CN106519092A - Method for preparing polymer nanometer composite by using Pickering emulsion with organic modified magadiite as emulsifying agent - Google Patents

Abstract

The invention discloses a method for preparing a polymer nanocomposite material from a Pickering emulsion using an organically modified magadiite as an emulsifier. In the method, an organically modified magadiite is used as an emulsifier, and a polymerized monomer is used as an oil phase to prepare a stable Pickering emulsion, and then a water-soluble radical polymerization initiator is added for emulsion polymerization to prepare a polymer nanocomposite material. The invention adopts organically modified magadiite solid particles to replace traditional surfactants for emulsification, greatly reduces the usage of emulsifiers, is non-toxic and harmless, and has the advantages of being green and environment-friendly. The preparation method of the invention has simple process and convenient operation, and the polymerization product does not need post-treatment.

Description

Preparation and polymerization of Pickering emulsion with organically modified magadiite as emulsifier method for nanocomposites

technical field

The invention relates to the technical field of preparing polymer nanomaterials by emulsion polymerization, in particular to a method for preparing polymer nanocomposite materials from Pickering emulsions using organically modified magadiite as an emulsifier.

Background technique

Emulsion polymerization is a common polymerization method for polymerizing monomers to synthesize polymers. It uses water as a solvent and is very beneficial to the environment. Emulsion polymerization is to disperse the monomer in water to form an emulsion with the aid of an emulsifier and mechanical stirring, and then add an initiator to initiate the polymerization of the monomer. In the early 1930s, the emulsion polymerization method has appeared in industrial production. In the production of many polymers including synthetic rubber, synthetic fibers, synthetic plastics, flocculants, adhesives, synthetic resin coatings and impact copolymers, emulsion polymerization has become one of the main methods, and the world passes emulsion polymerization every year. There are thousands of polymers produced, with vinyl emulsions - polymer emulsions being the fastest growing category and acrylic emulsions - polymer emulsions being the largest category. The production capacity of polymer emulsions has expanded significantly in the past five years. The main application areas of polymer emulsions are transportation, consumer durables, and building and construction industries, and the market has a high compound annual growth rate. Emulsion polymerization technology is of great significance to the world economy.

Emulsifier belongs to surfactant, which is a kind of substance that can form micelles, and plays an important role in emulsion polymerization. It is also widely used in other technical fields and people's daily life. Generally speaking, the emulsifier does not participate in the reaction during the reaction, but it plays a pivotal role as one of the main components of emulsion polymerization. The emulsifiers used in traditional emulsion polymerization can be divided into cationic emulsifiers, anionic emulsifiers, amphoteric emulsifiers and nonionic emulsifiers, and these types of emulsifiers and their systems have been thoroughly studied. More importantly, the traditional emulsifier has certain toxicity, and the stability of the formed emulsion is poor. After polymerization, the emulsifier remains in the polymer product, which affects the performance of the product. After the polymerization reaction, the product needs to be post-treated. The cost is high and cannot be completely divisible.

Solid particles can make water and oil two phases form a stable oil-in-water or water-in-oil emulsion, but there are few people who use solid particles to stabilize emulsions for polymerization. Magadiite can be used as an emulsifier instead of a traditional emulsifier to polymerize a polymer, and it can be mixed with a polymer to form a polymer nanocomposite material, and the dosage is only a few tenths of the traditional emulsifier. A good emulsification effect can be achieved; there is no research on using organically modified magadiite as an emulsifier to make a Pickering type emulsion for emulsion polymerization to form a polymer nanocomposite.

Contents of the invention

The object of the present invention is to provide a method for preparing polymer nanocomposite materials based on the Pickering emulsion of organically modified magadiite as emulsifier.

The method of the present invention uses organically modified magadiite as an emulsifier, polymerized monomers as an oil phase to prepare a stable Pickering emulsion, and then adds a water-soluble radical polymerization initiator to carry out emulsion polymerization to prepare a polymer nanocomposite material .

