Preparation method of metal-labeled carboxyl modified nano plastic microspheres

Abstract

The invention relates to preparation of metal-labeled plastic microspheres, and belongs to the technical field of high-molecular polymers. The preparation method comprises the following steps: firstly, preparing a polyacrylonitrile inner core by an emulsion polymerization method, adding rare metal salt into the polyacrylonitrile inner core while synthesizing the polyacrylonitrile inner core, slowly injecting styrene, a cross-linking agent divinyl benzene and a functional monomer into a system to form a carboxyl modified polystyrene outer shell, and carrying out heat treatment on the carboxyl modified polystyrene outer shell to obtain the high-performance polystyrene composite material. And thus, the metal-labeled carboxyl modified nano plastic microspheres are obtained. According to the preparation method disclosed by the invention, the rare metal is coated inside the acrylonitrile, and the crosslinking agent is used for enhancing the crosslinking degree of the styrene, so that the metal marker in the prepared metal-labeled nano-plastic microsphere is stable in combination and hardly leaks from the plastic microsphere, and the metal-labeled nano-plastic microsphere can be used for quantifying trace micro-plastic in the environment; the metal chelated polystyrene nanospheres prepared by the method are large in specific surface area and uniform in particle size.

Description

Technical Field

[0001] The invention relates to the technical field of high molecular polymers, in particular to a method for preparing metal-labeled carboxyl-modified nano plastic microspheres. Background Art

[0002] With the increasing importance of plastics as environmental pollutants, research on plastic particles has intensified to better understand their origin, fate, and transport, as well as their bioabsorption and impact. While extensive research has been conducted on nanoplastic particles, analytical methods to accurately measure modified nanoplastics in the environment remain elusive.

[0003] In the present invention, based on the above status quo, we have prepared metal-labeled carboxyl-modified nanoplastic particles with chemical coating, which can help study the potential mechanisms, processes and principles of the migration process of nanoplastics. There are several advantages to using rare metal-labeled plastic microspheres. One is that the rare metal tracer will not be quenched during the strong acid digestion process, and the trace metals in the nanoplastics can be measured by ICP-MS. In addition, when using the nanoplastic particles of the present invention, the particles can be directly added to various environmental samples without worrying about high metal or plastic background interference. Therefore, those skilled in the art provide a method for preparing metal-labeled carboxyl-modified nanoplastic microspheres to solve the problems raised in the above-mentioned background technology. Summary of the Invention

[0004] To address the difficulty in quantifying nanoplastics in the environment, the present invention provides a method for preparing metal-labeled nanoplastic microspheres. The method first uses emulsion polymerization to prepare a polyacrylonitrile core. A rare metal salt is then added to the core during synthesis. Styrene and the crosslinking agent divinylbenzene are then slowly injected into the system to form a polystyrene shell, thereby producing the metal-labeled nanoplastic microspheres.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing metal-labeled carboxyl-modified nanoplastic microspheres comprises the following steps: S1, mixing a surfactant, an acrylonitrile monomer and an initiator in water, stirring at a high speed of 400-900 r / min at 50-80°C, adding potassium chloropalladate and poly(ethylene glycol) 4-nonphenyl 3-sulfopropyl ether potassium salt after 2 minutes, polymerizing at 50-80°C for 8-12 hours to obtain a metal-coated acrylonitrile core; S2, after the reaction in step S1 is carried out for 4 hours, adding 0.18g of initiator to the system, then introducing a surfactant, a cross-linking agent, a styrene monomer, a functional monomer and a dispersion medium at a certain speed, and continuing the reaction until completion to obtain carboxyl-modified plastic microspheres with the metal-coated acrylonitrile as the core and styrene as the shell.

[0007] As a further solution of the present invention: in step S1, the surfactant is one or more of SDS and SDBS, accounting for 1%-3% of the weight of the acrylonitrile monomer.

[0008] As a further solution of the present invention: in step S1, the initiator is a water-soluble inorganic peroxide initiator, and the mass thereof is 1%-3% of the mass of the acrylonitrile monomer.

[0009] As a further embodiment of the present invention, the potassium chloropalladate accounts for 1.5% of the weight of the acrylonitrile monomer, and the poly(ethylene glycol) 4-nonphenyl 3-sulfopropyl ether potassium salt accounts for 2% of the weight of the acrylonitrile monomer.

[0010] As a further solution of the present invention: in step S2, the surfactant is one or more of SDS and SDBS, and the dispersion medium is water or alcohol.

[0011] As a further solution of the present invention: in step S2, the styrene monomer accounts for 32% of the total weight of the dispersion medium and the styrene monomer, and the cross-linking agent is divinylbenzene, accounting for 0.5-1.5% of the total weight of the styrene monomer.

