JP2012251110A - Transparent polymer nanocomposite material and production method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent polymer nanocomposite material and a production method of the material.SOLUTION: The transparent polymer nanocomposite material shows decrease (by 5 to 15%) in transmittance for visible light and changes into opaque in a high temperature field (at 60°C or higher). The transparent polymer nanocomposite material comprises: a matrix component formed of two kinds of monomers, in which one of the two monomers has a reactive functional terminal comprising one or more selected from a vinyl group and a Si-H group; and SiOnanoparticles included in an amount of most 30 wt.% with respect to the matrix component. A production method of the transparent polymer nanocomposite material is also provided. Thereby, a novel transparent polymer nanocomposite material and technology for producing the material can be obtained, the material responding to temperature (at 60°C or higher) and showing an instant and significant change (by 5 to 15%) in the transmittance for visible light.

Description

The present invention relates to a transparent polymer nanocomposite material whose visible light transmittance changes instantaneously (opaque) instantaneously in response to temperature (60 ° C. or more) and a method for producing the same. A bulk body (thickness ˜1 mm) of transparent polymer nanocomposites in which SiO ₂ ) nanoparticles (particle size of 25 nm or less) are uniformly dispersed and immobilized at a high concentration (up to 30 wt.%) In the polymer matrix; and , SiO ₂ nanoparticles are prepared in advance by surface-treating them in one of the two types of monomers used as raw materials for the polymer matrix, and then adding the remaining monomer solution and Pt catalyst (Karstedt catalyst) The bulk solution of the transparent polymer nanocomposite is poured by pouring the solution into a resin mold and promoting crosslinking by heat treatment. The shape at will, it relates to a manufacturing technique and a transparent polymeric nanocomposite material which makes it possible to form in the crack-free.

  The present invention is a transparent polymer nanocomposite that is excellent in mechanical strength, heat resistance, and durability, and capable of instantaneously and drastically changing (opaque) visible light transmittance in response to temperature (60 ° C. or higher). A transparent polymer nanocomposite material and its manufacture, which can be applied to, for example, optical switches, limiters such as sensors, simple heat detection materials, etc. It provides new technology and new products related to technology.

  Currently, polymer nanocomposite (hybrid) materials with inorganic fillers (mainly nanoparticles and nanofibers) added to polymers are lightweight, highly functional materials with significantly improved heat resistance, gas barrier properties, pulling properties, and wear resistance. It is used in various industrial fields.

  For example, 2 wt. It has been reported that the nanocomposite material produced with the addition of% increases the tensile modulus by about 42% compared to the non-additional material, and the glass transition temperature also increases and exhibits excellent heat resistance. (For example, Non-Patent Document 1).

  When a polymer nanocomposite material is applied to an optical material, the transparency of the material is extremely important. In general, the optical properties of polymer nanocomposites are governed by two factors: 1) the inorganic nanofiller to be added, the refractive index of the polymer constituting the matrix, and 2) the dispersibility of the former in the latter. . In order to produce a highly transparent polymer nanocomposite material, it is important to select a material having a refractive index close to each other, that is, matching of the refractive index.

  For example, Gilmer et al. Have developed an aromatic composite (refractive index: 1.48) in polymethyl methacrylate (PMMA, refractive index: 1.48) to develop a transparent composite material (for example, non-patent literature). 2). However, those having the same or close refractive index of the polymer matrix and the inorganic filler are limited in number, and combinations thereof are naturally limited, and are not practical.

  Moreover, in order to reduce light scattering and turbidity, it is necessary to add an inorganic filler having a particle diameter (size) of 50 nm or less. However, as the particle size of the inorganic filler nanoparticles to be added becomes smaller, the particles become more agglomerated and it is difficult to uniformly disperse the inorganic filler nanoparticles despite the very small addition amount (0.5 wt.%). And the transparency is significantly reduced (for example, Non-Patent Document 3).

