CN108084358B - Preparation method of collapse-proof polycarboxylate superplasticizer - Google Patents
Preparation method of collapse-proof polycarboxylate superplasticizer Download PDFInfo
- Publication number
- CN108084358B CN108084358B CN201711124168.3A CN201711124168A CN108084358B CN 108084358 B CN108084358 B CN 108084358B CN 201711124168 A CN201711124168 A CN 201711124168A CN 108084358 B CN108084358 B CN 108084358B
- Authority
- CN
- China
- Prior art keywords
- collapse
- ether
- polyoxyethylene polyoxypropylene
- polyoxypropylene ether
- polyoxyethylene
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F283/00—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G
- C08F283/06—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals
- C08F283/065—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polyethers, polyoxymethylenes or polyacetals on to unsaturated polyethers, polyoxymethylenes or polyacetals
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B24/00—Use of organic materials as active ingredients for mortars, concrete or artificial stone, e.g. plasticisers
- C04B24/24—Macromolecular compounds
- C04B24/26—Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
- C04B24/2688—Copolymers containing at least three different monomers
- C04B24/2694—Copolymers containing at least three different monomers containing polyether side chains
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/02—Polymerisation in bulk
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08F2/00—Processes of polymerisation
- C08F2/38—Polymerisation using regulators, e.g. chain terminating agents, e.g. telomerisation
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/30—Water reducers, plasticisers, air-entrainers, flow improvers
- C04B2103/302—Water reducers
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Macromonomer-Based Addition Polymer (AREA)
- Curing Cements, Concrete, And Artificial Stone (AREA)
Abstract
The invention provides a preparation method of a collapse-proof polycarboxylate superplasticizer, which is prepared through bulk polymerization and specifically comprises the following steps: (1) mixing polyoxyethylene polyoxypropylene ether and polyoxyethylene ether, controlling the temperature to be 40-60 ℃, uniformly stirring, and then adding an initiator and a mixture of unsaturated carboxylic acid, unsaturated carboxylic ester and a chain transfer agent; (2) and (3) curing for 0.5-1 h after the step (1) is finished, and cooling to obtain the collapse-proof polycarboxylic acid water reducing agent. The bulk polymerization reaction is carried out at a relatively low temperature, the conditions are mild, the operability is strong, and the synthesized polycarboxylic acid water reducing agent has high water reducing performance. The polycarboxylate superplasticizer prepared by the method is liquid at normal temperature, has the effective concentration of 100 percent, has stable storage performance and is suitable for long-distance transportation and use; meanwhile, the water reducing agent has excellent collapse-keeping performance, can solve the problem of concrete collapse caused by high temperature and long transportation time, and has wide industrial application prospect.
Description
Technical Field
The invention belongs to the technical field of concrete admixtures, and particularly relates to a preparation method of a collapse-resistant polycarboxylic acid water reducer.
Background
Concrete has become the foundation of human life and is the largest building material used at present. The concrete admixture is a fifth component in concrete except cement, sand, stone and water, and plays a very important role in the application of high-performance concrete. As one kind of concrete admixture, the water reducing agent (also called super plasticizer) can reduce the water consumption for mixing and improve the concrete strength under the condition of unchanged concrete workability and cement consumption, and becomes a focus of research and development in the field of concrete admixtures. The water reducing agent obstructs or destroys the flocculation structure of cement particles through surface activity, complexation, electrostatic repulsion force or three-dimensional repulsion force, and the like, thereby saving the cement consumption and ensuring the workability and strength of concrete. The polycarboxylate superplasticizer has the advantages of low mixing amount, high water reducing rate, high degree of freedom of molecular structure design, environmental friendliness and the like, is known as a third-generation concrete superplasticizer, and is widely applied to projects such as high-speed rails, roads, bridges, tunnels, high-rise buildings and the like.
