阅读说明：本技术 一种超高分子量的阴离子聚丙烯酰胺的制备方法 (Preparation method of anionic polyacrylamide with ultrahigh molecular weight ) 是由 汤玉业 何国锋 王勤 方叔迈 谢金生 龚敏杰 于 2020-12-14 设计创作，主要内容包括：本发明公开一种超高分子量的阴离子聚丙烯酰胺的制备方法,包括以下步骤：步骤一、将原料丙烯酰胺与阴离子单体溶于水并调节pH值；步骤二、将步骤一的聚合液加入光引发剂、偶氮引发剂、脱氧剂、金属螯合剂、金属螯合促进剂、助溶剂和链转移剂,搅拌均匀后,再次调节聚合液的pH值,将聚合液降温并通过超微气泡发生器除氧,将除氧后的聚合物投入到带有惰性气体保护、紫外光引发的聚合装置上；步骤三、当聚合装置上的聚合物达到最高温度时,进入保温区保温,将保温后的聚合物切胶、造粒、烘干,再进一步研磨、筛分制成阴离子聚丙烯酰胺产品。本发明提供的连续传输紫外光引发聚合方式,能够一步合成高或者超高分子量的阴离子聚丙烯酰胺产品。(The invention discloses a preparation method of ultra-high molecular weight anionic polyacrylamide, which comprises the following steps: firstly, dissolving raw materials of acrylamide and an anionic monomer in water and adjusting the pH value; step two, adding a photoinitiator, an azo initiator, a deoxidizer, a metal chelating agent, a metal chelating accelerator, a cosolvent and a chain transfer agent into the polymerization solution obtained in the step one, uniformly stirring, adjusting the pH value of the polymerization solution again, cooling the polymerization solution, deoxidizing through an ultramicro bubble generator, and putting the polymer subjected to deoxidization onto a polymerization device with inert gas protection and ultraviolet light initiation; and step three, when the polymer on the polymerization device reaches the highest temperature, entering a heat preservation area for heat preservation, cutting the heat-preserved polymer into glue, granulating, drying, further grinding and screening to prepare the anionic polyacrylamide product. The continuous transmission ultraviolet light initiated polymerization mode provided by the invention can synthesize the anionic polyacrylamide product with high or ultrahigh molecular weight in one step.)

1. A preparation method of ultra-high molecular weight anionic polyacrylamide is characterized by comprising the following steps:

firstly, dissolving raw materials of acrylamide and an anionic monomer in water and adjusting the pH value;

step two, adding a photoinitiator, an azo initiator, a deoxidizer, a metal chelating agent, a metal chelating accelerator, a cosolvent and a chain transfer agent into the polymerization solution with the pH value adjusted in the step one, uniformly stirring, adjusting the pH value of the polymerization solution again, cooling the polymerization solution, deoxidizing through an ultramicro bubble generator, and putting the polymer with the deoxidization onto a polymerization device with continuous transmission under the protection of inert gas and ultraviolet light initiation;

and step three, when the temperature of the polymer on the polymerization device does not rise any more and reaches the highest temperature, entering a heat preservation area for heat preservation, cutting the heat-preserved polymer into glue, granulating, drying, further grinding and screening to prepare the anionic polyacrylamide product.

2. The preparation method according to claim 1, wherein the anionic monomer comprises one or two of acrylic acid, methacrylic acid and sodium salt thereof, and the pH value is adjusted to 5.5-6.5 in the first step.

3. The preparation method according to claim 1, wherein the pH value of the polymerization solution in the second step is 5.5-6.5, the polymerization solution is cooled to-10-5 ℃, the oxygen content of the ultramicro bubble generator is reduced to less than 10ppb by oxygen, the gas source is carbon dioxide, and the diameter of the bubble is less than 100 nm.

4. The preparation method according to claim 1, wherein the heat preservation area in the third step is kept, when the temperature of the polymer on the polymerization device does not rise any more and reaches the highest temperature, the infrared lamp illumination is started to be switched to the polymer colloid, the illumination time is 5-20 min, and the heat preservation is continued for 0.5-1.0 h after the illumination is finished.

5. The preparation method according to claim 1, wherein the mass concentrations of the components in the polymerization solution in the second step are respectively as follows: 5-100 ppm of photoinitiator, 100-400 ppm of azo initiator, 10-100 ppm of deoxidizer, 15-100 ppm of metal chelating agent, 10-100 ppm of metal chelating accelerator, 100-300 ppm of cosolvent and 100-500 ppm of chain transfer agent.

6. The method of claim 1, wherein the metal chelating agent comprises one or more of propylene diamine tetraacetic acid, triethanolamine, and diethylene triamine pentaacetic acid; the metal chelating accelerant comprises one or two of tartaric acid, heptonic acid, gluconic acid, alginic acid, L-malic acid, citric acid and salts thereof.

7. The preparation method of claim 1, wherein the cosolvent comprises one or two of isomeric dodecyl polyoxyethylene ether, isomeric undecyl polyoxyethylene ether and isomeric tridecyl polyoxyethylene ether; the deoxidizer comprises one or more of sodium bicarbonate, ammonium carbonate and ammonium bicarbonate.

8. The production method according to claim 1, wherein the inert gas is nitrogen or carbon dioxide; the ultraviolet light initiation adopts the ultraviolet light initiation with the wavelength of 200-300 nm.

9. The method of claim 1, wherein the photoinitiator comprises one or more of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-hydroxy-4' - (2-hydroxyethoxy) -2-methylpropiophenone, 1-hydroxycyclohexyl phenyl methanone, 2-methyl-2- (4-morpholinyl) -1- [4- (methylthio) phenyl ] -1-propanone, 2,4, 6-trimethylbenzoyl-diphenylphosphine oxide; the azo initiator comprises one or more of azodiisobutyl amidine hydrochloride, azodiisobutyl imidazoline hydrochloride, azodicyano valeric acid, azodiisopropyl imidazoline and azodiisobutyronitrile.

10. The method of claim 1, wherein the chain transfer agent comprises one of 2-acrylamido-2-methyl-propanesulfonic acid and methacrylic sulfonic acid and one or a combination of ammonium formate and sodium formate.

Technical Field

The invention belongs to the field of preparation of polyacrylamide, and particularly relates to a preparation method of anionic polyacrylamide with ultrahigh molecular weight.

