A polymer nanosphere emulsion and its preparation method and application

Abstract

The present invention provides a polymer nanosphere emulsion, a preparation method, and applications of the emulsion. The polymer nanosphere emulsion contains only four elements: carbon, hydrogen, oxygen, and nitrogen, and the nanospheres have a particle size of 10 to 300 nm. The polymer nanosphere emulsion is prepared by mixing and emulsifying a monomer, an amine oxide emulsifier, an oxidizing agent, a reducing agent, and a pH adjuster at 20 to 60°C, and reacting within the aforementioned temperature range for 1 to 6 hours. The polymer nanosphere emulsion can be used as a pore-forming agent for precious metal catalysts or metal oxide catalytic materials. When used as a pore-forming agent for the aforementioned catalysts, it can effectively avoid adverse effects such as precious metal poisoning and decreased structural stability of the catalyst material.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer emulsions, in particular to polymer nano-microsphere emulsions and a preparation method and application thereof. Background Art

[0002] Polymer nanospheres offer advantages such as high specific surface area, high surface activity, good adsorption, and controllable structure. They can be used as templates for catalyst pore formation or catalyst coating pore formation, and possess enormous application prospects and practical value in the fields of catalysis and materials. Aqueous emulsion polymerization is the most widely used method for synthesizing polymer nanospheres, characterized by its non-toxicity, environmental friendliness, simplicity, low cost, and ease of industrialization. The raw materials involved in aqueous emulsion polymerization include water, monomers, emulsifiers, initiators, and pH adjusters. When conventional raw materials such as emulsifiers (e.g., hexadecyl ammonium bromide, sodium dodecylsulfonate), initiators (e.g., potassium persulfate, imidazolium azodihydrochloride, ammonium persulfate / potassium hyposulfite), catalysts (e.g., ferrous sulfate), or buffers (e.g., sodium dihydrogen phosphate, sodium bicarbonate) are used, the introduction of various heteroatoms, such as halogens, sulfur, phosphorus, sodium, potassium, or iron, into the polymer nanosphere emulsion system is unavoidable. However, the presence of these trace heteroatoms can lead to adverse effects such as precious metal poisoning and decreased catalyst structural stability, significantly limiting the application of polymer emulsion microspheres in catalyst pore formation. Furthermore, while common nonionic emulsifiers in the field (such as tween and span emulsifiers) do not contain heteroatoms, their emulsification performance is inferior to that of ionic emulsifiers. The resulting polymer microspheres are larger in size, have lower solids content, and exhibit poor emulsion stability. While diionic emulsifiers such as betaine lack heteroatoms, elements such as chlorine and sodium can be introduced during the production process, which is difficult to completely remove. Regarding initiators, azo and peroxide initiators (such as azobisisobutyronitrile and dibenzoyl peroxide) are oil-soluble, making them difficult to use in aqueous emulsion polymerization. Some redox initiation systems (such as hydrogen peroxide and ascorbic acid) often require ferrous salts as catalysts. Therefore, the present invention specifically develops a polymer nanosphere emulsion containing only four elements: carbon, hydrogen, oxygen, and nitrogen. It can be safely applied to the field of catalytic materials and effectively solves the technical problem of performance degradation of catalysts due to the presence of heteroatoms. Summary of the Invention

[0003] In response to the shortcomings of the existing technology, the present invention provides a polymer nanosphere emulsion, a preparation method and application thereof. By rationally screening and matching raw materials, a polymer nanosphere emulsion containing only four elements: carbon, hydrogen, oxygen and nitrogen is prepared, and used as a pore-forming agent for precious metal-containing catalysts and metal oxide catalyst materials and coatings, which can effectively avoid adverse effects such as precious metal poisoning and decreased material structural stability caused by impurities.

[0004] The present invention provides a polymer nanosphere emulsion, a preparation method, and an application thereof. The polymer nanosphere emulsion contains only four elements: carbon, hydrogen, oxygen, and nitrogen. The particle size of the polymer nanospheres is 10 to 300 nm, and the mass fraction of the polymer nanospheres in the emulsion is 5 to 50%.

