THREE-LAYERED NANOCOMPOSITE WITH IMPROVED THERMAL AND HEAT PROPERTIES AND PRODUCTION THEREOF

Abstract

The invention is related to three-layered nanocomposites which are created by encapsulating a ceramic particle in latex as coreshell and coating a conductive polymer on this structure.

Claims

1. A production method of a three-layered nanocomposite with improved thermal and heat properties comprising the steps of: preparing surfactant-water solution, while vigorously stirring the surfactant-water solution, adding ceramic particles at different rates into a structure forming acrylonitrile and copolymer, after stirring the surfactant-water solution for a certain amount of time, adding another monomer into the structure, leaving the structure in ultrasonic mixer in order to form a micro emulsion, adding an initiator into the structure, coating a latex shell on a ceramic particle core by polymerization and establishing a core-shell structure, and by adding conductive monomers into the core-shell structure established after polymerization, coating conductive polymer onto the latex coated ceramic particle.

2. The production method of a three-layered nanocomposite with improved thermal and heat properties according to claim 1, wherein all the monomers form copolymer with acrylonitrile, and all the monomers are suitable for a system.

3. The production method of a three-layered nanocomposite with improved thermal and heat properties according to claim 1, wherein the ceramic particle is barium titanate particle.

4. The production method of a three-layered nanocomposite with improved thermal and heat properties according to claim 1, wherein the conductive polymer is selected from the group consisting of pyrrole, aniline, and thiophene.

5. The production method of a three-layered nanocomposite with improved thermal and heat properties according to claim 1, wherein ratios of nanoparticle, monomers and conductive polymer monomer are defined depending on the ratio of the surfactant.

6. The production method of a three-layered nanocomposite with improved thermal and heat properties according to claim 4, wherein a ratio of BaTiO.sub.3/surfactant and a ratio of conductive monomer/surfactant are 1:4 mole/mole.

7. The production method of a three-layered nanocomposite with improved thermal and heat properties according to claim 1, wherein in situ emulsion polymerization is initiated by heat of reaction.

8. The production method of a three-layered nanocomposite with improved thermal and heat properties according to claim 7, wherein a reaction temperature is 70 C. while coating latex on nanoparticle and then at ambient temperature while coating conductive polymer on the latex.

9. The production method of a three-layered nanocomposite with improved thermal and heat properties according to claim 7, wherein a hardener is not used in a system.

10. The production method of a three-layered nanocomposite with improved thermal and heat properties according to claim 7, wherein a catalyst is not used in a system.

11. A three-layered nanocomposite produced by the following steps: preparing surfactant-water solution, while vigorously stirring the surfactant-water solution, adding ceramic particles at different rates into a structure forming acrylonitrile and copolymer, after stirring the surfactant-water solution for a certain amount of time, adding another monomer into the structure, leaving the structure in ultrasonic mixer in order to form a micro emulsion, adding an initiator into the structure, coating a latex shell on a ceramic particle core by polymerization and establishing a core-shell structure, and by adding conductive monomers into the core-shell structure established after polymerization, coating conductive polymer onto the latex coated ceramic particle.

12. The three-layered nanocomposite according to claim 11, wherein a particle size is approximately 700 nm.

13. The three-layered nanocomposite according to claim 11, wherein the nanocomposite is a conductive structure.

14. The three-layered nanocomposite according to claim 11, wherein the nanocomposite has capacitive properties in a frequency range of 0.16 Hz-0.85 Hz.

15. The three-layered nanocomposite according to claim 11, wherein the nanocomposite is a material with shielding properties.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1: Three-layered nanocomposite with improved thermal and heat properties.

[0015] FIG. 2: Particle size distribution of three-layered nanocomposite structure

[0016] FIG. 3: FTIR spectroscopy results of nanocomposites

[0017] FIG. 4: XRD results of nanocomposites

[0018] FIG. 5: a) SEM b) TEM and c) AFM results of three-layered structure

[0019] FIG. 6: Bode Phase and bode magnitude graphs of nanocomposites

DETAILED DESCRIPTION OF THE INVENTION

[0020] The differences of the present invention from the similar documents mentioned in the known state of the art are as follows: [0021] During the emulsion polymerization since they are separated due to surfactant (surface active agent) and since first latex and then conductive polymer is coated around the barium titanate which is suspended in aqueous media (without using any organic solvent), each barium titanate particle is homogenously coated by the two layers. PDI values are 0,05 and this proves that particle growth is rendered homogenously and in a controlled manner. [0022] Due to coreshell structure, since it is enabled that ions and electrons that provide electrical and thermal conductivity can regularly jump and move in the homogenous structure, conductance properties are considerably good. [0023] Moreover, electrochemical behaviours of the structures are capacitive since conductive polymer is coated on latex. Furthermore, it is possible to use them as shielding material depending on the selected frequency range. [0024] By adding latex layer in between and adding conductive polymer layer on it instead of directly coating conductive polymer on the particle, controlled coating and growth is ensured and also warping, film exfoliation and coating properties are improved due to improvement in mechanical properties.

