METHOD TO PREPARE POLYMER MATERIALS WITH INTERLOCKED POROUS STRUCTURES BY FREEZING AND DEMULSIFICATION OF EMULSION

Abstract

The present invention provides a method to prepare polymer materials with interlocked porous structures by freezing and demulsification, which includes: (1) Preparing an emulsion containing uncrosslinked polymers and crosslinking agents. The uncrosslinked polymers are presented in the organic phase, and the crosslinking agents are presented in the organic phase or water phase. Under freezing, the demulsification is occurred which leads to the interaction between polymers and crosslinking agents, and the crosslinked materials are obtained. (2) After removing the ice crystals, polymer materials with interlocked porous structures are synthesized. The method provided by the present invention is simple to operate, and can well adjust the porous structures of obtained porous polymer materials. In addition, it is suitable for large scale manufacturing. At the same time, this process can form different functional porous polymer materials by simply changing the used monomers. Particularly, it can prepare melt-blown fabrics with antibacterial property, high-throughput vertical porous structures and high-temperature sterilizable feature, therefore, it can be used to manufacture medical products such as masks.

Claims

1. A method to prepare polymer materials with interlocked porous structures by freezing and demulsification of emulsion, comprising the following steps: (1) preparing an emulsion containing uncrosslinked polymers and crosslinking agents, wherein the uncrosslinked polymers are presented in an organic phase, and the crosslinking agents are presented in the organic phase or a water phase; under freezing, demulsification occurs and leads to interaction between the uncrosslinked polymers and the crosslinking agents; and (2) after removing ice crystals, obtaining polymer materials with interlocked porous structures.

2. The method for preparing polymer materials with interlocked porous structures by freezing and demulsification according to claim 1, wherein the polymers used in step (1) are selected from one or a combination of two of polyacrylates, polyurethanes, epoxy resins, polycarbonate, or polystyrene; the polymers need contain crosslinkable groups; the polymers are directly added, or obtained from the in-situ polymerization of reactive monomers under action of an initiator.

3. The method for preparing polymer materials with interlocked porous structures by freezing and demulsification according to claim 2, wherein the crosslinkable groups is diacetone acrylamide, glycidyl methacrylate, or epoxy acrylate.

4. The method for preparing polymer materials with interlocked porous structures by freezing and demulsification according to claim 2, wherein functional monomers are added at the same time if using in-situ polymerization of the reactive monomers to synthesize polymers.

5. The method for preparing polymer materials with interlocked porous structures by freezing and demulsification according to claim 1, wherein, in step (1), the crosslinking agents are one or a combination of two of hexamethylene dihydrazide, hexamethylene diamine, triethyl hydrazide, tetramine, dithiothreitol, or methylene bisacrylamide.

6. The method for preparing polymer materials with interlocked porous structures by freezing and demulsification according to claim 1, wherein, in step (1), the freezing temperature is below −5° C., and the freezing approach is directional freezing or conventional random freezing.

7. The method for preparing polymer materials with interlocked porous structures by freezing and demulsification according to claim 1, wherein, in step (2), the ice crystals are removed by air drying, vacuum drying or heating.

8. The method for preparing polymer materials with interlocked porous structures by freezing and demulsification according to claim 1, wherein the porous structures can be controlled by adding additives to the emulsion or changing the wettability of substrates.

9. A method of using polymer materials with interlocked porous structures by freezing and demulsification made according to claim 1, wherein the obtained porous polymer materials are used as filters, mechanical damping objects, sound insulation materials, shocking absorption materials, shape memory materials, antibacterial materials, antiviral materials and absorbent materials.

10. The method of using polymer materials with interlocked porous structures according to claim 9, wherein the porous polymer materials replace melt-blown fabrics, prepare tissue clips, or be used as collodion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG. 1 is a photograph of obtained porous polymer material in example 1.

[0031] FIG. 2 is a SEM image of the polymer material with interlocked porous structures in example 1.

[0032] FIG. 3 is a SEM image of the polymer material with interlocked porous structures in example 2.

[0033] FIG. 4 is a SEM image of the polymer material with interlocked porous structures in example 3.

[0034] FIG. 5 is a SEM image of the polymer material with small pores in example 6;

[0035] FIG. 6 is a schematic diagram of continuously preparing porous polymer materials in example 7;

[0036] FIG. 7 is a schematic diagram of the preparing method of polymer through-hole materials.

