CN100512945C - Method of preparing temperature sensitive nano microcapsule by using small molecule hydrocarbon as template - Google Patents

Abstract

The invention relates to a method for preparing nanometer microcapsules, and aims to provide a method for preparing temperature-sensitive nanometer microcapsules by using small molecule hydrocarbons as templates. In this method, small organic molecule hydrocarbon droplets are used as a template, and the temperature-sensitive monomer, comonomer and cross-linking monomer are copolymerized by miniemulsion polymerization, and the cross-linking monomer is used to form a cross-linked shell, and then the A mixed aqueous solution of temperature-sensitive monomers and water-soluble cross-linking monomers is added to polymerize to form temperature-sensitive nano-microcapsules. The invention can simply, effectively and stably obtain temperature-sensitive nano-microcapsules with a size of 100-1000 nanometers, and can control the size of the capsules by adjusting the ambient temperature, thereby controlling loading and release. It is a new type of intelligent nano-capsules capsule. The obtained microcapsules can be applied to the fields of catalyst loading, controlled release of drugs, proteins and other bioactive substances, and the loading and controlled release of nanoscale particles and other reagents.

Description

Method for preparing temperature-sensitive nano-microcapsules using small molecular hydrocarbons as templates

technical field

The invention relates to a method for preparing nanometer microcapsules, in particular to a method for preparing temperature-sensitive nanometer microcapsules by using small molecule hydrocarbons as templates.

Background technique

Thermosensitive polymers respond intelligently and reversibly to environmental changes, especially temperature changes. Therefore, since the discovery of the temperature-sensitive properties of linear poly-N-isopropylacrylamide in 1969 (Heskins M, Guillet J E.J Macromol Sci Chem, 1969, 2: 1441), research on this type of polymer has always been a major issue in polymer science. One of the hotspots in the field. The phase transition phenomenon that thermosensitive polymers can exhibit near the lowest critical solution temperature (LCST), it is generally believed that the reason for the phase transition phenomenon of thermosensitive polymers is due to the thermosensitive polymerization above the lowest critical phase transition temperature. The hydrogen bond formed between the hydrophilic group on the macromolecular chain and water is destroyed, so that the temperature-sensitive polymer molecule loses water, so that the temperature-sensitive polymer is completely dissolved from the state below the lowest critical solution temperature (into a random coil structure) dehydration shrinks into granules. At present, many scholars have begun to study structured temperature-sensitive polymer particles, such as core-shell or porous structure temperature-sensitive nano-scale (micron-scale) particles. A copolymer core of N-isopropylacrylamide and styrene was synthesized by soap-free emulsion polymerization, and then coated with a layer of poly-N-isopropylacrylamide by seed emulsion polymerization of N-isopropylacrylamide Amide shell, successfully synthesized micron-sized temperature-sensitive core-shell particles (Xiao X C, Chu L Y, Chen W M, Wang S, Xie R. Langmuir, 2004, 20:5247). The temperature-sensitive particles with porous structure were prepared by physically cross-linking the copolymer of allylamine and N-isopropylacrylamide with sodium polystyrene sulfonate (Chen B, Gao C Y., Macromol Rapid Commun, 2005, 26: 1657 ). So far, the preparation of temperature-sensitive nanocapsules by combining miniemulsion and seed emulsion polymerization has not been reported.

In order to prepare nano-microcapsules, many methods have been reported in patents and literature, such as sacrificial template method, macromolecular self-assembly method, direct polymerization method and layer-by-layer self-assembly method. They have also been widely used in various occasions, such as white plastic pigments for paints and water-based paints, anti-ultraviolet additives and handle modifiers, paints, paper, leather, cosmetics and other industries; another important use is in Among them, functional compounds are encapsulated to make polymer materials with sustained release function, which are used in pharmaceutical, medical diagnosis, biotechnology and other occasions. Especially now that cells, DNA and other biologically active substances have been successfully coated, there may be breakthrough applications.