In order to suppress such aggregation of inorganic filler nanoparticles, Palkovits et al. Have reported that SiO ₂ having a particle size of 26 nm by a sol-gel method using a hydrolysis reaction of tetraethoxysilane in a polymethyl methacrylate (PMMA) matrix. A method for producing nanoparticles in-situ has been proposed (for example, Non-Patent Document 4). However, even in this case, 6.67Wt just SiO ₂ nanoparticles. With an addition amount of%, the visible light transmittance is significantly reduced.

Similarly, Chang et al. Also added 54.9 wt.% Of SiO ₂ component (domain size: 20 nm or less) in-situ by the sol-gel method. % Of a transparent polyimide-based nanocomposite is produced (for example, Non-Patent Document 5), but the film thickness is controlled to about 3 μm in order to maintain transparency.

  On the other hand, among various functions expected for polymer nanocomposites, recently, temperature-responsive optical characteristics have attracted attention, and their use as optical switches, sensors, lenses for eye protection, and limiter materials are being studied. Has been.

  poly (N-isopropyla lamide) (PNIPAM) is a typical temperature-responsive polymer that has a hydrogen-bonding moiety in the molecule, and water molecules adhere strongly around the polymer chain and dissolve in water at room temperature. is doing. When the temperature is raised, this hydrogen bond is broken, phase-separates from water, and contracts. Such a phenomenon is referred to as a lower critical solution temperature phenomenon, and the temperature at which phase separation occurs is referred to as a lower critical solution temperature (LCST).

  Hydrogel nanoparticles based on PNIPAM, various nanoparticles coated with PNIPAM, PNIPAM containing gold nanoparticles, and the like have been developed (for example, Non-Patent Documents 6 to 10). The LCST of these materials is 50 ° C. or lower, and the temperature range where the phase transition occurs is only 1 to 2 ° C. In addition, this phase transition is mainly observed in water, and a polymer nanocomposite in which optical properties change greatly (opacity) has occurred in the air and in a wide temperature range. In this technical field, there has been a strong demand to develop a polymer nanocomposite material that undergoes a phase transition in the atmosphere and in a wide temperature range, and whose optical properties are greatly changed (opaque).

T.A. Agag, T .; Koga, T .; Takeichi, Polymer 2001, 42, 3399 T.A. C. Gilmer, P.M. K. Hall, H .; Ehrenfeld, K.M. Wilson, T .; Bivens, D.M. Clay, C.I. Endreszl, J. et al. Polym. Sci. Pol. Chem. 1996, 34, 1025 Y. Q. Li, S.M. Y. Fu, Y .; Yang, Y. et al. W. Mai, Chem. Mat. 2008, 20, 2637 R. Parkovits, H .; Althues, A .; Rumplecker, B.M. Tesche, A .; Dreier, U .; Halle, G. et al. Fink, C.I. H. Cheng, D.C. F. Shantz, S .; Kaskel, Langmuir 2005, 21, 6048 C. C. Chang, W.M. C. Chen, Chem. Mat. 2002, 14, 4242 J. et al. P. Wang, D.W. J. et al. Gan, L.M. A. Lyon, M.M. A. El-Sayed, J.A. Am. Chem. Soc. 2001, 123, 11284 J. et al. Shan, H .; Chen, M.C. Nuopponen, T .; Viitala, H .; Jiang, J. et al. Peltonen, E .; Kauppinen, H.M. Tenhu, Langmuir 2006, 22, 794 Y. Lu, Y .; Mei, M .; Drechsler, M.M. Ballauff, Angew. Chem. , Int. Ed. 2006, 45, 813 A. M.M. Schmidt, Colloid Polym. Sci. 2007, 285, 953 C. Wang, N .; T.A. Flynn, R.M. Langer, Adv. Mater. 2004, 16, 1074

