Porous high molecular oil-absorbing particles with three-dimensional network structure and preparation method thereof

Abstract

The application discloses porous high-molecular oil-absorbing particles with a three-dimensional network structure and a preparation method thereof, and belongs to the technical field of functional materials. The preparation method of the porous high-molecular oil-absorbing particles comprises the following steps: (1) using an aqueous solution containing hydroxypropyl methyl cellulose, polyethylene glycol dipolyacrylate and a photoinitiator as a dispersed phase, using an oil phase containing a surfactant as a continuous phase, and using a microfluidic device to prepare water-in-oil microdroplets of the dispersed phase and the continuous phase into monodisperse; (2) performing light crosslinking on the water-in-oil microdroplets, and then performing freeze-drying to obtain the porous high-molecular oil-absorbing particles. The method can accurately control and manipulate the flow and mixing of small droplets or particles based on the microfluidic device, so that the particles have higher uniformity and stability; the prepared oil-absorbing particles are not easy to decompose in a 37 DEG C physiological environment, and the adsorption rate can reach 7 times of the weight of the particles.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of functional materials, in particular to a porous high polymer oil-absorbing particle with a three-dimensional network structure and a preparation method thereof. BACKGROUND

[0002] The porous high polymer oil-absorbing material is a polymer with a three-dimensional network chemical cross-linking structure. Compared with traditional oil-absorbing materials, the porous high polymer oil-absorbing material has the characteristics of large porosity, large adsorption capacity, and fast adsorption speed. At present, the monomers for synthesizing the high polymer oil-absorbing material are mainly acrylate and α-olefin. Due to the high price of α-olefin, acrylate monomers are mostly used to synthesize high polymer materials. There are mainly two synthesis methods: suspension polymerization and emulsion polymerization. Acrylate is used as raw material, and oil-soluble free radicals are used as initiators to initiate polymerization. These methods need to remove the pore-forming agent added in the preparation process by special means, and the preparation process is complex, the cost is high, and it is not conducive to the industrial scale-up and popularization and application of the product.

[0003] Polyethylene glycol diacrylate (PEGDA) is a blank slate hydrogel that can rapidly polymerize and gel at room temperature in the presence of a photoinitiator and ultraviolet light, and can form a cross-linked polymer as a supporting skeleton. Hydroxypropyl methylcellulose (HPMC) is a common natural biopolymer polysaccharide, and its good and sustainable source makes it widely used in the food industry as an emulsifier, thickener and gelling agent. However, hydroxypropyl methylcellulose cannot directly form a gel network in liquid oil. There is no prior art of preparing polyethylene glycol diacrylate and hydroxypropyl methylcellulose into an oil-absorbing material. SUMMARY

[0004] The purpose of the present application is to provide a porous high polymer oil-absorbing particle with a three-dimensional network structure and a preparation method thereof. The method of the present application uses ultraviolet light to cross-link polyethylene glycol diacrylate (PEGDA) and hydroxypropyl methylcellulose (HPMC) on the basis of PEGDA as a supporting skeleton, and then prepares a porous high polymer oil-absorbing particle with a three-dimensional network structure through freeze-drying.

[0005] The present application first provides a preparation method of a porous high polymer oil-absorbing particle, which comprises the following steps:

[0006] (1) using an aqueous solution containing hydroxypropyl methylcellulose (HPMC), polyethylene glycol diacrylate (PEGDA) and a photoinitiator as a dispersed phase, and an oil phase containing a surfactant as a continuous phase, using a microfluidic device to prepare single-dispersed water-in-oil microdroplets from the dispersed phase and the continuous phase;

[0007] (2) irradiating the water-in-oil microdroplets with light to crosslink, and then freeze-drying to obtain the porous polymer oil-absorbing particles.

[0008] The preparation method, in the dispersed phase, the mass-volume ratio of the hydroxypropyl methyl cellulose and water is 0.5-2.0 g:100 mL; specifically, it can be 0.5 g:100 mL, 1.0 g:100 mL or 1.5 g:100 mL; the mass-volume ratio of the polyethylene glycol diacrylate and water is 2.0-10.0 g:100 mL; specifically, it can be 5.0 g:100 mL; the mass-volume ratio of the photoinitiator and water is 0.1-1.0 g:100 mL; specifically, it can be 1.0 g:100 mL.