Background

The manufacture of polyacrylamides and derivatives thereof, it is common to obtain the corresponding products by free radical polymerization. The free radical polymerization reaction of acrylamide conforms to the general rule of free radical chain polymerization and consists of chain initiation, chain growth, chain termination and other radical reactions. The chain initiation reaction is a reaction for forming monomer free radical active species, a primary free radical is formed by an initiator, and the primary free radical is added with a monomer to form a monomer free radical. After the free radicals of the monomers are formed, the monomers continue to undergo addition polymerization with other monomers to chain-extend the monomers. The free radicals have high activity and are easy to interact and terminate. Chain growth and chain termination are a pair of competing reactions, and the influence factors are many. For example, oxygen can react with primary radicals to deactivate them, resulting in the initial absence of polymer formation and polymerization inhibition; the living chains in commercial processes may also end up as metal free electron impurities in the feedstock or on the reactor walls. Therefore, how to reduce the dissolved oxygen and metal ion impurities in the polymerization liquid has important significance on the growth of the polymer chain.

Compared with the large-block kettle type polymerization, the continuous transmission polymerization has the advantages that part of polymerization heat is dissipated to the surrounding environment, and the other part of the polymerization heat is absorbed by the steel belt carrier, so that the defects that the polyacrylamide colloid is a poor heat conductor and the heat in the rubber block is not easy to transfer are overcome, the relative molecular mass of the polymer is improved, the specific surface area of the continuous transmission polymerization is increased, the transmission device is dynamic, absolute sealing is required, the oxygen content is ultralow, and the difficulty is high. Therefore, how to reduce the dissolved oxygen in the polymerization solution is an urgent problem to be solved in the continuous polymerization apparatus.

Disclosure of Invention

The purpose of the invention is as follows: the invention aims to provide a method for preparing the anionic polyacrylamide with the ultrahigh molecular weight, aiming at overcoming the defects of the prior art, and the method is used for preparing the rapidly-dissolved anionic polyacrylamide with the ultrahigh molecular weight by reducing the influence of free oxygen and metal ions in a solution on a polymerization process so as to reduce the occurrence of side reactions such as crosslinking and the like caused by unreacted monomers.

The technical scheme for realizing the invention is as follows:

the invention relates to a preparation method of anionic polyacrylamide with ultrahigh molecular weight, which comprises the following steps:

firstly, dissolving raw materials of acrylamide and an anionic monomer in water and adjusting the pH value;

step two, adding a photoinitiator, an azo initiator, a deoxidizer, a metal chelating agent, a metal chelating accelerator, a cosolvent and a chain transfer agent into the polymerization solution with the pH value adjusted in the step one, uniformly stirring, adjusting the pH value of the polymerization solution again, cooling the polymerization solution, deoxidizing through an ultramicro bubble generator, and putting the polymer with the deoxidization onto a polymerization device with continuous transmission under the protection of inert gas and ultraviolet light initiation;

and step three, when the temperature of the polymer on the polymerization device does not rise any more and reaches the highest temperature, entering a heat preservation area for heat preservation, cutting the heat-preserved polymer into glue, granulating, drying by a fluidized bed, further grinding and screening to prepare the anionic polyacrylamide product.

Preferably, the anionic monomer comprises one or two of acrylic acid, methacrylic acid and sodium salt thereof, and the pH value is adjusted to 5.5-6.5 in the first step.

Preferably, the pH value of the polymerization liquid in the second step is 5.5-6.5, the polymerization liquid is cooled to-10-5 ℃, and the ultra-micro bubble generator is used for removing oxygen until the oxygen content is less than 10ppb, and further preferably, the oxygen content is less than 2 ppb; the gas source is carbon dioxide, and the diameter of the bubble is less than 100 nm. The invention creatively uses the ultramicro-bubble generator to generate a carbon dioxide gas source for deoxidizing, and the principle is that a large amount of carbon dioxide bubbles are generated in a polymerization liquid phase through the ultramicro-bubble generator; when the diameter of the carbon dioxide bubbles reaches the nanometer level, the specific surface area of the carbon dioxide bubbles is increased by tens of thousands of times, so that the solubility of a carbon dioxide gas source in water can be rapidly improved, the rising path of the carbon dioxide bubbles is small in volume, the speed of the rising path is slow, and the carbon dioxide bubbles can be retained in the water for a long time without floating; the acrylamide polymerization liquid drives out dissolved oxygen by adopting carbon dioxide which is slightly soluble in water as a gas source, so that the deoxygenation efficiency can be further improved, and the dissolved oxygen in the polymerization liquid is lower than 10ppb and even lower than 2ppb, thereby eliminating the inhibition effect of oxygen in the polymerization liquid, improving the utilization rate of an initiator, enabling polymerization to be stably and fully carried out, avoiding the occurrence of side reactions such as crosslinking and the like, further reducing water-insoluble substances of anionic polyacrylamide products, reducing the residual quantity of unsaturated monomers and improving the quality of the anionic polyacrylamide products.

Preferably, the heat preservation area in the third step is kept warm, when the temperature of the polymer on the polymerization device does not rise any more and reaches the highest temperature, the infrared lamp illumination is started to be switched to the polymer colloid, the illumination time is 5-20 min, and the heat preservation is continued for 0.5-1.0 h after the illumination is finished. According to the invention, the infrared lamp is used for preserving the heat of the polymer colloid surface layer, and the heat generated by the infrared lamp is used for preserving the heat of the polymer colloid surface layer which is easy to dissipate heat, so that the polymer colloid surface can be rapidly formed into a film, the heat conductivity coefficient of the polymer colloid is further reduced, the polymer colloid is maintained at the highest temperature for a period of time, the reaction is further promoted to be carried out stably, and the improvement of various performances of a product is facilitated; the invention solves the problems of large specific surface area, quick heat dissipation and high monomer residual rate of continuous polymerization colloid by arranging heat preservation, and avoids the formation of side reactions such as crosslinking and the like of high-residual monomers in the drying treatment process.

Preferably, the mass concentrations of the components in the polymerization solution in the second step are respectively as follows: 5-100 ppm of photoinitiator, 100-400 ppm of azo initiator, 10-100 ppm of deoxidizer, 15-100 ppm of metal chelating agent, 10-100 ppm of metal chelating accelerator, 100-300 ppm of cosolvent and 100-500 ppm of chain transfer agent.

Preferably, the metal chelating agent comprises one or more of the combination of propylenediaminetetraacetic acid, triethanolamine, diethylenetriaminepentaacetic acid, further preferably propylenediaminetetraacetic acid; the metal chelating accelerant comprises one or two of tartaric acid, heptonic acid, gluconic acid, alginic acid, L-malic acid, citric acid and salts thereof. In the invention, a metal chelating promoter is added into a polymerization solution to cooperate with a metal chelating agent, so that the chelating capacity of the polymerization solution is enhanced; the metal chelating agent chelates impurity metal ions such as iron ions, thereby avoiding the influence on the activity of the monomer and promoting the release of gas in the deoxidizer.

Preferably, the cosolvent comprises one or two of isomeric dodecyl polyoxyethylene ether, isomeric undecyl polyoxyethylene ether and isomeric tridecyl polyoxyethylene ether.