Under such circumstances, the present inventor, in view of the above-mentioned prior art, the transparent polymer nanoparticle whose visible light transmittance changes greatly (opacity) instantaneously in a certain temperature range (60 ° C. or higher) in the atmosphere. As a result of diligent research with the goal of developing composite materials, silicon oxide (SiO ₂ ) nanoparticles in one monomer liquid of two types of monomers used as raw materials for polymer (mainly silicone) matrices Is heated to form a monomer-derived molecular film with a film thickness of about 1 nm or less on the surface, and then the remaining monomer and Pt catalyst (Karstedt catalyst) are added to the monomer solution in which the SiO ₂ nanoparticles are dispersed. The solution prepared in this manner is poured into a resin mold and crosslinked by heat treatment, so that the SiO ₂ nanoparticles are strongly bonded to the polymer matrix by covalent bonds. By immobilizing and promoting cross-linking of the polymer matrix, a bulk body (thickness ˜1 mm: 1 mm or less) of a transparent polymer nanocomposite material excellent in mechanical properties, durability, heat resistance, and temperature responsiveness, It has been found that cracks can be formed in any shape, and the present invention has been completed.

  An object of the present invention is to provide a transparent nanocomposite material having excellent temperature response performance in which visible light transmittance changes reversibly and instantaneously in a high temperature field (60 ° C. or higher). It is. In addition, the present invention provides a technique for producing a nanocomposite material that makes it possible to produce the transparent polymer nanocomposite material as a bulk body (thickness to 1 mm) in any shape without causing cracks. It is intended. Another object of the present invention is to provide a nanoparticle surface modification technique that enables nanoparticles to be uniformly dispersed / filled in a polymer at a high concentration. Furthermore, an object of the present invention is to provide an effective transparent polymer nanocomposite material that can be applied to limiters such as optical switches and sensors, and simple heat detection materials.

The present invention for solving the above-described problems comprises the following technical means.
(1) A transparent polymer nanocomposite material composed of a silicone-based polymer that has a visible light transmittance that decreases (5 to 15%) and becomes opaque in a high-temperature field (60 ° C. or higher),
The matrix component of the transparent polymer nanocomposite material is formed from two types of monomers, and one of the two types of monomers is terminated with one or more reactive functional groups selected from vinyl groups and Si-H groups. Silicon oxide (SiO ₂ ) nanoparticles with a maximum of 30 wt. % Transparent polymer nanocomposite material, characterized in that
(2) The transparent polymer nanocomposite material according to (1), wherein the temperature responsiveness of the visible light transmittance of the transparent polymer nanocomposite material is reversible.
(3) The transparent polymer nanocomposite material according to (1) or (2), wherein the visible light transmittance and the amount of change of the transparent polymer nanocomposite material depend on the concentration of the contained nanoparticles.
(4) The transparent polymer nanocomposite material according to any one of (1) to (3), wherein the nanoparticles to be filled are SiO ₂ nanoparticles and the particle size thereof is 50 nm or less.
(5) From the above (1), the SiO ₂ nanoparticle surface is coated with a film of one kind of monomer component of two kinds of monomers forming a matrix, and the film thickness is 1 nm or less ( The transparent polymer nanocomposite material according to any one of 4).
(6) The transparent polymer nanocomposite material according to any one of (1) to (5), wherein the SiO ₂ nanoparticles are fixed to the polymer matrix via a covalent bond.
(7) The transparent polymer nanocomposite material according to any one of (1) to (6), wherein the refractive index of the SiO ₂ nanoparticles and the refractive index of the polymer matrix are substantially the same and become transparent at normal temperature.
(8) The transparent polymer nanocomposite according to any one of (1) to (7), wherein a mismatch between the refractive indexes of the SiO ₂ nanoparticles and the polymer matrix occurs due to heating, and the transmittance in the visible light region decreases. material.
(9) The transparent polymer nanoparticle according to any one of (1) to (8), wherein the refractive index of the SiO ₂ nanoparticles and the polymer matrix is restored to the original by cooling, and the transmittance in the visible light region is increased again. Composite material.
(10) A method for producing a transparent polymer nanocomposite material comprising a silicone polymer,
The matrix component of the transparent polymer nanocomposite material is formed from two types of monomers, and one of the two types of monomers is terminated with one or more reactive functional groups selected from vinyl groups and Si-H groups. After heating the SiO ₂ nanoparticles in one of the two types of monomer solution, the remaining monomer and Pt catalyst (Karstedt catalyst) are added, and the solution is made of resin. A method for producing a transparent polymer nanocomposite material, characterized by pouring into a mold and promoting crosslinking by heat treatment.
(11) After heat-treating SiO ₂ nanoparticles in one monomer liquid of two types at 80 to 100 ° C. for a maximum of 72 hours, the remaining monomer and Pt catalyst (Karstedt catalyst) are added, The solution is poured into a resin mold, and crosslinking is promoted by heat treatment at room temperature for a maximum of 24 hours, at 50 to 80 ° C. for a maximum of 24 hours, and further at 120 to 150 ° C. for a maximum of 24 hours. A method for producing a transparent polymer nanocomposite material.

