KR100705402B1 - Novel Organic Modifier for Making Nanocomposite and process for preparing the same - Google Patents

Abstract

The present invention relates to a novel organic compounding agent for a nanocomposite having a structure as follows and a method of manufacturing the same.

In particular, the novel organic compounding agent for nanocomposites of the present invention designed an organicizing agent in which imidazolium ions are introduced to further improve thermal stability. The novel organizing agent for nanocomposites with improved thermal stability of the organizing agent not only acts more advantageously for the production of peelable PET nanocomposites, but also finally improves various physical properties of the PET nanocomposites.

In addition, since the organic agent designed in the present invention has a hydroxy group, it is expected that strong commercial action by hydrogen bonding with PET resin is possible.

Nanocomposites, imidazoniums, organic agents, clays, PET

Description

Novel organic modifier for making nanocomposite and process for preparing the same

1 is a schematic diagram showing a method of synthesizing an organic agent used in the production of nanocomposites according to the present invention.

2 is a ¹ H NMR spectra of the present organic organizing agent.

Figure 3 is the weight of each sample according to the temperature rise as a result of the TGA test performed on the organic clay prepared by using the organic agent according to the present invention and commercially sold organic clays Clooisite 15A and Closite 30B It is a graph showing the decrease.

Figure 4 is an XRD pattern of the organic clay and clay, commercially sold organic clay Closite 15A and Closite 30B prepared using the organic agent according to the present invention.

5 is a XRD pattern graph of PET nanocomposites.

The present invention relates to a novel organic agent in which imidazolium ions are introduced to further improve thermal stability. The organic agent not only acts more advantageously in the manufacture of release PET clay nanocomposites but also finally, It improves the physical properties of PET clay nanocomposites in width.

It is important not only economically but also environmentally to replace metal or ceramic materials by using polymer materials having a lower specific gravity than metal or ceramic materials. In order for the polymer material to replace the metal or ceramic material, it is necessary to improve relatively weak physical properties such as mechanical or thermal properties of the polymer material. As part of such efforts, efforts have recently been actively made to solve this problem by preparing polymer / clay nanocomposites in which clay layered compounds such as montmorillonite (MMT) are well dispersed at the nanometer level. The results of the research on the polymer / clay nanocomposites up to now show that the manufacturing technology of the polymer / clay nanocomposites can greatly increase the properties of the material such as strength, thermal stability, gas barrier properties, and flame retardancy even with the addition of a small amount of clay. It can be seen that it is a core technology for developing next-generation composite materials.

Particularly, peelable PET in which clay is dispersed and peeled in PET in order to sufficiently improve heat resistance and gas barrier properties without losing the excellent mechanical properties inherent to the typical polyester polyethylene (poly (ethylene terephthalate)) (PET). Research into the manufacture of clay nanocomposites is underway worldwide.

The manufacture of polymer resin / clay nanocomposites is not a method of improving the physical properties by adding a micron (10 ^-6 m) reinforcing agent, but by dispersing the particle size of the inorganic filler / reinforcing agent to the nanometer scale. Its basic goal is to overcome the shortcomings of the system, and it is one of the key technologies that is expected to bring a big change in the next generation composite market in a very advantageous way in terms of cost performance.

In 1987, researchers in Japan and Japan have reported that peeling phenomenon of increasing the distance between layers by 10 nm by inserting nylon monomer between silicate layers by means of appropriate methods and polymerizing them interlayer has been studied in the United States and Japan. There was a problem that can be used only when possible and that existing industrial equipment cannot be used as it is.

In 1993, Japan's Yano et al prepared polyimide / clay nanocomposites in such a way that solvents penetrated between the silicate layers to disperse the silicate layer and maintain this dispersion by immersing the MMT treated with the organic agent in the polymer solution. There is a problem that a large amount of solvent is used and a separate solvent removal process is required, and the polymer is simply inserted into the organic MMT layer or the interlayer distance is narrowed again during the solvent drying process.

An object of the present invention is to design and synthesize a novel organic agent in which imidazolium ions are introduced to further improve the thermal stability in order to solve the above problems, and by using the silicate layer to form the MMT in the PET resin To provide a technique for producing a PET / clay nanocomposite dispersed and separated.

In order to achieve the above object, the present invention provides a novel organic compound for nanocomposites in which imidazolium ions are introduced to further improve thermal stability.

In addition, the nanocomposite is preferably a polyethylene terephthalate (PET) / clay nanocomposite.

In addition, the present invention is to react the organic compound intermediate (BrEth) synthesized by the reaction of 1,2-epoxy-3-phenoxypropane and 2-bromoethanol with 1,2-dimethylimidazole, the structural formula (I) It provides a method for producing a compound having a.

Hereinafter, the present invention will be described in more detail.