[0005] Among them, the particle size of the nanospheres can reach 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm, 100nm, 110nm, 120nm, 130nm, 140nm, 150nm, 160nm, 170nm, 180nm, 190nm, 200nm, 220nm, 240nm, 260nm, 280nm, and 300nm.

[0006] Among them, the content of polymer nanospheres in the emulsion is preferably 5%, 7%, 9%, 10, 12%, 15%, 18%, 20%, 22%, 25%, 27%, 30%, 32%, 35%, 37%, 40%, 42%, 45%, 47%, and 50%.

[0007] In the present invention, the polymer nanosphere emulsion is prepared by an emulsion polymerization method, and the emulsion polymerization system includes 41-94.997% water, 5-50% monomers, 0.001-5% emulsifier, 0.001-2% oxidant, 0.001-2% reducing agent and pH regulator.

[0008] In the present invention, the water is distilled water or deionized water, and the usage amount is 41-94.997%.

[0009] In the present invention, the monomer contains only four elements of carbon, hydrogen, oxygen and nitrogen, and is preferably vinyl acetate, acrylic acid, methacrylic acid, itaconic acid, dibutyl maleate, dioctyl maleate, acrylamide, methacrylamide, N,N-methylenebisacrylamide, vinyl pyrrolidone, acrylonitrile, methyl acrylate, ethyl acrylate, isobornyl acrylate, butyl acrylate, lauryl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, isobutyl acrylate, isodecyl acrylate, isooctyl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, isobutyl acrylate, isodecyl acrylate, isooctyl acrylate, 2-hydroxypropyl acrylate, One or more of ester, methyl methacrylate, ethyl methacrylate, isobornyl methacrylate, butyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, isobutyl methacrylate, isodecyl methacrylate, isooctyl methacrylate, dimethylaminoethyl methacrylate, 2-hydroxypropyl methacrylate, ethylene glycol dimethacrylate, styrene, 2,4-dimethylstyrene, α-methylstyrene, β-methylstyrene, α-ethylstyrene or divinylbenzene.

[0010] Among them, the monomer usage is 5~50%, preferably 5%, 7%, 9%, 10, 12%, 15%, 18%, 20%, 22%, 25%, 27%, 30%, 32%, 35%, 37%, 40%, 42%, 45%, 47%, and 50%.

[0011] In the present invention, the emulsion polymer is an amine oxide emulsifier, preferably one or more of octadecyl dimethyl amine oxide, octadecyl dihydroxyethyl amine oxide, octadecylamine polyoxyethylene ether oxide, stearyl amidopropyl dimethyl amine oxide, octadecyl amidopropyl dimethyl amine oxide, tallow amidopropyl dimethyl amine oxide, tetradecyl dimethyl amine oxide, dodecyl dimethyl amine oxide, dodecyl dihydroxyethyl amine oxide, cocoamidopropyl amine oxide or lauryl amidopropyl amine oxide.

[0012] Among them, the amount of emulsifier is 0.001~5%, preferably 0.001%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, 0.22%, 0.24%, 0.26%, 0.28%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.55%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, and 5%.

[0013] In the present invention, the oxidant is a hydrogen peroxide compound, preferably one or more of hydrogen peroxide, tert-butyl hydroperoxide, and cumene hydroperoxide.

[0014] The amount of oxidant is 0.001% to 2%, preferably 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.007%, 0.008%, 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045%, 0.05%, 0.055%, 0.06%, 0.065%, 0.07%, 0.075%, 0.08%, 0.085 %, 0.09%, 0.095%, 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, 0.22%, 0.24%, 0.26%, 0.28%, 0.3%, 0.32%, 0.35%, 0.37%, 0.4%, 0.42%, 0.45%, 0.47%, 0.5%, 0.52%, 0.55%, 0.57%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%.

[0015] In the present invention, the reducing agent is one or more of ascorbic acid, ethoxyacetic acid, glucose, formic acid, and ethylenediamine.

