Early-strength polycarboxylate superplasticizer with MOF structure and preparation method thereof

Abstract

An early-strength polycarboxylate superplasticizer with an MOF structure and a preparation method thereof are provided. The preparation method includes the following steps: 1) performing an amidation reaction on amine-containing nanocrystalline MOFs and a halogen acyl halide organic molecule to form the halogen-containing ATRP initiator; 2) performing an ATRP reaction on the obtained ATRP initiator, an unsaturated ester monomer, an unsaturated polyether macromonomer and a transition metal complex to obtain the early-strength polycarboxylate superplasticizer with the MOF structure. The present invention regulates the number and length of branch chains and product performance by controlling the number of amine groups contained in the nanocrystalline MOFs and ATRP, and has the advantages of rapid reaction, high efficiency, non-toxic and non-pollution, and simple operation. The prepared early-strength polycarboxylate superplasticizer with the MOF structure has early-strength performance and stable product performance.

Claims

1. A preparation method of an early-strength polycarboxylate superplasticizer with a MOF structure, comprising the following steps: 1) preparation of a halogen-containing atom transfer radical polymerization (ATRP) initiator: performing an amidation reaction on amine-containing nanocrystalline MOFs and a halogen acyl halide organic molecule at 0-25° C. for 30-90 min, to form the halogen-containing ATRP initiator; wherein a molar ratio of the amine-containing nanocrystalline MOFs to the halogen acyl halide organic molecule is 1: (1-5); 2) preparation of the early-strength polycarboxylate superplasticizer with the MOF structure: performing an ATRP reaction on the halogen-containing ATRP initiator prepared in step 1), an unsaturated ester monomer, an unsaturated polyether macromonomer and a transition metal complex at 60-80° C. for 30-90 min, to obtain the early-strength polycarboxylate superplasticizer with the MOF structure; wherein a molar ratio of the halogen-containing ATRP initiator, the unsaturated ester monomer, the unsaturated polyether macromonomer and the transition metal complex is 1: (0.3-6): (0.1-1): (0.001-0.01).

2. The preparation method according to claim 1, wherein a structural formula of the amine-containing nanocrystalline MOFs in step 1) is: ##STR00013## wherein, M is a metal ion, n≥1, and the metal ion is at least one selected from the group consisting of aluminum, magnesium, copper, gold, zinc, iron and a rare earth metal.

3. The preparation method according to claim 1, wherein a structural formula of the halogen acyl halide organic molecule in step 1) is: ##STR00014## wherein X is bromine or chlorine.

4. The preparation method according to claim 1, wherein, the halogen acyl halide organic molecule is at least one selected from the group consisting of 2-bromoisobutyryl bromide, 2-bromoisobutyryl chloride, 2-chloroisobutyryl chloride, 2-chloropropionyl chloride and 2-bromopropionyl chloride.

5. The preparation method according to claim 1, wherein a structural formula of the unsaturated ester monomer in step 2) is: ##STR00015## wherein, R.sub.2 is hydrogen or an alkyl group with 1-6 carbon atoms, and R.sub.1 is an alkyl group with 1-8 carbon atoms or a hydroxyl alkane with 1-8 carbon atoms.

6. The preparation method according to claim 1, wherein, the unsaturated ester monomer is at least one selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl acrylate, hydroxymethyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate and hydroxybutyl methacrylate.

7. The preparation method according to claim 1, wherein, the unsaturated polyether macromonomer in step 2) is at least one selected from the group consisting of allyl polyethylene glycol, methylallyl polyethylene glycol, 3-methyl-3-butene-1-polyethylene glycol, 2-methylallyl polyethylene glycol, methoxy polyethylene glycol methacrylate, methoxy polyethylene glycol acrylate, polyethylene glycol acrylic acid monoester and polyethylene glycol methacrylate; a weight-average molecular weight of the unsaturated polyether macromonomer is 300-8,000 g/mol.

8. The preparation method according to claim 1, wherein the transition metal complex in step 2) is at least one selected from the group consisting of CuBr/pentamethyldiethylenetriamine (PMDETA), CuCl/hexamethyltriethylenetetramine (HMTETA), CuBr/N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), CuBr/tri[2-(dimethylamine) ethyl] amine (Me6TREN), CuCl/PMDETA, CuBr/HMTETA, CuCl/TPEN and CuCl/Me6TREN.

Description

DETAILED DESCRIPTION OF THE EMBODIMENTS

(1) In order to make the technical objective, technical solutions and advantages of the present invention clearer, the present invention will be further described in combination with various embodiments.

Embodiment 1

(2) 1) Preparation of an ATRP initiator: 1 mol of nanocrystalline iron-organic frameworks containing one amine group and 1 mol of 2-bromoisobutyryl bromide are subjected to an amidation reaction at 0° C. for 90 min, to form a halogen-containing ATRP initiator.

