CN1837043A - Rare earth particle/montmorillonite nanocomposite material and preparation method thereof - Google Patents

Abstract

The invention discloses a Rare earth particle/montmorillonite nanocomposite material and process for preparing, this method depending on surface activator. Self-assembling to produce template, taking polymer monomer as oil phase, Rare earth ionic solution as aqueous phase, mixing them to form contrary Rare earth nano particle, getting Rare earth particle equally dispersed in oil phase, forming thermodynamical steady emulsion system, intercalating the emulsion between layers of montmorillonite, joining initiator, polymer monomer carrying through home position polymerization directly, and then doing microwave radiation, breaking up polymer to CO and H2O, getting Rare earth particle/MMT nanocomposite material.

Description

Rare earth particle/montmorillonite nanocomposite material and preparation method thereof

technical field

The present invention relates to a nanocomposite material with montmorillonite as the main body, in particular to a rare earth particle/montmorillonite nanocomposite material; the present invention also relates to a rare earth particle/montmorillonite nanocomposite prepared by emulsion intercalation microwave method methods for nanocomposites.

Background technique

Montmorillonite can be used as adhesives, absorbents, fillers, catalysts, detergents, enhancers, etc. Thickeners, etc., are widely used in the fields of industry, agriculture, medicine, and environmental governance, and are known as "clay with thousands of uses", "universal clay", and "living minerals".

In recent years, the research on interlayer compounds of montmorillonite has been developed, which makes montmorillonite more practical. Due to the particularity of montmorillonite, it is widely used as a filler for heat-resistant polymer composites and conductive polymer composites. The higher the filler content within a certain range, the better the performance of the composite material, but the mechanical properties of the material will decrease, especially the toughness of the material will decrease significantly. An effective way to improve the performance of composite materials is to uniformly fill inorganic particles into polymers at the nanometer level, which can improve their thermal, electrical and mechanical properties. However, it is difficult to obtain fillers at the nanometer level by traditional blending methods Disperse evenly. Due to the large difference in chemical structure and physical form between fillers and polymers, at present, it is difficult for interface modification technology to completely change the interfacial energy between fillers and polymer matrix to reduce interfacial tension and achieve nanoscale uniform dispersion and interfacial bonding. Therefore, the composite material cannot reach the level of molecular dispersion, but only belongs to the microscopic mixed material, which affects the improvement of the toughness, rigidity, heat resistance and electrical properties of the material. The way to improve is to uniformly disperse the phases to form a composite material. Due to the strong binding force between the montmorillonite sheets, it is easy to produce montmorillonite sheet aggregation, which causes the inhomogeneity of the rare earth particles in the composite system, beyond the nanometer level, and is no longer a nanocomposite material, which greatly affects the composite material. performance. In order to solve the problem that the rare earth particles in the prior art cannot be uniformly dispersed in the montmorillonite layer at the nanometer level and affect the properties of the composite material. During the polymerization process of composite materials, relying on surfactants to form microemulsions, spontaneously formed isotropic, thermodynamically stable, transparent or translucent colloidal emulsions, resulting in reverse micelles "pool reaction field", this "microreaction Nano-scale particles can be synthesized in the "device" space, without organic modification of inorganic nanoparticles and redispersion in the precursor, direct intercalation for bulk in-situ polymerization, and then microwave radiation to prepare rare earth particles/MMT nanocomposites. It not only overcomes the difficult problem of uniform dispersion of rare earth particles in the montmorillonite sheet, but also simplifies the process. Only when the montmorillonite sheet has a strong interaction with the rare earth particles and achieves nanoscale dispersion, can the synergy between the two be effectively brought into play, making it a perfect combination and obtaining a nanocomposite material with good performance.

Contents of the invention

The object of the present invention is to provide a kind of rare earth particle/montmorillonite nanocomposite material;

Another object of the present invention is to provide a method for preparing rare earth particle/montmorillonite nanocomposite material by using emulsion intercalation microwave technology.