Slump loss is a major problem in the concrete industry. The slump loss is more severe when the concrete is transported and pumped under high temperature conditions in summer. In order to ensure that the concrete keeps better fluidity and is easy to pump and pour, the phenomenon of adding water to remold the concrete can occur in the construction process, and the strength of the concrete is influenced. The water reducing agent and the retarder are used in a composite mode, the hydration rate of cement is slowed down through the delaying effect of the retarder on cement hydration, and the purpose of inhibiting slump loss of newly-mixed cement paste and concrete can be achieved. However, the traditional method of adding saccharides and the like as retarding components to solve the problem of too fast slump loss of concrete is far from meeting the engineering requirements, and particularly has a prominent problem when the transportation distance is long. The addition of the retarder cannot fundamentally overcome the defect of weak collapse retention capability, and excessive mixing amount can prolong the setting time of concrete, reduce the quality of the concrete and influence the construction progress. In addition, the retarder has adaptability problem with cement, and the effect of improving slump loss is unstable. Therefore, the development of a water reducing agent which can keep the slump constant for a long time without loss and does not influence the later performance of hardened concrete has become a research hotspot of concrete admixtures.
The excellent water reducing performance of the polycarboxylate water reducing agent is widely accepted by the industry, however, a large number of engineering examples and researches show that the polycarboxylate water reducing agent has the problem of poor compatibility with concrete raw materials. The aggregate is used as a main component of concrete, the soil in the aggregate is clay which expands with water, and the polycarboxylate superplasticizer is easily adsorbed by the clay in a large amount, so that the water reducing and dispersing capacity of the polycarboxylate superplasticizer is seriously reduced, the water consumption for actual mixing cannot be effectively reduced, the problem of serious slump loss is easily caused, and the strength of the hardened concrete is reduced.
Disclosure of Invention
Therefore, the invention aims to solve the technical problem of poor effect of preventing the collapse of the polycarboxylate superplasticizer in the prior art.
Therefore, the invention provides a preparation method of a collapse-proof polycarboxylic acid water reducing agent, which is prepared through bulk polymerization and specifically comprises the following steps:
(1) mixing polyoxyethylene polyoxypropylene ether and polyoxyethylene ether, controlling the temperature to be 40-60 ℃, uniformly stirring, and then adding an initiator and a mixture of unsaturated carboxylic acid, unsaturated carboxylic ester and a chain transfer agent;
in the step (1), the polyoxyethylene polyoxypropylene ether has a structure shown in a formula I,
wherein R is1Is methyl or ethyl, R2Hydrogen or methyl, EO is oxyethylene, PO is oxypropylene; m is 30-60, n is 0-20;
(2) and (3) curing for 0.5-1 h after the step (1) is finished, and cooling to obtain the collapse-proof polycarboxylic acid water reducing agent.
The preparation method further comprises the following steps: and after the collapse-retaining polycarboxylate water reducer is prepared, neutralizing the polycarboxylate water reducer to a pH value of 6-7 by using organic amine.
In the above preparation method, the organic amine is at least one of trihydroxypropyl hydroxyethyl ethylenediamine and tetrahydroxypropyl ethylenediamine.
In the above preparation method, in the step (1), the ratio of polyoxyethylene polyoxypropylene ether: polyoxyethylene ether: initiator: the mass ratio of the chain transfer agent is 1: (0.25-1) and (0.01-0.03): (0.01-0.03).
In the preparation method, the polyoxyethylene polyoxypropylene ether is at least one of isobutylene polyoxyethylene polyoxypropylene ether and isopentenyl polyoxyethylene polyoxypropylene ether, and the molecular weight of the polyoxyethylene polyoxypropylene ether is 2200-3200.
The above preparation method, the polyoxyethylene polyoxypropylene ether is prepared by the following steps:
mixing unsaturated alcohol serving as an initiator with an alkali catalyst, and adding ethylene oxide and propylene oxide in an oxygen-free environment, wherein the mass ratio of the ethylene oxide to the propylene oxide is 1: (0.1 to 0.3); the unsaturated alcohol and the ethylene oxide are subjected to polymerization reaction with the propylene oxide, the reaction temperature is controlled to be 100-130 ℃, and a reaction product containing unsaturated polyoxyethylene polyoxypropylene ether is prepared;
wherein the unsaturated alcohol is at least one of isobutene alcohol and isopentenol.
In the preparation method, the polyoxyethylene ether is isopentenyl polyoxyethylene ether, and the molecular weight of the polyoxyethylene ether is 500-1000.
In the above preparation method, the unsaturated carboxylic acid is at least one of acrylic acid, methacrylic acid, itaconic acid and maleic acid.
In the above production method, the unsaturated carboxylic acid ester is at least one of ethyl acrylate, ethyl methacrylate and propyl methacrylate.
In the above preparation method, the initiator is at least one of dimethyl azobisisobutyrate, azobisisobutyronitrile and diisopropyl peroxydicarbonate.