The methods for preparing nano-microcapsules have been proposed as follows:

(1) Use a block copolymer with one end hydrophobic and one end hydrophilic to self-assemble into micelles, and introduce units with siloxane on the hydrophilic end, and then use the hydrolysis-condensation of siloxane to form a hybrid Nano-microcapsules (Kyougmoo Koh, Kohji Ohno, Yoshinobu Tsujii, et al. Angew Chem Int Ed, 2003, 42:4197);

(2) Using polystyrene as a template, using a layer-by-layer self-assembly method outside the template, connecting multi-layer polyelectrolytes and inorganic nanoparticles, and then removing the template by chemical extraction or calcination to obtain nanocapsules (Caruso F, Caruso R A, Mohwald H. Science, 1998, 282: 1111);

(3) Using emulsion polymerization, a shell formed by copolymerization of styrene and double bond-containing siloxane monomer is formed outside the polymer template, in which the siloxane group is also hydrolyzed-condensed into an inorganic compound during the emulsion polymerization process. network, and then remove the core template to obtain nanocapsules (Tissot I, Novat C, Lefebvre F, et al.Macromolecules, 2001, 34:5737);

(4) Using a new emulsion polymerization method to encapsulate small molecular hydrocarbons in situ to synthesize microcapsules (US4, 973, 670, 1990; McDonald C J, Bouck K J, Chaput A B, et al. Macromolecules, 200, 33: 1593); Using hexadecane as a template, one-step method of miniemulsion polymerization of styrene to prepare nanocapsules (Tiarks, F, Landfester K, Antonietti M.Langmuir, 2001, 17:908); using n-octane as a template, styrene and 3-methyl Organic-inorganic hybrid nanocapsules prepared by copolymerization of acryloyl trimethoxysilylpropyl ester miniemulsion (NiK F, Shan G R, Weng Z X. Macromolecules, 2006, 39: 2529).

For method (1), it is necessary to use living radical polymerization to synthesize block polymers first, then self-assemble, use hydrolysis-condensation reactions to form inorganic phases, and then remove hydrophobic polymer cores. There are relatively many steps and there is an assembly efficiency. Limited problems; for method (2), the layer-by-layer self-assembly of polyelectrolytes also requires the step of removing the template, and because polyelectrolyte particles are easy to flocculate, they need to be carried out at extremely low concentrations, and cannot be stably dispersed in solvents, so Its scope of application is also limited; for method (3), although the synthesis is easier, it is relatively difficult for the removal of the polymer template, and the separation of the removed polymer and microcapsules is also troublesome; for method (4), the preparation The process is the most convenient, and the microcapsule can be obtained by only one step reaction, and the removal of the small molecular hydrocarbon template is convenient, so it is a good method for preparing the microcapsule. The present invention will prepare temperature-sensitive nano-microcapsules on the basis of this method, but there is no report on synthesizing temperature-sensitive nano-microcapsules by this method.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a novel method for preparing temperature-sensitive nano-microcapsules using small molecular hydrocarbons as a template. The preparation process is simple and can stably obtain nano-scale temperature-sensitive capsules. Moreover, the capsule can produce intelligent and reversible responses to changes in ambient temperature, and has broad application prospects.

In order to achieve the above object, the inventors have found through in-depth research that the method of miniemulsion polymerization is used to mix temperature-sensitive monomers, comonomers, crosslinking monomers and small molecule hydrocarbons before polymerization, and disperse them into a miniemulsion. Hydrocarbons are used as templates, directly polymerized to obtain nano-microcapsules, and then a layer of temperature-sensitive polymer shell is formed on the nano-microcapsules by continuing to drop the mixed aqueous solution of temperature-sensitive monomers and water-soluble cross-linking monomers, and finally The temperature-sensitive nano-microcapsules are obtained. In the process of synthesizing nano-microcapsules, by controlling the formulation and polymerization conditions, the shell containing thermosensitive monomer units can be coated on the interface of small molecule hydrocarbon droplets to form nano-microcapsules. The method does not need the step of removing the template, which greatly simplifies the preparation process of the microcapsules.