Preferably, the deoxidizer comprises one or more of sodium bicarbonate, ammonium carbonate and ammonium bicarbonate. The invention pre-embeds deoxidizer in the polymerization liquid, the deoxidizer can be one or a combination of sodium bicarbonate, ammonium carbonate and ammonium bicarbonate, the deoxidizer pre-embedded in the liquid phase has higher solubility compared with carbon dioxide, under the condition that the pH value of the polymerization liquid is acidic, after the polymerization liquid flows into a conveyor belt of a polymerization device, the temperature rises along with the irradiation of ultraviolet light, the release speed of carbon dioxide gas in the deoxidizer is gradually increased, the probability that oxygen in the gas phase above the conveyor belt is dissolved into the polymerization liquid phase again is greatly reduced, the problem of poor tightness of a continuous polymerization device is effectively solved, the aim of isolating oxygen is fulfilled for the polymerization system, the polymerization inhibition effect of oxygen is further eliminated, the polymerization is stably and fully carried out, the occurrence of side reactions such as cross-linking and the like is avoided, the molecular weight of anionic polyacrylamide products is further improved, and the residual quantity of unsaturated monomers is reduced, the use efficiency of the product is improved.

Preferably, the inert gas is nitrogen or carbon dioxide, preferably carbon dioxide, which has a greater solubility in water than nitrogen; the ultraviolet light initiation adopts ultraviolet light with the wavelength of 200-300 nm, the wavelength of the ultraviolet light is preferably 254nm, and the ultraviolet light in the wave band can better perform polymerization reaction. The preferred inert gas for gas phase protection in the invention is carbon dioxide, the density of the carbon dioxide is higher than that of air or oxygen, the carbon dioxide can be deposited on the surface layer of the polymerization liquid, and the carbon dioxide can be better consistent with the oxygen content in the gas phase and dissolved in the liquid phase polymerization liquid again; and the gas source adopted by the oxygen-removing ultramicro bubble generator is also carbon dioxide gas, and the same gas is adopted for reaction, so that other impurities can be prevented from being introduced in the reaction process, and the reaction flow is simplified.

Preferably, the photoinitiator comprises one or more combinations of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-hydroxy-4' - (2-hydroxyethoxy) -2-methylpropiophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2- (4-morpholinyl) -1- [4- (methylthio) phenyl ] -1-propanone, 2,4, 6-trimethylbenzoyl-diphenylphosphine oxide; the azo initiator comprises one or more of azodiisobutyl amidine hydrochloride, azodiisobutyl imidazoline hydrochloride, azodicyano valeric acid, azodiisopropyl imidazoline and azodiisobutyronitrile.

Preferably, the chain transfer agent comprises one of 2-acrylamido-2-methyl-propanesulfonic acid and methacrylic sulfonic acid and one or a combination of ammonium formate and sodium formate. The chain transfer agent can inhibit intramolecular and intermolecular crosslinking in the acrylamide polymerization process, and improves the solubility of the product.

The preparation method of the anionic polyacrylamide has the advantages of strong continuity of production modes and stable product quality; the deoxidization efficiency is high, deoxidization is carried out under the same gas filling of a liquid phase, the oxygen content in the polymerization liquid is ensured to be as low as possible, the influence of free oxygen and metal ions in the polymerization liquid on the polymerization process is reduced, and the occurrence of side reactions such as crosslinking and the like caused by unreacted monomers is reduced; the molecular weight and the dissolving speed of the polymer are effectively improved, the content of water insoluble substance colloid in the solution after the polymer is dissolved is reduced, the use efficiency of the product is effectively improved, and the anionic polyacrylamide product can better meet the requirements of application sites.

By adopting the technical scheme, the invention has the following beneficial effects:

(1) the invention adopts the ultramicro-bubble generator to carry out liquid-phase deoxygenation, reduces the oxygen content in the polymerization liquid, simultaneously adopts the pre-embedded deoxidizer to carry out gas-phase protection in the polymerization process, prevents oxygen in the air from being dissolved into the polymerization liquid again, further adopts double technical means to reduce the oxygen content in the polymerization liquid, and improves the quality of the final anionic polyacrylamide product.

(2) The continuous transmission ultraviolet light initiated polymerization mode provided by the invention has simple process and is easy to realize industrial production; the preparation method can effectively improve the molecular weight and the dissolution speed of the polymer, reduce the content of water insoluble substance colloid in the solution after the polymer is dissolved, effectively improve the use efficiency of the product and enable the anionic polyacrylamide product to better meet the requirements of application sites; meanwhile, the method has the advantages of low reaction temperature, short reaction time, high production efficiency, easily controlled polymerization heat capacity, stable product quality, capability of synthesizing high or ultrahigh molecular weight anionic polyacrylamide products in one step and the like, and is an environment-friendly polymerization technology.

(3) The invention creatively uses the ultramicro-bubble generator to generate a carbon dioxide gas source for deoxidizing, and the principle is that a large amount of carbon dioxide bubbles are generated in a polymerization liquid phase through the ultramicro-bubble generator; when the diameter of the carbon dioxide bubbles reaches the nanometer level, the specific surface area of the carbon dioxide bubbles is increased by tens of thousands of times, so that the solubility of a carbon dioxide gas source in water can be rapidly improved, the rising path of the carbon dioxide bubbles is small in volume, the speed of the rising path is slow, and the carbon dioxide bubbles can be retained in the water for a long time without floating; the acrylamide polymerization liquid is used for expelling dissolved oxygen by adopting carbon dioxide which is slightly soluble in water as a gas source, so that the oxygen removal efficiency can be further improved, the oxygen content in the liquid phase can be reduced to ppb level in a short time, and the dissolved oxygen content in the polymerization liquid is lower than 10ppb and even lower than 2ppb, thereby eliminating the polymerization inhibition effect of oxygen in the polymerization liquid and improving the utilization rate of an initiator; the polymerization is carried out stably and fully, side reactions such as crosslinking and the like are avoided, the water-insoluble substances of the anionic polyacrylamide product are reduced, the residual quantity of unsaturated monomers is reduced, and the quality of the anionic polyacrylamide product is improved.

(4) The gas source of the gas phase protection provided by the invention is nitrogen or carbon dioxide, preferably carbon dioxide, and compared with nitrogen, carbon dioxide has higher solubility in water; the density of the carbon dioxide is higher than that of air or oxygen, and the carbon dioxide can be deposited on the surface layer of the polymerization liquid and can be dissolved into the liquid-phase polymerization liquid again according to the oxygen content in the gas phase better; and the gas source adopted by the oxygen-removing ultramicro bubble generator is also carbon dioxide gas, and the same gas is adopted for reaction, so that other impurities can be prevented from being introduced in the reaction process, and the reaction flow is simplified.