Next, the present invention will be described in more detail.
The present invention utilizes the phenomenon that the refractive index of the silicon oxide (SiO ₂ ) nanoparticles and the polymer matrix of the silicone polymer reversibly change depending on the temperature, and the visible light transmittance due to the refractive index match / mismatch. It is characterized in that the transparent polymer nanocomposite material enabling control can be manufactured as a bulk body (thickness to 1 mm) in an arbitrary shape without cracks.

Specifically, the present invention heat-treats SiO ₂ nanoparticles in one monomer liquid selected from two types of monomers having vinyl groups and Si—H groups, and has a film thickness of 1 nm or less on the surface. A monomer-derived molecular film is formed, and then the remaining monomer solution and a Pt catalyst (Karstedt catalyst, about 10 ppm) are added to the monomer solution in which the modified SiO ₂ nanoparticles are uniformly dispersed. By pouring the solution into a resin mold and promoting crosslinking by heat treatment, not only between the monomers, but also promoting crosslinking between the SiO ₂ nanoparticles and the monomer, a transparent and arbitrarily shaped bulk body It is formed without cracks.

In the present invention, SiO ₂ nanoparticles having a particle size of 50 nm or less, for example, a particle size of 25 nm, which has been dried at 100 ° C. for 24 hours or more in advance, is one of two types of monomer raw materials used as a raw material for the polymer matrix. For example, in 1,3,5,7-tetramethylcyclotetrasiloxane (D ₄ ^H , liquid) under a nitrogen atmosphere with a relative humidity of 5% or less and stirred / heat treated at 50-80 ° C. for a maximum of 72 hours, A molecular film derived from D ₄ ^H having a thickness of 1 nm or less is formed on the surface of the SiO ₂ nanoparticles.

In this case, it is preferable that an active functional group (Si—H group) is contained in the monomer. Further, the monomer is between hydroxyl oxygen-containing polar group of SiO ₂ nanoparticle surface, which is preferably immobilized via covalent bonds. In the present invention, examples of the monomer raw material include the following compounds that exhibit the above D ₄ ^H or the same or similar effects.

That is, the following compounds can be used as the monomer raw material.
Hydride Terminated PolyDimethylsiloxanes;
polyPhenyl- (DiMethyl Hydrosiloxy) siloxane, hydride terminated;
Methyl Hydrosiloxane-Dimethyl Siloxane Copolymers, Trimethylsilylated terminated;
Methyl Hydrosiloxane-Dimethyl Siloxane Copolymers, Hydride terminated;
polyMethylHydrosiloxanes, Trimethylsilylated terminated;
polyEthyl Hydrosiloxane, Triethyl Siloxy t-erminated;
polyphenylmethylsiloxane, hydride terminated;
Methyl Hydrosiloxane-Phenyl Methyl Siloxane copolymer, hydride terminated;
Methyl Hydrosiloxane-Octyl Methyl Siloxane copolymers and terpolymers.

In the present invention, suitable inorganic nanoparticles such as SiO ₂ , alumina, zirconia oxide, and silicon carbide can be arbitrarily used as the inorganic nanoparticles that can be used, but the present invention provides high transparency. In addition, it is a preferred embodiment to use two kinds of monomers as raw materials for the polymer matrix and SiO ₂ nanoparticles having a refractive index close to each other. The size of these inorganic nanoparticles is desirably 50 nm or less, preferably 30 nm or less, more preferably 25 nm or less in order to suppress light scattering.