The rare earth particle/montmorillonite nanocomposite material of the present invention is that the rare earth particle and the montmorillonite sheet are evenly dispersed and closely combined; wherein the particle diameter of the rare earth particle is 20-30 nm, and the thickness of the montmorillonite sheet is 30-50 nm .

The mass ratio of the rare earth particles to the montmorillonite is: 1-20 parts of the rare earth nanoparticles and 1-30 parts of the montmorillonite.

The rare earth nanoparticles are rare earth oxide particles.

The preparation method of the rare earth particle/montmorillonite nano-composite material of the present invention is to dissolve a certain amount of polymer monomer in a dispersant that is dissolved with a surfactant, then add a certain amount of rare earth salt solution to it and stir, and Ultrasonic dispersion for 30-60 minutes to form a reverse micellar emulsion; then add the reverse micellar emulsion to the organic montmorillonite aqueous dispersion drop by drop under the protection of _N2 , adjust the temperature to 60-80 °C, and magnetically stir to disperse and insert Layer for 2 to 3 hours, then add an appropriate amount of initiator to initiate polymerization of the polymer monomer, add an appropriate amount of precipitant to completely precipitate the rare earth particles after 15 to 30 hours of reaction, filter, wash, and vacuum dry; then use a frequency of 2000 to 2500MHz Microwave radiation for 0.2 to 1.5 hours decomposes the polymer into CO ₂ and H ₂ O. The effect of microwave radiation on the crystallization of rare earth particles is not obvious, and the high temperature resistant montmorillonite remains unchanged, and the rare earth particle/montmorillonite nanocomposite is prepared Material.

The polymer monomer used in the method is any one of aniline, methyl methacrylate, methyl acrylate, pyrrole or o-phenylenediamine.

The surfactant that this method adopts is anionic surfactant, cationic surfactant or nonionic surfactant; Wherein anionic surfactant is sodium lauryl sulfate, sodium stearate or stearic acid; Cationic surfactant It is cetyltrimethylammonium chloride; the nonionic surfactant is alkylphenol polyoxyethylene ether. The added amount of the surfactant is 15-25% of the weight of the polymer monomer.

On the one hand, the presence of surfactants plays an important role in self-assembly to form reverse micellar microemulsions to prepare uniformly dispersed rare earth nanoparticles, and as a surface modifier for montmorillonite and rare earth nanoparticles, it improves the oil phase and water phase. compatibility and affinity. Emulsion is an isotropic, thermodynamically stable, translucent colloidal dispersion system formed spontaneously by surfactants. The "water pool reaction field" in the emulsion is nano-scale, small in size and evenly distributed, effectively limiting the growth space of nanoparticles, making the water phase and oil phase evenly dispersed during the reaction process, and when the polymer monomers are polymerized, the water The rare earth particles in the phase are pinned down in the polymer to maintain the original uniformly dispersed state, and then the rare earth particles/MMT nanocomposite material is prepared by microwave radiation, which effectively solves the problem of nanoparticle agglomeration and achieves nanoscale uniformity. Dispersion enables nanocomposites to have many excellent properties that are difficult to achieve by traditional methods.

The dispersion medium used in the present invention is chloroform, water or ethanol. The amount of the dispersion medium is 4-10 times of the mass of the polymer monomer. The role of the dispersion medium is to promote the dispersion of montmorillonite in the polymer monomer. The dispersion medium depends on the monomer, rare earth particles and initiator. A good dispersion medium should make the montmorillonite and rare earth nanoparticles easy to disperse and have good miscibility with the monomer and initiator, and the prepared composite material has good performance.

The rare earth salt used in the invention is nitrate or chloride of soluble rare earth; wherein the added amount of the rare earth salt is 1-20% of the mass of the polymer monomer.

The organic montmorillonite that the present invention adopts is to take hexadecyltrimethylammonium bromide, dodecyltrimethylammonium chloride or octadecyltrimethylammonium bromide as an organic modifier, and the natural The montmorillonite is obtained through organic modification; the addition amount of the organic montmorillonite is 1-30% of the mass of the polymer monomer.