In the present invention, the emulsifier is first dissolved in water, and the thermosensitive monomer, comonomer, crosslinking monomer, small molecule hydrocarbon and co-stabilizer are mixed, added to the above-mentioned aqueous solution, and the above-mentioned mixed solution is dispersed by ultrasonic waves to obtain Stable mini-emulsion; heat the above-mentioned mini-emulsion to 40-80°C, add a water-soluble initiator to initiate polymerization. In the system initiated by water-soluble initiators, the initiators are decomposed into primary free radicals in water. According to the different types of initiators, the primary free radicals can be positively charged, negatively charged or macromolecular hydrophilic chains. Primary free radicals or oligomer free radicals are trapped on the surface of the droplet due to electrostatic or steric effects during the diffusion into the droplet, making the surface of the droplet the main polymerization site, and the monomers are continuously released from the inside of the droplet. get replenished. Due to the incompatibility of the polymer and monomer droplet phases, the newly formed polymer rapidly precipitates on the droplet surface as the reaction proceeds. Thermosensitive monomers are hydrophilic monomers, so there are more oligomer free radicals formed from thermosensitive monomers in the polymerization system. The polymerization temperature is generally higher than the LCST, so the temperature-sensitive oligomer radicals will precipitate from the water phase and be captured by monomer droplets after reaching the critical chain length. Although the temperature-sensitive polymer exhibits hydrophobicity above the LCST, its hydrophobicity is still smaller than that of small molecular hydrocarbons and formed polymers. Under the thermodynamic driving force, the temperature-sensitive polymer free radicals tend to distribute in the droplet on the outside. Under the combined action of thermodynamic driving force, electrostatic effect or (and) steric hindrance effect, the oligomer radicals and dead polymers in the water phase will be adsorbed by the droplets, and the surface of the droplets becomes the main polymerization site, and most of the polymerization The substances are formed and precipitated on the surface of the droplet. The interfacial tension between the polymer phase and water is smaller than the interfacial tension between small molecular hydrocarbons and water, so the polymer formed by free radical polymerization entering the interior of the droplet will also diffuse from the interior of the droplet to the droplet under the action of thermodynamic driving force The surface is coated on the surface of the small molecular hydrocarbon droplet, and at the same time, a stable network structure is formed through the copolymerization reaction with the cross-linking monomer, and finally the nano-microcapsule with the shell layer containing the temperature-sensitive monomer unit is obtained.

After the conversion rate of the system reaches 90%, the water-soluble initiator is added, and the mixed aqueous solution of the temperature-sensitive monomer and the water-soluble cross-linking monomer is added dropwise. The homopolymers and copolymers of temperature-sensitive monomers formed in the original miniemulsion system can improve the affinity between the temperature-sensitive polymer and the nanocapsule shell, so the oligomers formed by the temperature-sensitive monomers in the second stage It tends to be adsorbed by nanocapsules and coated on the outside of nanocapsules; part of the temperature-sensitive monomers and the polymer on the nanocapsules undergo grafting reaction, and the above two processes can finally obtain temperature-sensitive nanocapsules.

The method used in the present invention is: the monomers participating in the reaction include at least one temperature-sensitive monomer, at least one comonomer and at least one crosslinking monomer, and the total amount of monomers refers to the temperature-sensitive monomer, copolymerization The total mass of monomers and cross-linking monomers, but excluding additional temperature-sensitive monomers and water-soluble cross-linking monomers;

The method includes the following steps:

(1) Dissolving the emulsifier in water to obtain an aqueous solution of the emulsifier, the ratio of the total amount of monomers to water is 0.0025:1 to 0.5:1, and the amount of emulsifier is 1% to 20% of the total amount of monomers;

(2) Mix thermosensitive monomer with small molecular hydrocarbon, co-stabilizer, comonomer and cross-linking monomer, join in the solution obtained in step (1), and disperse the above-mentioned mixed solution with ultrasonic waves to obtain stable fine emulsion;

Among them, the amount of small molecule hydrocarbons is 40% to 360% of the total amount of monomers, the amount of co-stabilizers is 3% to 25% of the amount of small molecule hydrocarbons, and the amount of temperature sensitive monomers is 2% to 2% of the total amount of monomers. 20%, the amount of comonomer used is 50% to 97% of the total amount of monomers, and the amount of crosslinking monomers is 1% to 40% of the total amount of monomers;

(3) The temperature of the emulsion that step (2) is obtained is adjusted to 40～80 ℃, under the protection of inert gas, add water-soluble initiator and carry out miniemulsion polymerization, and the consumption of water-soluble initiator is 3%～of the total monomer consumption 25%, after 120-600 minutes of reaction, the nano-microcapsules containing thermosensitive monomer units in the shell polymer are obtained;

(4) After the conversion rate of the system reaches more than 90%, add a water-soluble initiator and add dropwise a mixed aqueous solution of a temperature-sensitive monomer and a water-soluble cross-linking monomer. The dropping time is controlled within 30 to 240 minutes. After the monomer aqueous solution is added dropwise, keep warm for 3 to 20 hours;