[0009] The preparation method, in the continuous phase, the mass-volume ratio of the surfactant and solvent is 0.5-2.0 g:100 mL; specifically, it can be 0.5 g:100 mL.

[0010] In the preparation method, the molecular weight of the polyethylene glycol diacrylate is 400-800; specifically, it can be 600;

[0011] The photoinitiator is 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-ketone (Irgacure 2959), 1-hydroxyhexyl phenyl ketone (Irgacure 184) or benzoin dimethyl ether (Irgacure 651); specifically, it can be Irgacure 2959;

[0012] The surfactant is at least one of sorbitan laurate, polyoxyethylene sorbitan trioleate, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol), sorbitan monooleate, polyoxyethylene (10) oleyl ether, polyoxyethylene (2) oleyl ether and Krytox-PEG-Krytox; specifically, it can be Krytox-PEG-Krytox;

[0013] The solvent in the continuous phase is at least one of fluorinated oil, mineral oil, vegetable oil, olive oil, silicone oil and petroleum ether; specifically, it can be fluorinated oil.

[0014] In the preparation method, in the step of preparing water-in-oil microdroplets, the flow rate of the dispersed phase is 1000-2000 μL / h; specifically, it can be 1600 μL / h; the flow rate of the continuous phase is 10-20 mL / h; specifically, it can be 12 mL / h.

[0015] The flow channel width of the microfluidic chip of the microfluidic device is 500-2000 μm, specifically, it can be 800-2000 μm, 800-1200 μm or 1000 μm; the width-height ratio is 0.5:1-3:1.

[0016] In the preparation method, the photo-crosslinking in step (2) is performed under irradiation of an ultraviolet lamp.

[0017] The temperature of the freeze-drying is -50 to -80 DEG C, and the time is 6 to 16 h.

[0018] Specifically, the time of the ultraviolet lamp irradiation can be 30 to 90 s, and the ultraviolet exposure can be 1.5 x 10 6 to 3.0 x 10 6 J / m 2 ; specifically, 2 x 10 6 J / m 2 .

[0019] The preparation method further comprises a pre-freezing step of the water-in-oil microdroplets before the photo-crosslinking.

[0020] Specifically, the temperature of the pre-freezing is -50 to -80 DEG C, and specifically, -80 DEG C; the time is 0.5 to 2 h, and specifically, 1 h.

[0021] The application further provides the porous high-molecular oil-absorbing particles prepared by the preparation method.

[0022] Specifically, the size of the porous high-molecular oil-absorbing particles is 0.8 to 1.2 mm; specifically, 1.05 ± 0.081 mm, 0.95 ± 0.051 mm or 0.94 ± 0.057 mm.

[0023] The application of the porous high-molecular oil-absorbing particles in absorbing oil or oil in an oil-water mixture also belongs to the protection scope of the application.

[0024] Preferably, the oil absorbed by the porous high-molecular oil-absorbing particles is at least one of soybean oil and flaxseed oil.

[0025] The application has the following beneficial effects:

[0026] The method of the application can precisely control and manipulate the flow and mixing of microdroplets or particles based on a microfluidic device, so that the particles have higher uniformity and stability; the oil-absorbing particles are prepared from safe, non-toxic and edible materials, and are harmless to the environment and human bodies; PEGDA is used as a support skeleton, a photoinitiator is used to crosslink HPMC, and then the porous high-molecular oil-absorbing particles with a complex three-dimensional network structure are obtained through freeze-drying; the oil-absorbing particles prepared by the application are not easy to decompose in a 37 DEG C physiological environment, and the adsorption rate can reach 7 times of the weight of the particles. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1Structure diagram of microfluidic device used in the application; in the diagram, 1 is a syringe pump, 2 is a syringe, 3 is a microfluidic chip, 4 is a tetrafluoroethylene tube, and 5 is a collection tube;

[0028] Figure 2 Optical microscope image of water-in-oil microdroplets prepared in Example 1 and optical microscope image after freeze-drying;

[0029] Figure 3 Scanning electron microscope image of oil-absorbing particles prepared in Example 1;

[0030] Figure 4 Scanning electron microscope image of oil-absorbing particles prepared in Example 2;

[0031] Figure 5 Scanning electron microscope image of oil-absorbing particles prepared in Example 3.