The present invention is realized through the following technical solutions.

The method for preparing the polymer nanocomposite material with the Pickering emulsion of organically modified magadiite as emulsifier comprises the following steps:

(1) Add the organically modified magadiite into deionized water, stir and heat up, so that the organically modified magadiite is evenly dispersed in the deionized water; after the dispersion is uniform, cool down, add the polymer monomer, and continue stirring, Form a uniform and stable Pickering emulsion;

(2) Heat the Pickering emulsion, add a water-soluble free radical polymerization initiator dropwise; after the dropwise addition, raise the temperature to react, cool down after the reaction, stop stirring, and discharge.

Further, in step (1), the deionized water is 50wt%-90wt% of the Pickering emulsion.

Further, in step (1), the organically modified magadiite is 0.01wt%-1wt% of the polymerized monomer.

Further, in step (1), the organically modified magadiite is magadiite modified with quaternary ammonium salt, quaternary phosphonium salt or silane.

Further, in step (1), the polymerized monomer includes styrene, methyl methacrylate or vinyl acetate.

Further, in step (1), the temperature increase is to increase the temperature to 60-80°C.

Further, in step (1), the temperature reduction is to reduce the temperature to 40-60°C.

Further, in step (2), the water-soluble radical polymerization initiator is 0.1wt%-0.5wt% of the polymerized monomer.

Further, in step (2), the water-soluble radical polymerization initiator includes one of persulfate and redox initiation system.

Further, in step (2), the heating is to 70-90°C.

Further, in step (2), the reaction is carried out at 80-90° C. for 1-5 hours.

Further, in step (2), the temperature reduction is to reduce the temperature to below 50°C.

Further, the organically modified magadiite particles remain in the synthesized polymer material to constitute the polymer nanocomposite material.

Further, the preparation process is stirred throughout.

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

(1) The Pickering emulsion made of organically modified magadiite as an emulsifier in the present invention has a good emulsification effect, and the amount of organically modified magadiite is significantly less than that of traditional emulsifiers, greatly reducing emulsification Reduce the dosage of the agent and save the cost;

(2) Organically modified magadiite is a kind of mineral clay, which is non-toxic and harmless, and will not pollute the environment or endanger human health;

(3) The organically modified magadiite particles of the present invention are retained in the material to form a polymer nanocomposite material, and the polymerized product does not require post-processing, which improves economic benefits and is environmentally friendly;

(4) The Pickering emulsion prepared by using organically modified magadiite as an emulsifier in the present invention has strong stability, is not easily affected by external environments such as temperature, and has long-term stability;

(5) Organically modified magadiite has good biocompatibility with organisms, and does not affect the wide application of polymer nanocomposites in industrial fields such as oil exploration, daily life such as cosmetics and food, and in the field of medicine;

(6) The method of the present invention has simple process and convenient operation.

Description of drawings

Fig. 1 is the infrared spectrogram of the polymer nanocomposite material that makes in embodiment 1;

Fig. 2 is the infrared spectrogram of the polymer nanocomposite material that makes in embodiment 2;

Fig. 3 is the infrared spectrogram of the polymer nanocomposite material that makes in embodiment 3;

FIG. 4 is an X-ray diffraction pattern of the polymer nanocomposite material prepared in Example 3.

detailed description

The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments, but the present invention is not limited to the following embodiments.

Example 1

(1) Add deionized water accounting for 50% of the total emulsion mass and cetyl triphenyl quaternary phosphonium salt-modified magadiite accounting for 0.01% of the polymerized monomer mass to the three-necked flask in turn, start stirring, and heat up to 60°C After the organically modified magadiite is evenly dispersed in water, cool down to 40°C, then add methyl methacrylate monomer, and stir the mixed solution continuously with a mechanical paddle to make the mixed solution form a uniform and stable Pickering emulsion; take an appropriate amount of emulsion to Finger bottle, it can be observed that the previously stratified oil-water two-phase has become a uniform milky white emulsion, and through standing observation, the emulsion has always remained stable.