Clay is a mineral that constitutes the earth's surface and is classified as a layered compound because its structure is basically based on the layered structure of silicate layers. There are various types such as montmorillonite (hereinafter, “MMT”), saponite, hectorite, etc., but Na-MMT is used in the present invention.

Among the most commonly used clays for the production of polymer / clay nanocomposites, MMT is a layered compound commonly found in nature and is a mica-like layered silicate mineral belonging to the smectite group. Due to the cations such as Na ⁺ and Ca ²⁺ present between the silicate layers, inorganic compounds such as swelling property, various reactivity with organic compounds, ion exchange ability, etc. are rare. MMT is generally referred to as Na-MMT because most of the ion exchangeable cations present between the layers of MMT are Na ⁺ .

In order to facilitate intercalation of organics, an organic agent should be used to increase the lipophilic properties of Na-MMT. In general, clay is very difficult to exfoliate and disperse in polymer resin due to strong van der Waals attraction between the layers of silicate and narrow interlayer distance.The pretreatment process of inserting low molecular weight lipophilic organic agent into the silicate layer through ion exchange reaction Peeling and dispersion into the polymer resin can be induced through. Clay that has undergone such pretreatment is called organic clay.

In the present invention, a new organic agent having compatibility with PET resin and excellent thermal stability was designed and synthesized as shown in FIG. 1, and the organic clay was prepared by ion exchange reaction with Na-MMT. The thermal stability of the organic agent is required because the high melting point of the PET resin (260 ℃) in the production of PET / clay nanocomposites is inevitable high temperature melt mixing in the production of PET / clay nanocomposites.

In the present invention, imidazolium ions are introduced to improve thermal stability of the organic agent.

The organic agent designed as described above was synthesized as follows.

The synthesis route of the organic agent is shown in Reaction Scheme (1). The organic agent synthesized in the present invention is preferably an organic agent synthesized by reacting 1,2-epoxy-3-phenoxypropane and 2-bromoethanol. The intermediate (BrEth) was synthesized by reacting with 1,2-dimethylimidazole, respectively.

As a specific example, the magnesium perchlorate (magnesium perchlorate) is put in a round bottom flask, and the purified acetonitrile is added while stirring with nitrogen gas to make a uniform solution. Add 1,2-epoxy-3-phenoxypropane. Then add 2-bromoethanol and stir well to react. Then, the reaction product was extracted with diethyl ether, washed several times with distilled water, the diethyl ether layer was taken separately, dried over magnesium sulfate (anhydrous), and diethyl ether was removed to remove crude. crude) to yield the product. The crude product thus obtained was separated by column chromatography under a hexane: ethyl acetate (50: 50 / v: v) developing solvent to give a dark yellow organic agent intermediate (BrEth).

The organizing agent (BrEthN) was synthesized by reacting BrEth, which is the organizing agent intermediate, with 1,2-dimethylimidazole, as shown in Scheme (1). BrEth is placed in a round bottom flask and nitrogen gas is flowed into the purified acetonitrile to stir well to make a uniform solution. 1,2-dimethylimidazole is added thereto and stirred. After the reaction was completed, a small amount of dimethyl sulfoxide (DMSO) was added to the reaction flask and stirred to dissolve the resulting dark brown reaction product. Dilute the DMSO / reaction product solution in ethyl acetate in small portions. In this process, the organic form BrEthN in salt form precipitates and unreacted BrEth and 1,2-dimethylimidazole are dissolved in ethyl acetate. Filter the above precipitate solution and wash the reaction product on the filter paper with ethyl acetate sufficiently. The reaction product on the filter paper was then taken and dried sufficiently in a vacuum oven to give the organizing agent BrEthN.

반응식 (1)

Scheme (1)

<Production of Organic Clay>

The process for preparing organic clay by ion exchange reaction is described in detail below.

Na-MMT is sufficiently dispersed in distilled water. Then, the previously synthesized organic agent (BrEthN) is dissolved in DMSO: distilled water (50: 50 / v: v) mixed solvent, and then stirred in Na-MMT and reactor dispersed in the distilled water prepared above. The ion exchange reaction is allowed to proceed sufficiently. After the reaction was completed, the reaction product was filtered and the reaction product on the filter paper was sufficiently washed with a DMSO: distilled water (50: 50 / v: v) mixed solvent and methanol to remove the unreacted organic agent. Thereafter, the reaction product on the filter paper was taken and dried sufficiently to obtain BrEthNC, an organic clay newly prepared in the present invention.

The method of preparing the polymer / clay nanocomposite is largely a solution method, a polymerization method, a compounding method, etc. The compounding method used in the present invention is to finally insert the polymer resin into the silicate layer by the organic clay and melt mixing method. As a technique, the silicate layer is dispersed in the polymer resin.