(3) 2) Preparation of a polycarboxylate superplasticizer with an MOF structure: 1 mol of the ATRP initiator prepared in step 1), 6 mol of methyl acrylate, 0.1 mol of methylallyl polyethylene glycol (300 g/mol) and 0.01 mol of CuBr/PMDETA are subjected to a reaction at 60° C. for 90 min, and then water is added to obtain a 60 wt % polycarboxylate superplasticizer with the MOF structure having a weight-average molecular weight of 20,000 g/mol.

(4) The molecular structure of the polycarboxylate superplasticizer is as follows:

(5) ##STR00005##

Embodiment 2

(6) 1) Preparation of an ATRP initiator: 1 mol of nanocrystalline magnesium-organic frameworks containing two amine groups and 2 mol of 2-bromoisobutyryl chloride are subjected to an amidation reaction at 25° C. for 30 min, to form a halogen-containing ATRP initiator.

(7) 2) Preparation of a polycarboxylate superplasticizer with an MOF structure: 1 mol of the ATRP initiator prepared in step 1), 5 mol of ethyl acrylate, 1 mol of 3-methyl-3-butene-1-polyethylene glycol (800 g/mol) and 0.001 mol of CuBr/TPEN are subjected to a reaction at 70° C. for 30 min, and then water is added to obtain a 5-60 wt % polycarboxylate superplasticizer with the MOF structure having a weight-average molecular weight of 30,000 g/mol.

(8) The molecular structure of the polycarboxylate superplasticizer is as follows:

(9) ##STR00006##

Embodiment 3

(10) 1) Preparation of an ATRP initiator: 1 mol of nanocrystalline aluminum-organic frameworks containing three amine groups and 3 mol of 2-chloroisobutyryl chloride are subjected to an amidation reaction at 20° C. for 70 min, to form a halogen-containing ATRP initiator.

(11) 2) Preparation of a polycarboxylate superplasticizer with an MOF structure: 1 mol of the ATRP initiator prepared in step 1), 0.3 mol of propyl acrylate, 0.3 mol of 3-methyl-3-butene-1-polyethylene glycol (800 g/mol) and 0.002 mol of CuBr/TPEN are subjected to a reaction at 80° C. for 40 min, and then water is added to obtain a 50 wt % polycarboxylate superplasticizer with the MOF structure having a weight-average molecular weight of 50,000 g/mol.

(12) The molecular structure of the polycarboxylate superplasticizer is as follows:

(13) ##STR00007##

Embodiment 4

(14) 1) Preparation of an ATRP initiator: 1 mol of nanocrystalline zinc-organic frameworks containing four amine groups and 4 mol of 2-bromopropionyl chloride are subjected to an amidation reaction at 5° C. for 30 min, to form a halogen-containing ATRP initiator.

(15) 2) Preparation of a polycarboxylate superplasticizer with an MOF structure: 1 mol of the ATRP initiator prepared in step 1), 2 mol of methyl methacrylate, 1 mol of methoxy polyethylene glycol monomethyl ether(methyl)acrylate (1,000 g/mol) and 0.004 mol of CuCl/PMDETA are subjected to a reaction at 80° C. for 50 min, and then water is added to obtain a 50 wt % polycarboxylate superplasticizer with the MOF structure having a weight-average molecular weight of 60,000 g/mol.

(16) The molecular structure of the polycarboxylate superplasticizer is as follows:

(17) ##STR00008##

Embodiment 5

(18) 1) Preparation of an ATRP initiator: 1 mol of nanocrystalline copper-organic frameworks containing two amine groups and 2 mol of 2-bromoisobutyryl bromide are subjected to an amidation reaction at 10° C. for 90 min, to form a halogen-containing ATRP initiator.

(19) 2) Preparation of a polycarboxylate superplasticizer with an MOF structure: 1 mol of the ATRP initiator prepared in step 1), 3 mol of butyl acrylate, 0.5 mol of 2-methylallyl polyethylene glycol (2,000 g/mol) and 0.003 mol of CuBr/Me6TREN are subjected to a reaction at 75° C. for 80 min, and then water is added to obtain a 60 wt % polycarboxylate superplasticizer with the MOF structure having a weight-average molecular weight of 60,000 g/mol.

(20) The molecular structure of the polycarboxylate superplasticizer is as follows:

(21) ##STR00009##

Embodiment 6

(22) 1) Preparation of an ATRP initiator: 1 mol of nanocrystalline gold-organic frameworks containing five amine groups and 3 mol of 2-chloroisobutyryl chloride are subjected to an amidation reaction at 15° C. for 80 min, to form a halogen-containing ATRP initiator.