(2) Heat the Pickering emulsion to 70°C, add ammonium persulfate accounting for 0.1% of the mass of methyl methacrylate monomer into the three-necked flask through a constant pressure dropping funnel, and wash the container with deionized water after the addition is complete. container, and put it into the flask; raise the temperature to 80°C to continue the reaction for 1 hour, and then start to cool down; when the temperature of the reaction material drops below 50°C, stop stirring and discharge.

The infrared spectrum of the obtained polymer nanocomposite is shown in Figure 1, which shows that 1734 cm ^-1 is the characteristic peak of the stretching vibration of the C=O double bond, and the peak intensity is large; 1488 cm ^-1 and 1448 cm ^-1 is the characteristic absorption peak of -CH ₂ - bending vibration; 1281 cm ^-1 and 1244 cm ^-1 are the characteristic peaks of asymmetric stretching vibration of -COC-; it can be seen that the obtained polymer is polymethyl methacrylate; and Tests proved that magadiite remained in the polymer to form a polymer nanocomposite.

The molecular weight and dispersibility of the obtained product were determined by gel permeation chromatography (GPC), and the results are shown in Table 1.

Table 1 Molecular weight and dispersion of polymethyl methacrylate (PMMA) nanocomposites

mn mw Mz Mz+1 Polydispersity 165639 435675 903508 1349719 2.630267

It can be seen from Table 1 that higher molecular weight polymethyl methacrylate can be obtained through Pickering emulsion polymerization, the number average molecular weight is 165639, while the polydispersity (Mw/Mn) of polymethyl methacrylate is about 2.63, and the molecular weight distribution width.

Example 2

(1) Add deionized water accounting for 70% of the total mass of the emulsion and magadiite modified with hexadecyl triphenyl quaternary ammonium salt accounting for 0.5% of the mass of the polymerized monomer into the three-necked flask, start stirring, and heat up to 70 ℃, after the organically modified magadiite is uniformly dispersed in water, the temperature is lowered to 50 ℃, then styrene monomer is added, and the mixed solution is continuously stirred with a mechanical paddle, so that the mixed solution forms a uniform and stable Pickering emulsion;

(2) Heat the Pickering emulsion to 80°C, add dicumyl peroxide, which accounts for 0.3% of the mass of styrene monomer, into the three-necked flask through a constant pressure dropping funnel, and wash the container with deionized water after the addition is complete. container, and added to the flask; the temperature was raised to 85°C to continue the reaction for 3 hours, and then the temperature began to drop; when the temperature of the reaction material dropped below 50°C, the stirring was stopped and the material was discharged.

The infrared spectrum of the obtained polymer nanocomposite is shown in Figure 2. Figure 2 shows that 3000-3100 cm ^-1 is the characteristic peak of stretching vibration of benzene ring=CH; 2924 cm ^-1 and 2851 cm ^-1 are respectively CH ₂ asymmetric and symmetric stretching vibration characteristic peaks; confirmed that the obtained polymer is polystyrene; and proved that magadiite remained in the polymer to form a polymer nanocomposite material through testing.

Example 3

(1) Add deionized water accounting for 90% of the total mass of the emulsion and γ-aminopropyltriethoxysilane-modified magadiite accounting for 1% of the mass of the polymerized monomer to the three-necked flask in turn, start stirring, and heat up to 80°C, after the organically modified magadiite is uniformly dispersed in water, the temperature is lowered to 60°C, then vinyl acetate monomer is added, and the mixed solution is continuously stirred with a mechanical paddle, so that the mixed solution forms a uniform and stable Pickering emulsion;

(2) Heat the Pickering emulsion to 90°C, then add 0.5% hydrogen peroxide to the mass of vinyl acetate monomer into the three-necked flask through a constant pressure dropping funnel, and wash the container with deionized water after the addition is completed , and added to the flask; keep warm at 90°C and continue to react for 5h, then start to cool down; when the temperature of the reaction material drops below 50°C, stop stirring and discharge.