In the preparation method, the chain transfer agent is mercaptoethanol.
In the preparation method, the temperature in the step (3) is reduced to be less than or equal to 40 ℃.
Compared with the prior art, the invention has the following advantages:
1. the preparation method of the collapse-proof polycarboxylate superplasticizer provided by the invention can synthesize the polycarboxylate superplasticizer which is liquid at normal temperature and has the effective concentration of 100%. The molecular structure and the molecular weight range of the polyether macromonomer provided by the invention have low melting temperature, the reaction temperature of bulk polymerization reaction is reduced, the synthetic reaction can be carried out at 40-60 ℃, the phenomena of local implosion and the like caused by high temperature in the bulk polymerization reaction process are avoided, the reaction rate is controllable, a polycarboxylic acid water reducing agent with the effective concentration of 100% is synthesized in a solvent-free environment, and the synthesized water reducing agent has the performance of a product synthesized in an aqueous solution environment.
On the other hand, the polyoxyethylene polyoxypropylene ether leads the synthesized polycarboxylate water reducer to introduce polyoxyethylene polyoxypropylene ether side chains with terminal methyl groups and terminal unsaturated alkenyl groups, the polyoxyethylene polyoxypropylene ether and the polyoxyethylene ether are matched with each other to synthesize the polycarboxylate water reducer which is liquid at normal temperature and has stable performance, the synthesized polycarboxylate water reducer has polyether side chains with matched length, good extension conformation is formed, the water reducer can play a good steric hindrance effect after being adsorbed on cement particles, the dispersing capacity is continuously provided, and the collapse protection effect of the polycarboxylate water reducer is obviously improved. The water reducing agent is in a liquid state at normal temperature, and can be barreled and transported after being synthesized without cooling, solidifying and crushing treatment, so that the product synthesis process is simplified, and the production cost of the product is reduced; the synthesized polycarboxylate superplasticizer has stable performance, can not be separated out due to the rise of environmental temperature and the increase of storage time, is suitable for long-distance transportation, and greatly reduces the transportation cost.
In the preparation method provided by the invention, two polyether monomers are matched with each other, and form an alkane main chain with carboxylic acid groups and a hydrophilic polyether side chain comb-shaped molecular structure with unsaturated carboxylic acid and unsaturated carboxylic ester under the action of an initiator and a chain transfer agent. Unsaturated carboxylic acid ester small monomers in the synthetic raw materials can partially replace unsaturated carboxylic acid, carboxylic acid ester groups are introduced to the main chain of the polycarboxylate water reducer at the same time, the carboxylic acid ester groups can be slowly hydrolyzed in the alkaline environment of cement to release carboxyl groups, and the carboxyl groups can be adsorbed on the cement, so that the water reducer is ensured to be more firmly adsorbed on cement particles and is not easily adsorbed by soil, and a good collapse protection effect is obtained through slow release. The polycarboxylic acid prepared by the preparation method can avoid the problem of serious concrete collapse loss caused by long-distance transportation and temperature rise, and improves the strength of concrete; the polycarboxylic acid water reducing agent has good applicability, excellent collapse protection performance and wide industrial application prospect.
The reaction process of bulk polymerization does not need water or an organic solvent, thereby avoiding the toxic action of the organic solvent, and the reaction process is green and environment-friendly and has high environmental friendliness.
2. According to the invention, after the copolymerization reaction is finished, the organic amine is used for neutralizing the polycarboxylate superplasticizer until the PH value is 6-7, so that the density degree of side chains in the comb-shaped structure of the polycarboxylate superplasticizer is further improved and adjusted, the polycarboxylate superplasticizer can continuously disperse cement particles, and the collapse-keeping performance of polycarboxylate water reduction is improved. On the other hand, the hydroxypropyl hydroxyethyl ethylenediamine and the tetrahydroxypropyl ethylenediamine selected by the invention can be better compatible in a polymerization reaction system, cannot precipitate out, and simultaneously have certain slump improving capability.