(5) The deoxidizer pre-embedded in the liquid phase has higher solubility compared with carbon dioxide, and under the condition that the pH value of the polymerization system is slightly acidic, after the polymerization liquid flows into a conveyor belt of a polymerization device, the temperature is increased along with the illumination, the release speed of gas is gradually increased, the probability that oxygen in the gas phase above the conveyor belt is dissolved into the polymerization liquid phase again is greatly reduced, the problem of poor tightness of a continuous polymerization device is effectively solved, the aim of isolating oxygen is fulfilled for the polymerization system, the polymerization inhibition effect of oxygen is further eliminated, the polymerization is stably and fully carried out, the occurrence of side reactions such as crosslinking and the like is avoided, the molecular weight of a product is further improved, the residual quantity of unsaturated monomers is reduced, and the use efficiency of the product is improved.

(6) In the invention, a metal chelating promoter is added into a polymerization solution to cooperate with a metal chelating agent, so that the chelating capacity of the polymerization solution is enhanced; the metal chelating agent chelates impurity metal ions such as iron ions, thereby avoiding the influence on the activity of the monomer and promoting the release of gas in the deoxidizer.

(7) The heat preservation mode provided by the invention is that the infrared lamp is used for preserving heat of the surface layer of the colloid, and the heat generated by the infrared lamp is used for preserving heat of the surface layer of the colloid which is easy to dissipate heat, so that the surface of the colloid can be rapidly formed into a film, the heat conductivity coefficient of the colloid is further reduced, the colloid is maintained at the highest temperature for a period of time, the reaction is further promoted to be carried out stably, and the improvement of various performances of a product is facilitated; the problems of large specific surface area, quick heat dissipation and high monomer residual rate of continuous polymerization colloid are solved, and the formation of side reactions such as crosslinking and the like of high-residual monomers in the drying treatment process is avoided.

(8) The chain transfer agent provided by the invention comprises one of 2-acrylamido-2-methyl-propanesulfonic acid and methacrylic sulfonic acid and one or a combination of ammonium formate and sodium formate. The small amount of anionic monomer with steric effect and formate in the invention can effectively inhibit the generation of side reactions such as cross-linking and the like; the chain transfer agent can inhibit intramolecular and intermolecular crosslinking in the acrylamide polymerization process, and improve the solubility of the product.

Detailed Description

The technical solution of the present invention is described in detail below, but the scope of the present invention is not limited to the embodiments.

Example 1: a preparation method of ultra-high molecular weight anionic polyacrylamide comprises the following steps:

firstly, dissolving raw materials of acrylamide and an anionic monomer in water and adjusting the pH value, wherein the anionic monomer comprises one or two of acrylic acid, methacrylic acid and sodium salt thereof, and the pH value is adjusted to 5.5-6.5.

Step two, adding a photoinitiator, an azo initiator, a deoxidizer, a metal chelating agent, a metal chelating accelerator, a cosolvent and a chain transfer agent into the polymerization solution with the pH value adjusted in the step one, uniformly stirring, adjusting the pH value of the polymerization solution to 5.5-6.5 again, cooling the polymerization solution to-10-5 ℃, deoxidizing by using an ultramicro bubble generator until the oxygen content is less than 10ppb, preferably less than 2ppb in the embodiment, and putting the polymer subjected to deoxidization onto a polymerization device with inert gas protection and ultraviolet light initiated continuous transmission; in the second step of this embodiment, the mass concentrations of the components in the polymerization solution are respectively: 5-100 ppm of photoinitiator, 100-400 ppm of azo initiator, 10-100 ppm of deoxidizer, 15-100 ppm of metal chelating agent, 10-100 ppm of metal chelating accelerator, 100-300 ppm of cosolvent and 100-500 ppm of chain transfer agent; the polymerization liquid can be ensured to react smoothly by limiting the dosage of each component, and a high-quality anionic polyacrylamide product is obtained.

In the embodiment, ultraviolet light with the wavelength of 200-300 nm is adopted for initiating, and preferably, the wavelength of the ultraviolet light is 254nm, so that the ultraviolet light in the wave band can better perform polymerization reaction; the photoinitiator comprises one or more of 2-hydroxy-2-methyl-1-phenyl-1-acetone, 2-hydroxy-4' - (2-hydroxyethoxy) -2-methyl propiophenone, 1-hydroxycyclohexyl phenyl ketone, 2-methyl-2- (4-morpholinyl) -1- [4- (methylthio) phenyl ] -1-acetone and 2,4, 6-trimethylbenzoyl-diphenyl phosphine oxide; the azo initiator comprises one or more of azodiisobutyl amidine hydrochloride, azodiisobutyl imidazoline hydrochloride, azodicyano valeric acid, azodiisopropyl imidazoline and azodiisobutyronitrile; the deoxidizer comprises one or more of sodium bicarbonate, ammonium carbonate and ammonium bicarbonate.

In the embodiment, the deoxidizer is pre-embedded in the polymerization liquid, the deoxidizer can be one or a combination of sodium bicarbonate, ammonium carbonate and ammonium bicarbonate, the deoxidizer is pre-embedded in the liquid phase, the solubility is higher compared with carbon dioxide, under the condition that the pH value of the polymerization liquid is acidic, after the polymerization liquid flows into a conveyor belt of a polymerization device, the release speed of carbon dioxide gas in the deoxidizer is gradually increased along with the irradiation of ultraviolet light, the probability that oxygen in the gas phase above the conveyor belt is dissolved into the polymerization liquid phase again is greatly reduced, the problem of poor tightness of a continuous polymerization device is effectively solved, the aim of isolating oxygen is fulfilled for a polymerization system, the polymerization inhibition effect of oxygen is further eliminated, the polymerization is stably and fully carried out, the occurrence of side reactions such as crosslinking and the like is avoided, the molecular weight of an anionic polyacrylamide product is further improved, and the residual quantity of unsaturated monomers is reduced, the use efficiency of the product is improved;

the metal chelating agent in the present embodiment includes one or more combinations of propylenediaminetetraacetic acid, triethanolamine, diethylenetriaminepentaacetic acid, and further preferably propylenediaminetetraacetic acid; the metal chelating promoter comprises one or two of tartaric acid, heptonic acid, gluconic acid, alginic acid, L-malic acid, citric acid and its salt; in the embodiment, the metal chelating agent is added into the polymerization liquid to be coordinated with the metal chelating agent, so that the chelating capacity of the polymerization liquid is enhanced; the metal chelating agent chelates impurity metal ions such as iron ions, so that the influence of the metal chelating agent on the activity of the monomer is avoided, and the release of gas in the deoxidizer can be promoted; the cosolvent comprises one or two of isomeric dodecyl alcohol polyoxyethylene ether, isomeric undecyl alcohol polyoxyethylene ether and isomeric tridecyl alcohol polyoxyethylene ether; the chain transfer agent in this embodiment comprises one of 2-acrylamido-2-methyl-propanesulfonic acid and methacrylic sulfonic acid and one or a combination of ammonium formate and sodium formate. In the embodiment, the chain transfer agent can inhibit intramolecular and intermolecular crosslinking in the acrylamide polymerization process, so that the solubility of the product is improved;