As a specific example, pre-mixed organic clay to 0.1 to 30% by weight of PET resin sufficiently dried in advance, followed by melt mixing in an extruder to prepare a polymer / clay nanocomposite. It is preferable that the temperature of an extruder mixing zone shall be 250-320 degreeC.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail based on the following Example. However, the following examples are not intended to limit the present invention, but are not limited thereto. Various physical properties of the organic clay obtained by treating the organic agent prepared in Examples and Comparative Examples of the present invention and Na-MMT may be obtained. Evaluation was performed by the following method.

(1) Structural Analysis of Organic Agent

¹ H NMR was used to confirm the structure of the synthesized organic agent.

(2) Thermal Stability of Organic Agent

Thermogravimetric Analysis (TGA) analysis was performed to investigate the thermal stability of the organic agent. Prior to TGA analysis, all samples were dried sufficiently in a vacuum oven (40 ° C.) and all TGA analyzes were performed at a temperature rising rate of 10 ° C./min over a temperature range of 30 to 800 ° C. while flowing nitrogen gas.

(3) Structural analysis of organic clay and PET / clay nanocomposites

The structures of the organoclay and PET / clay nanocomposites were analyzed by measuring the d spacing for each of the organoclay and PET / clay nanocomposites using an X-ray diffractometer (XRD). Nickel-copper-potassium alpha radiation (wavelength = 0.154 nm, 40 kV, 30 mA) was used as an X-ray source to obtain an XRD pattern, and scanning was performed at a rate of 3 ° / min for a 1.5 to 10 ° region. In addition, the structure of the PET / clay nanocomposites were analyzed using a transmission electron microscope (TEM). PET / clay nanocomposite samples prepared by the flake cutter were placed on a 200 mesh copper mesh and observed under an accelerating voltage of 200 kV.

Example 1

Preparation of Organizer

0.133 mol (30 g) of magnesium perchlorate is added to a round-bottomed flask and purified acetonitrile is added while stirring with nitrogen gas to form a uniform solution. Add 0.133 mol (18 ml) of 1,2-epoxy-3-phenoxypropane. Then add 0.266 mol (19 ml) of 2-bromoethanol and stir well. The reaction proceeded for 24 hours at 80 ° C. Thereafter, the reaction product was extracted with diethyl ether, washed several times with distilled water, the diethyl ether layer was taken separately, dried over magnesium sulfate (anhydrous), and diethyl ether was removed to obtain a crude product. The crude product thus obtained was separated by column chromatography under a hexane: ethyl acetate (50: 50 / v: v) developing solvent to give a dark yellow organic agent intermediate (BrEth).

Organizer BrEthN was synthesized by reacting BrEth, the organizing agent intermediate, with 1,2-dimethylimidazole. BrEth 0.003 mol (0.8 g) is added to a round-bottomed flask, and purified acetonitrile is added while stirring with nitrogen gas to form a uniform solution. Add 0.01 mol (1 g) of 1,2-dimethylimidazole here and stir. The reaction proceeded at 100 ° C. for 7 days. After completion of the reaction, a small amount of DMSO was added to the reaction flask and stirred to dissolve the resulting dark brown reaction product. Dilute the DMSO / reaction product solution in ethyl acetate in small portions. In this process, the organic form BrEthN in salt form precipitates and unreacted BrEth and 1,2-dimethylimidazole are dissolved in ethyl acetate. Filter the above precipitate solution and wash the reaction product on the filter paper with ethyl acetate sufficiently. Then, the reaction product on the filter paper was taken and dried sufficiently in a vacuum oven (80 ° C.) to obtain an organic agent BrEthN (yield: 72%).

Preparation of Organic Clay

3 g of Na-MMT is sufficiently dispersed in 500 ml of distilled water. Then, 0.0028 mol (1.5 g) of the synthesized organic agent BrEthN was dissolved in a DMSO: distilled water (50: 50 / v: v) mixed solvent, and then Na-MMT dispersed in the distilled water prepared in the above was stirred well. The reaction proceeded at 70 ° C. for 12 hours to allow sufficient ion exchange reactions to occur. After the reaction was completed, the reaction product was filtered and the reaction product on the filter paper was sufficiently washed with a DMSO: distilled water (50: 50 / v: v) mixed solvent and methanol to remove the unreacted organic agent. The reaction product on the filter paper was then taken and dried sufficiently in a vacuum oven (80 ° C.) to obtain BrEthNC, an organic clay newly prepared according to the present invention.