[0012] As a further embodiment of the present invention: in step S2, the functional monomer is acrylic acid or benzoic acid, accounting for 0.5-1.5% of the total weight of the styrene monomer. As a further embodiment of the present invention: the polymerization reactions of step S1 and step S2 are both carried out under high-speed stirring conditions, with a rotation speed of 400-900 r / min. As a further embodiment of the present invention: the polymerization reaction temperature of step S1 and step S2 is both 50-80°C, and the total reaction time is 8-12 hours. A carboxyl nanoplastic microsphere, prepared by the preparation method according to any one of claims 1 to 9, wherein the microsphere has a metal-coated acrylonitrile as a core, styrene as a shell, and carboxyl groups on the surface.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The metal chelated polystyrene nanospheres prepared by the present invention have a large specific surface area and uniform particle size.

[0015] 2. The metal-labeled nanoplastic microspheres prepared by the present invention can be used for quantitative analysis.

[0016] 3. The metal markers in the metal-labeled nanoplastic microspheres prepared by the present invention are stably bound and hardly leak out of the plastic microspheres, and can be used to analyze the behavior of nanoplastics in complex environments in the laboratory. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1This is a scanning electron microscope image of the metal-labeled nanoplastic microspheres prepared in Example 2;

[0018] Figure 2 This is the particle size distribution diagram of the metal-labeled nanoplastic microspheres prepared in Example 2;

[0019] Figure 3 This is the zeta potential diagram of the prepared metal-labeled nanoplastic microspheres;

[0020] Figure 4 This is the infrared spectrum of the prepared metal-labeled nanoplastic microspheres. DETAILED DESCRIPTION

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0022] A method for preparing metal-labeled carboxyl-modified nanoplastic microspheres comprises the following steps: adding a surfactant to a three-necked flask, then adding a certain amount of water, heating and stirring to dissolve the surfactant, and aerating nitrogen for 30 minutes; heating the liquid in the three-necked flask to a reaction temperature and aerating nitrogen for a period of time; adding acrylonitrile monomer and poly(ethylene glycol) 4-nonphenyl 3-sulfopropyl ether potassium salt (KPE); stirring for 2 minutes, then adding an initiator; and adding potassium chloropalladate two minutes after the addition of the initiator. The potassium chloropalladate and acrylonitrile are polymerized to obtain a metal-coated acrylonitrile core.

[0023] The surfactant, crosslinking agent, styrene monomer, and a certain amount of dispersion medium were mixed in a conical flask. After the reaction was carried out for 4 hours, the liquid in the conical flask was introduced at a certain speed using a syringe peristaltic pump. After a period of reaction, carboxyl-modified latex microspheres with a metal-coated acrylonitrile as the core and a styrene shell were obtained. Experimental materials:

[0024] Raw material name Specification effect Acrylonitrile monomer AR-class Core polymer monomer Styrene monomer AR grade, remove polymerization inhibitor by vacuum distillation before use Shell polymerization monomer Potassium persulfate (KPS) AR-class initiator Potassium chloropalladate 99% Metal marking agents Poly(ethylene glycol) 4-nonylphenyl 3-sulfopropyl ether potassium salt (KPE) CP level Emulsification and dispersion Sodium dodecyl sulfate (SDS) AR-class surfactants Sodium dodecylbenzenesulfonate (SDBS) AR-class surfactants Divinylbenzene (DVB) Industrial grade, wash with sodium hydroxide solution to remove inhibitor before use crosslinking agent acrylic acid AR-class Functional monomer, introducing carboxyl group Ultrapure water Resistivity ≥18.2MΩ・cm Reaction medium Anhydrous ethanol AR-class dispersion medium

[0025] Experimental instruments:

[0026] Instrument name model use Three-necked flask 250mL reaction vessel Constant temperature water bath HH-6 Temperature control reaction electric mixer JJ-1 Provide stirring power Digital tachometer ZS-2 Monitoring stirring speed Ultrasonic cleaner KQ-500DE Ultrasonic dissolution of raw materials Peristaltic pump BT100-2J Precisely control the liquid drop acceleration rate Nitrogen cylinders - Provide inert protective gas Separatory funnel 50mL Feeding device Scanning electron microscopy (SEM) Sigma 300 Observation of microsphere morphology and particle size Fourier transform infrared spectrometer (FT-IR) NicoletiS50 Analysis of microsphere surface groups Potential particle size analyzer NANO ZS90 Analysis of microsphere particle size and Zeta potential

[0027] Example 1:

[0028] Add 6ml of ultrapure water to each of three centrifuge tubes, then add 0.15g of KPE, 0.15g of potassium persulfate, and 0.1125g of potassium chloropalladate. Sonicate for about 10 minutes to dissolve. Place 0.2ml of crosslinker DVB, 0.1152g of SDS, 6.4ml of styrene, 1ml of functional monomer acrylic acid, and 12ml of ultrapure water in a conical flask. Use a 50ml syringe to aspirate. Add 50ml of water to a three-necked flask, then add 0.15g of SDS and pass nitrogen for 30 minutes. Adjust the reactor speed to 500r / min and the reaction temperature to 70°C. After passing nitrogen for 30 minutes, add 9.3ml of PAN and poly(ethylene glycol) 4-nonphenyl 3-sulfopropyl ether potassium salt to the three-necked flask. After 2 minutes, add 6ml of KPS in the centrifuge tube. After reacting for 2 minutes, add potassium chloropalladate to the three-necked flask. After 4 hours of reaction, the liquid in the syringe was introduced at a rate of 90 μl / min, and 0.15 g of initiator was added before the introduction of the liquid. After 4 hours of reaction, the liquid was removed to obtain a metal-labeled nanoplastic microsphere emulsion.

[0029] Example 2:

[0030] Add 8ml of ultrapure water to each of three centrifuge tubes, followed by 0.15g of KPE, 0.225g of potassium persulfate, and 0.1125g of potassium chloropalladate. Ultrasonicate for approximately 3 minutes to dissolve. Place 0.2ml of the crosslinker DVB, 0.1152g of SDS, 6.4ml of styrene, 1ml of the functional monomer acrylic acid, and 12ml of ultrapure water in a conical flask. Aspirate using a 50ml syringe. Add 50ml of water to a three-necked flask, then add 0.225g of SDS and purge with nitrogen for 30 minutes. Adjust the reactor speed to 500 rpm and the reaction temperature to 70°C. After the 30-minute nitrogen purge, add 9.3ml of PAN and poly(ethylene glycol)-4-nonylphenyl-3-sulfopropyl ether potassium salt to the three-necked flask. After 2 minutes, add the 6ml of KPS from the centrifuge tube. After reacting for 2 minutes, add potassium chloropalladate to the three-necked flask. After 4 hours of reaction, the liquid in the syringe was introduced at a rate of 90 μl / min, and 0.15 g of initiator was added before the introduction of the liquid. After 4 hours of reaction, the liquid was removed to obtain a metal-labeled nanoplastic microsphere emulsion.

[0031] Example 3:

[0032] Add 8ml of ultrapure water to each of three centrifuge tubes, then add 0.15g of KPE, 0.3g of potassium persulfate, and 0.1125g of potassium chloropalladate. Ultrasonicate for about 3 minutes to dissolve. Place 0.2ml of crosslinker DVB, 0.1152g of SDS, 6.4ml of styrene, 1ml of functional monomer acrylic acid, and 12ml of ultrapure water in a conical flask. Use a 50ml syringe to draw up. Add 50ml of water to a three-necked flask, then add 0.3g of SDS and pass nitrogen for 30 minutes. Adjust the reactor speed to 500r / min and the reaction temperature to 70°C. After passing nitrogen for 30 minutes, add 9.3ml of PAN to the three-necked flask. After 2 minutes, add 6ml of KPS in the centrifuge tube. After reacting for 2 minutes, add KPE and potassium chloropalladate to the three-necked flask. After reacting for 4 hours, pass the liquid in the syringe at a rate of 90ul / min. Add 0.15g of initiator before passing the liquid. After reacting for 4 hours, the mixture was taken out to obtain a metal-labeled nanoplastic microsphere emulsion.

[0033] Example 4:

[0034] Add 8ml of ultrapure water to each of three centrifuge tubes, followed by 0.15g of KPE, 0.375g of potassium persulfate, and 0.1125g of potassium chloropalladate. Ultrasonicate for approximately 3 minutes to dissolve. Place 0.2ml of crosslinker DVB, 0.1152g of SDS, 6.4ml of styrene, 1ml of functional monomer acrylic acid, and 12ml of ultrapure water in a conical flask. Aspirate using a 50ml syringe. Add 50ml of water to a three-necked flask, then add 0.375g of SDS and flow nitrogen through it for 30 minutes. Adjust the reactor speed to 400 rpm and the reaction temperature to 60°C. After 30 minutes of nitrogen flow, add 9.3ml of PAN to the three-necked flask. Add 6ml of KPS from the centrifuge tube over 2 minutes. After reacting for 2 minutes, add KPE and potassium chloropalladate to the three-necked flask. After a 4-hour reaction, pass the liquid in the syringe through it at a rate of 90ul / min. Add 0.15g of initiator before passing the liquid through it. After reacting for 4 hours, the mixture was taken out to obtain a metal-labeled nanoplastic microsphere emulsion.

[0035] Preparation steps:

[0036] Step S1

[0037] Add 1-3 g of SDS and SDBS mixed surfactant (mass ratio 1:1), 100 g of acrylonitrile monomer and 1-3 g of sodium persulfate to 550 mL of deionized water, pour into a 250 mL three-necked flask, and install a stirring device and a condenser.