The modification method of organic montmorillonite is: put a certain amount of modifier in water, add an appropriate amount of hydrochloric acid to adjust to form a protonated solution; Stir and heat in a water bath for 30-60 minutes and then let stand to form a montmorillonite aqueous dispersion, then add the above-mentioned protonated solution to the montmorillonite aqueous dispersion drop by drop, and vibrate with ultrasonic waves for 3-4 hours, then filter and remove Wash with water to remove bromide ions and chloride ions, and finally vacuum-dry, grind and sieve at 70-90°C, and the obtained product is organic montmorillonite. The sheets of the organic montmorillonite are more uniformly dispersed in the organic modifier matrix, the thickness of the sheets is 40-50nm, and the interlamellar distance is 3-15nm. The special structure of the organic montmorillonite is suitable for the preparation of rare earth The nano-characteristics of the particle/montmorillonite nanocomposites are provided.

The initiator used in the present invention is azobisisobutyronitrile, ammonium persulfate or iron p-toluenesulfonate; the added amount of the initiator is 0.1-320% of the mass of the polymer monomer, which is determined according to the polymer monomer.

The precipitation agent that the present invention adopts is sodium hydroxide.

Compared with the prior art, the present invention has the following advantages:

1. In the rare earth particle/montmorillonite nanocomposite material of the present invention, the thickness of the montmorillonite sheet is about 30 to 50 nm, and it can be clearly seen that the montmorillonite after expansion maintains the original layered structure. There is a peeling phenomenon, forming a regular nanocomposite material. The average particle size of the rare earth nanoparticles is about 25nm, which has a very large interface area. The interface between the rare earth particles and the montmorillonite matrix has ideal bonding performance, which can eliminate the thermal expansion of the two substances. The coefficient mismatch and incompatibility problems make the physical and chemical properties of the composite materials improved very well.

2. The preparation method of the present invention uses a surfactant as a template, so that the formation of rare earth nanoparticles and the preparation of composite materials are carried out simultaneously, and the water phase and the oil phase are uniformly dispersed during the reaction process. When the monomers in the emulsion are polymerized, the rare earth The particles are held in the polymer to maintain the original uniformly dispersed state, and then microwave radiation is carried out for a period of time, and the polymer decomposes CO ₂ and H ₂ O in the microwave. The effect of microwave radiation on the crystallization of rare earth particles is not obvious. The desoil remains unchanged, effectively solves the problem of nanoparticle agglomeration, and achieves uniform dispersion at the nanometer scale, thereby effectively simplifying the preparation procedure of the composite material and shortening the preparation time. The method of the invention is simple in operation, high in production efficiency, low in cost and convenient for industrialized production.

Description of drawings

Fig. 1 is the formation schematic diagram of rare earth particle/montmorillonite nanocomposite material of the present invention

Fig. 2 is the SEM photograph of the rare earth particle/montmorillonite nanocomposite material of the present invention

Fig. 3 is the XRD figure of rare earth particle/montmorillonite nanocomposite material of the present invention

Figure 2 (a) is the SEM photo of the composite material enlarged at 6.2×10 ⁴ , and the structure of montmorillonite and rare earth nanoparticles dispersed on the sheet can be clearly seen; (b) is the SEM photo of one of the sheets , it can also be clearly seen that rare earth nanoparticles are uniformly dispersed on the montmorillonite sheet. From the figure (a), it can be estimated that the thickness of the montmorillonite layer is about 30-50nm, which is larger than that of the original MMT layer. This is because the CO ₂ and H ₂ O causes swelling of montmorillonite. From Figure (a), it can be clearly seen that the montmorillonite layer basically maintains its original layered structure, and the rare earth particles are inserted between its layers to form a regular rare earth particle/MMT nanocomposite material. It can be seen that Rare earth particles are closely combined with montmorillonite sheets, and there should be adsorption between them. From Figure (b), it can be clearly seen that the distribution of rare earth nanoparticles between montmorillonite sheets is relatively uniform, and the particle size is small, with an average particle size of about 25nm. Therefore, it can be considered that the nanoparticles of the composite material are in the The reverse micellar microemulsion is carried out in the "water pool reaction field". The emulsion "microreactor" is small in size and evenly distributed, so that the water phase and the oil phase are evenly dispersed during the reaction process. Being pinned in the organism to maintain the original uniformly dispersed state, limiting the aggregation and growth of nanoparticles. In the microwave, the polymer decomposes CO ₂ and H ₂ O, and the high temperature-resistant rare earth particles and montmorillonite remain unchanged, which effectively solves the problem of agglomeration of nanoparticles, and prepares rare earth particles/MMT nanocomposites.