Subsequently, the remaining monomer and a Pt catalyst (Karsttedt catalyst, platinum-diethyltetramethyldisiloxane complex, 2.1 to 2.4% Pt in xylene, about 10 ppm) are added to the surface-treated SiO ₂ nanoparticle-containing monomer solution. The final solution is gently poured into a resin container and allowed to stand at room temperature for a maximum of 24 hours, followed by heat treatment at 50 to 80 ° C. for a maximum of 24 hours, and further at 120 to 150 ° C. for a maximum of 24 hours. Form material.

For the resin container, resin containers having various shapes such as PET and Teflon (registered trademark) can be used. Monomers include, for example, 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (D ₄₎ having a vinyl group that reacts with the Si—H group terminating the surface of the SiO ₂ nanoparticles. ^V ) is preferred. In the present invention, examples of the monomer raw material include D ₄ ^V or the following compounds that exhibit the same or similar effects.

That is, the following compounds can be used as the monomer raw material.
Vinyl Terminated PolyDimethylsiloxanes;
Vinyl Terminated Diphenylsiloxane-Dimethylsiloxane Copolymers;
Vinyl Terminated polyPhenylMethylsiloxane;
Vinyl Phenyl Methyl Terminated Vinyl Phenyl Siloxane-Phenyl Methyl Siloxane Copolymer;
Vinyl Terminated Trifluoropropylmethylmethylsiloxane-Dimethylsiloxane Copolymer;
VinylTerminated Diethylsiloxane-Dimethylsiloxane Copolymers;
Vinylmethylsiloxane-Dimethylsiloxane Copolymers, trimethylsiloxy terminated;
Vinylmethylsiloxane-Dimethylsiloxane Copolymers, silanol terminated 4-6% OH;
Vinylmethylsiloxane-Dimethylsiloxane Copolymers, vinyl terminated;
MonoVinyl terminated polydimethylsiloxanes-asymmetric;
MonoVinyl Functional PolyDimethylsiloxane-symmetric;
(3-5% Vinylmethylsiloxane)-(35-40% OctylmethylSiloxane)-(Dimethylsiloxane) terpolymer;
(3-5% Vinylmethylsiloxane)-(35-40% PhenylmethylSiloxane)-(Dimethylsiloxane) terpolymer;
Vinylmethysiloxanexane Homopolymer;
Vinylethysiloxane Homopolymer;
sVinyloxysiloxane-Propyloxysiloxane Copolymer.

Further, in order to increase the amount of change in the visible light transmittance, the SiO ₂ nanoparticles are added at a maximum of 30 wt. It is also possible to fill up to%. If the concentration of the SiO ₂ nanoparticles is higher than this, it is not preferable because it becomes difficult to form a highly transparent polymer nanocomposite material.

  The curing conditions are not particularly limited, but it is desirable to treat at room temperature for a maximum of 24 hours at 50 to 80 ° C. for a maximum of 24 hours, and further at 120 to 150 ° C. for a maximum of 24 hours. When the treatment is performed at a temperature higher than this, the hardness increases due to the promotion of crosslinking, but cracks tend to occur, which is not preferable.

  By using the manufacturing technology of the present invention, the mechanical strength, durability, heat resistance, temperature response, visible light transmittance changes instantaneously and drastically (5-15%) in response to temperature (60 ° C. or higher). The advantage is that it is easy to form a transparent polymer nanocomposite having excellent properties as a bulk body (˜1 mm) in an arbitrary shape without cracks.

