CN105273131A - Preparation method of cationic polyacrylamide emulsion - Google Patents

Abstract

The invention relates to a preparation method of a cationic polyacrylamide emulsion, which comprises the following steps: respectively adding polyethylene glycol, acrylamide and cationic monomer acrylamide group (2-hydroxyl) propyltrimethylammonium chloride into deionized water , dimethyl diallyl ammonium chloride and additives β-dimethylaminopropionitrile, urea, stir to dissolve, and mix well; feed high-purity nitrogen to remove oxygen, add initiator ammonium persulfate, sodium formaldehyde sulfoxylate and V -50, stirring reaction to obtain a polymer emulsion product. The beneficial effect of the present invention is that: a cationic polyacrylamide emulsion product with low production cost, low viscosity, uniform particle size distribution and high stability is prepared by adopting a novel cationic monomer through a two-phase dispersion polymerization method.

Description

A kind of preparation method of cationic polyacrylamide emulsion

technical field

The invention relates to a preparation method of cationic polyacrylamide emulsion.

Background technique

Cationic polyacrylamide is a copolymer composed of a cationic unit and acrylamide non-ionic unit. Its molecular chain has positively charged groups that can be ionized, and can be ionized into polycations and small anions in water. Adsorption and bridging of suspended particles in the solution has a strong flocculation effect. Cationic polyacrylamide is widely used in water treatment, metallurgy, papermaking, petroleum, chemical industry, textile, mineral processing and other fields. Cationic polyacrylamide is especially suitable for dehydration treatment of municipal sewage, municipal sludge, paper sludge and other industrial sludge.

As far as the current technology is concerned, homogeneous aqueous solution polymerization is still mostly used to produce solid cationic polyacrylamide products. However, the advantages of preparing cationic polyacrylamide emulsions by two-phase dispersion polymerization have begun to attract the attention of merchants, and this method has emerged one after another to synthesize emulsions. product. In the aqueous two-phase dispersion polymerization method, the particle size distribution of the product cannot be well controlled at present, and the problems of low stability and high viscosity of the dispersion have not been well resolved. At the same time, comonomers mostly use methacryloyloxyethyltrimethylammonium chloride or acryloyloxyethyltrimethylammonium chloride. Due to high purity and quality requirements, they rely on imports and are relatively expensive. When mass production Costs are hard to come down. Therefore, we prepare and select suitable cheap monomers to study the two-phase aqueous phase terpolymerization method of acrylamide and two cationic monomers, and develop new cationic polyacrylamide emulsion products.

Contents of the invention

The technical problem to be solved by the present invention is: based on the above problems, the present invention provides a preparation method of cationic polyacrylamide emulsion.

A technical solution adopted by the present invention to solve its technical problem is: a kind of preparation method of cationic polyacrylamide emulsion, comprises the following steps:

(1) Add polyethylene glycol, acrylamide, cationic monomer acrylamido (2-hydroxyl) propyl trimethyl ammonium chloride, dimethyl diallyl ammonium chloride and auxiliary agent β respectively in deionized water - Dimethylaminopropionitrile, urea, stir to dissolve, and mix well;

(2) adjusting the pH value of the solution system in step (1) with dilute nitric acid is 3～5;

(3) Passing high-purity nitrogen gas to drive away dissolved oxygen in the solution, adding initiator ammonium persulfate, sodium formaldehyde sulfoxylate and V-50, stirring and reacting at 40°C for 3-4 hours to obtain a polymer emulsion product.

Further, in step (1), relative to the deionized water in the system, the polyethylene glycol content is 12-14%, the acrylamide content is 12-14%, and the cationic monomer acrylamide group (2 -Hydroxy) propyl trimethyl ammonium chloride content is 2-3%, dimethyl diallyl ammonium chloride content is 1.2-1.4%, polyethylene glycol molecular weight is 20000.

Further, in step (1), β-dimethylaminopropionitrile accounts for 0.020-0.025% of the total mass of monomers, urea accounts for 5.5-6.5% of the total mass of monomers, and the total mass of monomers is acrylamide, cationic monomer propylene The mass sum of the three monomers of amido (2-hydroxyl) propyl trimethyl ammonium chloride and dimethyl diallyl ammonium chloride.

Further, the dilute nitric acid volume concentration is 50% in the step (2).

Further, in step (3), ammonium persulfate, sodium formaldehyde sulfoxylate and V-50 all account for 0.35-0.40% of the total mass of monomers, and the total mass of monomers is acrylamide, cationic monomer acrylamide group (2-hydroxyl) The mass sum of the three monomers of propyl trimethyl ammonium chloride and dimethyl diallyl ammonium chloride.

The beneficial effect of the present invention is that: a cationic polyacrylamide emulsion product with low production cost, low viscosity, uniform particle size distribution and high stability is prepared by adopting a novel cationic monomer through a two-phase dispersion polymerization method.

detailed description

The present invention will now be further described in conjunction with specific examples, and the following examples are intended to illustrate the present invention rather than further limit the present invention.

Example 1

(1) prepare 13% polyethylene glycol solution 150ml, stir;

(2) Add 20 g of acrylamide, 50% of cationic monomer acrylamide (2-hydroxyl) propyl trimethylammonium chloride solution 5ml, 60% of dimethyl diallyl ammonium chloride to the above solution Solution 3ml, and β-dimethylaminopropionitrile 6mg, urea 1g, stir to dissolve, mix well;

(3) adjust solution pH value to be 3 with 50% nitric acid, change in the reactor;

(4) Feed into high-purity nitrogen for 20 minutes, add initiator 2% ammonium persulfate solution 4ml, 2% sodium formaldehyde sulfoxylate solution 4ml and 2% V-50 solution 4ml;

(5) Heating to 40° C. in a water bath, stirring and reacting for 3.5 hours to obtain an emulsion product.