in the embodiment, a carbon dioxide gas source is creatively used for deoxidizing by using an ultramicro bubble generator, the bubble diameter of carbon dioxide is less than 100nm, and the principle is that a large amount of carbon dioxide bubbles are generated in a polymerization liquid phase through the ultramicro bubble generator; when the diameter of the carbon dioxide bubbles reaches the nanometer level, the specific surface area of the carbon dioxide bubbles is increased by tens of thousands of times, so that the solubility of a carbon dioxide gas source in water can be rapidly improved, the rising path of the carbon dioxide bubbles is small in volume, the speed of the rising path is slow, and the carbon dioxide bubbles can be retained in the water for a long time without floating; the acrylamide polymerization liquid is used for expelling dissolved oxygen by adopting carbon dioxide which is slightly soluble in water as a gas source, so that the deoxygenation efficiency can be further improved, and the dissolved oxygen in the polymerization liquid is lower than 10ppb and even lower than 2ppb, thereby eliminating the inhibition effect of oxygen in the polymerization liquid, improving the utilization rate of an initiator, enabling polymerization to be stably and fully carried out, avoiding the occurrence of side reactions such as crosslinking and the like, further reducing water-insoluble substances of anionic polyacrylamide products, reducing the residual quantity of unsaturated monomers and improving the quality of the anionic polyacrylamide products;

in this embodiment, the inert gas is nitrogen or carbon dioxide, preferably carbon dioxide. In this embodiment, the preferred inert gas for gas phase protection is carbon dioxide, which has a higher density than air or oxygen, and can be deposited on the surface layer of the polymerization liquid, so as to better conform the oxygen content in the gas phase and dissolve into the liquid phase polymerization liquid again; and the gas source adopted by the oxygen-removing ultramicro bubble generator is also carbon dioxide gas, and the same gas is adopted for reaction, so that other impurities can be prevented from being introduced in the reaction process, and the reaction flow is simplified.

And step three, when the temperature of the polymer on the polymerization device does not rise any more and reaches the highest temperature, entering a heat preservation area for heat preservation, cutting the heat-preserved polymer into glue, granulating, drying by a fluidized bed, further grinding and screening to prepare the anionic polyacrylamide product. In the third step of the present embodiment, the heat preservation area is insulated, when the temperature of the polymer on the polymerization device does not rise any more and reaches the highest temperature, the infrared lamp is switched to illuminate the polymer colloid, the illumination time is 5-20 min, and the heat preservation is continued for 0.5-1.0 h after the illumination is finished. In the embodiment, the infrared lamp is used for preserving the heat of the polymer colloid surface layer, and the heat generated by the infrared lamp is used for preserving the heat of the polymer colloid surface layer which is easy to dissipate heat, so that the polymer colloid surface can be rapidly formed into a film, the heat conductivity coefficient of the polymer colloid is further reduced, the polymer colloid is maintained at the highest temperature for a period of time, the reaction is further promoted to be carried out stably, and the improvement of various performances of a product is facilitated; the embodiment solves the problems of large specific surface area, quick heat dissipation and high monomer residual rate of continuous polymerization colloid by setting heat preservation, and avoids the formation of side reactions such as crosslinking of high-residual monomers in the drying treatment process.

The preparation method of the anionic polyacrylamide in the embodiment has the advantages of strong consistency of production modes and stable product quality; the deoxidization efficiency is high, deoxidization is carried out under the same gas filling of a liquid phase, the oxygen content in the polymerization liquid is ensured to be as low as possible, the influence of free oxygen and metal ions in the polymerization liquid on the polymerization process is reduced, and the occurrence of side reactions such as crosslinking and the like caused by unreacted monomers is reduced; the molecular weight and the dissolving speed of the polymer are effectively improved, the content of water insoluble substance colloid in the solution after the polymer is dissolved is reduced, the use efficiency of the product is effectively improved, and the anionic polyacrylamide product can better meet the requirements of application sites.

The following procedure was carried out according to the preparation method of ultra-high molecular weight anionic polyacrylamide in this example, and experimental data of specific values were used to prepare anionic polyacrylamide, and the procedure was as follows:

step one, adding 4760kg of industrial grade acrylamide with the mass fraction of 30%, 275.9kg of anionic monomer acrylic acid with the mass fraction of 70% and 1000kg of deionized water into a batching kettle, and adjusting the pH value to 6.2 by adopting NaOH with the mass fraction of 32%;

adding auxiliary materials including a photoinitiator, an azo initiator, a deoxidizer, a metal chelating agent, a metal chelating accelerator, a cosolvent and a chain transfer agent into a batching kettle, and uniformly mixing; preferably, 0.05kg of 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] -1-acetone is adopted as the photoinitiator, 0.14kg of azodiisobutyramidine hydrochloride and 0.64kg of azodiisobutyronitrile are adopted as the azo initiator, 0.1kg of ammonium bicarbonate is adopted as the deoxidizer, 0.2kg of propylenediamine tetraacetic acid is adopted as the metal chelating agent, 0.1kg of gluconic acid is adopted as the metal chelating accelerant, 0.5kg of isoundecyl polyoxyethylene ether is adopted as the cosolvent, 1.2kg of methacrylic sulfonic acid and 0.5kg of ammonium formate are adopted as the chain transfer agent; then hydrochloric acid or NaOH with the mass fraction of 32% is adopted to adjust the pH value to 6.0, the polymerization liquid is deoxidized through an ultramicro bubble generator, and the deoxidized polymerization liquid is pumped into a polymerization device with an ultraviolet lamp and carbon dioxide protection through a feeding pump;

and step three, when the temperature of the polymer reaches the highest temperature, allowing the colloid to enter an infrared lamp for irradiation and heat preservation for 10min, continuing heat preservation for 30min after the lamp is turned off, cutting the colloid, granulating, drying and grinding to obtain an anionic polyacrylamide product, wherein the molecular weight of the anionic polyacrylamide product is 2052 ten thousand, the dissolving time is 39min, the residual monomer is 357ppm and the insoluble substances are 0.06%.