DETAILED EMBODIMENTS OF THE PRESENT INVENTION

[0037] The present invention will be further described below with the embodiments, but the ranges of protection claimed in the present invention is not limited to the embodiments.

[0038] The schematic diagram of the method for preparing polymer materials with interlocked porous structures by freezing and demulsification is shown in FIG. 7.

Example 1 (Using Diacetone Acrylamide and Adipic Acid Dihydrazide to Form Crosslinking Network)

[0039] The used raw materials and their ratios:

TABLE-US-00002 Reagent Dosage/g Reagent Dosage/g Primer liquid: Deionized water 80.00 Emulsifier 0.40 A-980 Ammonium 0.30 Emulsifier 0.60 persulfate A-6828 Sodium Bisulfite 0.30 Sodium 0.35 bicarbonate Butyl acrylate 8.00 Pre-emulsion liquid: Deionized water 80.00 Emulsifier 1.00 246 Ammonium 0.32 Emulsifier 1.00 persulfate A151 Emulsifier 102 3.00 Diacetone 1.00 acrylamide Emulsifier T-40 3.00 Acrylonitrile 15.00 Butyl acrylate 88.00 Ethyl acrylate 90.00 Initiation system: Sodium 0.32 Sodium 0.50 Bisulfite Dodecyl Sulfonate Deionized water 15.00 Post-treatment liquid: Ammonia 1.50 Adipic 0.60 acid hydrazide Deionized water 7.00

[0040] Preparation Steps:

[0041] (1) The primer was prepared in a reaction container according to the formulas, and stirred at 60° C. for 20 minutes until appearing light blue color. Then, according to pre-emulsion liquid formula, emulsifiers and other additives were added to the water phase, and stirred until completely dissolved. Next, other monomers were added to the previous liquid and emulsified under large shearing rate to form stable pre-emulsion liquid. Finally, after the blue light of the primer appeared, the pre-emulsion liquid was gradually added into the primer. The total dripping time was 4 hours.

[0042] (2) 30 minutes after the start of the pre-emulsion dripping, the initiator was dripped into the pre-emulsion and the dripping time was 4 hours.

[0043] (3) After addition of the pre-emulsion liquid and the initiator, the reaction was initiated and continued for 2 hours. Then, the temperature was lowered to 45° C. The post-treatment liquid was added and kept for 15 minutes. Then the product was filtered out.

[0044] (4) Above acrylic emulsion was poured into a container and frozen at −100° C. for 10 minutes. After removing the ice at room temperature, the polyacrylate material with interlocked porous structures was obtained.

Example 2 (Using Glycidyl Acrylate and Triethyltetramine to Form Crosslinking Network)

[0045] The used raw materials and their ratios:

TABLE-US-00003 Reagent Dosage/g Reagent Dosage/g Primer liquid: Deionized water 90.00 Span 80 0.40 Dibenzoyl 0.50 Tween 60 0.60 peroxide Ethyl acrylate 8.00 Sodium 0.35 bicarbonate Pre-emulsion liquid: Deionized water 80.00 Tween 40 3.00 Emulsifier 102 3.00 Glycidyl 5.00 acrylate Butyl acrylate 80.00 Ethyl 92.00 acrylate Post-treatment liquid: Ammonia 1.50 Triethyltetra- 3.00 mine Deionized water 7.00

[0046] The total preparation steps are similar to those in Example 1.

[0047] (1) The primer was prepared in a reaction container according to the formulas, and stirred at room temperature for 20 minutes until appearing light blue color. Then, according to pre-emulsion formula, emulsifiers and other additives were added to the water phase, and stirred until completely dissolved. Next, other monomers were added to the previous liquid and emulsified under large shearing rate to form a stable pre-emulsion liquid. Finally, after the blue light of the primer appeared, the pre-emulsion was gradually added into the primer liquid. The total dripping time was 6 hours.

[0048] (2) After completing the previous process, the temperature was increased to 70° C. to initiate the polymerization. The reaction lasted for 24 hours, and then recover to room temperature.

[0049] (3) The post-treatment liquid was added and stirred for 15 minutes. Then, the products were filtered out.

[0050] (4) Above acrylic emulsion was poured into a container and frozen at −50° C. for 5 minutes. After removing the ice by freezing drying, the polymer material with interlocked porous structures was obtained.