3. The mass ratio of the polyoxyethylene polyoxypropylene ether, the polyoxyethylene ether, the initiator and the chain transfer agent ensures high conversion rate of polymerization reaction on one hand, and can adjust the matching proportion of polyether side chains with different lengths on the polycarboxylate superplasticizer on the other hand, avoid difficult mutual winding among the side chains, ensure that the side chains form good stretching conformation, enable the steric hindrance effect of the polycarboxylate superplasticizer side chains and the electrostatic repulsion force of the carboxylic acid groups on the polycarboxylate superplasticizer main chain to act synergistically, hinder and destroy the flocculation structure of cement particles, thereby saving the cement consumption, ensuring the activity and the strength of concrete and improving the application performance of the polycarboxylate superplasticizer.
4. The specific types of the polyoxyethylene polyoxypropylene ether and the polyoxyethylene ether selected by the invention have proper space chemical structures and polymerization reaction activation energy, and the polyoxyethylene polyoxypropylene ether and the polyoxyethylene ether are matched with each other, can be used as effective reaction media to participate in polymerization reaction, reduce the temperature of bulk polymerization reaction, improve the reaction polymerization rate, effectively control the reaction efficiency, and synthesize the polycarboxylic acid water reducing agent which has high water reducing performance, is liquid at normal temperature and has the effective content of 100%. The polyoxyethylene ether with the molecular weight of 500-1000 has a lower melting point than that of the polyoxyethylene ether with the high molecular weight, and the completion of the bulk polymerization reaction in a relatively low-temperature environment is guaranteed.
5. According to the invention, the selected unsaturated carboxylic acid, the selected unsaturated carboxylic ester, the selected initiator and the selected chain transfer agent are effectively matched with the two polyether monomers, so that the high polymerization efficiency of bulk polymerization is ensured, the reaction rate of the unsaturated carboxylic acid at the reaction temperature of 40-60 ℃ is controllable, the self-polymerization phenomenon of the unsaturated carboxylic acid is reduced, and the possibility of overlong main chain of the polycarboxylic acid water reducing agent is avoided.
The initiator selected by the invention has proper activation energy, can be matched with the melting temperature of the polyether composition to initiate bulk polymerization reaction at the temperature of 40-60 ℃, has proper reaction rate, can avoid side reaction caused by excessively fast reaction rate, and ensures that the synthesized polycarboxylic acid water reducing agent has high water reducing performance.
The mercaptoethanol selected by the invention is beneficial to forming the comb-shaped polycarboxylic acid molecules with compact structure and high sequence regularity, and the synthesized product has narrow molecular weight distribution range and proper size. The mercaptoethanol has the advantages of strong chain transfer activity, low toxicity and strong operability, and the addition amount is small under the requirement of the mixing amount of the same proportion, so that the reaction cost can be reduced.
Detailed Description
The embodiments of the present invention are illustrated below by specific examples, and unless otherwise indicated, the experimental methods disclosed in the present invention are performed by using conventional techniques in the art, and reagents and raw materials used in the examples are commercially available.
Example 1
The embodiment provides a synthesis method of a polycarboxylate superplasticizer, which specifically comprises the following steps:
1. preparation of Isopentenyl polyoxyethylene polyoxypropylene Ether
(1) 125g of prenol and 0.35g of KOH base catalyst were added to the reaction vessel, and the atmosphere in the vessel was replaced with nitrogen.
(2) When the temperature of the kettle rises to 100 ℃, introducing 2325g of ethylene oxide and 1450g of propylene oxide, keeping the polymerization temperature at 130 ℃, the reaction pressure at 0.35Mpa, and curing for 3.5 hours to obtain the reaction product containing the isopentenyl polyoxyethylene polyoxypropylene ether.
(3) The reaction product was neutralized and degassed in a reactor to obtain isopentenyl polyoxyethylene polyoxypropylene ether having an average molecular weight of 2553.16, where m is 30 and n is 20.
2. Preparation of polycarboxylic acid water reducing agent
(1) 250g of the prenylpolyoxyethylene polyoxypropylene ether (m: 30, n: 20, average molecular weight 2553.16) synthesized in step 1 was charged into a four-necked flask, and 62.5g of prenylpolyoxyethylene ether (average molecular weight 1000) was added thereto, and the mixture was heated to 40 ℃ and dissolved by stirring.
(2) 6g of dimethyl azobisisobutyrate was added to the kettle while controlling the temperature at 60 ℃ and stirred for 10min, and then a mixed solution (mass concentration: 98%) comprising 30g of acrylic acid, 10g of ethyl methacrylate and 2.5g of mercaptoethanol was added dropwise over a period of 2.5 h.