Wherein, the amount of additional temperature-sensitive monomers is 2 to 15 times that of the temperature-sensitive monomers in step (2), and the amount of water-soluble crosslinking monomers is 10% to 50% of that of the additional temperature-sensitive monomers. The ratio of the total amount of monomers to water is 0.05:1 to 0.5:1, the total amount of added monomers refers to the total mass of additional temperature-sensitive monomers and water-soluble cross-linking monomers, and the amount of added water-soluble initiators is Add 0.5% to 10% of the total amount of monomers;

The temperature-sensitive monomer and the additional temperature-sensitive monomer are at least one of vinyl caprolactam or the following structural formula:

In the structural formula (1), R ¹ and R ² are H, C ₂ to C ₅ aliphatic chains, and R ¹ and R ² cannot be H at the same time, and R ³ is H and CH ₃ ;

In the structural formula (2), R ¹ is an aliphatic chain of C ₁ to C ₅ , and R ² and R ³ are H and CH ₃ ;

The comonomer structure is at least one of the following structural formulas:

In the structural formula (3), R ¹ is H, CH ₃ or C ₂ H ₅ , R ² is phenyl, substituted phenyl, Cl, CN, alkyl ether or OCOCH ₃ ;

In the structural formula (4), R ¹ is H, CH ₃ or C ₂ H ₅ , X is a C ₁ -C ₁₂ aliphatic chain or a C ₁ -C ₁₂ aliphatic chain containing a hydroxyl group;

The cross-linking monomer structure is at least one of the following structural formulas:

In the structural formula (5), R is a benzene ring, C _n H _2n , wherein n=0～8;

The water-soluble crosslinking monomer is at least one of structural formula (6), formula (7) and formula (8).

In the present invention, the small molecular hydrocarbon is at least one of naphthenes, aromatic hydrocarbons or alkanes with 5-14 carbons.

In the present invention, the co-stabilizer is at least one of C ₁₂ -C ₁₈ aliphatic hydrocarbon, C ₁₂ -C ₁₈ fatty alcohol, structural formula (9) or structural formula (10):

In the structural formula (9), R ¹ is H, CH ₃ , C ₂ H ₅ , and X is an aliphatic chain of C ₁₂ to C ₁₈ ;

In the structural formula (10), R ¹ is H, CH ₃ , CF ₃ , m=0-17, R _f is C _n H _j F _2n+1-j fluorinated fat (n=1-18, j=0 ~34), and m+n=12~18.

In the present invention, the emulsifier is organic carboxylate, organic sulfate, organic sulfonate, organic phosphate anionic emulsifier, organic quaternary ammonium salt cationic emulsifier, zwitterionic emulsifier or polyoxyethylene ester , polyoxyethylene ether, polyoxyethylene amine nonionic emulsifier at least one.

In the present invention, the water-soluble water-soluble initiator is at least one of hydrogen peroxide, persulfate, cationic azo salt, polyethylene glycol azo macroinitiator, and water-soluble redox initiation system; The reducing substance added in the water-soluble redox initiation system is at least one of primary amine, secondary amine, tertiary amine alcohol, sulfite, thiosulfate and ferrous salt.

Considering that the high hydrophilicity of monomers can easily cause secondary nucleation, and it is difficult to obtain nanocapsules with hollow structures, it is necessary to control the amount of temperature-sensitive monomers in the formulation of miniemulsion polymerization to reduce the number of secondary nucleation. The amount of temperature-sensitive monomers in the system should be controlled within the range of 2.5% to 20% of the total amount of monomers.

Considering that the nano-microcapsules must have sufficient mechanical strength to maintain a certain structural shape, a certain amount of cross-linking monomer must be added to the system. The cross-linking monomer can be hydrophobic divinylbenzene or hydrophilic N, N'-methylenebisacrylamide, etc. The amount of cross-linking monomer needs to be controlled within the range of 1% to 40%.

The ratio of the total amount of monomer to water is 0.0025:1-0.5:1.

The medium and small molecule hydrocarbons of the present invention are at least one of alkanes (such as pentane, octane, dodecane, etc.), cycloalkanes (such as cyclohexane) or aromatic hydrocarbons (benzene, toluene, etc.) with 5 to 14 carbons. It is 40% to 360% of the total amount of monomers used.

