CN115785347A

CN115785347A - Salt-tolerant thickening agent and preparation method thereof

Info

Publication number: CN115785347A
Application number: CN202211403740.0A
Authority: CN
Inventors: 赵宇
Original assignee: Ocean University of China
Current assignee: Ocean University of China
Priority date: 2022-11-10
Filing date: 2022-11-10
Publication date: 2023-03-14

Abstract

The invention belongs to the technical field of high polymer materials, and discloses a salt-tolerant thickening agent and a preparation method thereof.

Description

Salt-tolerant thickening agent and preparation method thereof

Technical Field

The invention belongs to the technical field of high polymer materials, and particularly relates to a salt-tolerant thickening agent and a preparation method thereof.

Background

The earliest thickeners were mostly natural water soluble thickeners such as algin and the like. The thickening agent has the advantages of low yield, high cost and poor thickening performance, so the application range of the thickening agent is greatly restricted. The second generation subsequently gradually replaced the first generation thickener. Most of the thickeners are emulsion thickeners, particularly W/O type emulsion thickeners are widely applied in some industrial fields, but a large amount of kerosene is needed in the process of producing and manufacturing the emulsion thickeners, so that the environment is not protected, and the cost is high. Because of these problems and deficiencies, the third generation thickener, a synthetic thickener, was soon after its advent to replace the previous generation thickeners. The synthetic thickeners are developed most rapidly as acrylic (co) polymer-based thickeners. The COODRICH company in the fifties of the twentieth century commercialized the artificially prepared polyacrylic thickeners first, and the related work in China on the artificially synthesized thickeners began in the seventies of the twentieth century.

Because the related production technology is strictly blocked by related foreign institutions, reports on the preparation method of the high-performance thickening agent and specific components of related products are few, and reports and descriptions on the thickening performance are common. The thickening agent synthesized at present stage in China has thickening performance and salt resistance to be further improved ^[7-8] 。

The polyacrylic acid has the advantages of low toxicity, obvious thickening effect, environmental friendliness and the like, so that the acrylic acid thickener has wide application prospects in the fields of medicine and health, food, cosmetics and the like. Although a simple polyacrylic acid thickener has excellent thickening performance and high light transmittance, when salt substances such as sodium chloride exist in the thickener system, the viscosity of the thickener system is rapidly reduced and even disappears. Therefore, the improvement of the salt tolerance of the thickener becomes a problem to be solved urgently by researchers at home and abroad.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a salt-tolerant thickening agent and a preparation method thereof.

In order to solve the technical problems, the invention adopts the technical scheme that:

a preparation method of a salt-tolerant thickener takes acrylic acid as a monomer, takes octadecyl methacrylate, acrylamide, allyl polyoxyethylene ether, 2-acrylamide-2-methylpropanesulfonic acid and maleic anhydride as comonomers, and adopts a precipitation polymerization method to synthesize the salt-tolerant thickener, which comprises the following steps:

step 1, adding a mixed solvent A liquid consisting of n-hexane, methyl acetate and ethyl acetate into a three-neck flask with a stirrer and a reflux device in a water bath at 50 ℃, and refluxing for 8-12 min under electric stirring, wherein the volume ratio of the n-hexane to the methyl acetate to the ethyl acetate is 1;

and 2, adding a mixed solution B consisting of acrylic acid, octadecyl methacrylate, acrylamide, allyl polyoxyethylene ether, 2-acrylamide-2-methylpropanesulfonic acid and maleic anhydride, and reacting for 15min, wherein the mass ratio of the acrylic acid to the octadecyl methacrylate to the acrylamide to the allyl polyoxyethylene ether to the 2-acrylamide-2-methylpropanesulfonic acid to the maleic anhydride is 200:5:6:10:6:2;

and 3, heating the water bath to 60 ℃, adding pentaerythritol triallyl ether, glyceryl monostearate and azobisisoheptonitrile, reacting for 40min after the reaction system turns to milk white, cooling to room temperature, performing suction filtration, drying the product at 40 ℃ in vacuum to constant weight, and crushing to obtain loose white solid powder.

Further, the raw materials of the thickening agent comprise, by weight, 60% -70% of a liquid A, 20% -30% of a liquid B, 0.01% -5% of pentaerythritol triallyl ether, 0.05% -5% of glycerol monostearate, and 0.02% -5% of azobisisoheptonitrile.