The present invention has the following effects.
(1) It is possible to provide a novel transparent polymer nanocomposite material whose visible light transmittance changes instantaneously and greatly (5 to 15%) in response to temperature (60 ° C. or higher) and its manufacturing technology.
(2) Since the surface of the SiO ₂ nanoparticles to be filled is covered with a molecular film (with a film thickness of 1 nm or less) of the same component as one of the two types of monomers constituting the polymer matrix, the SiO ₂ nanoparticles are It can be uniformly dispersed at a high concentration (up to 30 wt.%) In the polymer matrix without agglomeration.
(3) Since the SiO ₂ nanoparticles are fixed to the polymer matrix via a covalent bond, they are extremely stable and do not desorb from the matrix.
(4) The bulk body (thickness ˜1 mm) of the SiO ₂ nanoparticle nanocomposite can be produced in various shapes without cracks.
(5) The present invention provides a transparent polymer nanocomposite that can be applied to, for example, an optical switch, a limiter such as a sensor, a simple heat detection material, etc. by imparting a temperature-responsive optical property to the polymer nanocomposite material. It is possible to provide material manufacturing technology.
(6) The temperature responsiveness of the visible light transmittance of the transparent nanocomposite material is reversible and has excellent durability.
(7) The transparent nanocomposite material is excellent in heat resistance (about 200 ° C.) and does not crack even after repeated heating / cooling.
(8) The method for producing the transparent nanocomposite material is simple (only mixing, heating and molding), and does not require any special operation or apparatus.

The permeability | transmittance of the transparent polymer nanocomposite material as described in Examples 1-4 is shown. (A) is 6 wt. %, (B) is 12 wt. %, (C) is 18 wt. %, (D) is 24 wt. %. The permeability at various temperatures of the transparent polymer nanocomposite material described in Example 4 is shown. (A) is room temperature, (B) is 100 ° C, and (C) is 150 ° C. The UV-vis spectrum in various temperature of the transparent polymer nanocomposite material as described in Examples 1-4 is shown. (A) is 6 wt. %, (B) is 12 wt. %, (C) is 18 wt. %, (D) is 24 wt. %.

  Next, the present invention will be specifically described based on examples. The following examples show preferred examples of the present invention, and the present invention is not limited to the examples.

In a glass container, 3.0 g of SiO ₂ nanoparticles (particle size 25 nm) dried at 100 ° C. for 24 hours, together with 12.0 g of a liquid monomer; 1,3,5,7-tetramethylcyclotetrasiloxane (D ₄ ^H ), After sealing in a nitrogen atmosphere, the mixture was heated in an oil bath (80 ° C.) for 72 hours while stirring with a magnetic stirrer, and 20 wt. % Solution was prepared.

To 0.3 g of this solution, 0.7 g (0.3080 g / 0) of a mixture of monomers (D ₄ ^H / 1,3,5,7-tetravinyl-1,3,5,7-tetramethylcyclotetrasiloxane (D ₄ ^V )) 392 g) and 0.5 ml of a solution (6 wt.%) Prepared by adding about 10 ppm of Karstedt catalyst (platinum-divinyltetramethyldisiloxane complex, 2.1 to 2.4% Pt in xylene) was poured into a PET container. After standing at room temperature for 24 hours, heat treatment was performed at 80 ° C. for 24 hours to produce a bulk body of 2.7 cm × 2.7 cm × 700 μm.

In a glass container, 3.0 g of silicon oxide nanoparticles (particle size 25 nm) dried at 100 ° C. for 24 hours, together with 12.0 g of a liquid monomer; 1,3,5,7-tetramethylcyclotetrasiloxane (D ₄ ^H ), After sealing in a nitrogen atmosphere, the mixture was heated in an oil bath (80 ° C.) for 72 hours while stirring with a magnetic stirrer, and 20 wt. % Solution was prepared.

In a PET container, 0.5 ml of a solution (12 wt.%) Prepared by adding about 10 ppm of D ₄ ^H / D ₄ ^V = 0.033 g / 0.367 g and Karstedt catalyst to 0.6 g of this solution. After pouring and leaving at room temperature for 24 hours, heat treatment was performed at 80 ° C. for 24 hours to produce a bulk body of 2.7 cm × 2.7 cm × 700 μm.

In a glass container, 3.0 g of silicon oxide nanoparticles (particle size 25 nm) dried at 100 ° C. for 24 hours, together with 12.0 g of a liquid monomer; 1,3,5,7-tetramethylcyclotetrasiloxane (D ₄ ^H ), After sealing in a nitrogen atmosphere, the mixture was heated in an oil bath (80 ° C.) for 72 hours while stirring with a magnetic stirrer, and 20 wt. % Solution was prepared.