(3) After the dropwise addition is finished, continuously curing for 0.8h, and then cooling to 35 ℃ to obtain the liquid-state collapse-proof polycarboxylic acid water reducing agent.
(4) Adding tetrahydroxyethyl ethylenediamine into the liquid-state collapse-proof polycarboxylate superplasticizer for neutralization, and adjusting the pH to 6 to obtain the collapse-proof polycarboxylate superplasticizer with the effective concentration of 100%.
Example 2
The embodiment provides a synthesis method of a polycarboxylate superplasticizer, which specifically comprises the following steps:
1. preparation of isobutylene-based polyoxyethylene polyoxypropylene Ether
(1) A2L reactor was charged with 100g of isobutylene alcohol and 0.25g of KOH base catalyst, and the atmosphere in the reactor was replaced with nitrogen.
(2) And (3) after the temperature of the kettle rises to 100-110 ℃, introducing 1620g of ethylene oxide and 935g of propylene oxide, keeping the polymerization temperature at 100 ℃ and the reaction pressure at 0.25Mpa, and curing for 3 hours to obtain a reaction product containing the isobutylene polyoxyethylene polyoxypropylene ether.
(3) The reaction product was neutralized and degassed in the reactor to obtain an isobutylene polyoxyethylene polyoxypropylene ether having an average molecular weight of 2210.58, wherein m is 42 and n is 5.
2. Preparation of polycarboxylic acid water reducing agent
(1) 200g of isobutylene-based polyoxyethylene polyoxypropylene ether (m: 42, n: 5, average molecular weight 2210.58) synthesized in step 1 was charged into a four-necked flask, and 200g of isopentenyl polyoxyethylene ether (average molecular weight 500) was added thereto, and the mixture was heated to 45 ℃ and dissolved with stirring.
(2) And controlling the temperature at 50 ℃, adding 6g of azobisisobutyronitrile into the kettle, stirring for 10min, and then dropwise adding a mixed solution (mass concentration is 98%) comprising 15g of methacrylic acid, 15g of ethyl acrylate and 4.5g of mercaptoethanol for 2.5 h.
(3) After the dropwise addition is finished, continuously curing for 1h, and then cooling to 40 ℃ to obtain the liquid-state collapse-proof polycarboxylic acid water reducing agent.
(4) And (3) adding the trihydroxypropyl hydroxyethyl ethylenediamine into the liquid collapse-protecting polycarboxylic acid water reducer for neutralization, and adjusting the pH to 7 to obtain the collapse-protecting polycarboxylic acid water reducer with the effective concentration of 100%.
Example 3
The embodiment provides a synthesis method of a polycarboxylate superplasticizer, which specifically comprises the following steps:
1. preparation of Isopentenyl polyoxyethylene polyoxypropylene Ether
(1) 85g of prenol and 0.35g of KOH as an alkali catalyst were added to a reaction vessel, and the atmosphere in the vessel was replaced with nitrogen.
(2) And (3) after the temperature of the kettle rises to 100-110 ℃, introducing 2440g of ethylene oxide and 800g of propylene oxide, keeping the polymerization reaction temperature at 125 ℃ and the reaction pressure at 0.35Mpa, and curing for 3 hours to obtain a reaction product containing the isopentenyl polyoxyethylene polyoxypropylene ether.
(3) The reaction product was neutralized and degassed in the reactor to obtain isopentenyl polyoxyethylene polyoxypropylene ether with m being 48, n being 17 and average molecular weight of 3171.8.
2. Preparation of polycarboxylic acid water reducing agent
(1) 270g of the prenylpolyoxyethylene polyoxypropylene ether (m: 48, n: 17, average molecular weight 3171.86) synthesized in step 1 was charged into a four-necked flask, and 135g of prenylpolyoxyethylene ether (average molecular weight 1000) was added thereto, and the mixture was heated to 60 ℃ and dissolved with stirring.
(2) A total of 2.7g of dimethyl azobisisobutyrate and diisopropyl peroxydicarbonate were added to the autoclave while controlling the temperature at 60 ℃ and stirred for 10 minutes, followed by dropwise addition of a mixed solution (mass concentration: 98%) comprising 15g of maleic acid, 15g of propyl methacrylate and 8.1g of mercaptoethanol over a period of 2.5 hours.