The invention also provides a salt-tolerant thickening agent obtained based on the preparation method of the salt-tolerant thickening agent.

Furthermore, the salt-tolerant thickening agent has a three-dimensional space structure, is powdery particles, has the particle size of 1-2 mu m, and has the initial viscosity of 60100mPa & s.

Further, the viscosity of the system was 27700 mPas when the concentration of sodium chloride was 2g/L, and was 4200 mPas when the concentration of sodium chloride was 5 g/L.

Compared with the prior art, the invention has the advantages that:

the acrylic acid thickening agent obtained by the preparation process has the characteristics of obvious thickening effect, small using amount and the like in the aspect of improving the viscosity of a water system, and has good salt tolerance and wide application range.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a structural formula of a polymer of the present invention;

FIG. 2 is an electron micrograph of a thickener according to an embodiment of the present invention magnified 40K times;

FIG. 3 is a relationship between thickener concentration and system viscosity for an example of the present invention;

FIG. 4 is a graph of viscosity versus pH for two thickener systems of the examples;

FIG. 5 is a salt viscosity resistance curve for the three thickener systems of the examples.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments.

Example 1

A preparation method of a salt-tolerant thickener takes Acrylic Acid (AA) as a monomer, takes octadecyl methacrylate (SMA), acrylamide (AM), allyl Polyoxyethylene Ether (APEG), 2-acrylamide-2-methylpropanesulfonic Acid (AMPS), maleic Anhydride (MA) and other six raw materials as comonomers, takes pentaerythritol triallyl ether (APE) as a cross-linking agent, and adopts a precipitation polymerization method to synthesize the polyacrylic thickener with a three-dimensional structure. The method specifically comprises the following steps:

step 1, adding 120ml of mixed solvent A liquid consisting of n-hexane, methyl acetate and ethyl acetate into a three-neck flask with a stirrer and a reflux device under a water bath at 50 ℃, and refluxing for 8-12 min under electric stirring, wherein the volume ratio of the n-hexane to the methyl acetate to the ethyl acetate is 1.

And 2, adding 40ml of mixed solution B consisting of acrylic acid, octadecyl methacrylate, acrylamide, allyl polyoxyethylene ether, 2-acrylamide-2-methylpropanesulfonic acid and maleic anhydride, and reacting for 15min, wherein the mass ratio of the acrylic acid, the octadecyl methacrylate, the acrylamide, the allyl polyoxyethylene ether, the 2-acrylamide-2-methylpropanesulfonic acid and the maleic anhydride is 200:5:6:10:6:2;

and step 3, heating the water bath temperature to 60 ℃, adding 0.5ml of pentaerythritol triallyl ether, 0.1g of glyceryl monostearate and 0.08g of Azobisisoheptonitrile (ABVN), reacting for 40min after the reaction system becomes milky, cooling to room temperature, performing suction filtration, drying the product at 40 ℃ in vacuum to constant weight, and crushing to obtain loose white solid powder.

The acrylic acid hexahydric polymer is a salt-tolerant thickener P (AA/APEG/AM/AMPS/MA/SMA), and the structural formula is shown in figure 1 (in the figure, R represents a polymer long chain).

Example 2

In this example, the proportions of the added components are 60% of the solution a, 30% of the solution B, 3% of pentaerythritol triallyl ether, 4% of glycerol monostearate, and 3% of azobisisoheptonitrile, and the preparation process is the same as that in example 1, and details are not repeated here.

Example 3

In this example, the proportions of the added components are 70% of the solution a, 20% of the solution B, 5% of pentaerythritol triallyl ether, 3% of glycerol monostearate, and 2% of azobisisoheptonitrile, and the preparation process is the same as that in example 1, and details are not repeated here.

Example 4

This example also provides a salt-tolerant thickener P (AA/SMA/AM/MA/APEG/AMPS) obtained by the method of preparing a salt-tolerant thickener according to example 1, which is in the form of powder particles having a particle size of 1 to 2 μm.

The technical effects of the present invention will be described below with reference to specific test data.

As shown in figure 2, the thickening agent powder is fine solid particles which are loosely distributed, the particles are uniformly dispersed with each other, and obvious adhesion and agglomeration phenomena are not generated.