(23) 2) Preparation of a polycarboxylate superplasticizer with an MOF structure: 1 mol of the ATRP initiator prepared in step 1), 4 mol of ethyl methacrylate, 1 mol of polyethylene glycol acrylate (1,200 g/mol) and 0.005 mol of CuBr/HMTETA are subjected to a reaction at 65° C. for 70 min, and then water is added to obtain a 40 wt % polycarboxylate superplasticizer with the MOF structure having a weight-average molecular weight of 80,000 g/mol.

(24) The molecular structure of the polycarboxylate superplasticizer is as follows:

(25) ##STR00010##

Embodiment 7

(26) 1) Preparation of an ATRP initiator: 1 mol of nanocrystalline chromium-organic frameworks containing four amine groups and 4 mol of 2-chloropropionyl chloride are subjected to an amidation reaction at 25° C. for 60 min, to form a halogen-containing ATRP initiator.

(27) 2) Preparation of a polycarboxylate superplasticizer with an MOF structure: 1 mol of the ATRP initiator prepared in step 1), 5 mol of butyl methacrylate, 1 mol of methoxy polyethylene glycol acrylate (2,400 g/mol) and 0.006 mol of CuCl/TPEN are subjected to a reaction at 75° C. for 90 min, and then water is added to obtain a 30 wt % polycarboxylate superplasticizer with the MOF structure having a weight-average molecular weight of 45,000 g/mol.

(28) The molecular structure of the polycarboxylate superplasticizer is as follows:

(29) ##STR00011##

Embodiment 8

(30) 1) Preparation of an ATRP initiator: 1 mol of nanocrystalline zirconium-organic frameworks containing three amine groups and 5 mol of 2-bromopropionyl chloride are subjected to an amidation reaction at 0° C. for 40 min, to form a halogen-containing ATRP initiator.

(31) 2) Preparation of a polycarboxylate superplasticizer with an MOF structure: 1 mol of the ATRP initiator prepared in step 1), 6 mol of hydroxybutyl methacrylate, 1 mol of polyethylene glycol methacrylate (3,000 g/mol) and 0.007 mol of CuCl/Me6TREN are subjected to a reaction at 80° C. for 50 min, and then water is added to obtain a 20 wt % polycarboxylate superplasticizer with the MOF structure having a weight-average molecular weight of 60,000 g/mol.

(32) The molecular structure of the polycarboxylate superplasticizer is as follows:

(33) ##STR00012##

Test Example

(34) 1. Cement Paste Fluidity Test

(35) A cement paste fluidity test is performed respectively on the samples obtained from embodiments 1-8 according to GB 8077-2000 Methods for Testing Uniformity of Concrete Admixture. The results are shown in Table 1. The water-cement ratio (W/C) is 0.29, and the dosage (solid content) of admixture is 0.10% of the amount of cement.

(36) There is no significant loss of cement paste fluidity within 1 h.

(37) TABLE-US-00001 TABLE 1 Cement paste fluidity and gradual loss of different samples Cement paste fluidity/mm Sample Dosage 0 h 1 h 1 0.10% 206 203 2 208 201 3 216 212 4 205 205 5 219 209 6 207 204 7 217 212 8 226 213

(38) 2. Concrete Performance Test

(39) Tests including slump loss and concrete early-strength are performed on the samples obtained from embodiments 1-8 according to GB8076-2008 Concrete Admixtures. Ordinary polycarboxylate superplasticizer is set as a blank sample. The results are shown in Table 2. When the dosage (solid content) of admixture is 1.2% (relative to the amount of cement), the water-reducing ratios are all higher than 40%, the compressive strengths measured at 1st day are all increased by more than 92%, and the compressive strengths measured at 3rd day are all increased by more than 60%.

(40) TABLE-US-00002 TABLE 2 Concrete slump retention and early mechanical performance of different samples Slump (mm)/expansion Compressive degree (mm) strength/MPa sample Dosage 0 h 1 h 1 d 3 d 7 d Blank 1.2% 200/455 — 16.7 21.6 42.1 sample 1 210/515 180/455 28.2 34.6 44.5 2 205/510 185/465 29.1 35.5 45.3 3 205/515 180/455 28.2 35.6 46.2 4 205/510 180/445 29.4 36.8 45.1 5 210/515 190/465 29.4 39.5 46.7 6 210/520 195/475 28.1 38.3 45.8 7 205/510 185/455 27.1 37.4 44.9 8 210/510 200/470 26.1 36.7 45.6

(41) Obviously, the above described embodiments are only a part of the preferred embodiments of the present invention, not all of them. Based on the embodiments of the present invention, modifications, replacements and improvements made by a person skilled in the art without creative labor shall fall within the scope of protection of the present invention.