In the present invention, the co-stabilizer is an alkane with 12 to 18 carbons (such as hexadecane, etc.), an alcohol with 12 to 18 carbons (such as cetyl alcohol, etc.), structural formula (9) (such as lauryl methacrylate, etc.), At least one of the structural formula (10) (such as perfluorooctyl ethyl methacrylate, etc.) is used in an amount of 3% to 25% of the amount of small molecular hydrocarbons.

The emulsifier in the present invention can be selected ionic emulsifier (such as anionic emulsifier sodium lauryl sulfate, sodium lauryl sulfonate, cationic emulsifier cetyltrimethylammonium bromide etc., amphoteric Ionic emulsifier (dodecyl dimethyl propylamine sulfonic acid, etc.) or non-ionic emulsifier (such as TWEEN series, SPAN series, OP series, etc.) or their mixture, the amount is 1% to 20% of the total amount of monomers %.

The initiator can be selected from water-soluble peroxide initiators (such as potassium persulfate, ammonium persulfate, etc.) or water-soluble redox initiator systems (such as persulfate and triethanolamine, tetramethyldiethylenediamine, morpholine, etc. , hydrogen peroxide and ferrous sulfate system) or at least one of water-soluble cationic azo initiators (such as 2,2'-azo(2-amidinopropane) dichloride, etc.), the amount is the total monomer 3%~25% of the dosage.

Considering the stability of the system and the ratio of primary free radicals and oligomer free radicals trapped on the droplet interface, the selected emulsifier and initiator must be matched. Cationic initiators can be combined with cationic or (and) nonionic Emulsifiers are used at the same time; nonionic initiators can be used with single ionic and nonionic emulsifiers, and can also be used in combination with ionic and nonionic emulsifiers; anionic initiators can be used with anionic or (and) non-ionic emulsifiers are used at the same time.

The beneficial effects of the present invention are:

The preparation process of the invention is simple, and the temperature-sensitive nanometer hollow capsule can be obtained stably, and the permeability property of the capsule can be reversibly adjusted through the change of the ambient temperature, thus having a wide application range. The hollow capsule obtained by the present invention can be widely used in the fields of catalyst loading, controlled release of drugs, proteins and other bioactive substances, nanoscale particles, loading and controlled release of other reagents, and the like.

The present invention will be described in detail below through specific examples.

Example 1:

Weigh 0.53 g of emulsifier sodium dodecylsulfonate and add it to 1000 g of water to obtain an emulsifier solution. Mix 10g of octane, 0.6g of hexadecane, 0.3g of N-isopropylacrylamide, 2g of styrene, and 0.5g of divinylbenzene, add them to the above emulsifier aqueous solution, and disperse the above mixed solution with ultrasonic waves to obtain Stable emulsion; the temperature was adjusted to 80°C, and under the protection of nitrogen, 0.25 g of potassium persulfate was added to initiate the reaction for 120 minutes. The particle size is measured with a dynamic light scattering particle size analyzer: at 25°C, its hydrodynamic diameter is 106.5nm; at 40°C, its hydrodynamic diameter is 102.4nm, and the particles are basically insensitive to temperature. Observing its morphology with a transmission electron microscope, it is a capsule with a hollow structure. Add 0.05 g of potassium persulfate, add dropwise an aqueous solution prepared by 4.5 g of N-isopropylacrylamide, 0.45 g of acrylamine, and 95 g of water, drop it in 0.5 hours, keep warm for 3 hours after the drop, and terminate the reaction. The particle size was measured with a dynamic light scattering particle size analyzer: at 25°C, its hydrodynamic diameter was 419.5nm; at 40°C, its hydrodynamic diameter was 140.3nm, and the particles showed obvious temperature sensitivity. Observing its morphology with a transmission electron microscope, the particles are still hollow capsules.