The infrared spectrogram of the obtained polymer nanocomposite is shown in Figure 3. The characteristic peak of CH stretching vibration is at 2925 cm ^-1 ; the characteristic peak of C=O stretching vibration is at 1739 cm ^-1 , and the intensity is relatively large; The characteristic peak of bending vibration of CH ₂ is at 1443 cm ^-1 ; it can be known that the obtained polymer is polyvinyl acetate.

The X-ray diffraction test is carried out to the product, and the test results are as shown in Figure 4: the characteristic diffraction peak at 2θ=4.34° is the characteristic diffraction peak of polyvinyl acetate, and 24.76°-28.60° is the characteristic peak region of magadiite; The emulsifier successfully prepared the polymer, and the magadiite remained in the polymer to form a polymer nanocomposite.

The above-mentioned embodiments of the present invention are only examples for clearly illustrating the present invention, rather than limiting the implementation of the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the claims of the present invention.

Claims (10)

1. the method that the Pickering emulsion of emulsifying agent prepares polymer nanocomposite with organically modified magadiite, is characterized in that, comprises the steps: (1) Add the organically modified magadiite into deionized water, stir and heat up, so that the organically modified magadiite is evenly dispersed in the deionized water; after the dispersion is uniform, cool down, add the polymer monomer, and continue stirring, Form a uniform and stable Pickering emulsion; (2) Heat the Pickering emulsion, add a water-soluble free radical polymerization initiator dropwise; after the dropwise addition, raise the temperature to react, cool down after the reaction, stop stirring, and discharge. 2. The method for preparing polymer nanocomposites using organically modified magadiite as emulsifier's Pickering emulsion according to claim 1, characterized in that, in step (1), the deionized water is Pickering 50wt%-90wt% of the emulsion. 3. the method for preparing polymer nanocomposites using organically modified magadiene as emulsifier Pickering emulsion according to claim 1, characterized in that, in step (1), said organically modified magadiene Sodium silicate is 0.01wt%-1wt% of the polymerized monomer. 4. The method for preparing polymer nanocomposites using organically modified magadiene as emulsifier Pickering emulsion according to claim 1, characterized in that, in step (1), said organically modified magadiene Disoblastite is magadiite modified by quaternary ammonium salt, quaternary phosphonium salt or silane. 5. The method for preparing polymer nanocomposites using organically modified magadiite as emulsifier Pickering emulsion according to claim 1, characterized in that, in step (1), the polymerized monomer comprises benzene Ethylene, methyl methacrylate, or vinyl acetate. 6. The method for preparing polymer nanocomposites using organically modified magadiite as emulsifier's Pickering emulsion according to claim 1, characterized in that, in step (1), the heating up is heating up to 60 -80°C; the temperature drop is to drop the temperature to 40-60°C. 7. The method for preparing polymer nanocomposites using organically modified magadiite as emulsifier's Pickering emulsion according to claim 1, characterized in that, in step (2), the water-soluble radical polymerization The initiator is 0.1wt%-0.5wt% of the polymerized monomer. 8. The method for preparing polymer nanocomposites using organically modified magadiite as emulsifier Pickering emulsion according to claim 1, characterized in that, in step (2), the water-soluble radical polymerization The initiator includes one of a persulfate and a redox initiation system. 9. The method for preparing polymer nanocomposites using organically modified magadiite as emulsifier Pickering emulsion according to claim 1, characterized in that, in step (2), the heating is heated to 70 -90°C; the reaction is to react at 80-90°C for 1-5h; the temperature reduction is to lower the temperature to below 50°C. 10. the method for preparing polymer nanocomposites with organically modified magadiite according to claim 1 as the Pickering emulsion of emulsifier, it is characterized in that the organically modified magadiite particles remain in the synthetic Said polymer nanocomposite is formed in a polymer material; the preparation process is stirred throughout.