(3) After the dropwise addition is finished, continuously curing for 0.8h, and then cooling to 38 ℃ to obtain the liquid-state collapse-proof polycarboxylic acid water reducing agent.
(4) And adding hydroxypropyl hydroxyethyl ethylenediamine into the liquid-state collapse-proof polycarboxylic acid water reducing agent for neutralization, and adjusting the pH to 6.5 to obtain the collapse-proof polycarboxylic acid water reducing agent with the effective concentration of 100%.
Example 4
The embodiment provides a synthesis method of a polycarboxylate superplasticizer, which specifically comprises the following steps:
1. preparation of isobutylene-based polyoxyethylene polyoxypropylene Ether
(1) 125g of prenol and 0.50g of KOH were added to the reaction vessel, and the atmosphere in the reaction vessel was replaced with nitrogen.
(2) After the temperature of the kettle rises to 100-110 ℃, introducing 2620g of ethylene oxide and 880g of propylene oxide, keeping the polymerization temperature at 120-130 ℃ and the reaction pressure at 0.35Mpa, and curing for 3 hours to obtain a reaction product containing the isopentenyl polyoxyethylene polyoxypropylene ether.
(3) The reaction product was neutralized and then degassed in the reactor to obtain an isobutylene polyoxyethylene polyoxypropylene ether having an average molecular weight of 2757.2, wherein m is 60 and n is 1.
2. Preparation of polycarboxylic acid water reducing agent
(1) 150g of isobutylene-based polyoxyethylene polyoxypropylene ether (m 60, n 1, average molecular weight 2757.2) synthesized in step 1 was charged into a four-necked flask, 90g of isopentenyl polyoxyethylene ether (average molecular weight 650) was added thereto, and the mixture was heated to 40 ℃ and dissolved with stirring.
(2) 4.5g of dimethyl azobisisobutyrate was added to the kettle while controlling the temperature at 40 ℃ and stirred for 10min, and then a mixed solution (mass concentration: 98%) comprising 15g of acrylic acid, 15g of ethyl acrylate and 1.5g of mercaptoethanol was added dropwise over a period of 2.5 hours.
(3) After the dropwise addition is finished, continuously curing for 0.5h, and then cooling to 32 ℃ to obtain the liquid-state collapse-proof polycarboxylic acid water reducing agent.
(4) Adding tetrahydroxypropyl ethylenediamine into the liquid-state collapse-proof polycarboxylate superplasticizer for neutralization, and adjusting the pH to 6 to obtain the collapse-proof polycarboxylate superplasticizer with the effective concentration of 100 percent.
Detection example 1
Referring to GB8076-2008 'concrete admixture specification', the application performance of the polycarboxylic acid water reducing agent synthesized in the embodiments 1 to 4 and the commercial water reducing agent is respectively detected under the same mixing amount. Wherein the mixing amount of the water reducing agent is based on the weight of the cement after being folded and solidified; as comparison, the commercial water reducing agents are a liquid polycarboxylate water reducing agent PC-1 with the solid content of 40% and a powder collapse-proof polycarboxylate water reducing agent PC-1; the water reducing rate, slump and loss with time of slump of each water reducing agent were measured after preparing the cement with a grade of conch cement P.O 42.5.5 at a c30 concrete mixing ratio, and the measurement results are shown in table 1.
TABLE 1 application Properties of polycarboxylic acid Water reducing agent
As can be seen from Table 1, compared with the commercially available liquid polycarboxylate superplasticizers PC-1 and the slump-retaining powder polycarboxylate superplasticizers PC-2 with the solid content of 40%, the concrete using the product has no loss of slump within 30min, no obvious slump loss within 1h and 15-40mm slump loss within 2h under the same dosage; the preparation method provided by the invention can solve the problem of excessive concrete slump loss, and the slump retaining effect is superior to that of the commercial slump retaining polycarboxylate superplasticizer PC-2. Therefore, the preparation method provided by the invention effectively reduces the reaction temperature of bulk polymerization, reasonably controls the rate of the bulk polymerization reaction, improves the conversion rate of the polymerization reaction, and finally synthesizes the polycarboxylic acid water reducing agent which is liquid at normal temperature, has the effective concentration of 100% and has high collapse protection performance. The polycarboxylate superplasticizer solves the problem of slump loss of the polycarboxylate superplasticizer during high-temperature or long-distance transportation, improves the performance of concrete, ensures the quality of construction sites, and is suitable for large-scale industrial popularization and application.