[0038] Place the three-necked flask in a constant temperature water bath, set the temperature to 65°C, turn on the electric stirrer, and stir at a high speed of 600 r / min for 2 minutes to mix the system evenly.

[0039] 1.5 g of potassium chloropalladate and 2 g of poly(ethylene glycol) 4-nonylphenyl 3-sulfopropyl ether potassium salt were added, and polymerization was continued at 65° C. for 10 hours. During this period, the stirring speed was monitored in real time by a digital tachometer to ensure stable reaction, thereby forming a metal-coated acrylonitrile core.

[0040] Step S2

[0041] After the reaction in step S1 was carried out for 4 hours, 0.18 g of sodium persulfate initiator was added to ensure that the initiator was evenly dispersed in the reaction system.

[0042] 1-2g SDS, 0.5-1.5g divinylbenzene, 47g styrene monomer, 0.5-1.5g acrylic acid and 100g water and alcohol mixture (volume ratio 1:1) were sequentially introduced at a dropwise rate of 90μL / min. Stirring and temperature were kept stable during the addition process.

[0043] The reaction was continued for 6 hours until completion. After the reaction was completed, the three-necked flask was taken out from the water bath and naturally cooled to room temperature to obtain a carboxyl-modified plastic microsphere emulsion with metal-coated acrylonitrile as the core and styrene as the shell.

[0044] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include," "comprise," or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations. The phrase "includes an element defined by..." does not exclude the presence of other identical elements in the process, method, article, or device that includes the element.

[0045] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing metal-labeled carboxyl-modified nanoplastic microspheres, characterized in that: The following steps are involved: S1. Mix a surfactant, acrylonitrile monomer, and an initiator in water, stir at a high speed of 400-900 r / min at 50-80° C., add potassium chloropalladate and poly(ethylene glycol) 4-nonylphenyl 3-sulfopropyl ether potassium salt after 2 minutes, and polymerize at 50-80° C. for 8-12 hours to obtain a metal-coated acrylonitrile core: S2. After the reaction in step S1 is carried out for 4 hours, an initiator accounting for 0.18% of the mass of the acrylonitrile monomer is added, and then a surfactant, a cross-linking agent, a styrene monomer, a functional monomer and a dispersion medium are introduced, and the reaction is continued until completion to obtain carboxyl-modified plastic microspheres with metal-coated acrylonitrile as the core and styrene as the shell.

2. The method for preparing metal-labeled carboxyl-modified nanoplastic microspheres according to claim 1, wherein In step S1, the surfactant is one or more of SDS and SDBS, accounting for 1%-3% of the weight of the acrylonitrile monomer.

3. The method for preparing metal-labeled carboxyl-modified nanoplastic microspheres according to claim 1, wherein In step S1, the initiator is a water-soluble inorganic peroxide initiator, and the mass thereof is 1%-3% of the mass of the acrylonitrile monomer.

4. The method for preparing metal-labeled carboxyl-modified nanoplastic microspheres according to claim 1, wherein In step S1, the potassium chloropalladate accounts for 1.5% of the weight of the acrylonitrile monomer, and the poly(ethylene glycol) 4-nonylphenyl 3-sulfopropyl ether potassium salt accounts for 2% of the weight of the acrylonitrile monomer.

5. The method for preparing metal-labeled carboxyl-modified nanoplastic microspheres according to claim 1, wherein In step S2, the surfactant is one or more of SDS and SDBS, and the dispersion medium is water or alcohol.

6. The method for preparing metal-labeled carboxyl-modified nanoplastic microspheres according to claim 1, wherein: In step S2, the styrene monomer accounts for 32% of the total weight of the dispersion medium and the styrene monomer, and the cross-linking agent is divinylbenzene, accounting for 0.5-1.5% of the total weight of the styrene monomer.

7. The method for preparing metal-labeled carboxyl-modified nanoplastic microspheres according to claim 1, wherein: In step S2, the functional monomer is acrylic acid or benzoic acid, accounting for 0.5-1.5% of the total weight of the styrene monomer.

8. The method for preparing metal-labeled carboxyl-modified nanoplastic microspheres according to claim 1, wherein: The polymerization reactions in step S1 and step S2 are both carried out under high-speed stirring conditions at a rotation speed of 400 to 900 r / min.

9. The method for preparing metal-labeled carboxyl-modified nanoplastic microspheres according to claim 1, wherein: The polymerization reaction temperature in step S1 and step S2 is both 50-80° C., and the total reaction time is 8-12 hours.

10. A carboxyl nanoplastic microsphere, characterized in that: The microspheres are prepared by the preparation method according to any one of claims 1 to 9, wherein the microspheres have metal-coated acrylonitrile as the core, styrene as the shell, and carboxyl groups on the surface.

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