Ester-terminated polyether monomer and preparation method and application thereof

Abstract

The present invention relates to an ester-terminated polyether monomer and a preparation method and application thereof. The molecular structure of the ester-terminated polyether monomer prepared by the present invention is obtained by block copolymerization of ethylene oxide (EO) and propylene oxide (PO), wherein EO is a hydrophilic group and PO is a lipophilic group, the hydrophilicity and lipophilicity are adjustable, and the molecular weight is controllable. Compared with the polyether monomer of the traditional water-reducing polycarboxylic acid water-reducing agent, the ester-terminated polyether monomer is gradually hydrolyzed in concrete, so that the prepared water-reducing agent has higher slump-retaining performance. The present invention introduces epoxy groups into macromonomer molecules to form hydrophobic units in water-reducing agent molecules, thereby overcoming the problems that the water-reducing agent synthesized by traditional straight-chain monomers is easy to bleed and separate, resulting in poor workability of concrete, thereby greatly improving the workability of the synthesized polycarboxylic acid water-reducing agent, and further improving the slump-retaining performance.

Description

Technical Field

[0001] The invention relates to the technical field of concrete admixtures, in particular to an ester-terminated polyether monomer and a preparation method and application thereof. Background Art

[0002] As the technical requirements for sand and gravel in key projects such as modern concrete and high-speed rail become increasingly higher, and the amount of natural sand and gravel that can meet these requirements is decreasing, in order to meet the rigid demand of the sand and gravel market, machine-made sand has become the first choice in the construction market, and gradually replacing natural sand and gravel materials with machine-made sand has become a necessity for the development of the market situation.

[0003] However, the quality of machine-made sand is difficult to guarantee, and the mud and stone powder content in machine-made sand are relatively high, and the amount of adsorption to the outside is large, which has a great impact on the workability and retention performance of concrete. The polycarboxylic acid water reducer synthesized from ordinary carboxylic acid monomers can no longer meet the development needs of the construction market materials. The changes in sand and gravel materials urgently require new design and development of the polymer monomer structure to improve the workability and collapse retention performance of the water reducer. Summary of the invention

[0004] Based on this, it is necessary to provide an ester-terminated polyether monomer capable of improving workability and collapse retention performance, and a preparation method and application thereof.

[0005] To achieve the above object, the present invention provides a technical solution:

[0006] An ester-terminated polyether monomer, the structural formula of the ester-terminated polyether monomer is as follows:

[0007]

[0008] Among them, R 1 =(CH 2 ) n , n is an integer from 2 to 8;

[0009] R 2 C 1 -C 12 A straight-chain or branched saturated alkyl group;

[0010] B is an integer from 0 to 100;

[0011] b is an integer from 0 to 100.

[0012] The present invention also provides a method for preparing the above-mentioned ester-terminated polyether monomer, wherein the raw materials for preparing the ester-terminated polyether monomer include terminal enol ester, a catalyst and alkylene oxide.

[0013] Preferably, the structural formula of the terminal enol ester is as follows:

[0014]

[0015] Among them, R 1 =(CH 2 ) n , n is an integer from 2 to 8.

[0016] R 2 C 1 -C 12 A straight chain or branched saturated alkyl group.

[0017] Preferably, the catalyst comprises a mixture of catalyst A and catalyst B;

[0018] Wherein, the catalyst A comprises KOH, NaOH and CH 3 At least one of ONa;

[0019] The catalyst B includes a rare earth metal catalyst.

[0020] Preferably, the alkylene oxide includes at least one of ethylene oxide and propylene oxide.

[0021] Preferably, the preparation steps of the ester-terminated polyether monomer include:

[0022] Under the catalysis of a catalyst, the terminal enol ester and the alkylene oxide are subjected to a ring-opening polymerization reaction at 100-120° C. and 0.2-0.5 MPa. After the reaction is completed, the ester-terminated polyether monomer is obtained.

[0023] The present invention also provides a use of any one of the above ester-terminated polyether monomers as a raw material in preparing a polycarboxylic acid water-reducing agent.