Table 1 below shows the results of gel permeation chromatogram analysis of thickener P of the present invention (AA/SMA/AM/MA/APEG/AMPS).

TABLE 1 gel permeation chromatogram analysis results of thickeners

From the results of gel chromatogram analysis, it was found that: the thickener P (AA/SMA/AM/MA/APEG/AMPS) has a large molecular weight and a narrow molecular weight distribution, and the weight-average molecular weight (Mw) is 8.315 × 10 ³ (ii) a The molecular weight distribution (Mw/Mn) was 1.201.

As can be seen from the relationship between the concentration of the thickener P (AA/SMA/AM/MA/APEG/AMPS) and the viscosity of the system shown in FIG. 3, when the mass fraction is less than 0.25%, the viscosity of the aqueous solution of the thickener is not changed obviously; when the mass fraction is more than 0.25%, the viscosity of the solution rapidly increases.

Figure 4 shows the viscosity versus pH relationship for two thickener systems, with the viscosity of both P (AA/SMA) and P (AA/SMA/AM/MA/APEG/AMPS) aqueous solutions reaching a maximum at pH =7, with viscosities of 139100mPa · s and 87500mPa · s, respectively. When the pH is less than 6 or greater than 8, the solution concentration decreases to various degrees.

FIG. 5 shows the viscosity of the three thickeners as a function of NaCl concentration, the viscosity of the aqueous solutions of the three thickeners all decreasing with increasing NaCl concentration. The P (AA/SMA) system is most sensitive to NaCl, and the thickening agents P (AA/SMA/AM) and P (AA/SMA/AM/MA/APEG/AMPS) prepared by the invention have lower sensitivity to NaCl.

The performance test shows that: compared with the existing acrylic acid terpolymer, the white powdery acrylic acid hexatomic copolymer salt-resistant thickener P (AA/APEG/AM/AMPS/MA/SMA) obtained by the process has improved thickening performance and salt resistance. Although the addition amount of several comonomers is not very large, the salt resistance of the thickening agent is greatly improved, and the thickening agent with the best thickening performance and salt resistance is obtained through orthogonal experiments and single-factor experiments. The initial viscosity was 60100 mPas, the viscosity of the system was 27700 mPas when the concentration of sodium chloride was 2g/L, and the viscosity of the system was 4200 mPas when the concentration of sodium chloride was 5 g/L.

The thickener prepared by the invention has the characteristics of obvious thickening effect, small using amount and the like in the aspect of improving the viscosity of a water system, is used as a novel functional polymer material, and is widely applied to the fields of medical treatment and health, food, cosmetics, batteries, coatings, rubber, oil extraction and the like.

It is understood that the above description is not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art should understand that they can make various changes, modifications, additions and substitutions within the spirit and scope of the present invention.

Claims

1. A preparation method of a salt-tolerant thickener is characterized in that acrylic acid is taken as a monomer, octadecyl methacrylate, acrylamide, allyl polyoxyethylene ether, 2-acrylamide-2-methylpropanesulfonic acid and maleic anhydride are taken as comonomers, and the salt-tolerant thickener is synthesized by a precipitation polymerization method, and specifically comprises the following steps:

step 1, adding a mixed solvent A liquid consisting of n-hexane, methyl acetate and ethyl acetate into a three-neck flask with a stirrer and a reflux device in a water bath at 50 ℃, and refluxing for 8-12 min under electric stirring, wherein the volume ratio of the n-hexane to the methyl acetate to the ethyl acetate is 1:1:1;

2. The preparation method of the salt-tolerant thickener according to claim 1, wherein the raw materials of the thickener comprise, by weight, 60% -70% of solution A, 20% -30% of solution B, 0.01% -5% of pentaerythritol triallyl ether, 0.05% -5% of glycerol monostearate, and 0.02% -5% of azobisisoheptonitrile.

3. A salt-tolerant thickener obtained based on the preparation method of the salt-tolerant thickener according to claim 1 or 2.

4. The salt-tolerant thickener of claim 3, wherein the thickener has a three-dimensional structure, is a powdery particle having a particle size of 1 to 2 μm, and has an initial viscosity of 60100mPa · s.

5. The salt-tolerant thickener of claim 4, wherein the viscosity of the system is 27700 mPa-s at a sodium chloride concentration of 2g/L and 4200 mPa-s at a sodium chloride concentration of 5 g/L.