Example 3 (Using Glycidyl Methacrylate and Dithiothreitol to Form Crosslinking Network)

[0051] The used raw materials and their ratios:

TABLE-US-00004 Reagent Dosage/g Reagent Dosage/g Primer liquid: Deionized water 100.00 Emulsifier A- 0.40 980 Azobisisobutyronitrile 0.80 Emulsifier 246 1.00 Methyl methacrylate 10.00 Sodium 0.10 carbonate Pre-emulsion liquid: Deionized water 50.00 Emulsifier 246 1.00 Azobisisobutyronitrile 0.35 Emulsifier 1.00 A151 Emulsifier 102 3.00 Glycidyl 5.00 methacrylate Methyl acrylate 100.00 Methyl 50.00 methacrylate Post-treatment liquid: Sodium acetate 5.00 Dithiothreitol 5.00 Deionized water 10.00

[0052] Preparation Steps:

[0053] (1) The primer was prepared in a reaction container according to the formulas, and stirred at 40° C. until appearing light blue color. Then a stable pre-emulsion liquid was made according to the pre-emulsion liquid formula. The pre-emulsion liquid was added into the reaction container by dripping after appearing light blue color, and the total process was 6 hours.

[0054] (2) 10 minutes after the start of the pre-emulsion dripping, the temperature was increased to 60° C., and whole process was 6 hours.

[0055] (3) After the addition of the pre-emulsion liquid, the reaction was continuously reacted for 6 hours, then the temperature was decreased to room temperature. The post-treatment liquid was added and stirred for 5 minutes. The obtained product was filtered out.

[0056] (4) Above acrylic emulsion was poured into a container and frozen at −180° C. for 0.5 minutes. After removing the ice by directly heating, the polymer material with interlocked porous structures was obtained.

Example 4 (Adjusting Glass Transition Temperature of Obtained Materials)

[0057] By adding different monomers to the original precursor, the glass transition temperature of obtained polymers can be adjusted.

The used raw materials and their ratios:

TABLE-US-00005 Reagent Dosage/g Reagent Dosage/g Primer liquid: Deionized water 90.00 Emulsifier A-980 0.40 Ammonium persulfate 0.50 Emulsifier A-6828 1.00 Sodium Bisulfite 0.35 Sodium bicarbonate 0.10 Butyl acrylate 8.00 Pre-emulsion liquid: Deionized water 100.00 Emulsifier 246 1.00 Ammonium persulfate 0.40 Emulsifier A151 1.00 Emulsifier 102 3.00 Diacetone acrylamide 1.00 Emulsifier T-40 3.00 Acrylonitrile 15.00 Butyl acrylate 88.00 Styrene 120.00 Initiation system: Sodium Bisulfite 0.32 Sodium Dodecyl 0.50 Sulfonate Deionized water 15.00 Post-treatment liquid: ammonia 1.50 Adipic acid hydrazide 0.60 Deionized water 7.00

[0058] Preparation Steps:

[0059] (1) The primer was prepared in the kettle by using the raw materials according to the primer formula, then the primer was stirred and kept at 60° C. for 20 minutes, until blue light appeared; then according to the pre-emulsification formula, emulsifiers and other additives were added into the water, and after they are completely dissolved, other monomers are added and emulsified in a high-shear emulsifier to form a stable pre-emulsion liquid. The pre-emulsion liquid was added dropwise to the kettle after the blue light of the primer appeared. The dropping time was 4 hours;

[0060] (2) 30 minutes after the start of the pre-emulsion liquid dripping, the initiator was dripped in for 4 hours.

[0061] (3) After addition of the pre-emulsion liquid and the initiator, the reaction was initiated and continued for 2 hours. Then, the temperature was lowered to 45° C. The post-treatment liquid was added and kept for 15 minutes. Then the product was filtered out.

[0062] (4) Above acrylic emulsion was poured into a container and frozen at −100° C. for 10 minutes. After removing the ice by melting and evaporation at room temperature, the polyacrylate material with interlocked porous structures was obtained. Such polymer has different glass transition temperatures from the polymer obtained in Example 1. Specifically, the glass transition temperature of the polymer obtained in Example 1 was 20° C., and the glass transition temperature of the material prepared in this example was 61° C.

Example 5 (Adjusting Porous Morphologies by Additives)

[0063] The porous structures of obtained polymer materials are controlled by adding hydrophilic additives to the original formulas.