[0032] Figure 6 Optical microscope image of water-in-oil microdroplets prepared in the comparative example and optical microscope image after freeze-drying. DETAILED DESCRIPTION

[0033] The application will be further described in detail below with reference to the specific embodiments, and the examples given are only for illustrating the application, but not for limiting the scope of the application.

[0034] In the following examples, the experimental methods are all conventional methods unless otherwise specified.

[0035] In the quantitative tests in the following examples, three repeated experiments were set up, and the average value was taken.

[0036] In the following examples, the materials and reagents used are commercially available unless otherwise specified.

[0037] Irgacure 2959 used in the following examples was purchased from sigma-aldrich with the item number 410896.

[0038] The molecular weight of polyethylene glycol diacrylate (PEGDA) used in the following examples was 600.

[0039] The microfluidic chip used in the application was referred to the flow focusing droplet chip of the company Topstar Micro, and the width and height of the collection channel of the chip were changed accordingly. The width-to-height ratio of the flow channel of the microfluidic chip 3 used in the following examples was 10:3, specifically, the channel width was 1000 μm, and the channel height was 300 μm. The width-to-height ratio of the flow channel of the microfluidic chip used in the comparative example was 1:1, specifically, the channel width was 100 μm, and the channel height was 100 μm.

[0040] The schematic diagram of the microfluidic device used in the application is as follows Figure 1As shown, it includes a syringe pump 1, a syringe 2, a microfluidic chip 3, a tetrafluoroethylene tube 4 and a collection tube 5; the syringe 2 is connected to the inlet of the microfluidic chip 3 through the tetrafluoroethylene tube 4, the outlet of the microfluidic chip 3 is connected to the tetrafluoroethylene tube 4, and the other end of the tetrafluoroethylene tube 4 is connected to the collection tube 5; the syringe pump 1 is used to control the liquid flow rate.

[0041] Example 1

[0042] (1) Prepare dispersed phase and continuous phase solutions: Weigh 0.025 g of HPMC, 0.25 g of PEGDA, and 0.05 g of Irgacure 2959 and dissolve them in 5 mL of deionized water to obtain a dispersed phase; weigh 0.05 g of Krytox-PEG-Krytox and dissolve it in 10 mL of fluorinated oil to obtain a fluorinated oil containing 0.5% Krytox-PEG-Krytox as the continuous phase;

[0043] (2) The continuous phase and the dispersed phase were injected into the inlet of the microfluidic chip, respectively, with a flow rate of 1600 μL / h for the dispersed phase and 12 mL / h for the continuous phase, to form monodisperse water-in-oil droplets in the microchannel;

[0044] (3) collecting the water-in-oil droplets from step (2) into a collection tube and pre-cooling them at -80°C for 1 hour to solidify the droplets and facilitate UV cross-linking;

[0045] (4) The frozen droplets were exposed to UV light for 60 seconds, with a UV exposure of 2×10 6 J / m 2 ; Then use a freeze dryer to dry at -80℃ for 6h to obtain oil-absorbing particles.

[0046] Optical microscope image of the water-in-oil droplets prepared in this example ( Figure 2 A) and optical microscope image of oil-absorbing particles ( Figure 2 B) in Figure 2 ;Depend on Figure 2 It can be seen that the droplets formed by the microfluidic chip are uniform in size, about 1 mm; pores can be observed on the surface of the oil-absorbing particles.

[0047] Example 2

[0048] (1) Preparation of dispersed phase and continuous phase solutions: Weigh 0.05 g of HPMC, 0.25 g of PEGDA, and 0.05 g of Irgacure 2959 and dissolve them in 5 mL of deionized water to obtain a dispersed phase; weigh 0.05 g of Krytox-PEG-Krytox and dissolve it in 10 mL of fluorinated oil to obtain a fluorinated oil containing 0.5% Krytox-PEG-Krytox as the continuous phase.