Nitrogen gas was blown into this solution to evaporate the D ₄ ^H component, and the concentration was adjusted to 40 wt. Concentrated to%. In a PET container, 0.5 ml of a solution (18 wt.%) Prepared by adding about 10 ppm of D ₄ ^H / D ₄ ^V = 0.208 g / 0.342 g and Karstedt catalyst to 0.45 g of this solution After pouring and leaving at room temperature for 24 hours, heat treatment was performed at 80 ° C. for 24 hours to produce a bulk body of 2.7 cm × 2.7 cm × 700 μm.

In a glass container, 3.0 g of silicon oxide nanoparticles (particle size 25 nm) dried at 100 ° C. for 24 hours, together with 12.0 g of a liquid monomer; 1,3,5,7-tetramethylcyclotetrasiloxane (D ₄ ^H ), After sealing in a nitrogen atmosphere, the mixture was heated in an oil bath (80 ° C.) for 72 hours while stirring with a magnetic stirrer, and 20 wt. % Solution was prepared.

Nitrogen gas was blown into this solution to evaporate the D ₄ ^H component, and the concentration was adjusted to 40 wt. Concentrated to%. In a PET container, 0.5 ml of a solution (24 wt.%) Prepared by adding approximately 10 ppm of D ₄ ^H / D ₄ ^V = 0.083 g / 0.317 g and Karstedt catalyst to 0.6 g of this solution. After pouring and leaving at room temperature for 24 hours, heat treatment was performed at 80 ° C. for 24 hours to produce a bulk body of 2.7 cm × 2.7 cm × 700 μm.

  The samples prepared in Examples 1 to 4 were evaluated by UV-vis, TGA, and nanoindenter. FIG. 1 shows the results of permeability of the samples of Examples 1 to 4. FIG. 2 shows the results of permeability of the sample described in Example 4 at various temperatures. FIG. 3 shows the results of optical characteristics (UV-vis spectra at various temperatures) of the samples described in Examples 1 to 4.

[Comparative Example 1]
In a glass container, D ₄ ^H / D ₄ ^V = 1 g / 0.7165 g and a solution prepared by adding about 10 ppm of Karstedt catalyst, 0.5 ml of a solution was poured into a PET container and left at room temperature for 24 hours. It heat-processed at 80 degreeC for 24 hours, and produced the bulk body of 2.7cmx2.7cmx700micrometer.

[Comparative Example 2]
The sample prepared in Comparative Example 1 was evaluated by UV-vis, TGA, and nanoindenter.

When the samples prepared in Examples 1 to 4 and Comparative Example 1 were relatively evaluated, as is clear from the evaluation results of Example 5 above, in Examples 1 to 4, SiO ₂ nanoparticles were used. It was found that it was possible to uniformly disperse at a high concentration while maintaining transparency. On the other hand, in Comparative Example 1, it was possible to produce a highly transparent polymer bulk body, but no temperature responsiveness of visible light transmittance was obtained. Further, the visible light transmittance slightly decreased as the amount of SiO ₂ nanoparticles added increased, but the amount of change was significantly increased. The mechanical strength (Young's modulus) also increased with increasing amount of SiO ₂ nanoparticles.

  The Young's modulus of the samples produced in Examples 1 and 4 were 2.45 and 3.37 GPa, respectively, and the Young's modulus was 1.7 to 2.3 even when compared with Comparative Example 1 (1.46 GPa). It was found that it increased about twice. Moreover, the sample produced in Examples 1-4 and the comparative example 1 did not produce a crack, even after repeating the thermal history test of room temperature to 200 degreeC several dozen times. Further, the mass loss at 500 ° C. of the samples prepared in Examples 1 to 4 is about 2.3%, about 1.8%, about 1.3%, and about 1 for the samples of Examples 1 to 4, respectively. The sample of Comparative Example 1 was about 1.1%, and excellent heat resistance was confirmed for all the samples.