[0024] Preferably, in parts by weight, the raw materials for preparing the polycarboxylate water-reducing agent include:

[0025]

[0026] Preferably, the preparation steps of the polycarboxylate water-reducing agent include:

[0027] Stirring and dissolving the ester-terminated polyether monomer, the oxidant and the water to obtain a macromonomer solution;

[0028] The functional monomer, the unsaturated acid and water are stirred and mixed to obtain liquid A;

[0029] The molecular weight regulator, the reducing agent and water are stirred and mixed to obtain liquid B;

[0030] Under the condition of stirring at room temperature, the A solution and the B solution are simultaneously added dropwise to the macromonomer solution. After the addition is completed, alkali is added to adjust the pH of the solution to 5-7, thereby obtaining the polycarboxylate water-reducing agent.

[0031] Preferably, the unsaturated acid includes at least one of acrylic acid, methacrylic acid and itaconic acid.

[0032] Beneficial effects of the present invention:

[0033] The molecular structure of the ester-terminated polyether monomer prepared by the invention is obtained by block copolymerization of ethylene oxide (EO) and propylene oxide (PO), wherein EO is a hydrophilic group and PO is a lipophilic group, the hydrophilicity and lipophilicity are adjustable, and the molecular weight is controllable. Compared with the polyether monomer of the traditional water-reducing polycarboxylic acid water-reducing agent, the ester-terminated polyether monomer is gradually hydrolyzed in concrete, so that the prepared water-reducing agent has higher slump retention performance.

[0034] The present invention introduces epoxy groups into macromonomer molecules to form hydrophobic units in water-reducing agent molecules, thereby overcoming the problems that water-reducing agents synthesized from traditional straight-chain monomers are prone to water exudation and segregation, resulting in poor workability of concrete, and the like, thereby greatly improving the workability of the synthesized polycarboxylic acid water-reducing agent and further improving the collapse-preserving performance. DETAILED DESCRIPTION

[0035] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0036] In the examples, the test methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0037] An ester-terminated polyether monomer, the structural formula of the ester-terminated polyether monomer is as follows:

[0038]

[0039] Among them, R 1 =(CH 2 ) n , n is an integer from 2 to 8;

[0040] R 2 C 1 -C 12 A straight-chain or branched saturated alkyl group;

[0041] a is an integer from 0 to 100;

[0042] b is an integer from 0 to 100.

[0043] The present invention also provides a method for preparing the ester-terminated polyether monomer as described above, wherein the raw materials for preparing the ester-terminated polyether monomer include terminal enol ester, a catalyst and alkylene oxide.

[0044] The amount of terminal enol ester is 0.1-15% of the total mass of raw materials for preparing ester-terminated unsaturated polyether monomers;

[0045] In one embodiment, the structural formula of the terminal enol ester is as follows:

[0046]

[0047] Among them, R 1 =(CH 2 ) n ;

[0048] R 2 C 1 -C 12 A straight chain or branched saturated alkyl group.

[0049] In one embodiment, the catalyst includes a mixture of catalyst A and catalyst B;

[0050] The catalyst A includes KOH, NaOH and CH 3 At least one of ONa;

[0051] Catalyst B includes a rare earth metal catalyst, and specifically, the catalyst includes a metal lanthanum catalyst.

[0052] The dosage of the catalyst is 0.01-0.2% of the total mass of the raw materials for preparing the ester-terminated unsaturated polyether monomer; wherein the dosage of catalyst B is 0.002%-0.01% of the total mass of the raw materials for preparing the ester-terminated unsaturated polyether monomer, and catalyst B rare earth metal catalyst is added to improve the catalytic effect.

[0053] In one embodiment, the alkylene oxide includes at least one of ethylene oxide and propylene oxide. The amount of alkylene oxide used is 85-99% of the total mass of the raw materials for preparing the ester-terminated unsaturated polyether monomer.

[0054] Specifically, the preparation steps of the ester-terminated polyether monomer include:

[0055] Under the catalysis of a catalyst, a ring-opening polymerization reaction is carried out between terminal enol ester and alkylene oxide at 100-120° C. and 0.2-0.5 MPa. After the reaction is completed, an ester-terminated polyether monomer is obtained.