[0016] The amount of reducing agent is 0.001% to 2%, preferably 0.001%, 0.002%, 0.003%, 0.004%, 0.005%, 0.007%, 0.008%, 0.01%, 0.015%, 0.02%, 0.025%, 0.03%, 0.035%, 0.04%, 0.045%, 0.05%, 0.055%, 0.06%, 0.065%, 0.07%, 0.075%, 0.08%, 0.085 %, 0.09%, 0.095%, 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, 0.22%, 0.24%, 0.26%, 0.28%, 0.3%, 0.32%, 0.35%, 0.37%, 0.4%, 0.42%, 0.45%, 0.47%, 0.5%, 0.52%, 0.55%, 0.57%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.5%, 2%.

[0017] In the present invention, the ratio of the oxidant to the reducing agent is 1:5 to 5:1, preferably 1:5, 1:4.5, 1:4, 1:3.5, 1:3, 1:2.5, 1:2, 1:1.8, 1:1.6, 1:1.4, 1:1.3, 1:1.2, 1:1.1, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.8:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, and 5:1.

[0018] In the present invention, the pH regulator is an organic acid and ammonia water, wherein the organic acid is selected from one or more of acetic acid, oxalic acid, citric acid and lactic acid.

[0019] Among them, the pH range of the emulsion is 2~6, preferably 2:, 2.2, 2.4, 2.6, 2.8, 3, 3.2, 3.4, 3.6, 3.8, 4, 4.2, 4.4, 4.6, 4.8, 5, 5.2, 5.4, 5.6, 5.8, and 6.

[0020] In the present invention, emulsion polymerization is implemented according to the following steps:

[0021] i. Water, an emulsifier, and a pH adjuster were added to the reactor and stirred evenly, and the pH of the system was controlled to be 2 to 6 and the temperature to be 20 to 60 ° C to form an aqueous phase;

[0022] ii. The monomer is added to the aqueous phase system and stirred at high speed for 10 to 30 minutes to form a milky white emulsion;

[0023] iii. dissolving the oxidizing agent and the reducing agent in water to form an aqueous solution;

[0024] iv. adding the oxidizing agent solution and the reducing agent solution to the above emulsion system and reacting for 1 to 6 hours to terminate the polymerization reaction to obtain a nano-scale polymer microsphere emulsion with high solid content and good stability.

[0025] Among them, the polymerization reaction temperature is preferably 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, or 60°C.

[0026] In the present invention, the oxidant solution and the reducing agent solution in the emulsion polymerization step iv are added in a one-time addition or gradually added dropwise, and the addition time is 10 minutes to 3 hours.

[0027] Among them, the gradual addition time is preferably: 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 40 minutes, 50 minutes, 1 hour, 1.5 hours, 2 hours, 2.5 hours, and 3 hours.

[0028] In the present invention, the polymer nanosphere emulsion can be applied to catalysts containing precious metals or metal oxide catalyst materials or coatings to form pores.

[0029] Among them, the amount of polymer nanosphere emulsion is 5% to 500% of the mass of the precious metal-containing catalyst or metal oxide catalyst material or coating, preferably 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, 80%, 90%, 100%, 120%, 140%, 160%, 180%, 200%, 250%, 300%, 350%, 400%, 450%, and 500%.

[0030] Among them, the precious metal is preferably one or more of silver, gold, ruthenium, rhodium, palladium, osmium, iridium and platinum.

[0031] Among them, the metal oxide is preferably one or more of copper oxide, titanium oxide, zinc oxide, nickel oxide, zirconium oxide, cerium oxide, lanthanum oxide, yttrium oxide, manganese oxide, bismuth oxide, cobalt oxide, aluminum oxide, neodymium oxide, and tungsten oxide.

[0032] Beneficial effects of the present invention:

[0033] By implementing this patented technology, a polymer nanosphere emulsion containing only four elements, carbon, hydrogen, oxygen, and nitrogen, can be obtained. The emulsion is applied to precious metal-containing catalysts or metal oxide catalytic materials or coating pore formation, which can effectively avoid adverse effects such as precious metal poisoning and reduced material structural stability; the diameter of the polymer nanospheres can be as low as 10nm, the content of the polymer nanospheres can be as high as 50%, and the conversion rate exceeds 85%, reaching 99.9%; the preparation method adopted does not involve organic solvents (it is a water emulsion system) and has a high conversion rate. Whether in the preparation process or the actual application process of the polymer nanosphere emulsion, there will be no environmental pollution due to the large-scale volatilization of organic solvents or monomers. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 These are the experimental results of the catalytic conversion of propane using platinum-based catalysts.