[0049] (2) The continuous phase and the dispersed phase are injected into the microfluidic chip inlet respectively, wherein the flow rate of the dispersed phase is 1600 μL / h, and the flow rate of the continuous phase is 12 mL / h, to form monodisperse water-in-oil microdroplets in the microchannel.

[0050] (3) The water-in-oil microdroplets of step (2) are collected into a collection tube, pre-cooled at -80°C for 1 h to solidify the droplets, and then subjected to ultraviolet crosslinking.

[0051] (4) The frozen microdroplets are irradiated under a UV lamp for 60 s, the UV exposure is 2×10 6 J / m 2 ; and then dried in a freeze dryer at -80°C for 6 h to obtain oil-absorbing particles.

[0052] Example 3

[0053] (1) The dispersed phase and the continuous phase solution are prepared: 0.075 g of HPMC, 0.25 g of PEGDA and 0.05 g of Irgacure 2959 are dissolved in 5 mL of deionized water to obtain the dispersed phase; 0.05 g of Krytox-PEG-Krytox is dissolved in 10 mL of fluorinated oil to obtain fluorinated oil containing 0.5% Krytox-PEG-Krytox as the continuous phase;

[0054] (2) The continuous phase and the dispersed phase are injected into the microfluidic chip inlet respectively, wherein the flow rate of the dispersed phase is 1600 μL / h, and the flow rate of the continuous phase is 12 mL / h, to form monodisperse water-in-oil microdroplets in the microchannel.

[0055] (3) The water-in-oil microdroplets of step (2) are collected into a collection tube, pre-cooled at -80°C for 1 h to solidify the droplets, and then subjected to ultraviolet crosslinking.

[0056] (4) The frozen microdroplets are irradiated under a UV lamp for 60 s, the UV exposure is 2×10 6 J / m 2 ; and then dried in a freeze dryer at -80°C for 6 h to obtain oil-absorbing particles.

[0057] The electron microscope images of the oil-absorbing particles prepared in Examples 1-3 are shown in FIG. 1. Figures 3-5In the dense polymer network, the pore size is an important parameter, and the capillary force of the pore determines the constraint ability to oil, because different size of the pore has different absorption intensity. High porosity and higher pore size accelerate the oil absorption of the particles. By scanning electron microscopy characterization of the oil absorption particles obtained in Examples 1, 2, 3, it can be seen that the HPMC / PEGDA oil absorption particle surface is rich in pore structure, and the particle size is 1.05±0.081mm, 0.95±0.051mm, 0.94±0.057mm respectively. With the increase of the proportion of HPMC used in Examples 1, 2, 3, it is found that the small pores of 13μm of the porous particles gradually grow into flat pores of about 170μm. The porosity of the oil absorption particles prepared in Examples 1, 2, 3 is 87.5±2.8%, 83.2±1.3% and 79.6±1.5% respectively.

[0058] Comparative Example

[0059] (1) Configure the dispersed phase and continuous phase solution: the same as Example 2;

[0060] (2) Inject the continuous phase and the dispersed phase into the microfluidic chip inlet respectively, wherein the flow rate of the dispersed phase is 100μL / h, and the flow rate of the continuous phase is 600μL / h, to form monodisperse water-in-oil droplets in the microchannel;

[0061] (3) Collect the water-in-oil droplets of step (2) into a collection tube, and pre-cool at-80℃ for 1h to make the droplets solidify, so as to facilitate ultraviolet crosslinking;

[0062] (4) Freeze the microdroplets under ultraviolet light for 60s, and the ultraviolet exposure is 2×10 6 J / m 2 ; then dry at-80℃ for 6h with a freeze dryer to obtain oil absorption particles. The particle size of the oil absorption particles is 96±4.7μm, and the porosity is 65.5±4.1%.

[0063] The optical microscope image of the water-in-oil droplets prepared in the comparative example (A in Figure 6 ) and the optical microscope image of the oil absorption particles (B in Figure 6 ) are shown in Figure 6 ; it can be seen from Figure 6 that the droplets formed by the microfluidic chip are uniform in size, and the droplet size is about 100μm; the surface of the oil absorption particles is rough.