[0056] The present invention also provides an application of the above ester-terminated polyether monomer as a raw material in preparing a polycarboxylic acid water-reducing agent.

[0057] In one embodiment, the raw materials for preparing the polycarboxylate water-reducing agent include, by weight:

[0058]

[0059]

[0060] In one embodiment, the preparation steps of the polycarboxylate water reducer include:

[0061] S100. Stir and dissolve the ester-terminated polyether monomer, the oxidant and water to obtain a macromonomer solution.

[0062] S200. Stir and mix the functional monomer, unsaturated acid and water to obtain liquid A.

[0063] S300. The molecular weight regulator, the reducing agent and the water are stirred and mixed to obtain liquid B.

[0064] S400. Under the condition of stirring at room temperature, liquid A and liquid B are simultaneously added dropwise to the macromonomer solution. After the addition is completed, alkali is added to adjust the pH of the solution to 5-7 to obtain a polycarboxylic acid water reducer.

[0065] R 1 =(CH 2 ) n , n is an integer from 2 to 8;

[0066] R 2 C 1 -C 12 A straight-chain or branched saturated alkyl group;

[0067] a is an integer from 0 to 100;

[0068] b is an integer from 0 to 100.

[0069] Specifically, the unsaturated acid includes at least one of acrylic acid, methacrylic acid and itaconic acid;

[0070] The structural formula of the functional monomer is as follows:

[0071]

[0072] Where R is H or CH 3 , X is CH 2 or CH 2 CH 2 .

[0073] The reducing agent is at least one of L-ascorbic acid, azobisisopropylimidazoline hydrochloride, azobiscyclohexylcarbonitrile, sodium bisulfite, sodium pyrosulfite, bleaching agent, ferrous sulfate heptahydrate and ammonium ferrous sulfate;

[0074] The oxidant comprises at least one of hydrogen peroxide, ammonium persulfate, potassium persulfate and sodium persulfate;

[0075] The molecular weight regulator includes at least one of mercaptopropionic acid, mercaptoethanol, sodium hypophosphite, mercaptopropanol, mercaptopropionic acid ester and p-phenol.

[0076] Example 1

[0077] Preparation of ester-terminated polyether macromonomers

[0078] Add 36.1g of terminal enol ester, 1.1g of KOH and 0.03g of rare earth metal lanthanum catalyst into the reactor, control the pre-reaction temperature to 30-40°C, and the pre-reaction time to 0.8 hours; after the pre-reaction is completed, heat and raise the temperature, maintain vacuum at 90°C, replace with nitrogen, raise the temperature to 100°C, introduce 442g of ethylene oxide, control the reaction temperature at 105°C, react under a pressure of 0.35MPa until the pressure no longer decreases, continuously introduce 277g of propylene oxide, control the reaction temperature at 105°C, react under a pressure of 0.35MPa until the pressure no longer decreases. After the reaction is completed, cool to 60°C to obtain the final product (ester-terminated polyether monomer).

[0079] Among them, the structural formula of terminal enol ester is: CH 2 =CH-OCH 2 CH 2 -OOC-CH 2 CH 3

[0080] The molecular weight of the prepared ester-terminated polyether macromonomer is 3000, and the structural formula is as follows:

[0081] CH 2 =CH-O-CH 2 CH 2 -O-(CH 2 CH 2 O) a -(CHCH 3 CH 2 O) b -OC-CH 2 CH 3 .

[0082] Preparation of polycarboxylate water reducer

[0083] S100. 200 parts by weight of the ester-terminated polyether macromonomer prepared above, 1.5 parts by weight of an oxidant hydrogen peroxide, 5 parts by weight of ethylene glycol monovinyl polyoxyethylene ether and 180 parts by weight of deionized water were added to a reactor and stirred to dissolve to obtain a macromonomer solution;

[0084] S200. 17 parts by weight of acrylic acid and 20 parts by weight of deionized water were stirred and mixed to obtain a liquid A;

[0085] S300. 1.0 parts by weight of a molecular weight regulator, mercaptopropionic acid, 0.5 parts by weight of a reducing agent, ascorbic acid, and 20 parts by weight of deionized water were stirred and mixed to obtain liquid B;

[0086] S400. Under stirring conditions at room temperature, liquid A and liquid B are simultaneously added dropwise to the macromonomer solution. After the addition is completed, alkali is added to neutralize the pH of the solution to 7, thereby obtaining a polycarboxylic acid water reducer.