[0035] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the examples given are not intended to limit the present invention. DETAILED DESCRIPTION

[0036] To further illustrate the technical means and effects of the present invention, the present invention is further described below with reference to the following examples. It should be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention.

[0037] Example 1

[0038] i 70g of water, 0.3g of tetradecyl dimethylamine oxide emulsifier, acetic acid and ammonia were added to the reactor and stirred evenly, and the pH of the system was controlled to 3 and the temperature was 20 ℃ to form an aqueous phase;

[0039] ii. 20g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0040] iii. 0.05g of hydrogen peroxide and 0.05g of ascorbic acid were dissolved in 5g of water to form an aqueous solution;

[0041] iv. The oxidant solution and the reducing agent solution were added to the above emulsion system at one time, and the reaction was carried out for 3 hours to terminate the polymerization reaction.

[0042] Example 2

[0043] The polymer nanosphere emulsion prepared in Example 1 was applied to a platinum-containing catalyst to form pores, and the platinum-based catalyst after forming pores was used in a propane catalytic conversion test.

[0044] Comparative Example 1

[0045] i. 70g of water, 0.3g of nonionic emulsifier lauryl alcohol polyoxyethylene (23) ether, acetic acid and ammonia were added to the reactor and stirred evenly, and the pH of the system was controlled to 3 and the temperature was 20 ℃ to form an aqueous phase;

[0046] ii. 20g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0047] iii. 0.05g of hydrogen peroxide and 0.05g of ascorbic acid were dissolved in 5g of water to form an aqueous solution;

[0048] iv. The oxidant solution and the reducing agent solution were added to the above emulsion system at one time, and the reaction was carried out for 3 hours to terminate the polymerization reaction.

[0049] Comparative Example 2

[0050] i 70g of water, 0.3g of reactive nonionic emulsifier MAXEMUL 5011, acetic acid and aqueous ammonia were added to the reactor and stirred uniformly, and the pH of the system was controlled to 3 and the temperature was 20 ℃ to form an aqueous phase;

[0051] ii. 20g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0052] iii. 0.05g of hydrogen peroxide and 0.05g of ascorbic acid were dissolved in 5g of water to form an aqueous solution;

[0053] iv. The oxidant solution and the reducing agent solution were added to the above emulsion system at one time, and the reaction was carried out for 3 hours to terminate the polymerization reaction.

[0054] Comparative Example 3

[0055] i 70g of water, 0.3g of tetradecyl dimethylamine oxide emulsifier, acetic acid and ammonia were added to the reactor and stirred evenly, and the pH of the system was controlled to 3 and the temperature was 70 ℃ to form an aqueous phase;

[0056] ii. 20g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0057] iii. 0.01g of tert-butyl hydroperoxide was dissolved in 10g of water to form an aqueous solution;

[0058] iv. The tert-butyl hydroperoxide solution was added to the above emulsion system at one time and reacted for 3 hours to terminate the polymerization reaction.

[0059] Comparative Example 4

[0060] The platinum-containing catalyst without microsphere pore formation was directly used in the propane catalytic conversion experiment.

[0061] Comparative Example 5

[0062] i 70g of water, 0.3g of sodium dodecyl sulfate emulsifier was stirred in the reactor at a temperature of 20 ° C to form an aqueous phase;

[0063] ii. 20g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0064] iii. 0.05g of hydrogen peroxide and 0.05g of ascorbic acid were dissolved in 5g of water to form an aqueous solution;

[0065] iv. The oxidant solution and the reducing agent solution were added to the above emulsion system at one time, and the reaction was carried out for 3 hours to terminate the polymerization reaction.