[0025] In the system used for the invention, by in situ processing in one-step, it is both ensured that the particle better hangs on to the structure by moving and the polymer is homogenously distributed onto the surface. Moreover, since the flexibility, workability and according to obtained results mobility of the structure in the solution have increased due to used latex, its electrical conductivity is increased as well. Obtaining nanocomposite in this way and transforming it to textile surfaces is an innovational approach. Furthermore, it is an environmentalist approach to use aqueous media and ambient temperature in the conducted studies.

Creating Three-layered Nanocomposite:

[0026] In this invention, acrylonitrile copolymer is coated around the barium titanate particle by in situ emulsion polymerization method. By coating a conductive polymer on this established coreshell structure, the three-layered structure is successfully created. Said structure is created because of introduction of monomer molecules between the swelled plates and polymerization. During in-situ polymerization, monomer molecules settle between the layers by polarity effect and polymerization occurs. Polymerization is started by the heat of the reaction. Thus, first, surfactant-water solution is prepared and while this solution is vigorously stirred ceramic particles at different rates are added into the structure. After stirring this solution for a certain amount of time, another monomer that will form the acrylonitrile (AN) and the copolymer is added into the structure. All the monomers that can form acrylonitrile and copolymer are suitable for this system. The structure is kept in ultrasonic mixer in order to form the micro emulsion. Then the initiator (precursor) is added to the structure and the ceramic particle is coated on the core by polymerization of the latex shell. After the polymerization, conductive monomers are added into the structure and conductive polymer is coated onto the latex coated ceramic particle. Conductive polymers such as pyrrole, aniline and thiophene are suitable for this system.

[0027] In the process of establishing the three-layered structure, the ratio of the nanoparticle, monomers and conductive polymer monomer are specified depending on the surfactant ratio. In said system, it is defined as 1:4-1:4 and 2:1 (mole/mole).

[0028] In this invention, the surfactants that are used as carrier also have the dopant duty besides their carrier duty. In the conducted studies, it is seen that type of the surfactant material is effective in carrying and doping the particle and depending on this efficiency and conductivity values as well as particle size and micro structures are also changed.

Conducted Analysis and Results:

[0029] As a result of conducted analysis, it is seen that the three-layered structure is successfully created by the method of the invention. It is seen that particle size distributions are homogenous via particle size distribution value which is approximately 0,05 (FIG. 2). In other words, approximately 100% of the particles have the same size. In FTIR analysis results (FIG. 3), results of the latex coating and conductive polymer coating around the particle and the results of the three-layered structure can be seen top to bottom. As can be understood by the peaks on the analysis graph, the peaks obtained as a result of interaction of three structures in the nanocomposite show that a new structure is obtained and the nanoparticle is coated by the latex and the conductive polymer. When XRD graphs (FIG. 4) are examined, it is seen that nanoparticle peak amplitudes decrease when in three-layered structure. This attenuation in the peaks shows that detection of X-rays scattered by the inorganic particle due to polymer chains growing on the nanoparticle surface are prevented, in other words the surrounding of the particle is coated by an organic structure. Establishment of the three-layered structure, the layers, surface roughness and homogeneity of distribution on the surface are investigated by SEM, TEM and AFM analysis (FIG. 5). Additionally, when this analysis results are examined, it is seen that the structure is completely coated. By the conducted DC conductivity measurements (Table 1), when compared to other structures, it is seen that a more conductive structure is obtained by the three-layered structure. Besides, capacitive and magnetic properties of the structure are examined by using electrochemical impedance spectroscopy results (FIG. 6) and it is seen that a conductive, capacitive and shielding material is created by the three-layered structure.

TABLE-US-00001 TABLE 1 Conductivity and particle size values Nanoparticle- AN copolymer- Nanoparticle-AN conductive conductive copolymer-conductive polymer polymer polymer Conductivity 69.83 143.15 154.38 (S) Particle Size 117.16 69 704 (nm)