[0087] Example 2

[0088] Preparation of ester-terminated polyether macromonomers

[0089] Add 56.3g of terminal enol ester, 1.3g of NaOH and 0.03g of rare earth metal lanthanum catalyst into the reactor, control the pre-reaction temperature to 30-40°C, and the pre-reaction time to 0.8 hours; after the pre-reaction is completed, heat and raise the temperature, maintain vacuum at 90°C, replace with nitrogen, raise the temperature to 100°C, pass 576g of ethylene oxide, control the reaction temperature at 105°C, under a pressure of 0.35MPa, react until the pressure no longer decreases, continuously pass 152g of propylene oxide, control the reaction temperature at 105°C, under a pressure of 0.35MPa, react until the pressure no longer decreases. After the reaction is completed, cool to 60°C to obtain the final product (ester-terminated polyether macromonomer).

[0090] Among them, the structural formula of terminal enol ester is: CH 2 =CH-OCH 2 CH 2 CH 2 CH 2 -OOC-CH 2 CH 3 .

[0091] The molecular weight of the prepared ester-terminated polyether macromonomer is 2400, and the structural formula is as follows:

[0092] CH 2 =CH-O-CH 2 CH 2 CH 2 CH 2 -O-(CH 2 CH 2 O) a -(CHCH 3 CH 2 O) b -OC-CH 2 CH 3 .

[0093] Preparation of polycarboxylate water reducer

[0094] S100. 200 parts by weight of the ester-terminated polyether macromonomer prepared above, 2.5 parts by weight of an oxidant hydrogen peroxide, 8 parts by weight of glycidyl methacrylate and 180 parts by weight of deionized water were added to a reactor and stirred to dissolve to obtain a macromonomer solution;

[0095] S200. 12 parts by weight of acrylic acid and 20 parts by weight of deionized water were stirred and mixed to obtain a liquid A;

[0096] S300. 1.5 parts by weight of a molecular weight regulator, mercaptoethanol, 0.5 parts by weight of a reducing agent, ascorbic acid, and 20 parts by weight of deionized water were stirred and mixed to obtain a solution B;

[0097] S400. Under stirring conditions at room temperature, liquid A and liquid B are simultaneously added dropwise to the macromonomer solution. After the addition is completed, alkali is added to neutralize the pH of the solution to 7, thereby obtaining a polycarboxylic acid water reducer.

[0098] Comparative Example 1

[0099] S100. 200 parts by weight of ethylene glycol monovinyl polyoxyethylene ether macromonomer (molecular weight 3000), 1.5 parts by weight of oxidant hydrogen peroxide, 5 parts by weight of ethylene glycol monovinyl polyoxyethylene ether and 180 parts by weight of deionized water were added to the reactor and stirred to dissolve to obtain a macromonomer solution;

[0100] S200. 17 parts by weight of acrylic acid and 20 parts by weight of deionized water were stirred and mixed to obtain a liquid A;

[0101] S300. 1.0 parts by weight of a molecular weight regulator, mercaptopropionic acid, 0.5 parts by weight of a reducing agent, ascorbic acid, and 20 parts by weight of deionized water were stirred and mixed to obtain liquid B;

[0102] S400. Under stirring conditions at room temperature, liquid A and liquid B are simultaneously added dropwise to the macromonomer solution. After the addition is completed, alkali is added to neutralize the pH of the solution to 7, thereby obtaining a polycarboxylic acid water reducer.