Example 2:

Weigh 8 g of emulsifier cetyltrimethylammonium bromide and add it into 1000 g of water to obtain an emulsifier solution. Mix 200g of octane, 12g of hexadecane, 6g of vinyl caprolactam, 60g of styrene, and 40g of divinylbenzene, add them to the above-mentioned emulsifier aqueous solution, and disperse the above-mentioned mixed solution with ultrasonic waves to obtain a stable emulsion; adjust the temperature to At 60°C, under nitrogen protection, 5 g of 2,2'-azo(2-amidinopropane) dihydrochloride was added to initiate the reaction for 240 minutes. The particle size is measured with a dynamic light scattering particle size analyzer: the hydrodynamic diameter is 134.2nm at 25°C; the hydrodynamic diameter is 129.5nm at 40°C, and the particles are basically insensitive to temperature. Observing its morphology with a transmission electron microscope, it is a capsule with a hollow structure. Add 0.1 g of potassium persulfate, add dropwise the aqueous solution prepared by 12 g of vinylcaprolactam, 6 g of tartrate diacrylamide and 100 g of water, drop it in 2 hours, keep it warm for 20 hours after the drop, and terminate the reaction. The particle size was measured with a dynamic light scattering particle size analyzer: at 25°C, its hydrodynamic diameter was 335.6nm; at 40°C, its hydrodynamic diameter was 140.5nm, and the particles showed obvious temperature sensitivity. Observing its morphology with a transmission electron microscope, the particles are still hollow capsules.

Example 3:

Take by weighing emulsifier OP-10 70g, add in 1000g water, obtain emulsifier solution. Mix 200g of pentane, 50g of cetyl alcohol, 12g of vinyl isobutyramide, 440g of styrene, and 4.6g of N,N'-methylenebisacrylamide, add them to the above-mentioned aqueous solution containing an emulsifier, and ultrasonically shake the above-mentioned The mixed solution was dispersed to obtain a stable emulsion; the temperature was adjusted to 50°C, and under the protection of nitrogen, 10 g of potassium persulfate and 5 g of sodium sulfite were added to initiate the reaction for 260 min. The particle size is measured with a dynamic light scattering particle size analyzer: at 25°C, its hydrodynamic diameter is 150.3nm; at 40°C, its hydrodynamic diameter is 147.6nm, and the particles are basically insensitive to temperature. Observing its morphology with a transmission electron microscope, it is a capsule with a hollow structure. Add 5g of potassium persulfate, 2.5g of ethylamine, dropwise add 60g of vinyl isobutyramide, 20g of N,N'-methylenebisacrylamide and 160g of water to prepare an aqueous solution, drop it in 3 hours, and keep it warm for 20 hours, the reaction was terminated. The particle size was measured with a dynamic light scattering particle size analyzer: at 25°C, its hydrodynamic diameter was 470.6nm; at 40°C, its hydrodynamic diameter was 168.5nm, and the particles showed obvious temperature sensitivity. Observing its morphology with a transmission electron microscope, the particles are still hollow capsules.

Example 4:

Weigh 0.63 g of emulsifier sodium lauryl sulfate and add it to 1000 g of water to obtain an emulsifier solution. Mix 100g of cyclohexane, 3g of perfluorooctylethyl methacrylate, 8g of N-isopropylacrylamide, 50g of methyl methacrylate, and 5g of divinylbenzene, and add them to the above-mentioned aqueous solution containing an emulsifier, The above mixed solution was dispersed by ultrasonic waves to obtain a stable emulsion; the temperature was adjusted to 40°C, under the protection of nitrogen, 10 g of potassium persulfate was added, 5 g of triethanolamine was added for initiation, and the reaction was carried out for 600 min. The particle size is measured with a dynamic light scattering particle size analyzer: at 25°C, its hydrodynamic diameter is 95.8nm; at 40°C, its hydrodynamic diameter is 92.3nm, and the particles are basically insensitive to temperature. Observing its morphology with a transmission electron microscope, it is a microcapsule with a hollow structure. Add 1 g of potassium persulfate, add 0.5 g of diethylamine dropwise to an aqueous solution prepared by adding 32 g of N-isopropylacrylamide, 8 g of N, N'-methylenebisacrylamide and 200 g of water, and finish dropping in 2 hours. Incubate for 10 hours to terminate the reaction. The particle size was measured with a dynamic light scattering particle size analyzer: at 25°C, its hydrodynamic diameter was 374.6nm; at 40°C, its hydrodynamic diameter was 129.5nm, and the particles showed obvious temperature sensitivity. Observing its morphology with a transmission electron microscope, it is still a hollow capsule.