It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.
Claims (7)
1. The preparation method of the collapse-protecting polycarboxylate superplasticizer is characterized by preparing the collapse-protecting polycarboxylate superplasticizer through bulk polymerization, and specifically comprises the following steps:
(1) mixing polyoxyethylene polyoxypropylene ether and polyoxyethylene ether, controlling the temperature to be 40-60 ℃, uniformly stirring, and then adding an initiator and a mixture of unsaturated carboxylic acid, unsaturated carboxylic ester and a chain transfer agent;
in the step (1), the polyoxyethylene polyoxypropylene ether has a structure shown in a formula I,
wherein R is1Is methyl or ethyl, R2Hydrogen or methyl, EO is oxyethylene, PO is oxypropylene; m is 30-60, n is 1-20;
(2) curing for 0.5-1 h after the step (1) is completed, and cooling to prepare the collapse-proof polycarboxylic acid water reducer;
the polyoxyethylene polyoxypropylene ether is at least one of isobutylene polyoxyethylene polyoxypropylene ether and isopentenyl polyoxyethylene polyoxypropylene ether, and the molecular weight of the polyoxyethylene polyoxypropylene ether is 2200-3200;
the polyoxyethylene polyoxypropylene ether is prepared by the following method:
mixing unsaturated alcohol serving as an initiator with an alkali catalyst, and adding ethylene oxide and propylene oxide in an oxygen-free environment, wherein the mass ratio of the ethylene oxide to the propylene oxide is 1: (0.1 to 0.3); the unsaturated alcohol and the ethylene oxide are subjected to polymerization reaction with the propylene oxide, the reaction temperature is controlled to be 100-130 ℃, and a reaction product containing polyoxyethylene polyoxypropylene ether is prepared;
wherein the unsaturated alcohol is at least one of isobutene alcohol and isopentenol;
further comprising: neutralizing the collapse-proof polycarboxylate superplasticizer with organic amine until the pH value is 6-7;
in the step (1), polyoxyethylene polyoxypropylene ether: polyoxyethylene ether: initiator: the mass ratio of the chain transfer agent is 1: (0.25-1) and (0.01-0.03): (0.01-0.03);
the polyoxyethylene ether is isopentenyl polyoxyethylene ether, and the molecular weight of the polyoxyethylene ether is 500-1000.
2. The method according to claim 1, wherein the organic amine is at least one of trimethylolpropane hydroxyethylethylenediamine and tetrahydroxypropylethylenediamine.
3. The production method according to claim 1 or 2, characterized in that the unsaturated carboxylic acid is at least one of acrylic acid, methacrylic acid, itaconic acid, and maleic acid.
4. The method according to claim 3, wherein the unsaturated carboxylic acid ester is at least one of ethyl acrylate, ethyl methacrylate, and propyl methacrylate.
5. The method according to claim 1, wherein the initiator is at least one of dimethyl azobisisobutyrate, azobisisobutyronitrile, and diisopropyl peroxydicarbonate.
