.22g of mannitol into the reactor, raise the temperature to 80°C, add 0.06g of p-tert-butylcatechol, 57.65g of acrylic acid, and 1.52g of sulfamic acid to the reactor in turn, and stir for 5 minutes between each addition. When the temperature rises to 100°C, 11.38g of toluene is added, and the temperature continues to rise to 150°C for esterification reaction. During the reaction, the water obtained in the reaction is separated out. After 2 hours of reaction, the water-carrying agent is removed by vacuuming to obtain the first Step 1 esterification reaction product; take 100g of polyethylene glycol (molecular weight = 1000) into the reactor, raise the temperature to 70°C, add 0.22g of p-tert-butylcatechol, 21.6g of acrylic acid, and 2g of sulfamic acid to the reactor in turn , and the stirring time between each feeding is 5 minutes. When the temperature rises to 100°C, 12.16g cyclohexane is added, and the temperature is continued to rise to 150°C to carry ou...

technical field

[0001] The invention relates to the technical field of a polycarboxylic acid high-performance water reducer for cement concrete, in particular to a polyhydric alcohol and acrylic monomer first esterified to form an active core and then combined with (meth)acrylic acid polyethylene glycol A specific preparation method for copolymerizing ester macromonomers into a star-shaped structure polycarboxylic acid high-performance water reducer. Background technique

[0002] With the continuous increase of the amount of concrete and cement, and the continuous development to the direction of high workability, high strength, and no pollution, concrete and cement admixtures have become one of its important components. The emergence of polycarboxylic acid-based high-performance water-reducing agents has solved the problems of low water-reducing rate and retardation of ordinary lignosulfonate-based water-reducing agents, and made up for the environmental pollution and rapid ...

Examples

Embodiment 1

[0030] First, 9.11g of sorbitol was added to the reactor, the temperature was raised to 40°C, 1.8g of phenothiazine, 36.03g of acrylic acid, and 4.51g of phosphoric acid were added to the reactor in turn, and the stirring time between each addition was 20 minutes, and the temperature was raised to Add 13.54g cyclohexane at 80°C, continue to heat up to 100°C for esterification reaction, separate the water obtained during the reaction, and remove the water-carrying agent by vacuuming after 10 hours of reaction to obtain the first step of esterification Reaction product: Take 50g of methoxypolyethylene glycol (molecular weight = 2500) into the reactor, raise the temperature to 50°C, add 0.36g of phenothiazine, 7.21g of acrylic acid, and 5g of phosphoric acid into the reactor in sequence, and add each time Stir at intervals of 20 minutes, add 17.16g of toluene when the temperature rises to 80°C, continue to heat up to 105°C for esterification reaction, and separate the water obtain...

Embodiment 2

[0032] After the polycarboxylate superplasticizer with a concentration of 20% obtained in Example 1 was stored at 6°C for 20 days, its implementation effect was measured.

Embodiment 3

[0034] First, add 18.22g of mannitol into the reactor, raise the temperature to 80°C, add 0.06g of p-tert-butylcatechol, 57.65g of acrylic acid, and 1.52g of sulfamic acid to the reactor in turn, and stir for 5 minutes between each addition. When the temperature rises to 100°C, 11.38g of toluene is added, and the temperature continues to rise to 150°C for esterification reaction. During the reaction, the water obtained in the reaction is separated out. After 2 hours of reaction, the water-carrying agent is removed by vacuuming to obtain the first Step 1 esterification reaction product; take 100g of polyethylene glycol (molecular weight = 1000) into the reactor, raise the temperature to 70°C, add 0.22g of p-tert-butylcatechol, 21.6g of acrylic acid, and 2g of sulfamic acid to the reactor in turn , and the stirring time between each feeding is 5 minutes. When the temperature rises to 100°C, 12.16g cyclohexane is added, and the temperature is continued to rise to 150°C to carry ou...

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