[0064] Performance test: The mass of the oil-absorbing particles was measured and recorded first, and then the particles were immersed in soybean oil or oil-water mixture (a mixture of soybean oil and water with a volume ratio of 1:1 or a mixture of linseed oil and water) at 37°C for 2h. After the oil absorption process was completed, the oil-absorbing particles saturated with oil were taken out, the excess soybean oil on the surface of the particles was gently wiped off, and then the mass of the saturated oil-absorbing particles was measured and recorded. The oil absorption capacity of the oil-absorbing material was calculated by the following formula: oil absorption rate = (M-M0) / M0 (g / g), M (g) is the mass of the oil-absorbing particles after oil absorption, and M0 (g) is the initial mass of the oil-absorbing particles. The calculation results are shown in Table 1.

[0065] Table 1 Oil absorption rate of oil-absorbing particles prepared in examples and comparative examples

[0066]

[0067]

[0068] As can be seen from Table 1, the oil-absorbing particles prepared in Example 1 have the best oil absorption effect. In the oil-water mixture, the oil absorption effect of linseed oil is better, and the oil absorption effect of soybean oil is slightly worse. The liquid droplet size of the comparative example is small, and under the same ultraviolet exposure, the cross-linking degree is higher, the porosity is 65.5±4.1%, which leads to a decrease in oil absorption rate.

Claims

1. Application of porous polymer oil-absorbing particles in absorbing oil or oil in oil-water mixture; The method for preparing the porous polymer oil-absorbing particles comprises the following steps: (1) An aqueous solution containing hydroxypropyl methylcellulose, polyethylene glycol diacrylate, and a photoinitiator is used as a dispersed phase, and an oil phase containing a surfactant is used as a continuous phase, and the dispersed phase and the continuous phase are prepared into monodispersed water-in-oil droplets using a microfluidic device; (2) The water-in-oil droplets are subjected to photo-crosslinking and then freeze-dried to obtain the porous polymer oil-absorbing particles.

2. The use according to claim 1, characterized in that: In the dispersed phase, the mass volume ratio of the hydroxypropyl methylcellulose and water is 0.5-2.0 g:100 mL; the mass volume ratio of the polyethylene glycol diacrylate and water is 2.0-10.0 g:100 mL; and the mass volume ratio of the photoinitiator and water is 0.1-1.0 g:100 mL.

3. The use according to claim 1 or 2, characterized in that: In the continuous phase, the mass volume ratio of the surfactant to the solvent is 0.5-2.0 g:100 mL.

4. The use according to claim 1 or 2, characterized in that: The photoinitiator is 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one, 1-hydroxyhexyl phenyl ketone or benzoin dimethyl ether; The surfactant is at least one of sorbitan laurate, polyoxyethylene sorbitan trioleate, poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol), sorbitan monooleate, polyoxyethylene (10) oleyl ether, polyoxyethylene (2) oleyl ether and Krytox-PEG-Krytox; The solvent in the continuous phase is at least one of fluorinated oil, mineral oil, vegetable oil, silicone oil and petroleum ether.

5. The use according to claim 1 or 2, characterized in that: The solvent in the continuous phase is olive oil.

6. The use according to claim 1 or 2, characterized in that: In the step of preparing water-in-oil droplets, the flow rate of the dispersed phase is 1000-2000 μL / h; the flow rate of the continuous phase is 10-20 mL / h; The flow channel width of the microfluidic chip of the microfluidic device is 500-2000 μm.

7. The use according to claim 1 or 2, characterized in that: In step (2), the photocrosslinking is carried out under ultraviolet light; The freeze-drying temperature is -50 to -80°C, and the time is 6 to 16 hours.

8. The use according to claim 7, characterized in that: The UV lamp irradiation time is 30 to 90 seconds, and the UV exposure is 1.5×10 6 ~3.0×10 6 J / m 2 .

9. The use according to claim 1 or 2, characterized in that: The method further comprises a step of pre-freezing the water-in-oil microdroplets before the water-in-oil microdroplets are subjected to light cross-linking.

10. The use according to claim 9, characterized in that: The pre-freezing temperature is -50 to -80°C, and the pre-freezing time is 0.5 to 2 hours.

11. The use according to claim 1 or 2, characterized in that: The oil adsorbed by the porous polymer oil-absorbing particles is at least one of soybean oil and linseed oil.

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