[0066] v. The prepared polymer microsphere emulsion is applied to a platinum-containing catalyst to form pores, and the platinum-based catalyst after the pores are formed is used in a propane catalytic conversion test.

[0067] Comparative Example 6

[0068] i 70g of water, 0.3g of tetradecyl dimethylamine oxide emulsifier, acetic acid and ammonia were added to the reactor and stirred evenly, and the pH of the system was controlled to 3 and the temperature was 70 ℃ to form an aqueous phase;

[0069] ii. 20g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0070] iii. 0.05 g of azobisisobutylimidazoline hydrochloride was dissolved in 10 g of water to form an aqueous solution;

[0071] iv. The azobisisobutylimidazoline hydrochloride solution was added to the above emulsion system at one time and reacted for 3 hours to terminate the polymerization reaction.

[0072] v. The prepared polymer microsphere emulsion is applied to a platinum-containing catalyst to form pores, and the platinum-based catalyst after the pores are formed is used in a propane catalytic conversion test.

[0073] Comparative Example 7

[0074] i 70g of water, 0.3g of tetradecyl dimethylamine oxide emulsifier, 0.01 ferrous sulfate, acetic acid and ammonia were added to the reactor and stirred, and the pH of the system was controlled to 3 and the temperature was 20 ℃ to form an aqueous phase;

[0075] ii. 20g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0076] iii. 0.05g of hydrogen peroxide and 0.05g of ascorbic acid were dissolved in 5g of water to form an aqueous solution;

[0077] iv. The oxidant solution and the reducing agent solution were added to the above emulsion system at one time, and the reaction was carried out for 3 hours to terminate the polymerization reaction.

[0078] v. The prepared polymer microsphere emulsion is applied to a platinum-containing catalyst to form pores, and the platinum-based catalyst after the pores are formed is used in a propane catalytic conversion test.

[0079] Example 3

[0080] i 70g of water, 0.8g of tetradecyl dimethylamine oxide emulsifier, acetic acid and ammonia were added to the reactor and stirred evenly, and the pH of the system was controlled to 3 and the temperature was 20 ℃ to form an aqueous phase;

[0081] ii. 20g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0082] iii. 0.05g of hydrogen peroxide and 0.05g of ascorbic acid were dissolved in 5g of water to form an aqueous solution;

[0083] iv. The oxidant solution and the reducing agent solution were added to the emulsion system at one time, and the reaction was carried out for 3 hours to terminate the polymerization reaction.

[0084] Example 4

[0085] i 70g of water, 0.3g of tetradecyl dimethylamine oxide emulsifier, oxalic acid and ammonia were added to the reactor and stirred evenly, and the pH of the system was controlled to 3 and the temperature was 20 ℃ to form an aqueous phase;

[0086] ii. 10g of butyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0087] iii. 0.05g of hydrogen peroxide and 0.05g of ascorbic acid were dissolved in 5g of water to form an aqueous solution;

[0088] iv. The oxidant solution and the reducing agent solution were added to the above emulsion system at one time, and the reaction was carried out for 3 hours to terminate the polymerization reaction.

[0089] Example 5

[0090] i 70g of water, 0.3g of tetradecyl dimethylamine oxide emulsifier, acetic acid and ammonia were added to the reactor and stirred evenly, and the pH of the system was controlled to 3 and the temperature was 20 ℃ to form an aqueous phase;

[0091] ii 10g of styrene monomer and 10g of acrylonitrile were added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0092] iii. Dissolve 0.05g of hydrogen peroxide and 0.05g of glucose in 5g of water to form an aqueous solution;

[0093] iv. The oxidant solution and the reducing agent solution were added to the emulsion system at one time, and the reaction was carried out for 3 hours to terminate the polymerization reaction.

[0094] Example 6

[0095] i 70g of water, 0.3g of tetradecyl dimethylamine oxide emulsifier, acetic acid and ammonia were added to the reactor and stirred evenly, and the pH of the system was controlled to 3 and the temperature was 40 ℃ to form an aqueous phase;

[0096] ii. 20g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0097] iii. 0.05g of hydrogen peroxide and 0.05g of ascorbic acid were dissolved in 5g of water to form an aqueous solution;

[0098] iv. The oxidant solution and the reducing agent solution were added to the above emulsion system at one time, and the reaction was carried out for 3 hours to terminate the polymerization reaction.