As described above in detail, the present invention relates to a transparent polymer nanocomposite material in which the visible light transmittance changes instantaneously and greatly in response to temperature, and a method for producing the transparent polymer nanocomposite material. A transparent polymer nanocomposite bulk body (thickness ~ 1mm) that has excellent properties, durability, and transparency, and whose visible light transmittance sharply decreases (opacity) at 60 ° C or higher, in any shape, crack-free Techniques for producing new polymer nanocomposite materials that can be produced can be provided. Moreover, according to the present invention, it is possible to uniformly disperse the SiO ₂ nanoparticles in the polymer matrix at a high concentration without agglomerating the SiO ₂ nanoparticles. By utilizing the reversible temperature response performance of visible light transmittance, the present invention can be applied to, for example, optical devices that can be used at high temperatures, optical components that can adjust translucency, and disposable heat detection materials. It is useful as it makes it possible to provide transparent polymer nanocomposite materials.

Claims (11)

A transparent polymer nanocomposite material composed of a silicone-based polymer that has a visible light transmittance that decreases (5 to 15%) at high temperature (60 ° C. or higher) and becomes opaque,
The matrix component of the transparent polymer nanocomposite material is formed from two types of monomers, and one of the two types of monomers is terminated with one or more reactive functional groups selected from vinyl groups and Si-H groups. Silicon oxide (SiO ₂ ) nanoparticles with a maximum of 30 wt. % Transparent polymer nanocomposite material, characterized in that   The transparent polymer nanocomposite material according to claim 1, wherein the temperature responsiveness of the visible light transmittance of the transparent polymer nanocomposite material is reversible.   The transparent polymer nanocomposite material according to claim 1 or 2, wherein the visible light transmittance and the amount of change of the transparent polymer nanocomposite material depend on the concentration of the contained nanoparticles. The transparent polymer nanocomposite material according to any one of claims 1 to 3, wherein the nanoparticles to be filled are SiO ₂ nanoparticles, and the particle size thereof is 50 nm or less. The surface of SiO ₂ nanoparticles is coated with a film of one monomer component of two kinds of monomers forming a matrix, and the film thickness is 1 nm or less. The transparent polymer nanocomposite material as described. The transparent polymer nanocomposite material according to claim 1, wherein the SiO ₂ nanoparticles are immobilized on the polymer matrix via a covalent bond. The transparent polymer nanocomposite material according to any one of claims 1 to 6, wherein at a normal temperature, the refractive index of the SiO ₂ nanoparticles and the refractive index of the polymer matrix are substantially the same and become transparent. The transparent polymer nanocomposite material according to any one of claims 1 to 7, wherein a mismatch between the refractive indexes of the SiO ₂ nanoparticles and the polymer matrix occurs by heating, and the transmittance in the visible light region is reduced. The transparent polymer nanocomposite material according to any one of claims 1 to 8, wherein upon cooling, the refractive indexes of the SiO ₂ nanoparticles and the polymer matrix are restored, and the transmittance in the visible light region is increased again. A method for producing a transparent polymer nanocomposite material comprising a silicone polymer,
The matrix component of the transparent polymer nanocomposite material is formed from two types of monomers, and one of the two types of monomers is terminated with one or more reactive functional groups selected from vinyl groups and Si-H groups. After heating the SiO ₂ nanoparticles in one of the two types of monomer solution, the remaining monomer and Pt catalyst (Karstedt catalyst) are added, and the solution is made of resin. A method for producing a transparent polymer nanocomposite material, characterized by pouring into a mold and promoting crosslinking by heat treatment. After SiO ₂ nanoparticles are heat-treated at 80-100 ° C. for a maximum of 72 hours in one monomer liquid of two kinds of monomers, the remaining monomer and Pt catalyst (Karsttedt catalyst) are added, and the solution is added. The transparent polymer nanocomposite according to claim 10, which is poured into a resin mold and promotes crosslinking by heat treatment at room temperature for a maximum of 24 hours, at 50 to 80 ° C. for a maximum of 24 hours, and further at 120 to 150 ° C. for a maximum of 24 hours. Material manufacturing method.