The specific experimental data show that the molecular weight of the anionic polyacrylamide product of the vegetation prepared by the preparation method in the embodiment is up to 2052 ten thousand, the product belongs to ultrahigh molecular weight, wherein the dissolving time is 39min, 357ppm of residual monomer and 0.06% of insoluble substance are obtained, the anionic polyacrylamide product can be quickly dissolved, the molecular weight and the dissolving speed of the anionic polyacrylamide product are improved, the content of water insoluble substance colloid in the solution after the product is dissolved is reduced, and the quick-dissolving type ultrahigh molecular weight anionic polyacrylamide is obtained.

The continuous transmission ultraviolet light initiated polymerization mode provided by the embodiment has simple process and is easy to realize industrial production; the preparation method of the embodiment can effectively improve the molecular weight and the dissolution speed of the polymer, reduce the content of water insoluble substance colloid in the solution after the polymer is dissolved, effectively improve the use efficiency of the product, and enable the anionic polyacrylamide product to better meet the requirements of application sites; meanwhile, the method has the advantages of low reaction temperature, short reaction time, high production efficiency, easy control of polymerization heat capacity, stable product quality, capability of synthesizing high or ultrahigh molecular weight anionic polyacrylamide products in one step and the like, and is an environment-friendly polymerization technology.

Example 2: in this embodiment, the method for preparing the ultra-high molecular weight anionic polyacrylamide according to embodiment 1 and experimental data with specific values includes the following steps:

step one, adding 4592kg of industrial grade acrylamide with the mass fraction of 30%, 344kg of anionic monomer methacrylic acid with the mass fraction of 70% and 1000kg of deionized water into a batching kettle, and adjusting the pH value to 6.2 by adopting NaOH with the mass fraction of 32%;

adding auxiliary materials including a photoinitiator, an azo initiator, a deoxidizer, a metal chelating agent, a metal chelating accelerator, a cosolvent and a chain transfer agent into a batching kettle, and uniformly mixing; preferably, 0.12kg of 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] -1-acetone is adopted as the photoinitiator, 0.24kg of azodiisobutyramidine hydrochloride and 1.2kg of azodicyano valeric acid are adopted as the azo initiator, 0.1kg of ammonium bicarbonate is adopted as the deoxidizer, 0.2kg of propylenediamine tetraacetic acid is adopted as the metal chelating agent, 0.12kg of gluconic acid is adopted as the metal chelating accelerant, 0.5kg of isoundecyl polyoxyethylene ether is adopted as the cosolvent, 1.2kg of methacrylic sulfonic acid and 0.5kg of ammonium formate are adopted as the chain transfer agent; then hydrochloric acid or NaOH with the mass fraction of 32% is adopted to adjust the pH value to 6.0, the polymerization liquid is deoxidized through an ultramicro bubble generator, and the deoxidized polymerization liquid is pumped into a polymerization device with an ultraviolet lamp and carbon dioxide protection through a feeding pump;

and step three, when the temperature of the polymer reaches the highest temperature, allowing the colloid to enter an infrared lamp for irradiation and heat preservation for 10min, continuing heat preservation for 30min after the lamp is turned off, cutting the colloid, granulating, drying and grinding to obtain an anionic polyacrylamide product, wherein the molecular weight of the anionic polyacrylamide product is 1874 ten thousand, the dissolving time is 35min, the residual monomer is 357ppm, and the insoluble substances are 0.02%.

The specific experimental data show that the molecular weight of the anionic polyacrylamide product prepared by the preparation method in the embodiment is up to 1874 ten thousand, and the product belongs to ultrahigh molecular weight, wherein the dissolution time is 35min, the insoluble substance is 0.02%, the anionic polyacrylamide product can be quickly dissolved, the molecular weight and the dissolution speed of the anionic polyacrylamide product are improved, the content of water insoluble substance colloid in the solution after the product is dissolved is reduced, and the quick-dissolving type ultrahigh molecular weight anionic polyacrylamide is obtained.

The continuous transmission ultraviolet light initiated polymerization mode provided by the embodiment has simple process and is easy to realize industrial production; the preparation method of the embodiment can effectively improve the molecular weight and the dissolution speed of the polymer, reduce the content of water insoluble substance colloid in the solution after the polymer is dissolved, effectively improve the use efficiency of the product, and enable the anionic polyacrylamide product to better meet the requirements of application sites; meanwhile, the method has the advantages of low reaction temperature, short reaction time, high production efficiency, easy control of polymerization heat capacity, stable product quality, capability of synthesizing high or ultrahigh molecular weight anionic polyacrylamide products in one step and the like, and is an environment-friendly polymerization technology.

Example 3: in this embodiment, the method for preparing the ultra-high molecular weight anionic polyacrylamide according to embodiment 1 and experimental data with specific values includes the following steps:

step one, adding 3920kg of industrial grade acrylamide with the mass fraction of 30%, 573.5kg of anionic monomer methacrylic acid with the mass fraction of 70% and 1000kg of deionized water into a batching kettle, and adjusting the pH value to 6.2 by adopting NaOH with the mass fraction of 32%;

adding auxiliary materials including a photoinitiator, an azo initiator, a deoxidizer, a metal chelating agent, a metal chelating accelerator, a cosolvent and a chain transfer agent into a batching kettle, and uniformly mixing; preferably, 0.15kg of 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] -1-acetone is adopted as the photoinitiator, 0.18kg of azodiisobutyramidine hydrochloride and 1.0kg of azodicyano valeric acid are adopted as the azo initiator, 0.12kg of ammonium bicarbonate is adopted as the deoxidizer, 0.2kg of propylenediamine tetraacetic acid is adopted as the metal chelating agent, 0.1kg of gluconic acid is adopted as the metal chelating accelerant, 0.5kg of isoundecyl polyoxyethylene ether is adopted as the cosolvent, 1.2kg of methacrylic sulfonic acid and 0.5kg of ammonium formate are adopted as the chain transfer agent; then hydrochloric acid or NaOH with the mass fraction of 32% is adopted to adjust the pH value to 6.0, the polymerization liquid is deoxidized through an ultramicro bubble generator, and the deoxidized polymerization liquid is pumped into a polymerization device with an ultraviolet lamp and carbon dioxide protection through a feeding pump;

and step three, when the temperature of the polymer reaches the highest temperature, the colloid enters an infrared lamp for irradiation and heat preservation for 10min, the temperature is kept for 30min after the lamp is turned off, and then the anion polyacrylamide product is obtained by cutting, granulating, drying and grinding, wherein the molecular weight of the anion polyacrylamide product is 1989 ten thousand, the dissolving time is 34min, and the insoluble substance is 0.03%.