[0099] Example 7

[0100] i 70g of water, 0.3g of dodecyl dimethylamine oxide emulsifier, acetic acid and ammonia were added to the reactor and stirred evenly, and the pH of the system was controlled to 4.5 and the temperature was 20 ℃ to form an aqueous phase;

[0101] ii. 20g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0102] iii. 0.05g of hydrogen peroxide and 0.1g of ascorbic acid were dissolved in 5g of water to form an aqueous solution;

[0103] iv. The oxidant solution and the reducing agent solution were added to the above emulsion system at one time, and the reaction was carried out for 3 hours to terminate the polymerization reaction.

[0104] Example 8

[0105] i 70g of water, 0.3g of tetradecyl dimethylamine oxide emulsifier, acetic acid and ammonia were added to the reactor and stirred evenly, and the pH of the system was controlled to 3 and the temperature was 20 ℃ to form an aqueous phase;

[0106] ii. 20g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0107] iii. 0.05g of hydrogen peroxide and 0.05g of ascorbic acid were dissolved in 5g of water to form an aqueous solution;

[0108] iv. The oxidant solution and the reducing agent solution were added dropwise to the emulsion system for 30 minutes. After the addition was completed, the reaction was continued for 3 hours to terminate the polymerization reaction.

[0109] Example 9

[0110] i 70g of water, 1.5 g of dodecyl dimethylamine oxide emulsifier, acetic acid and ammonia were added to the reactor and stirred evenly, and the pH of the system was controlled to 3 and the temperature was 30 ℃ to form an aqueous phase;

[0111] ii. 20g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to a milky white emulsion;

[0112] iii. 0.05g of hydrogen peroxide and 0.05g of ascorbic acid were dissolved in 5g of water to form an aqueous solution;

[0113] iv. The oxidant solution and the reducing agent solution were added to the above emulsion system at one time, and the reaction was carried out for 3 hours to terminate the polymerization reaction.

[0114] Example 10

[0115] i 70g of water, 3 g of octadecyl dimethylamine oxide emulsifier, acetic acid and ammonia were added to the reactor and stirred evenly, and the pH of the system was controlled to 3 and the temperature was 30 ℃ to form an aqueous phase;

[0116] ii. 40g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to obtain a milky white emulsion;

[0117] iii. 0.1g of hydrogen peroxide and 0.15g of ascorbic acid were dissolved in 5g of water to form an aqueous solution;

[0118] iv. The oxidant solution and the reducing agent solution were added to the above emulsion system at one time, and the reaction was carried out for 3 hours to terminate the polymerization reaction.

[0119] Example 11

[0120] i 70g of water, 0.1 g of octadecyl dimethylamine oxide emulsifier, acetic acid and ammonia were added to the reactor and stirred evenly, and the pH of the system was controlled to 3.5 and the temperature was 30 ℃ to form an aqueous phase;

[0121] ii. 40g of methyl methacrylate monomer was added to the aqueous phase system and stirred at high speed for 10 minutes to obtain a milky white emulsion;

[0122] iii. 0.1g of hydrogen peroxide and 0.15g of ascorbic acid were dissolved in 5g of water to form an aqueous solution;

[0123] iv. The oxidant solution and the reducing agent solution were added to the above emulsion system at one time, and the reaction was carried out for 3 hours to terminate the polymerization reaction.

[0124] The emulsion polymerization experimental results of Examples 1, 3-11 and Comparative Examples 1-3 are shown in Table 1.

