Preparation method of pH responsive polycarboxylic acid of comb-shaped structure

A comb-like structure, polycarboxylic acid technology, applied in the field of pH-responsive polycarboxylic acid for cement concrete, achieves the effects of low energy consumption, easy industrial production and low price

Active Publication Date: 2019-01-18
BEIJING UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, this requires the synthetic pH-responsive polycarboxylate material to realize the innovation of molecular structure, which can not only have application properties such as shrinkage reduction and crack resistance according to the change of the pH environment of cement concrete, but also ensure convenient process operation and low cost. Preparation cost, simple and easy-to-obtain reaction raw materials are conducive to industrial production and popularization and application, and there are no reports on this aspect of work at home and abroad

Method used

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  • Preparation method of pH responsive polycarboxylic acid of comb-shaped structure
  • Preparation method of pH responsive polycarboxylic acid of comb-shaped structure
  • Preparation method of pH responsive polycarboxylic acid of comb-shaped structure

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] First, 90g of N,N-dimethylformamide, 30g of ethyl acrylate and 32.75g of isooctyl 3-mercaptopropionate were added to the reactor, stirred and heated to 60°C, then 5.96g of azobisisoheptanonitrile was added dropwise Mix the solution with 8.94g N,N-dimethylformamide for 10 hours, and continue to react at a constant temperature of 60°C for 5 hours after the dropwise addition to obtain a polyethylacrylate solution of the self-polymerized product; adjust the temperature of the obtained self-polymerized product to 60°C , add 24.29g of tert-dodecyl mercaptan and stir for 35 minutes until it is evenly mixed, then add dropwise 377.31g of dimethylaminoethyl methacrylate, 29.80g of azobisisoheptanonitrile and 44.71g of N,N-dimethyl Dimethylformamide mixed solution for 10 hours, continue to react at constant temperature at 60°C for 5 hours after the dropwise addition, and then distill under reduced pressure to remove N,N-dimethylformamide to obtain graft copolymerization product; 40...

Embodiment 2

[0036] First, 30g of tetrahydrofuran, 30g of methyl acrylate and 12.54g of isopropanol were added to the reactor, stirred and heated to 50°C, and then a mixed solution of 2.86g of azobisisobutyronitrile and 2.86g of tetrahydrofuran was added dropwise for 12 hours. After the addition, continue to react at a constant temperature of 50°C for 6 hours to obtain a self-polymerized product polymethyl acrylate solution; adjust the temperature of the obtained self-polymerized product to 50°C, add 35.22g of n-dodecyl mercaptan and stir for 40 minutes until it is mixed Evenly, add dropwise a mixed solution of 498.27g dimethylaminoethyl acrylate, 28.57g azobisisobutyronitrile and 28.57g tetrahydrofuran for 12 hours, continue to react at a constant temperature of 50°C for 6 hours after the dropwise addition, and then distill under reduced pressure to remove Tetrahydrofuran to obtain graft copolymerization product; mix 528.27g graft copolymerization product with 62.64g deionized water, stir ...

Embodiment 3

[0038] First, 270g dimethyl sulfoxide, 30g amyl acrylate and 1.27g isopropanol were added to the reactor, stirred and heated to 70°C, then 6.56g tert-butyl peroxybenzoate and 59.02g dimethyl Mix the solution of sulfoxide for 8 hours, continue to react at a constant temperature of 70°C for 4 hours after the dropwise addition, and obtain a polyamyl acrylate solution of the self-polymerized product; adjust the temperature of the obtained self-polymerized product to 80°C, and add 32.03g of n-dodecyl Mercaptan and stirred for 25 minutes until it is evenly mixed, then add dropwise a mixed solution of 66.55g 4-vinylpyridine, 19.67g tert-butyl peroxybenzoate and 177.04g dimethyl sulfoxide for 6 hours, and continue to keep the temperature after the dropwise addition React at 80°C for 3 hours, then distill off dimethyl sulfoxide under reduced pressure to obtain a graft copolymerization product; mix 96.55g of graft copolymerization product with deionized water, stir and raise the temperat...

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Abstract

The invention relates to a preparation method of a pH responsive polycarboxylic acid of a comb-shaped structure. The preparation method comprises the following steps: by taking acrylate and a pH responsive monomer as raw materials, preparing a polycarboxylic acid material by self-polymerization and graft copolymerization and hydrolysis: by taking acrylate as a reaction monomer, carrying out polymerization under the action of an initiator and a chain transfer agent to generate polyacrylate with controllable molecular weight and then copolymerizing with the pH responsive monomer to obtain a grafted copolymer taking the polyacrylate polymer as a main chain and the pH responsive polymer as a side chain; and finally, hydrolyzing the grafted copolymer to prepare the polycarboxylic acid of the comb-shaped structure taking polyacrylic acid as the main chain and the pH responsive polymer as the side chain. The preparation method is mild in condition and energy-saving and efficient. By introducing the pH responsive polymer by means of a molecular structural design, the polycarboxylic acid with a special functional side chain is synthesized, so that a pH responsive behavior is achieved successfully. The polycarboxylic acid shows an excellent characteristic of inhibiting shrinkage of cement mortar and has a wide market prospect and a popularizing and applying potential.

Description

technical field [0001] The invention relates to the technical field of pH-responsive polycarboxylic acid for cement concrete, in particular to a comb-shaped polycarboxylic acid material synthesized by self-polymerization of acrylic monomers and then grafting of pH-responsive monomers by hydrolysis specific preparation method. Background technique [0002] Concrete is currently one of the most widely used building materials in the field of construction engineering. It is an important structural engineering material, but it is prone to shrinkage and deformation in a dry environment with low water content, resulting in cracking and other defects in hardened concrete. Cracks in large foundation slabs, building exterior walls, underground structures, floor slabs, and beams are relatively common quality problems in construction projects. With the continuous development of green concrete and high-strength concrete, the types of concrete are changing with each passing day. However,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08F265/04C08F220/34C08F226/06C08F220/54C08F8/12C04B24/26C04B103/30
CPCC04B24/2688C04B2103/006C04B2103/302C08F8/12C08F265/04C08F220/34C08F226/06C08F220/54
Inventor 刘晓许谦赖光洪管佳男王子明张琳
Owner BEIJING UNIV OF TECH
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