The typical reagents and their proportions are as follows:

TABLE-US-00006 Reagent Dosage/g Reagent Dosage/g Primer liquid: Deionized water 180.00 Emulsifier A-980 0.50 Ammonium persulfate 0.50 Emulsifier A-6828 0.40 Sodium Bisulfite 0.35 Sodium 0.4 bicarbonate Butyl acrylate 8.00 Polyvinyl alcohol 2.0 Pre-emulsion liquid: Deionized water 100.00 Emulsifier 246 1.00 Ammonium persulfate 0.40 Emulsifier A151 1.00 Emulsifier 102 3.00 Diacetone 1.00 acrylamide Emulsifier T-40 3.00 Acrylonitrile 15.00 Butyl acrylate 88.00 Ethyl acrylate 90.00 Initiation system: Sodium Bisulfite 0.32 Sodium Dodecyl 0.50 Sulfonate Deionized water 15.00 Post-treatment liquid: ammonia 1.50 Adipic acid 0.60 hydrazide Deionized water 7.00

[0064] Preparation Steps:

[0065] (1) The primer was prepared according to the formulas in a reaction container, and stirred at 60° C. for 20 minutes until appearing light blue color. Then, according to pre-emulsion formula, emulsifiers and other additives were added to the water phase, and stirred until completely dissolved. Next, other monomers were added to the previous liquid and emulsified under large shearing rate to form a stable pre-emulsion liquid. Finally, the pre-emulsion liquid was gradually added into the primer in the container. The total time was 4 hours.

[0066] (2) 30 minutes after the start of the pre-emulsion dripping, the initiator was dripped for 4 hours.

[0067] (3) After addition of the pre-emulsion and the initiator, the reaction was initiated and continued for 2 hours. Then, the temperature was lowered to 45° C. The post-treatment liquid was added and kept for 15 minutes. Then the product was filtered out.

[0068] (4) Above acrylic emulsion was poured into a container and frozen at −18° C. for 1 hour. After removing the ice at room temperature through melting and evaporation, the polyacrylate material with interlocked porous structures was obtained. The porosity of such polymer was different from the materials obtained in Example 1. Specifically, porosity of the material prepared in Example 1 was 45%, and the porosity of the material prepared in this example was 90%.

Example 6 (Adjusting Porous Morphologies by Changing Wettability of Used Substrates)

[0069] The used reagents and steps were the same as Example 1. The difference was that before step (4), the freezing stage was coated with polyvinyl alcohol. Then, the emulsion was frozen on this stage at −100° C. for 10 min. After removing the ice by drying at room temperature, the porous polymer material was obtained. In Example 1, the pore size of the material was 100 μm, while the pore size of the material prepared here was 1 μm.

Example 7 (Preparing Polymer Materials with Interlocked Porous Structures Continuously)

[0070] The used reagents and steps were the same as Example 2. The difference was that in step (4), the emulsion was casted rather than molded. The emulsion was frozen at −180° C. cooling platform on the track. After recovered to room temperature, the ice was melting and porous materials can be continuously produced.

Example 8 (Antibacterial Porous Polymer Material)

[0071] The used reagents and steps were the same as Example 1, except adding 20 g of acrylated betaine into the pre-emulsion liquid. After the ice crystals were removed by drying at room temperature, the obtained porous polymer materials will own antibacterial properties.

Example 9 (Shape Memory Porous Polymer Material)

[0072] The porous polymer materials prepared in Example 1 have a glass transition temperature of 20° C. The shape were manipulated above 20° C. and fixed when the temperature decreases to below 20° C. When the temperature rose above 20° C. again, the previous material recovered to its original shape, thus finishing one cycle of shape memory process.

Example 10 (Water Absorbent Collodion)

[0073] The used reagents and steps were the same as Example 1, except adding 50 g of sodium acrylate into the emulsion. By polymerized at 50° C. for 12 hours, the emulsion was cooled to room temperature. Then, it was poured into rectangular mold for freezing. After completely frozen, the system was recovered to room temperature, and the polymer material with interlocked porous structures was obtained after removing ice crystal by freezing drying. Such porous polymer materials had good water absorption property. After characterization, the obtained porous polymer material can absorb water over 10 times of its own weight. Therefore, it can be used in daily water absorption products.