[0125] Table 1. Experimental results of Examples 1, 3 to 11 and Comparative Examples 1 to 3

[0126] Test samples Average particle size (nm) Monomer conversion rate (%) Example 1 76 92.5 Example 3 43 95.3 Example 4 38 99.9 Example 5 49 93.6 Example 6 71 89.4 Example 7 113 86.5 Example 8 97 99.2 Example 9 23 99.5 Example 10 53 98.5 Example 11 300 93.1 Comparative Example 1 Demulsification - Comparative Example 2 Demulsification Low conversion rate Comparative Example 3 156 68.5

[0127] Note: “-” means there is no test data

[0128] As can be seen from Table 1, the polymer nanoemulsion synthesized by the present invention has high stability (observation shows that it has no obvious sedimentation after storage for 3 months), and the monomer conversion rate is high, most of which exceed 90%, and polymer nanospheres with a particle size far below 50nm can be obtained. Comparative Examples 1 to 3 all use similar heteroatom-free emulsifiers or initiators as in the examples instead, and their implementation effects are poor: Comparative Example 1 uses a non-ionic emulsifier to replace the amine oxide emulsifier defined in the present invention, and the synthesized emulsion has poor stability and severe demulsification during the polymerization process; Comparative Example 2 uses a reactive non-ionic emulsifier to replace the amine oxide emulsifier defined in the present invention, and the synthesized emulsion stability is also poor, demulsification occurs during the polymerization process, and it is difficult to form stable polymer nanospheres. In addition, the system has a clear monomer layer, indicating a low monomer conversion rate; Comparative Example 3 uses a thermal initiator with a certain water solubility for thermal initiation, resulting in a significant increase in the surface polymer nanosphere particle size and a significant decrease in monomer conversion rate.

[0129] The experimental results of Example 2 and Comparative Examples 4 to 7 are shown in the attached Figure 1 As shown. In Example 2, the platinum-based catalyst pore-forming using the polymer nanosphere emulsion of the present invention achieved a catalytic conversion efficiency of over 90% for propane, and the conversion temperature was the lowest. In Comparative Example 4, the platinum-based catalyst was not pore-formed using any polymer nanosphere emulsion. It was found that the final catalytic conversion efficiency of the platinum-based catalyst for propane was less than 90%, and the conversion temperature was higher than that of Example 2. Comparative Examples 5 to 7 use a polymer microsphere emulsion containing heteroatoms to form pores on a platinum-based catalyst. After the pores are formed, the catalyst shows obvious poisoning, the conversion efficiency is lower than that of Example 2 and Comparative Example 4, and the conversion temperature is higher than that of Example 2 and Comparative Example 4: Comparative Example 5 uses a sulfur-containing polymer nanosphere emulsion to form pores on a platinum-based catalyst. After the pores are formed, the catalytic conversion efficiency of propane is about 80%, and the conversion temperature is higher than that of Example 2 and Comparative Example 4; Comparative Example 6 uses a halogen-containing polymer nanosphere emulsion to form pores on a platinum-based catalyst. After the pores are formed, the catalytic conversion temperature of propane increases significantly. At the highest test temperature, the conversion efficiency is about 70%; Comparative Example 7 uses an iron-containing polymer nanosphere emulsion to form pores on a platinum-based catalyst. After the pores are formed, the catalytic conversion temperature of propane increases significantly. At the highest test temperature, the conversion efficiency is about 70%.

Claims

1. A polymer nanosphere emulsion, characterized in that: The polymer nanosphere emulsion contains only four elements: carbon, hydrogen, oxygen and nitrogen. The polymer nanosphere emulsion is prepared by an emulsion polymerization method, and the emulsion polymerization raw materials are composed of the following substances: water with a mass fraction of 41 to 94.997%, 5 to 50% of monomers, 0.001 to 5% of an amine oxide emulsifier, 0.001 to 2% of an oxidant, 0.001 to 2% of a reducing agent and a pH regulator.

2. A polymer nanosphere emulsion according to claim 1, characterized in that, The particle size of the polymer nano-microspheres is 10-300nm, and the mass fraction of the polymer nano-microspheres in the entire emulsion is 5-50%.