The specific experimental data show that the molecular weight of the anionic polyacrylamide product of the vegetation prepared by the preparation method in the embodiment is up to 1989 ten thousand, and the product belongs to ultrahigh molecular weight, wherein the dissolution time is 34min, the insoluble substance is 0.03%, the anionic polyacrylamide product can be quickly dissolved, the molecular weight and the dissolution speed of the anionic polyacrylamide product are improved, the content of water insoluble substance colloid in the solution after the product is dissolved is reduced, and the quickly-dissolved type ultrahigh molecular weight anionic polyacrylamide is obtained.

The continuous transmission ultraviolet light initiated polymerization mode provided by the embodiment has simple process and is easy to realize industrial production; the preparation method of the embodiment can effectively improve the molecular weight and the dissolution speed of the polymer, reduce the content of water insoluble substance colloid in the solution after the polymer is dissolved, effectively improve the use efficiency of the product, and enable the anionic polyacrylamide product to better meet the requirements of application sites; meanwhile, the method has the advantages of low reaction temperature, short reaction time, high production efficiency, easy control of polymerization heat capacity, stable product quality, capability of synthesizing high or ultrahigh molecular weight anionic polyacrylamide products in one step and the like, and is an environment-friendly polymerization technology.

Example 4: in this embodiment, the method for preparing the ultra-high molecular weight anionic polyacrylamide according to embodiment 1 and experimental data with specific values includes the following steps:

step one, 4200kg of industrial grade acrylamide with the mass fraction of 30%, 459.8kg of anionic monomer acrylic acid with the mass fraction of 70% and 1000kg of deionized water are added into a batching kettle, and NaOH with the mass fraction of 32% is adopted to adjust the pH value to 6.2;

adding auxiliary materials including a photoinitiator, an azo initiator, a deoxidizer, a metal chelating agent, a metal chelating accelerator, a cosolvent and a chain transfer agent into a batching kettle, and uniformly mixing; preferably, 0.14kg of 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] -1-acetone is adopted as the photoinitiator, 0.23kg of azodiisobutyramidine hydrochloride and 0.71kg of azodiisobutyronitrile are adopted as the azo initiator, 0.1kg of ammonium bicarbonate is adopted as the deoxidizer, 0.2kg of propylenediamine tetraacetic acid is adopted as the metal chelating agent, 0.1kg of gluconic acid is adopted as the metal chelating accelerant, 0.35kg of isoundecyl polyoxyethylene ether is adopted as the cosolvent, 1.2kg of methacrylic sulfonic acid and 0.5kg of ammonium formate are adopted as the chain transfer agent; then hydrochloric acid or NaOH with the mass fraction of 32% is adopted to adjust the pH value to 6.0, the polymerization liquid is deoxidized through an ultramicro bubble generator, and the deoxidized polymerization liquid is pumped into a polymerization device with an ultraviolet lamp and carbon dioxide protection through a feeding pump;

and step three, when the temperature of the polymer reaches the highest temperature, the colloid enters an infrared lamp for irradiation and heat preservation for 10min, the temperature is kept for 30min after the lamp is turned off, and then the anion polyacrylamide product is obtained by cutting, granulating, drying and grinding, wherein the molecular weight of the anion polyacrylamide product is 2259 ten thousand, the dissolving time is 35min, and the insoluble substances are 0.008%.

The specific experimental data show that the molecular weight of the anionic polyacrylamide product of the vegetation prepared by the preparation method in the embodiment is up to 2259 ten thousand, and the product belongs to an ultrahigh molecular weight, wherein the dissolution time is 35min, the insoluble substance is 0.008%, the anionic polyacrylamide product can be quickly dissolved, the molecular weight and the dissolution speed of the anionic polyacrylamide product are improved, the content of water insoluble substance colloid in the solution after the product is dissolved is reduced, and the quickly-dissolved type ultrahigh molecular weight anionic polyacrylamide is obtained.

The continuous transmission ultraviolet light initiated polymerization mode provided by the embodiment has simple process and is easy to realize industrial production; the preparation method of the embodiment can effectively improve the molecular weight and the dissolution speed of the polymer, reduce the content of water insoluble substance colloid in the solution after the polymer is dissolved, effectively improve the use efficiency of the product, and enable the anionic polyacrylamide product to better meet the requirements of application sites; meanwhile, the method has the advantages of low reaction temperature, short reaction time, high production efficiency, easy control of polymerization heat capacity, stable product quality, capability of synthesizing high or ultrahigh molecular weight anionic polyacrylamide products in one step and the like, and is an environment-friendly polymerization technology.

Example 5: in this embodiment, the method for preparing the ultra-high molecular weight anionic polyacrylamide according to embodiment 1 and experimental data with specific values includes the following steps:

step one, 3640kg of industrial acrylamide with the mass fraction of 30%, 643.7kg of anionic monomer acrylic acid with the mass fraction of 70% and 1000kg of deionized water are added into a batching kettle, and NaOH with the mass fraction of 32% is adopted to adjust the pH value to 6.2;

adding auxiliary materials including a photoinitiator, an azo initiator, a deoxidizer, a metal chelating agent, a metal chelating accelerator, a cosolvent and a chain transfer agent into a batching kettle, and uniformly mixing; preferably, 0.10kg of 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] -1-acetone is adopted as the photoinitiator, 0.18kg of azodiisobutyramidine hydrochloride and 0.72kg of azodiisobutyronitrile are adopted as the azo initiator, 0.13kg of ammonium bicarbonate is adopted as the deoxidizer, 0.2kg of propylenediamine tetraacetic acid is adopted as the metal chelating agent, 0.1kg of gluconic acid is adopted as the metal chelating accelerant, 0.2kg of isoundecanol polyoxyethylene ether is adopted as the cosolvent, 1.2kg of methacrylic sulfonic acid and 0.5kg of ammonium formate are adopted as the chain transfer agent; then hydrochloric acid or NaOH with the mass fraction of 32% is adopted to adjust the pH value to 6.0, the polymerization liquid is deoxidized through an ultramicro bubble generator, and the deoxidized polymerization liquid is pumped into a polymerization device with an ultraviolet lamp and carbon dioxide protection through a feeding pump;

and step three, when the temperature of the polymer reaches the highest temperature, allowing the colloid to enter an infrared lamp for irradiation and heat preservation for 10min, continuing heat preservation for 30min after the lamp is turned off, cutting the colloid, granulating, drying, and grinding to obtain an anionic polyacrylamide product, wherein the molecular weight of the anionic polyacrylamide product is 2052 ten thousand, the dissolving time is 34min, and insoluble substances are 0.

According to the specific experimental data, the molecular weight of the anionic polyacrylamide product of the vegetation prepared by the preparation method in the embodiment is up to 2052 ten thousand, the product belongs to ultrahigh molecular weight, the dissolution time is 34min, the insoluble substance is 0, the anionic polyacrylamide product can be quickly dissolved, the molecular weight and the dissolution speed of the anionic polyacrylamide product are improved, the content of water insoluble substance colloid in the solution after the product is dissolved is reduced, and the quick-dissolving type ultrahigh molecular weight anionic polyacrylamide is obtained.