In Fig. 3, (a) is the XRD pattern of MMT, (b) is the XRD pattern of Pr ₂ O ₃ /MMT nanocomposite material, and (c) is the XRD pattern of polymer/rare earth particle/MMT nanocomposite material. According to the Bragg equation 2dsinθ=nλ, it can be known that the angle corresponding to the diffraction peak decreases, and the layer spacing of montmorillonite increases. Comparing (c) and (a) in Figure 3, it can be seen that the diffraction peak corresponding to the polymer/rare earth particle/MMT nanocomposite at 2θ=7.2° disappears relative to the diffraction peak of pure MMT, while at 2θ=2.1° Diffraction peaks appeared at , which indicated that the distance between the layers of montmorillonite was further increased, and the polymer was inserted into the interlayer of montmorillonite. In Figure 3 (a), (b) compared with (c), it can be seen that (b) has a diffraction peak at 2θ=2.6°, indicating that the interlayer spacing of rare earth particles/MMT nanocomposites is smaller than that of polymer/rare earth particles/MMT The layer spacing of the nanocomposite material is larger than that of MMT. Compared with (a), (b) and (c) have new diffraction peaks at 2θ=12.5° and 2θ=27.6°, indicating that montmorillonite The rare earth particles are inserted in the composite material at the same time, and the intensity of the diffraction peak is stronger, indicating that the rare earth particles in the composite material crystallize better. The above analysis shows that the polymer decomposes CO ₂ and H ₂ O in the microwave, which reduces the interlayer distance, microwave radiation has no obvious effect on the crystallization of rare earth particles, and the high temperature resistant montmorillonite remains unchanged, and the rare earth particles are inserted into the montmorillonite Between the layers, the problem of agglomeration of nanoparticles is effectively solved, and the rare earth particle/MMT nanocomposite material is prepared.

Detailed ways

Example 1. Add 100 parts of aniline and 15 parts of sodium lauryl sulfate to 400 parts of water and stir evenly; dissolve 20 parts of rare earth _Nd2O3 in hydrochloric acid to prepare a 0.1mol/L _NdCl3 aqueous _solution , and added to the above mixed solution, and ultrasonically dispersed at room temperature for 30 minutes to form a reverse micellar emulsion. Put 1 weight of purified and organically modified montmorillonite in water, stir and heat it in a water bath at a constant temperature of 40-60°C for 30-60 minutes, and then let it stand to form an aqueous dispersion of montmorillonite; then protect it under _N2 The reverse micellar emulsion was added dropwise to the organic montmorillonite aqueous dispersion, the temperature was adjusted to 60° C., and magnetic stirring was performed to disperse the intercalation for 2 hours. Then lower the temperature, move the reactant to an ice-water bath at about 2°C, and add 100 parts of ammonium sulfate initiator dropwise to initiate polymerization of the polymer monomer. After 15 hours of reaction, add 0.3mol/L NaOH solution to make the rare earth particles Precipitate completely, filter, wash, and dry in vacuum; then irradiate the polymer with a frequency of 2000MHz for 0.2 hours to decompose the polymer into CO ₂ and H ₂ O, and obtain Nd ₂ O ₃ /MMT nanocomposite material.