3. The polymer nanosphere emulsion according to any one of claims 1 to 2, characterized in that: The monomer is one or more of vinyl acetate, acrylic acid, methacrylic acid, itaconic acid, dibutyl maleate, dioctyl maleate, acrylamide, methacrylamide, N,N-methylenebisacrylamide, vinyl pyrrolidone, acrylonitrile, methyl acrylate, ethyl acrylate, isobornyl acrylate, butyl acrylate, lauryl acrylate, 2-hydroxyethyl acrylate, glycidyl acrylate, isobutyl acrylate, isodecyl acrylate, isooctyl acrylate, 2-hydroxypropyl acrylate, methyl methacrylate, ethyl methacrylate, isobornyl methacrylate, butyl methacrylate, lauryl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, isobutyl methacrylate, isodecyl methacrylate, isooctyl methacrylate, dimethylaminoethyl methacrylate, 2-hydroxypropyl methacrylate, ethylene glycol dimethacrylate, styrene, 2,4-dimethylstyrene, α-methylstyrene, β-methylstyrene, α-ethylstyrene or divinylbenzene.

4. The polymer nanosphere emulsion according to any one of claims 1 to 2, characterized in that: The amine oxide emulsifier is one or more of octadecyl dimethyl amine oxide, octadecyl dihydroxyethyl amine oxide, octadecylamine polyoxyethylene ether oxide, stearyl amidopropyl dimethyl amine oxide, octadecyl amidopropyl dimethyl amine oxide, tallow amidopropyl dimethyl amine oxide, tetradecyl dimethyl amine oxide, dodecyl dimethyl amine oxide, dodecyl dihydroxyethyl amine oxide, cocoamidopropyl amine oxide or lauryl amidopropyl amine oxide.

5. The polymer nanosphere emulsion according to claim 1, characterized in that: The oxidant is one or more of hydrogen peroxide, tert-butyl hydroperoxide, and cumene hydroperoxide; the reducing agent is one or more of ascorbic acid, ethoxyacetic acid, glucose, formic acid, and ethylenediamine; and the molar ratio of the oxidant to the reducing agent is 1:5 to 5:

1.

6. The polymer nanosphere emulsion according to claim 1, characterized in that: The pH regulator is an organic acid and ammonia water, wherein the organic acid is selected from one or more of acetic acid, oxalic acid, citric acid or lactic acid.

7. The method for preparing a polymer nanosphere emulsion according to any one of claims 1 to 6, comprising the following steps: i. Water, an amine oxide emulsifier, and a pH adjuster are added to the reaction vessel and stirred evenly, and the pH of the system is controlled to be 2 to 6 and the temperature is 20 to 60 ° C to form an aqueous phase; ii. Add the monomer to the aqueous phase system and stir for 10 to 30 minutes until a milky white emulsion is obtained; iii. dissolving the oxidizing agent and the reducing agent in water to form an aqueous solution; iv. The oxidizing agent solution and the reducing agent solution are added to the above emulsion system, and the reaction is carried out for 1 to 6 hours to terminate the polymerization reaction to obtain a nano-scale polymer microsphere emulsion with a high solid content and good stability; In step iv, the oxidant solution and the reducing agent solution are added in a one-time addition or in a gradual dropwise addition manner. When the gradual dropwise addition manner is adopted, the addition time is 10 minutes to 3 hours.

8. Use of the polymer nanosphere emulsion according to any one of claims 1 to 6 in pore formation of noble metal-containing catalysts, pore formation of metal oxide catalyst materials, or pore formation of coatings.

9. The use of the polymer nanosphere emulsion according to claim 8, characterized in that: The amount of polymer nano-microsphere emulsion used is 5% to 500% of the mass of the catalyst containing precious metal or metal oxide catalyst material or coating.

10. The use of the polymer nanosphere emulsion according to any one of claims 8 to 9, characterized in that: Precious metals include one or more of silver, gold, ruthenium, rhodium, palladium, osmium, iridium, and platinum; metal oxides include one or more of copper oxide, titanium oxide, zinc oxide, nickel oxide, zirconium oxide, cerium oxide, lanthanum oxide, yttrium oxide, manganese oxide, bismuth oxide, praseodymium oxide, cobalt oxide, aluminum oxide, neodymium oxide, tungsten oxide, and strontium oxide.

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