The continuous transmission ultraviolet light initiated polymerization mode provided by the embodiment has simple process and is easy to realize industrial production; the preparation method of the embodiment can effectively improve the molecular weight and the dissolution speed of the polymer, reduce the content of water insoluble substance colloid in the solution after the polymer is dissolved, effectively improve the use efficiency of the product, and enable the anionic polyacrylamide product to better meet the requirements of application sites; meanwhile, the method has the advantages of low reaction temperature, short reaction time, high production efficiency, easy control of polymerization heat capacity, stable product quality, capability of synthesizing high or ultrahigh molecular weight anionic polyacrylamide products in one step and the like, and is an environment-friendly polymerization technology.

Comparative example 1: this comparative example is compared to the experimental data of example 5.

Step one, 3640kg of industrial acrylamide with the mass fraction of 30%, 643.7kg of anionic monomer acrylic acid with the mass fraction of 70% and 1000kg of deionized water are added into a batching kettle, and NaOH with the mass fraction of 32% is adopted to adjust the pH value to 6.2;

adding auxiliary materials including a photoinitiator, an azo initiator, a metal chelating agent, a metal chelating accelerator, a cosolvent and a chain transfer agent into a batching kettle, and uniformly mixing; preferably, 0.10kg of 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] -1-propanone is adopted as the photoinitiator, 0.18kg of azobisisobutyramidine hydrochloride and 0.72kg of azobisisobutyronitrile are adopted as the azo initiator, 0.2kg of propylenediaminetetraacetic acid is adopted as the metal chelating agent, 0.1kg of gluconic acid is adopted as the metal chelating accelerator, 0.2kg of isomeric undecylenic alcohol polyoxyethylene ether is adopted as the cosolvent, 1.2kg of methacrylic sulfonic acid and 0.5kg of ammonium formate are adopted as the chain transfer agent; then hydrochloric acid or NaOH with the mass fraction of 32% is adopted to adjust the pH value to 6.0, the polymerization liquid is deoxidized through an ultramicro bubble generator, and the deoxidized polymerization liquid is pumped into a polymerization device with an ultraviolet lamp and nitrogen protection through a feeding pump;

and step three, when the temperature of the polymer reaches the highest temperature, the colloid enters an infrared lamp for irradiation and heat preservation for 10min, the temperature is kept for 30min after the lamp is turned off, and then the anion polyacrylamide product is obtained by cutting, granulating, drying and grinding, wherein the molecular weight of the anion polyacrylamide product is 1643 ten thousand, the dissolving time is 67min, and the insoluble substances are 0.82%.

The specific experimental data of the comparative example 1 show that the molecular weight of the anionic polyacrylamide product of the vegetation prepared by the preparation method in the embodiment is only 1643 ten thousand, wherein the dissolution time is 67min, and the insoluble substance is 0.82%.

Comparative example 2: this comparative example is compared to the experimental data of example 5.

Step one, 3640kg of industrial acrylamide with the mass fraction of 30%, 643.7kg of anionic monomer acrylic acid with the mass fraction of 70% and 1000kg of deionized water are added into a batching kettle, and NaOH with the mass fraction of 32% is adopted to adjust the pH value to 6.2;

adding auxiliary materials including a photoinitiator, an azo initiator, a deoxidizer, a metal chelating agent, a metal chelating accelerator, a cosolvent and a chain transfer agent into a batching kettle, and uniformly mixing; preferably, 0.10kg of 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] -1-acetone is adopted as the photoinitiator, 0.18kg of azodiisobutyramidine hydrochloride and 0.72kg of azodiisobutyronitrile are adopted as the azo initiator, 0.13kg of ammonium bicarbonate is adopted as the deoxidizer, 0.2kg of propylenediamine tetraacetic acid is adopted as the metal chelating agent, 0.1kg of gluconic acid is adopted as the metal chelating accelerant, 0.2kg of isoundecanol polyoxyethylene ether is adopted as the cosolvent, 1.2kg of methacrylic sulfonic acid and 0.5kg of ammonium formate are adopted as the chain transfer agent; then hydrochloric acid or NaOH with the mass fraction of 32% is adopted to adjust the pH value to 6.0, the polymerization liquid is deoxidized by a common aeration plate, and the deoxidized polymerization liquid is pumped to a polymerization device with an ultraviolet lamp and carbon dioxide protection through a feeding pump;

and step three, when the temperature of the polymer reaches the highest temperature, allowing the colloid to enter an infrared lamp for irradiation and heat preservation for 10min, continuing heat preservation for 30min after the lamp is turned off, cutting the colloid, granulating, drying and grinding to obtain an anionic polyacrylamide product, wherein the molecular weight of the anionic polyacrylamide product is 1375 ten thousand, the dissolving time is 64min, and insoluble substances are 1.05%.

The specific experimental data of the comparative example 2 show that the molecular weight of the anionic polyacrylamide product of the vegetation prepared by the preparation method in the embodiment is only 1375 ten thousand, wherein the dissolution time is 64min, and the insoluble substance is 1.05 percent, compared with the experimental data of the embodiment 5, the molecular weight of the anionic polyacrylamide product in the comparative example is obviously reduced, the dissolution time is prolonged, and the content of the insoluble substance is obviously increased; the effect of the method for preparing the anionic polyacrylamide product of comparative example 2 is much lower than that of the method for preparing the anionic polyacrylamide product of example 5.

The differences between the preparation of the anionic polyacrylamide in comparative example 1 and comparative example 2 and that in example 5 are shown in table 1 below:

TABLE 1

As is apparent from the differences listed in table 1, the liquid-phase oxygen removal method adopted in the preparation of the anionic polyacrylamide in comparative example 1 is common aeration plate oxygen removal, and simultaneously, pre-buried ammonium bicarbonate is used for gas-phase protection; in the comparative example 2, the liquid-phase oxygen removal mode adopted in the preparation of the anionic polyacrylamide is that the ultramicro bubble generator removes oxygen without gas-phase protection; in example 5, the anion polyacrylamide preparation method of the present invention is adopted, wherein the liquid-phase deoxygenation mode is that the ultramicro-bubble generator is deoxygenated, and the pre-buried deoxidizer, i.e., ammonium bicarbonate, is adopted for gas-phase protection, so that the liquid-phase deoxygenation and the weather protection can be simultaneously adopted to achieve a good effect, so as to obtain the fast-dissolving type anion polyacrylamide with ultra-high molecular weight in example 5, but the single technical means can not achieve the effect of example 5.

As noted above, while the present invention has been shown and described with reference to certain preferred embodiments, it is not to be construed as limited thereto. Various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.