Example 2, 100 parts of methyl methacrylate and 18 parts of sodium stearate were added to 500 parts of chloroform and stirred evenly; 15 parts of rare earth Nd ₂ O ₃ were dissolved in hydrochloric acid to prepare 0.1mol/ L of EuCl ₃ aqueous solution, and added to the above mixed solution, ultrasonically dispersed at room temperature for 35 minutes to form a reverse micellar emulsion; put 6 parts of purified and organically modified montmorillonite in water, at 40 ~ 60 ° C Stir and heat in a constant temperature water bath for 30-60 minutes and then let it stand to form a montmorillonite aqueous dispersion; then add the reverse micellar emulsion dropwise to the organic montmorillonite aqueous dispersion under the protection of _N2 , and adjust the temperature to 65°C , magnetically stirred to disperse the intercalation for 2.5 hours, then added 0.001 part of azobisisobutyronitrile to initiate polymerization of the polymer monomer, and added 0.3mol/L NaOH solution after 18 hours of reaction to completely precipitate the rare earth particles, filtered, Washing and drying in vacuum; then irradiating the polymer with a frequency of 2200MHz for 0.5 hours to decompose the polymer into CO ₂ and H ₂ O to prepare the Nd ₂ O ₃ /montmorillonite nanocomposite.

Example 3, 100 parts of methyl acrylate and 20 parts of stearic acid were added to 700 parts of ethanol and stirred evenly; ₁₀ parts of rare earth _La2O3 was dissolved in hydrochloric acid to prepare a 0.1mol/L _LaCl3 aqueous solution , and added to the above mixed solution, and ultrasonically dispersed at room temperature for 40 minutes to form a reverse micellar emulsion; 12 parts of purified and organically modified montmorillonite were placed in water and placed in a water bath at a constant temperature of 40-60°C Stir and heat for 30 to 60 minutes and then stand still to form a montmorillonite aqueous dispersion; then add the reverse micellar emulsion to the organic montmorillonite aqueous dispersion drop by drop under the protection of _N2 , adjust the temperature to 70°C, and magnetically stir to disperse Intercalation for 3 hours, then add 1 part of azobisisobutyronitrile as an initiator to initiate polymerization of polymer monomers, after 20 hours of reaction, add 0.3mol/L NaOH solution to completely precipitate rare earth particles, filter and wash , dried in vacuum; and then irradiated with microwaves at a frequency of 2100MHz for 0.7 hours to decompose the polymer into CO ₂ and H ₂ O to obtain La ₂ O ₃ /montmorillonite nanocomposites.

Example 4. Add 100 parts of pyrrole and 22 parts of cetyltrimethylammonium chloride to 900 parts of chloroform and stir evenly; dissolve 5 parts of rare earth salt Pr ₂ (CO ₃ ) ₃ in nitric acid to prepare 0.1mol/LPr(NO ₃ ) ₃ aqueous solution, and added to the above mixed solution, ultrasonically dispersed at room temperature for 45 minutes to form a reverse micellar emulsion; 25 parts of purified and organically modified montmorillonite In water, stir and heat in a water bath at a constant temperature of 40-60°C for 30-60 minutes and then stand still to form a montmorillonite aqueous dispersion; then add the reverse micellar emulsion dropwise to the organic montmorillonite water dispersion under the protection of _N2 solution, adjust the temperature to 75°C, and disperse the intercalation with magnetic stirring for 2.5 hours. Then lower the temperature, move the reactant to an ice-water bath at about 2°C, add 150 parts of iron p-toluenesulfonate initiator dropwise to initiate polymerization of the polymer monomer, and add 50 parts by weight of NaOH to precipitate after 25 hours of reaction agent, filtered, washed, and dried in vacuum; then irradiated by microwaves with a frequency of 2300MHz for 1 hour to decompose the polymer into CO ₂ and H ₂ O, and obtain Pr ₂ O ₃ /montmorillonite nanocomposites.

