Acrylamide-acrylic acid (salt) copolymer

[Preparation method] The preparation methods of acrylamide-acrylic acid (salt) copolymer mainly include aqueous solution polymerization, inverse emulsion polymerization and inverse suspension polymerization
.

(1) Aqueous polymerization

ChenHaun-lin uses aqueous solution polymerization to prepare acrylamide ammonium acrylate copolymer, and the Brookfield viscosity of the product can reach 1420mPa·s
.

The specific process is: adding 774.
57g deionized water, about 38.
49g 54.
5% acrylamide solution, and about 15g 5% ethylenediaminetetraacetic acid disodium solution in a reactor equipped with a stirring device, thermocouple and nitrogen system.
And about 408.
11g 99% acrylic monomer, use 303.
66g 30% ammonium hydroxide solution to adjust the pH value of the above mixed solution to 5.
75, pass nitrogen protection, and reduce the system temperature to 6°C
.

After about 40 minutes, add 67.

In addition, domestic scientific researchers also use aqueous solution polymerization to prepare high molecular weight polyacrylamide
.

Ji Hongjian et al.

(2) Inverse emulsion polymerization

There are two products of acrylamide-acrylic acid (sodium) copolymer prepared by inverse emulsion method: latex and powder
.

The specific process of powdered acrylamide sodium acrylate copolymer product is: first neutralize acrylic acid with NaOH solution, and then add acrylamide to prepare monomer solution; then a 250mL four-necked reaction flask is equipped with a stirrer, temperature control probe, thermometer, Airway
.

Flask were sequentially added to the monomer solution, sodium dodecyl sulfate, stirred and mixed, while passing nitrogen flooding oxygen 20min, after the addition of sodium bisulfite , Span80, petroleum ether and peroxide; warmed to system At the reaction temperature, the monomer is polymerized for 4 hours, then the temperature is increased, and the azeotropic dehydration is performed.

The preparation process of the acrylamide acrylic copolymer latex product is: a 0.
5L four-neck bottle is equipped with a stirrer, a reflux condenser, a thermometer, an air duct and a sampler, and is placed in a super constant temperature water bath to emulsify the compound Add solvent oil and 200# solvent oil to a four-necked bottle in turn, replace with nitrogen for 30 minutes, heat on a water bath and stir to completely dissolve it; then gradually add the deoxygenated monomer aqueous solution to the oil phase while stirring at high speed (400r/min) emulsify it to form an emulsion.
After the emulsification operation, reduce the stirring speed (200r/min), add the toluene solution of azobisisobutyronitrile (AIBN), keep it at 45℃ for 4h, and then add ( NH ₄ ) ₂ S ₂ O ₈ /Na ₂ S ₂ O ₅ redox initiator, continue the reaction at the same temperature for 2 hours; after the reaction is finished, it is cooled to room temperature and terminator is added, and the stirring is stopped to obtain a uniform and stable W/O type acrylamide-sodium acrylate copolymer latex product
.

(3) Inverse suspension polymerization

Acrylamide-sodium acrylate copolymer can be prepared by aqueous solution polymerization method, inverse emulsion polymerization method and inverse suspension polymerization method.
The acrylamide sodium acrylate copolymer on the domestic market is mainly a product of aqueous solution polymerization, which has slow dissolution and incomplete dissolution.
And other shortcomings
.

The inverse emulsion polymerization method is conducive to the dissipation of reaction heat, can prepare products with high molecular weight and good solubility, but the process is more complicated, the production cost is high, it is difficult to prepare a stable emulsion, and the transportation of milky products is inconvenient

Zhang Zhongxing et al.
used acrylamide and sodium acrylate as monomers to conduct a pilot study on the synthesis of anionic polyacrylamide by inverse suspension free radical copolymerization, and obtained an ultra-high molecular weight with a relative molecular mass of 1.
45×10 ⁷ Acrylamide-sodium acrylate copolymer
.

The specific process is as follows

In addition, they also compared the different polymerization conditions between the pilot test and the laboratory test, determined the content of metal impurities copper and iron in the raw material acrylamide, and studied the raw material acrylamide in the organic complex ethylenediamine tetramine.
Copolymerization with sodium acrylate in the presence of disodium acetate (EDTA), and the effects of some factors such as initiator concentration and dehydration time on the molecular weight and solubility of the product under pilot conditions were studied
.

It was found that adding EDTA accounting for 0.

Liu Lianying et al.
synthesized a powdery, fast-dissolving anionic polyacrylamide with a relative molecular mass of 107, that is, acrylamide sodium acrylate copolymer, by using reversed-phase suspension polymerization, alkali hydrolysis, and azeotropic dehydration
.

The specific process is: adding cyclohexane and emulsifier into a three-necked reaction flask equipped with a reflux condenser and stirring, heating in a water bath to control the temperature until it is completely dissolved; weighing the metered acrylamide with deionized water to make a mass fraction of 50% The aqueous solution is added to the reaction flask; after the water phase and the oil phase are evenly dispersed, the initiator is dropped into the reaction vessel for 1.

Related links: Sodium methacrylate-2-acrylamido-2-methyl propane sulfonate copolymer