Example 2

(1) prepare 14% polyethylene glycol solution 150ml, stir;

(2) Add acrylamide 22g, 50% cationic monomer acrylamido (2-hydroxyl) propyl trimethyl ammonium chloride solution 8ml, 60% dimethyl diallyl ammonium chloride to the above solution Solution 5ml, and β-dimethylaminopropionitrile 7mg, urea 1g, stir to dissolve, mix well;

(3) the solution pH value is 5 with 50% dilute nitric acid, and is transferred to the reactor;

(4) Feed high-purity nitrogen for 20 minutes, add initiator 2% ammonium persulfate solution 5ml, 2% sodium formaldehyde sulfoxylate solution 5ml and 2% V-50 solution 5ml;

(5) Heating to 40° C. in a water bath, stirring and reacting for 3 hours to obtain an emulsion product.

Example 3

(1) prepare 12% polyethylene glycol solution 150ml, stir;

(2) Add acrylamide 18g, 50% cationic monomer acrylamido (2-hydroxyl) propyl trimethyl ammonium chloride solution 4ml, 60% dimethyl diallyl ammonium chloride to the above solution Solution 4ml, and β-dimethylaminopropionitrile 8mg, urea 1g, stir to dissolve, mix well;

(3) adjust the solution pH value to 4 with 50% dilute nitric acid, and transfer it to the reactor;

(4) Feed into high-purity nitrogen for 20 minutes, add initiator 2% ammonium persulfate solution 4.5ml, 2% sodium formaldehyde sulfoxylate solution 4.5ml and 2% V-50 solution 4.5ml;

(5) Heating to 40° C. in a water bath, stirring and reacting for 4 hours to obtain an emulsion product.

This process adopts two-phase aqueous system polymerization, no three wastes are discharged during the synthesis process, the heating temperature is not high, and the final product does not need to be heated and dried, which is energy-saving and environmentally friendly.

The cationic monomer dimethyl diallyl ammonium chloride has good structure and performance, and the formation of copolymers has the advantages of high positive charge density, good water solubility, high efficiency, non-toxicity, and low cost, but its activity is low, and it is difficult to form high molecular weight polymers affect the flocculation performance. Adding cationic monomer acrylamide group (2-hydroxyl) propyltrimethyl ammonium chloride has high reactivity and is easy to polymerize. The structure contains hydroxyl groups, which can improve the flocculation performance of the product.

Using more effective ammonium persulfate, sodium formaldehyde sulfoxylate and V-50 redox-azo compound composite initiation system, through the addition of additives, a new type of cationic polymer with good solubility, good emulsion stability and excellent flocculation performance is prepared. Acrylamide products.

The cost of the synthesis method is reduced, and compared with conventional cationic monomers, the cost per ton of the product is reduced by about 1,000 yuan. The stability of the emulsion is improved, the stability is more than half a year, the monomer residue is less than 1%, and the flocculation performance is better than similar emulsion products and solid cationic polyacrylamide products. In the treatment of 0.1% bentonite simulated wastewater, when the addition amount of cationic polyacrylamide is 4mg/L, it shows a good flocculation effect, and the turbidity is less than 20NTU.

Inspired by the above-mentioned ideal embodiment according to the present invention, through the above-mentioned description content, relevant workers can make various changes and modifications within the scope of not departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, but must be determined according to the scope of the claims.

Claims (5)

1. a kind of preparation method of cationic polyacrylamide emulsion is characterized in that: comprise the following steps: (1) Add polyethylene glycol, acrylamide, cationic monomer acrylamido (2-hydroxyl) propyl trimethyl ammonium chloride, dimethyl diallyl ammonium chloride and auxiliary agent β respectively in deionized water - Dimethylaminopropionitrile, urea, stir to dissolve, and mix well; (2) adjusting the pH value of the solution system in step (1) with dilute nitric acid is 3～5; (3) Passing high-purity nitrogen gas to drive away dissolved oxygen in the solution, adding initiator ammonium persulfate, sodium formaldehyde sulfoxylate and V-50, stirring and reacting at 40°C for 3-4 hours to obtain a polymer emulsion product. 2. the preparation method of a kind of cationic polyacrylamide emulsion according to claim 1 is characterized in that: in described step (1), with respect to the deionized water in the system, by mass percentage, polyethylene glycol The content is 12-14%, the content of acrylamide is 12-14%, the content of cationic monomer acrylamido (2-hydroxyl) propyl trimethyl ammonium chloride is 2-3%, and the content of dimethyl diallyl chloride The content of ammonium chloride is 1.2-1.4%, and the molecular weight of polyethylene glycol is 20000. 3. the preparation method of a kind of cationic polyacrylamide emulsion according to claim 1 is characterized in that: in the described step (1), β-dimethylaminopropionitrile accounts for 0.020～0.025% of the total monomer mass, Urea accounts for 5.5-6.5% of the total mass of monomers, and the total mass of monomers is acrylamide, cationic monomers acrylamido (2-hydroxyl) propyl trimethyl ammonium chloride and dimethyl diallyl ammonium chloride The sum of the masses of the three monomers. 4. the preparation method of a kind of cationic polyacrylamide emulsion according to claim 1 is characterized in that: in the described step (2), the volume concentration of dilute nitric acid is 50%. 5. the preparation method of a kind of cationic polyacrylamide emulsion according to claim 1 is characterized in that: in described step (3), ammonium persulfate, sodium formaldehyde sulfoxylate and V-50 all account for monomer gross mass 0.35-0.40%, the total mass of the monomer is the sum of the mass of the three monomers of acrylamide, cationic monomer acrylamido (2-hydroxy) propyl trimethyl ammonium chloride and dimethyl diallyl ammonium chloride .