Example 5. Add 100 parts of o-phenylenediamine and 25 parts of alkylphenol polyoxyethylene ether to 1000 parts of ethanol and stir _evenly ; dissolve 1 part of rare earth _Eu2O3 in hydrochloric acid to prepare 0.1mol/L aqueous solution, and added to the above mixed solution, ultrasonically dispersed at room temperature for 30 minutes to form a reverse micellar emulsion; 30% of the purified and organically modified montmorillonite was placed in water, and placed in a water bath with a constant temperature of 40-60°C Stir and heat for 30-60 minutes and then let it stand to form a montmorillonite aqueous dispersion; then add the reverse micellar emulsion to the organic montmorillonite aqueous dispersion drop by drop under the protection of _N2 , adjust the temperature to 60°C, and magnetically stir to disperse Intercalation for 2 hours. Then lower the temperature, move the reactant to an ice-water bath at about 2°C, and add 100 parts of ammonium persulfate dropwise as an initiator to initiate polymerization of the polymer monomer. After reacting for 15 hours, add 0.3 mol/L NaOH solution to make The rare earth particles were completely precipitated, filtered, washed, and vacuum-dried; then irradiated with microwaves at a frequency of 2500 MHz for 1.5 hours to decompose the polymer into CO ₂ and H ₂ O to obtain Eu ₂ O ₃ /MMT nanocomposites.

Claims (10)

1, a kind of rare earth particle/montmorillonite nanocomposite material, it is characterized in that: the particle diameter of rare earth particle is 20～30nm, the thickness of montmorillonite layer is 30～50nm, and rare earth particle and montmorillonite layer are evenly dispersed And tightly combined. 2. A rare earth particle/montmorillonite nanocomposite material as claimed in claim 1, characterized in that: the mass ratio of the rare earth particle to montmorillonite is: 1 to 20 parts of rare earth nanoparticles, 1 to 20 parts of montmorillonite 1 to 30 copies. 3. A rare earth particle/montmorillonite nanocomposite material as claimed in claim 1, characterized in that: said rare earth nanoparticles are rare earth oxides. 4, a kind of preparation method of rare earth particle/montmorillonite nano-composite material is that a certain amount of polymer monomer is dissolved in the dispersant that is dissolved with surfactant, then adds a certain amount of rare earth saline solution to it and stirs, Ultrasonic disperse at room temperature for 30-60 minutes to form a reverse micellar emulsion; then add the reverse micellar emulsion to the organic montmorillonite aqueous dispersion drop by drop under the protection of N2, adjust the temperature to 60-80°C, and magnetically stir to disperse Intercalation for 2 to 3 hours, then add an appropriate amount of initiator to initiate polymerization of the polymer monomer, add an appropriate amount of precipitant after 15 to 30 hours of reaction to completely precipitate the rare earth particles, filter, wash, and vacuum dry; then use a frequency of 2000~ 2500MHz microwave radiation for 0.2 to 1.5 hours, the polymer is decomposed into CO2 and H2O, and the rare earth particle/montmorillonite nanocomposite material is prepared. 5. The preparation method of rare earth particle/montmorillonite nanocomposite material as claimed in claim 4, characterized in that: the polymer monomer is aniline, methyl methacrylate, methyl acrylate, pyrrole or o-phenylenediamine any of the. 6. The preparation method of rare earth particle/montmorillonite nanocomposite material as claimed in claim 4, characterized in that: the surfactant is an anionic surfactant, a cationic surfactant or a nonionic surfactant; wherein the anionic surfactant The active agent is sodium lauryl sulfate, sodium stearate or stearic acid; the cationic surfactant is cetyltrimethylammonium chloride; the nonionic surfactant is alkylphenol polyoxyethylene ether; the surface The addition amount of the active agent is 15-25% of the weight of the polymer monomer. 7. The preparation method of rare earth particles/montmorillonite nanocomposites as claimed in claim 4, characterized in that: the dispersion medium is chloroform, water or ethanol; the amount of the dispersion medium is 4% of the mass of the polymer monomer ~10 times. 8. The preparation method of rare earth particle/montmorillonite nanocomposite material as claimed in claim 4, characterized in that: the rare earth salt is nitrate or chloride of soluble rare earth; wherein the amount of rare earth salt added is the polymer monomer 1 to 20% of the mass. 9. The preparation method of rare earth particle/montmorillonite nanocomposite material as claimed in claim 4, characterized in that: the initiator is azobisisobutyronitrile, ammonium persulfate or iron p-toluenesulfonate; The addition amount of the agent is 0.1-320% of the mass of the polymer monomer. 10. The preparation method of rare earth particle/montmorillonite nanocomposite material according to claim 4, characterized in that: the precipitating agent is sodium hydroxide.

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