Example 5:

Take by weighing emulsifier sodium lauryl sulfate 5g, OP-10 5g, add in 1000g water and obtain emulsifier solution. Mix 100g of toluene, 10g of hexadecane, 8g of N-isopropylacrylamide, 80g of acrylonitrile, and 15g of divinylbenzene, add them to the above-mentioned aqueous solution containing emulsifier, and disperse the above-mentioned mixed solution with ultrasonic waves to obtain a stable Emulsion: adjust the temperature to 50°C, under the protection of nitrogen, add 10g of hydrogen peroxide, 5g of sodium thiosulfate to initiate, and react for 210min. The particle size is measured with a dynamic light scattering particle size analyzer: at 25°C, its hydrodynamic diameter is 105.9nm; at 40°C, its hydrodynamic diameter is 98.3nm, and the particles are basically insensitive to temperature. Observing its morphology with a transmission electron microscope, it is a microcapsule with a hollow structure. Add 3g of potassium persulfate, 1.5g of ferrous sulfate, dropwise add 80g of N-isopropylacrylamide, 30g of N,N'-methylenebisacrylamide and 500g of water to prepare an aqueous solution, drop it in 2 hours, after the drop Keep warm for 20 hours to terminate the reaction. The particle size was measured with a dynamic light scattering particle size analyzer: at 25°C, its hydrodynamic diameter was 568.3nm; at 40°C, its hydrodynamic diameter was 145.2nm, and the particles showed obvious temperature sensitivity. Observing its morphology with a transmission electron microscope, it is still a hollow capsule.

Embodiment 6:

Take by weighing emulsifier OP-10 10g, add in 1000g water, obtain emulsifier solution. Mix 100g of octane, 10g of hexadecane, 30g of vinyl caprolactam, 80g of styrene, and 50g of divinylbenzene, add them to the above-mentioned aqueous solution containing emulsifier, and disperse the above-mentioned mixed solution with ultrasonic waves to obtain a stable emulsion; temperature Adjust to 75°C, under the protection of nitrogen, add polyethylene glycol 800 azo macroinitiator 24g to initiate, and react for 260min. The particle size is measured with a dynamic light scattering particle size analyzer: at 25°C, its hydrodynamic diameter is 230.2nm; at 40°C, its hydrodynamic diameter is 185.2nm, and the particles have certain temperature sensitivity. Observing its morphology with a transmission electron microscope, it is a microcapsule with a hollow structure. Add 7.5g of polyethylene glycol 800 azo macroinitiator, add dropwise the aqueous solution prepared by 60g of vinyl caprolactam, 15g of N, N'-methylenebisacrylamide and 300g of water, drop it in 4 hours, drop it off After incubation for 20 hours, the reaction was terminated. The particle size was measured with a dynamic light scattering particle size analyzer: at 25°C, its hydrodynamic diameter was 682.3nm; at 40°C, its hydrodynamic diameter was 223.2nm, and the particles showed obvious temperature sensitivity. Observing its morphology with a transmission electron microscope, it is still a hollow capsule.

The present invention may be embodied in other specific forms without departing from the spirit and main characteristics of the invention. Therefore, no matter from which point of view, the above-mentioned experimental scheme of the present invention can only be considered as explanation of the present invention and can not limit the present invention, and the claims have pointed out the scope of the present invention, and above-mentioned description does not point out the scope of the present invention Therefore, any changes within the meaning and scope equivalent to the claims of the present invention should be considered to be included in the scope of the claims.

Claims (5)

1, a kind of is the method that template prepares temperature sensitive nano microcapsule with the small molecule hydrocarbon, it is characterized in that, the monomer that participates in reaction comprises at least a temperature sensitive monomer, at least a comonomer and at least a cross-linking monomer, the total consumption of monomer is meant the gross mass of temperature sensitive monomer, comonomer, cross-linking monomer, but does not comprise and add temperature sensitive monomer and water-soluble cross-linked monomer;

This method comprises the following steps:

(1) with emulsifiers dissolve in water, obtain the aqueous solution of emulsifying agent, the ratio of total consumption of monomer and water is 0.0025:1～0.5:1, the emulsifying agent consumption is 1%～20% of the total consumption of monomer;

(2) temperature sensitive monomer is mixed with small molecule hydrocarbon, co-stabilizer, comonomer, cross-linking monomer, join in the solution that step (1) obtains, above-mentioned mixed liquor is disperseed, obtain stable miniemulsion with ultrasonic wave;