[0103] Comparative Example 2

[0104] S100. 200 parts by weight of the ester-terminated polyether macromonomer prepared in Example 1, 1.5 parts by weight of an oxidizing agent, hydrogen peroxide, and 180 parts by weight of deionized water were added to a reactor and stirred to dissolve to obtain a macromonomer solution;

[0105] S200. 17 parts by weight of acrylic acid and 20 parts by weight of deionized water were stirred and mixed to obtain a liquid A;

[0106] S300. 1.0 parts by weight of a molecular weight regulator, mercaptopropionic acid, 0.5 parts by weight of a reducing agent, ascorbic acid, and 20 parts by weight of deionized water were stirred and mixed to obtain liquid B;

[0107] S400. Under stirring conditions at room temperature, liquid A and liquid B are simultaneously added dropwise to the macromonomer solution. After the addition is completed, alkali is added to neutralize the pH of the solution to 7, thereby obtaining a polycarboxylic acid water reducer.

[0108] Comparative Example 3

[0109] The S13 polycarboxylic acid mother liquor produced by Kezhijie New Materials Group Fujian Co., Ltd. is obtained by copolymerizing isobutylene alcohol polyoxyethylene ether and acrylic acid under a redox system. The mother liquor is a colorless transparent liquid with a solid content of 50%. The molecular structure of the mother liquor is as follows:

[0110]

[0111] Minfu P.O42.5 ordinary Portland cement is used, and the concrete mix ratio is: cement 360kg / m 3 、Sand 880kg / m 3 、Stone 970kg / m 3 , water 170kg / m 3 Each embodiment and comparative example was diluted with water to a solid content of 10% for performance testing.

[0112] The test method is based on GB / T 8076-2008 "Concrete Admixtures", GB / T 50080-2016 "Standard for Test Methods for Performance of Ordinary Concrete Mixtures", and GB / T 50081-2019 "Standard for Test Methods for Physical and Mechanical Properties of Concrete". The performance test results are shown in Table 1.

[0113] Table 1 Performance test results

[0114]

[0115] As can be seen from Table 1, the polycarboxylic acid water-reducing agents prepared in Example 1 and Example 2 have high water reduction rates, good slump retention performance, fast initial concrete flow rates, good workability, and no water seepage.

[0116] Comparative Example 1 uses a traditional polycarboxylic acid water-reducing polyether monomer (ethylene glycol monovinyl polyoxyethylene ether). The water reduction rate of Comparative Example 1 is lower than that of Example 1 and Example 2, the encapsulation is also average, and no hydrophobic group is introduced to cause water exudation.

[0117] In Comparative Example 2, the functional monomer ethylene glycol monovinyl polyoxyethylene ether was not added, and the concrete condition was obviously poor, with obvious exposed stones and more water seepage.

[0118] Comparative Example 3 uses HPEG polyether monomer to prepare polycarboxylate water reducer, which has the lowest initial dispersion performance, rapid loss, and easy water exudation.

[0119] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing an ester-terminated polyether monomer, characterized in that: The structural formula of the ester-terminated polyether monomer is as follows: ； Where R1=(CH2) n , n is an integer from 2 to 8; R2 is C1-C 12 A straight-chain or branched saturated alkyl group; a is an integer from 0 to 100; b is an integer from 0 to 100; a and b are not 0 at the same time; The raw materials for preparing the ester-terminated polyether monomer include terminal ene alcohol ester, catalyst and alkylene oxide; The catalyst comprises a mixture of catalyst A and catalyst B; Wherein, the catalyst A comprises at least one of KOH, NaOH and CH3ONa; The catalyst B comprises a rare earth metal catalyst; The preparation steps of the ester-terminated polyether monomer include: Under the catalysis of a catalyst, a ring-opening polymerization reaction is carried out on the terminal enol ester and the alkylene oxide at 100-120° C. and 0.2-0.5 MPa. After the reaction is completed, the ester-terminated polyether monomer is obtained.

2. The method for preparing an ester-terminated polyether monomer according to claim 1, characterized in that: The structural formula of the terminal enol ester is as follows: ； Where R1=(CH2) n , n is an integer from 2 to 8; R2 is C1-C 12 A straight chain or branched saturated alkyl group.

3. The method for preparing an ester-terminated polyether monomer according to claim 1, characterized in that: The alkylene oxide includes at least one of ethylene oxide and propylene oxide.

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