6. The method according to claim 1, wherein the chain transfer agent is mercaptoethanol.
7. The method according to claim 1, wherein the temperature in the step (2) is reduced to a temperature of 40 ℃ or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711124168.3A CN108084358B (en) | 2017-11-14 | 2017-11-14 | Preparation method of collapse-proof polycarboxylate superplasticizer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711124168.3A CN108084358B (en) | 2017-11-14 | 2017-11-14 | Preparation method of collapse-proof polycarboxylate superplasticizer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108084358A CN108084358A (en) | 2018-05-29 |
| CN108084358B true CN108084358B (en) | 2021-01-15 |
Family
ID=62172336
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201711124168.3A Active CN108084358B (en) | 2017-11-14 | 2017-11-14 | Preparation method of collapse-proof polycarboxylate superplasticizer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108084358B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113683738B (en) * | 2021-08-25 | 2022-06-28 | 佳化化学科技发展（上海）有限公司 | Polycarboxylate superplasticizer and preparation method thereof |
| CN115558061A (en) * | 2022-09-30 | 2023-01-03 | 安徽海螺材料科技股份有限公司 | Polycarboxylate superplasticizer and preparation method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102504239A (en) * | 2011-11-03 | 2012-06-20 | 山西合盛邦砼建材有限公司 | Catalyst for preparing polycarboxylate water reducing agent macromonomer and preparation method thereof |
| CN102585115A (en) * | 2011-12-26 | 2012-07-18 | 东华理工大学 | Isobutylene polyether polycarboxylic water reducer and preparation method thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102206314B (en) * | 2011-04-25 | 2013-01-02 | 武汉格瑞林建材科技股份有限公司 | Polycarboxylic acid and application thereof, and cement water reducing agent containing polycarboxylic acid |
| CN103865007A (en) * | 2014-03-17 | 2014-06-18 | 南京瑞迪高新技术有限公司 | Preparation method of viscosity-reduction type polycarboxylate water reducer |
| CN104261721B (en) * | 2014-09-22 | 2016-06-29 | 科之杰新材料集团有限公司 | A kind of ethers polycarboxylic acid slump retaining agent and preparation method thereof |
| CN106967200A (en) * | 2017-03-31 | 2017-07-21 | 刘翠芬 | It is a kind of to have poly carboxylic acid series water reducer that guarantor is collapsed with viscosity-reducing performance and preparation method thereof concurrently |
-
2017
- 2017-11-14 CN CN201711124168.3A patent/CN108084358B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102504239A (en) * | 2011-11-03 | 2012-06-20 | 山西合盛邦砼建材有限公司 | Catalyst for preparing polycarboxylate water reducing agent macromonomer and preparation method thereof |
| CN102585115A (en) * | 2011-12-26 | 2012-07-18 | 东华理工大学 | Isobutylene polyether polycarboxylic water reducer and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN108084358A (en) | 2018-05-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108003301B (en) | Preparation method of viscosity-reducing polycarboxylate superplasticizer | |
| CN105236800B (en) | A kind of poly carboxylic acid series water reducer mother liquor and its preparation method and application | |
| WO2021217762A1 (en) | Unsaturated polyether monomer, and polycarboxylate superplasticizer and preparation method therefor | |
| CN107586366B (en) | Modified polycarboxylate superplasticizer and preparation method thereof | |
| CN110642993B (en) | Preparation method of retarding ether polycarboxylate superplasticizer | |
| CN108948288B (en) | Preparation method of crosslinking type polycarboxylate superplasticizer by adopting carboxyl functional monomer | |
| CN108821633B (en) | Water-reducing solid polycarboxylate superplasticizer and preparation method thereof | |
| CN108623208B (en) | Composite cement additive and preparation method thereof | |
| CN109337024B (en) | Preparation method of retarding polycarboxylate superplasticizer | |
| CN109455971B (en) | Preparation method of powdery carboxylic acid water reducing agent | |
| CN107337769B (en) | Slump-retaining type polycarboxylate superplasticizer and preparation method thereof | |
| CN108409193A (en) | A kind of Machine-made Sand C120 super high strength concrete polycarboxylic admixtures and preparation method thereof | |
| CN107652405A (en) | A kind of polycarboxylate water-reducer of acid amides/imide structure and preparation method thereof | |
| CN111548459A (en) | Preparation method of high slump loss resistant polycarboxylate superplasticizer | |
| CN106519137A (en) | Cross-star-shaped slow-release slump-retaining type polycarboxylic-acid water-reducing agent and preparation method thereof | |
| CN111349199B (en) | Steady-state polycarboxylic acid superplasticizer with core-shell structure and preparation method thereof | |
| CN106632881A (en) | Low water-reducing and high slump loss resistant type polycarboxylate superplasticizer master batch | |
| CN111234131B (en) | Glucolactone-based polycarboxylate water reducer and preparation method thereof | |
| CN102503221B (en) | Cyclohexanol grafted polycarboxylic acid water reducing agent and preparation method thereof | |
| CN108084358B (en) | Preparation method of collapse-proof polycarboxylate superplasticizer | |
| CN111978482A (en) | Polycarboxylic acid plastic retention agent for self-compacting concrete and preparation method thereof | |
| CN111533862A (en) | High-water-retention type lipid polycarboxylate superplasticizer and preparation method thereof | |
| CN109021179B (en) | Phosphonic acid-based polymer, preparation method thereof and phosphate mother liquor | |
| CN109111146B (en) | Multifunctional ester polycarboxylate superplasticizer and preparation method thereof | |
| CN110643003B (en) | Preparation method of retarding type ester polycarboxylate superplasticizer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |