阅读说明：本技术 一种高吸水树脂及其制备方法 (Super absorbent resin and preparation method thereof ) 是由 李焕焕 毛萃 孟凡锦 霍晓楠 于 2019-09-04 设计创作，主要内容包括：本发明公开了一种高吸水树脂及其制备方法,所述的高吸水树脂,含有以下组分：丙烯酸、助吸盐单体、纳米纤维素、可降解天然高分子、引发剂、交联剂、氢氧化物、去离子水,所述高吸水树脂通过水溶液聚合,得到水凝胶后进行切割成块,烘箱干燥,经粉碎、筛分得高吸水树脂。本发明所制备的高吸水树脂生物降解率高,60天内降解率可达80％,且吸收量高、保水能力强、力学性能和耐盐性好,生产过程简单高效,可大幅减少环境污染,具有广阔的市场前景与较高的应用价值。(The invention discloses a super absorbent resin and a preparation method thereof, wherein the super absorbent resin comprises the following components: the super absorbent resin is prepared by the steps of polymerizing a water solution to obtain hydrogel, cutting the hydrogel into blocks, drying the hydrogel in an oven, crushing and screening the hydrogel, and then obtaining the super absorbent resin. The super absorbent resin prepared by the invention has high biodegradation rate, the degradation rate can reach 80% within 60 days, the absorption capacity is high, the water retention capacity is strong, the mechanical property and the salt tolerance are good, the production process is simple and efficient, the environmental pollution can be greatly reduced, and the super absorbent resin has wide market prospect and higher application value.)

1. A preparation method of super absorbent resin is characterized by comprising the following steps:

(1) weighing a certain amount of nano-cellulose, adding a proper amount of water, and uniformly stirring and dispersing to obtain nano-cellulose dispersion liquid;

(2) weighing a certain amount of acrylic acid, adding a hydroxide solution for neutralization, wherein the neutralization degree is 50-80%, taking a proper amount of salt absorption assisting monomers to completely dissolve the salt absorption assisting monomers in deionized water, adding the salt absorption assisting monomers into the solution, and uniformly stirring;

(3) weighing a certain amount of degradable natural polymer, uniformly stirring and completely dissolving the degradable natural polymer in water to obtain a colorless transparent solution, or weighing a certain amount of corn starch in a beaker, adding a proper amount of deionized water, stirring for gelatinization, and slowly cooling to obtain a gelatinized starch solution;

(4) and (3) adding the solution obtained in the step (1) and the solution obtained in the step (2) into the solution obtained in the step (3), stirring and mixing uniformly, adding a certain amount of initiator and cross-linking agent into the solution, slowly heating to a certain temperature, and preserving heat for 1-6 hours to initially prepare a crude product of the super absorbent resin.

(5) And (4) drying the crude product of the super absorbent resin obtained in the step (4), cutting the crude product into pieces, then crushing and granulating the pieces, screening the pieces by using a sieve, and drying the pieces again to constant weight to obtain the super absorbent resin.

2. The preparation method of claim 1, wherein the salt absorption enhancer monomer is one or more selected from acrylamide, acrylonitrile, and 2-acrylamide-2-methylpropanesulfonic acid.

3. The preparation method of claim 1, wherein the degradable natural polymer is one or more of carboxymethyl chitosan, chitosan quaternary ammonium salt, corn starch, sodium alginate and sodium carboxymethyl cellulose.

4. The method of claim 1, wherein the hydroxide is: sodium hydroxide or potassium hydroxide.

5. The method according to claim 1, wherein the initiator is any one of potassium persulfate, sodium persulfate, and ammonium persulfate.

6. The method of claim 1, wherein the crosslinking agent is N, N-methylene-bisacrylamide.

7. The method according to claim 1, wherein the salt-adsorbing monomer is added in an amount of 1 to 30 wt% based on the mass of acrylic acid.

8. The method according to claim 1, wherein the degradable natural polymer is added in an amount of 5 wt% to 40 wt% based on the total mass of the acrylic acid and the salt absorption enhancer monomer.

9. The method of claim 1, wherein the nanocellulose is added in an amount of 0.5 wt% to 20 wt% based on the total mass of acrylic acid and salt-absorbing monomer.

Technical Field

The invention belongs to the field of functional polymer materials, and particularly relates to a super absorbent resin and a preparation method thereof.

Background

Super Absorbent Polymer (SAP) is a new type of water insoluble polymer material with three-dimensional network cross-linked structure. The super absorbent resin can rapidly absorb liquid water which is hundreds of times or even thousands of times higher than the self-quality water through hydration, has good water retention capacity at normal temperature, is not easy to lose water even being heated or pressed, and has good stability in light, heat, acid and alkali. Therefore, compared with the traditional water-absorbing material, the super absorbent resin has the advantages of low crosslinking density, high water absorption expansion, high water retention property, strong absorption to alkalescent substances, insolubility in water and organic solvents, reusability and the like, becomes a research hotspot of functional polymer materials, and is widely applied to the fields of sanitary products such as sanitary towels, paper diapers, pet pads and the like, agriculture, food industry, petrochemical industry and the like.

The most widely used SAP in the market is non-degradable, and although the SAP has the advantages of simple production process, easy operation, low cost and the like, the SAP is difficult to decompose by microorganisms and bacteria in the nature, has poor biodegradability and inevitably causes huge pollution to the environment after being used in large quantities. With the enhancement of global environmental awareness, the research and development of biodegradable environment-friendly super absorbent resin has been increasingly paid attention. At present, the degradable super absorbent resin is mainly prepared by polymerizing corn starch, sodium alginate and sodium acrylate, but the mechanical strength of the super absorbent resin is reduced due to too large addition amount of the degradable material, and the degradation performance of the super absorbent resin is poor due to too small addition amount. The above problems must be overcome to achieve true degradation of the SAP, thereby reducing its environmental hazards.

The nano-cellulose is the physical minimum structural unit of cellulose, and refers to a fiber with the diameter of 1-100 nm. The nano cellulose is light in weight, degradable, and has the advantages of liquid absorption and retention property, high Young modulus, high strength, large specific surface area and the like, so that the nano cellulose has good application in various fields. By utilizing the characteristics of good biocompatibility, biodegradability, renewability, high reaction activity and the like of the nano-cellulose, the nano-cellulose is applied to the preparation of the degradable SAP, so that the physical property of the degradable SAP can be effectively enhanced, and the liquid absorption performance and the water retention performance are greatly improved.

Disclosure of Invention

In order to solve the problems, the invention provides a super absorbent resin and a preparation method thereof.

A high-hydroscopicity resin is prepared from acrylic acid, salt-absorbing monomer, nano cellulose and degradable natural high-molecular material. Firstly, neutralizing acrylic acid by adopting hydroxide, adding uniformly dispersed absorption-assisting salt monomer solution, degradable natural polymer solution and nano-cellulose solution, stirring and mixing uniformly, adding an initiator and a crosslinking agent, heating to 55-75 ℃, putting into an oven to polymerize for 1-3 h to obtain hydrogel, cutting into blocks, drying in the oven, crushing and screening to obtain the super absorbent resin. The preparation method comprises the following steps:

(1) weighing a certain amount of nano-cellulose, adding a proper amount of water, and uniformly stirring and dispersing to obtain nano-cellulose dispersion liquid;

(2) weighing a certain amount of acrylic acid, adding a hydroxide solution for neutralization, wherein the neutralization degree is 50-80%, taking a proper amount of salt absorption assisting monomers to completely dissolve the salt absorption assisting monomers in deionized water, adding the salt absorption assisting monomers into the solution, and uniformly stirring;

(3) weighing a certain amount of degradable natural polymer, uniformly stirring and completely dissolving the degradable natural polymer in water to obtain a colorless transparent solution, or weighing a certain amount of corn starch in a beaker, adding a proper amount of deionized water, stirring for gelatinization, and slowly cooling to obtain a gelatinized starch solution;

(4) and (3) adding the solution prepared in the step (1) and the solution prepared in the step (2) into the solution obtained in the step (3), stirring and mixing uniformly, adding a certain amount of initiator and cross-linking agent into the solution, slowly heating to a certain temperature, and preserving heat for 1-6 hours to initially prepare a crude product of the super absorbent resin.

(5) And (4) drying the crude product of the super absorbent resin obtained in the step (4), cutting the crude product into pieces, crushing and granulating the pieces, screening the pieces by using a screen, and drying the pieces again to constant weight to obtain the super absorbent resin.

Preferably, the addition amount of the salt absorption aid monomer is 1 to 30 weight percent of the mass of acrylic acid. .

Preferably, the degradable natural polymer can be: one or a mixture of any several of carboxymethyl chitosan, chitosan quaternary ammonium salt, corn starch, sodium alginate and sodium carboxymethyl cellulose in any ratio;

preferably, the hydroxide may be: sodium hydroxide or potassium hydroxide.

Preferably, the addition amount of the nano-cellulose is 0.5 wt% -20 wt% of the total mass of the acrylic acid and the salt absorption assisting monomer.

Preferably, the crosslinking agent in step (4) is N, N-methylene-bisacrylamide.

The invention has the beneficial effects that:

the invention controls the degradation capability of the super absorbent resin by adding the amount of the degradable natural high polymer, and introduces the nano-cellulose, thereby eliminating the defect that the mechanical strength of the water absorbent resin is reduced due to the large addition amount of the degradable high polymer. The nano-cellulose is used as a natural degradable material with large specific surface area and good hydrophilicity, can effectively improve the mechanical strength of the degradable super absorbent resin, and can improve the water absorption capacity and water retention capacity of SAP (super absorbent polymer), and the nano-cellulose and the SAP supplement each other, so that the prepared super absorbent resin has excellent degradability, large water absorption capacity and strong water retention capacity.

Detailed Description

Example 1

(1) Weighing 0.045g of nano-cellulose, adding a proper amount of water, and stirring and dispersing at 1000rpm for 20min to obtain nano-cellulose dispersion liquid;

(2) weighing 8g of acrylic acid, adding 15.54mL of 5mol/L sodium hydroxide solution for neutralization, dissolving 0.08g of 2-acrylamide-2-methylpropanesulfonic acid in deionized water completely, adding the solution into the sodium acrylate solution, and stirring uniformly;

(3) weighing 0.45g of carboxymethyl chitosan, completely dissolving the carboxymethyl chitosan in water, and uniformly stirring to obtain a colorless transparent solution;

(4) and (3) adding the solutions obtained in the steps (1) and (2) into the solution obtained in the step (3), stirring and mixing uniformly, adding 0.25g of potassium persulfate and 0.04g N of N-methylene-bisacrylamide into the solution, slowly heating to 65 ℃, and keeping the temperature for 3 hours to obtain a crude product of the super absorbent resin.

(5) And (3) putting the crude product of the super absorbent resin obtained in the step (4) into an oven at 80 ℃ for 1h, cutting the crude product, drying again, crushing and granulating, sieving by using a sieve of 40-80 meshes, and drying at 90 ℃ to constant weight to obtain the super absorbent resin.

Example 2

(1) Weighing 0.045g of nano-cellulose, adding a proper amount of water, and stirring and dispersing at 1000rpm for 20min to obtain nano-cellulose dispersion liquid;

(2) weighing 8g of acrylic acid, adding 15.54mL of 5mol/L sodium hydroxide solution for neutralization, dissolving 0.08g of 2-acrylamide-2-methylpropanesulfonic acid in deionized water completely, adding the solution into the sodium acrylate solution, and stirring uniformly;

(3) weighing 3.6g of carboxymethyl chitosan, completely dissolving the carboxymethyl chitosan in water, and uniformly stirring to obtain a colorless transparent solution;

(4) and (3) adding the solutions obtained in the steps (1) and (2) into the solution obtained in the step (3), stirring and mixing uniformly, adding 0.25g of potassium persulfate and 0.04g N of N-methylene-bisacrylamide into the solution, slowly heating to 65 ℃, and keeping the temperature for 3 hours to obtain a crude product of the super absorbent resin.

(5) And (3) putting the crude product of the super absorbent resin obtained in the step (4) into an oven at 80 ℃ for 3 hours, cutting the crude product, drying the crude product again, crushing and granulating the crude product, sieving the crushed product by using a sieve of 40-80 meshes, and drying the crushed product at 90 ℃ to constant weight to obtain the super absorbent resin.

Example 3

(1) Weighing 0.4g of nano-cellulose, adding a proper amount of water, stirring and dispersing at 1000rpm for 20min to obtain nano-cellulose dispersion liquid;

(2) weighing 8g of acrylic acid, adding 20mL of 7.5mol/L sodium hydroxide solution for neutralization, dissolving 0.4g of acrylamide in deionized water completely, adding the acrylamide solution into the sodium acrylate solution, and stirring uniformly;

(3) weighing 3g of corn starch in a beaker, adding 60mL of deionized water, stirring and gelatinizing at 90 ℃ for 30min, and then slowly cooling to 30 ℃ to obtain a gelatinized corn starch solution;

(4) and (3) adding the solutions obtained in the step (1) and the step (2) into the solution obtained in the step (3), stirring and mixing uniformly, adding 0.3g of potassium persulfate and 0.05g N, N-methylene-bisacrylamide into the solution, slowly heating to 65 ℃, and keeping the temperature for 6 hours to obtain a crude product of the super absorbent resin.

(5) And (3) putting the crude product of the super absorbent resin obtained in the step (4) into an oven at 80 ℃ for 4 hours, cutting the crude product, drying again, crushing and granulating, sieving by using a sieve of 40-80 meshes, and drying at 90 ℃ to constant weight to obtain the super absorbent resin.

Example 4

(1) Weighing 0.8g of nano-cellulose, adding a proper amount of water, stirring and dispersing at 1000rpm for 20min to obtain nano-cellulose dispersion liquid;

(2) weighing 8g of acrylic acid, adding 30mL of 10mol/L sodium hydroxide solution for neutralization, dissolving 0.8g of acrylonitrile in deionized water completely, adding the solution into the sodium acrylate solution, and stirring uniformly;

(3) weighing 1.77g of sodium carboxymethyl cellulose, completely dissolving the sodium carboxymethyl cellulose in water, and uniformly stirring to obtain a colorless transparent solution;

(4) and (3) adding the solutions obtained in the steps (1) and (2) into the solution obtained in the step (3), stirring and mixing uniformly, adding 1g of ammonium persulfate and 0.16g N, N-methylene-bisacrylamide into the solution, slowly heating to 55 ℃, and keeping the temperature for 2 hours to obtain a crude product of the super absorbent resin.

(5) And (3) putting the crude product of the super absorbent resin obtained in the step (4) into a 60 ℃ oven for 3 hours, cutting the crude product, drying the crude product again, crushing and granulating the crude product, sieving the crushed product by using a 40-80-mesh sieve, and drying the crushed product at 80 ℃ to constant weight to obtain the super absorbent resin.

Example 5

(1) Weighing 1.6g of nano-cellulose, adding a proper amount of water, stirring and dispersing at 1000rpm for 20min to obtain nano-cellulose dispersion liquid;

(2) weighing 8g of acrylic acid, adding 15.54mL of 5mol/L sodium hydroxide solution for neutralization, dissolving 1.6g of acrylonitrile in deionized water completely, adding the solution into the sodium acrylate solution, and stirring uniformly;

(3) weighing 3.84g of sodium alginate powder, completely dissolving the sodium alginate powder in water, and uniformly stirring to obtain a colorless transparent solution;

(4) and (3) adding the solution prepared in the step (1) and the solution prepared in the step (2) into the solution obtained in the step (3), stirring and mixing uniformly, adding 0.25g of potassium persulfate and 0.04g N of N-methylene-bisacrylamide into the solution, slowly heating to 75 ℃, and keeping the temperature for 5 hours to obtain a crude product of the super absorbent resin.

(5) And (3) putting the crude product of the super absorbent resin obtained in the step (4) into an oven at 80 ℃ for 5 hours, cutting the crude product, drying the crude product again, crushing and granulating the crude product, sieving the crushed product by using a sieve of 40 to 80 meshes, and drying the crushed product at 110 ℃ to constant weight to obtain the super absorbent resin.

Comparative example 1

(1) Weighing 8g of acrylic acid, adding 15.54mL of 5mol/L sodium hydroxide solution for neutralization, dissolving 12g of acrylamide in deionized water completely, adding the acrylamide solution into the sodium acrylate solution, and stirring uniformly;

(2) adding 0.25g of potassium persulfate and 0.04g N g of N-methylene-bisacrylamide into the solution, slowly heating to 65 ℃, and keeping the temperature for 3 hours to obtain a crude product of the super absorbent resin.

(3) And (3) putting the crude product of the super absorbent resin obtained in the step (2) into an oven at 80 ℃ for 3 hours, cutting the crude product, drying the crude product again, crushing and granulating the crude product, sieving the crushed product by using a sieve of 40-80 meshes, and drying the crushed product at 90 ℃ to constant weight to obtain the super absorbent resin.

Comparative example 2

(1) Weighing 8g of acrylic acid, adding 15.54mL of 5mol/L sodium hydroxide solution for neutralization, dissolving 0.08g of 2-acrylamide-2-methylpropanesulfonic acid in deionized water completely, adding the solution into the sodium acrylate solution, and stirring uniformly;

(2) weighing 3.6g of carboxymethyl chitosan, completely dissolving the carboxymethyl chitosan in water, and uniformly stirring to obtain a colorless transparent solution;

(3) and (3) adding the solution obtained in the step (1) into the solution obtained in the step (2), stirring and mixing uniformly, adding 0.25g of potassium persulfate and 0.04g N, N-methylene-bisacrylamide into the solution, slowly heating to 65 ℃, and keeping the temperature for 3 hours to obtain a crude product of the super absorbent resin.

(5) And (3) putting the crude product of the super absorbent resin obtained in the step (4) into an oven at 80 ℃ for 3 hours, cutting the crude product, drying the crude product again, crushing and granulating the crude product, sieving the crushed product by using a sieve of 40-80 meshes, and drying the crushed product at 90 ℃ to constant weight to obtain the super absorbent resin.

The following are the results of performance tests of absorption capacity, water retention capacity, absorption capacity under pressure, degradation rate and the like performed on the super absorbent resins prepared in examples 1 and 2 and comparative examples 1 and 2:

	example 1	Example 2	Comparative example 1	Comparative example 2
					Absorption capacity (g/g)	65.8	63.4	46.9	53.4
Water retention (g/g)	55.7	52.6	35.9	43.8
					Absorption capacity under pressure (g/g)	31	28	22	17
Degradation Rate (%) in 60 days	25	80	0	60

It can be seen from comparative examples 1 and 2 that the addition of the natural polymer can effectively degrade the prepared SAP;

as can be seen from the example 1, the comparative example 1 and the comparative example 2, the addition of the nanocellulose greatly improves the liquid absorption performance, the water retention capacity and the pressurized absorption capacity of the SAP, and can effectively promote the degradation of the SAP;

it can be seen from examples 1 and 2 that as the addition amount of the degradable polymer increases, the degradation rate of the SAP increases;

the above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.