Wherein, the small molecule hydrocarbon consumption is 40%～360% of the total consumption of monomer, the consumption of co-stabilizer is 3%～25% of a small molecule hydrocarbon consumption, the temperature sensitive monomer consumption is 2%～20% of the total consumption of monomer, the comonomer consumption is 50%～97% of the total consumption of monomer, and amount ofthe cross-linking monomer is 1%～40% of a monomer total amount;

(3) adjustment to 40～80 of the emulsion that step (2) is obtained ℃, under inert gas shielding, add water soluble starter and carry out mini-emulsion polymerization, the water soluble starter consumption is 3%～25% of the total consumption of monomer, react after 120～600 minutes, obtain the capsule of nano that the shell polymer contains the temperature sensitive monomer unit;

(4) after the system conversion ratio reaches more than 90%, add water soluble starter and drip the mixed aqueous solution add temperature sensitive monomer and water-soluble cross-linked monomer, the dropping time was controlled in 30～240 minutes, after adding monomer solution and dripping, was incubated 3～20 hours;

Wherein, the consumption of adding temperature sensitive monomer is 2～15 times of the middle temperature sensitive monomer of step (2), water-soluble cross-linked monomer consumption is to add 10%～50% of temperature sensitive monomer, the ratio of adding total consumption of monomer and water is 0.05:1～0.5:1, add the total consumption of monomer and be meant the gross mass of adding temperature sensitive monomer and water-soluble cross-linked monomer, adding the water soluble starter consumption is to add 0.5%～10% of the total consumption of monomer;

Described temperature sensitive monomer is at least a in caprolactam or the following structural formula with adding temperature sensitive monomer:

R in the structural formula (1) ¹, R ²Be H, C ₂～C ₅Aliphatic chain, and R ¹, R ²Can not be H simultaneously, R ³Be H, CH ₃

R in the structural formula (2) ¹Be C ₁～C ₅Aliphatic chain, R ², R ³Be H, CH ₃

Described comonomer structure is at least a in the following structural formula:

In the structural formula (3), R ¹Be H, CH ₃Perhaps C ₂H ₅, R ²Be phenyl, substituted-phenyl, Cl, CN, alkyl ether or OCOCH ₃

In the structural formula (4), R ¹Be H, CH ₃Perhaps C ₂H ₅, X is C ₁～C ₁₂Aliphatic chain or the C of hydroxyl ₁～C ₁₂Aliphatic chain;

Described cross-linking monomer structure is at least a in the following structural formula:

In the structural formula (5), R is phenyl ring, C _nH _2n, n=0～8 wherein;

Described water-soluble cross-linked monomer is at least a in structural formula (6), formula (7), the formula (8).

According to the described method for preparing temperature sensitive nano microcapsule of claim 1, it is characterized in that 2, described small molecule hydrocarbon is at least a in the alkane of cycloalkane, aromatic hydrocarbon or 5～14 carbon.

According to the described method for preparing temperature sensitive nano microcapsule of claim 1, it is characterized in that 3, described co-stabilizer is C ₁₂～C ₁₈Aliphatic hydrocarbon, C ₁₂～C ₁₈Fatty alcohol, structural formula (9) or structural formula (10) at least a:

In the structural formula (9), R ¹Be H, CH ₃, C ₂H ₅, X is C ₁₂～C ₁₈Aliphatic chain;

In the structural formula (10), R ¹Be H, CH ₃, CF ₃, m=0～17, R _fBe C _nH _jF _2n+1-jFluoro fat (n=1～18, j=0～34), and m+n=12～18.

4, according to the described method for preparing temperature sensitive nano microcapsule of claim 1, it is characterized in that, described emulsifying agent is organic carboxylate, organic sulfate, organic sulfonate, organic phosphate anionic emulsifier, the organic quaternary ammonium salt cationic emulsifier, at least a in amphoteric ion type emulsifying agent or polyoxyethylene ester, APEO, the polyoxyethylene amine nonionic emulsifier.

5, according to the described method for preparing temperature sensitive nano microcapsule of claim 1, it is characterized in that described water soluble starter is at least a in hydrogen peroxide, persulfate, cationic diazo salt, polyethylene glycol azo macromole evocating agent, the water soluble oxidized reduction initiating system; The reducing substances that is added in the described water soluble oxidized reduction initiating system is at least a in primary amine alcohol, secondary amine alcohol, tertiary amine alcohol, sulphite, thiosulfate, the ferrous salt.