Preparation of PET / clay nanocomposites

PET / BrEthNC nanocomposites were prepared by compounding and melt-mixed using twin screw extruders. Prior to preparing the PET nanocomposite, the PET resin was sufficiently dried for 12 hours in a vacuum oven (120 ° C.). 29.1 g of PET resin sufficiently dried in a vacuum oven and 0.9 g of BrEthNC were premixed in advance and then injected into an extruder to perform melt mixing. The temperature of the mixing zone of the extruder was adjusted to 280 ° C. and the rotation speed of the screw was fixed at 50 rpm. The first 10 g was discarded and the subsequent 10 g was taken as a sample of PET / BrEthNC nanocomposite. The commercialized organic clay Closite 15A and Closite 30B were melt mixed with PET under the same conditions to prepare PET / 15A and PET / 30B nanocomposites.

Comparative Example 1

Organic clays were prepared using Closite Na-MMT from Southern Clay Products and compared using Closite 15A and Closite 30B in commercially available organic clays for comparative experiments.

Whether or not BrEthN, an organic agent synthesized in Example 1, was successfully synthesized was confirmed by ¹ H NMR and elemental analysis. The results for BrEthN ¹ H NMR spectra are shown in FIG. 2. As shown in FIG. 2, it can be seen that the peak position and area ratio of the ¹ H NMR spectra with BrEthN agree well with the theoretical value.

In order to investigate the thermal stability of BrEthN, an organic agent synthesized in Example 1, thermogravimetric analysis (TGA) experiments were performed on BrEthNC prepared from them. In the present invention, TGA experiments were also carried out under the same conditions for commercially available Closite 15A and Closite 30B for comparison. Figure 3 shows the TGA results showing the weight loss of each sample with increasing temperature. The weight loss of each sample in the TGA results is due to the thermal decomposition of organics with increasing temperature.

It can be seen from the results of FIG. 3 that BrEthNC begins to lose weight due to pyrolysis at around 300 ° C. This temperature is increased by about 100 ° C. compared to 200 ° C., which is the starting temperature of pyrolysis of Closite 15A and 30B. The large increase in pyrolysis temperature observed in the TGA results for BrEthNC can be attributed to the introduction of imidazonium ions with better thermal stability into the head group of the organic agent. As described above, in the present invention, the molecular design of the new organic agent BrEthN having imidazonium ions having more excellent thermal stability at one end was successfully synthesized.

XRD experiments on BrEthNC were performed to determine whether BrEthN synthesized in Example 1 was successfully inserted into the interlayer of the silicate layers of Na-MMT. For comparison, XRD experiments were performed under the same conditions for CloSite 15A and 30B and the results are shown in FIG. 4, respectively.

The unique characteristic peak to view seen in FIG 2θ = 7.5 ° in the XRD pattern for the four of Na-MMT There This silicate layer while maintaining the d spacing (spacing) of about 1 nm layer structure constituting the Na-MMT Is due to The interlayer distance of the silicate layers of Na-MMT can be increased by intercalation of compounds with cationic groups such as organizing agents. The increase in interlayer distance of this silicate layer, as can be seen from Bragg's law, indicates that the 2θ represents the position of the peak in the XRD experiment. This can be seen by moving the value to a small angle. 4 shows the XRD patterns for the BrEthNC prepared in the present invention as well as the commercialized organic clays Closite 15A and Closite 30B. From the XRD pattern for BrEthNC of FIG. 4, it can be seen that the 2θ = 7.5 ° peak seen in Na-MMT disappeared and a new characteristic peak of 2θ = 4.8 ° occurred. This result means that the value of 2θ has shifted to incineration. From these XRD results, it can be seen that BrEthN synthesized in the present invention was inserted by ion exchange reaction between the silicate layers of Na-MMT to successfully prepare BrEthNC, an organic clay. These BrEthNCs have a structure in which the silicate layer maintains the overall layer structure but increases the interlayer distance.

The XRD pattern for the PET / clay nanocomposite prepared in Example 1 is shown. In order to directly compare the structure of each PET nanocomposite, the content of organoclay was fixed at 3 wt%.

As shown in FIG. 5, in the XRD pattern of the PET nanocomposite prepared from BrEthNC, the characteristic peak of Na-MMT of 2θ = 7.5 ° as well as the characteristic peak of BrEthNC itself, which was seen at 2θ = 4.8 °, are almost disappeared. That is, it can be seen that the silicate layers lost much of their layered structure and were well dispersed and exfoliated in the PET matrix.

As described above, the present invention provides a novel organicating agent compound, a method for producing the same, and a PET / clay nanocomposite material having imidazonium ions introduced to improve thermal stability.

When the PET / clay nanocomposite is manufactured using the organic agent of the present invention, the silicate layers of Na-MMT are more finely peeled and dispersed, so that the mechanical properties of the PET / clay nanocomposite are not reduced in physical properties such as impact resistance, toughness and transparency. Can be remarkably improved.

While the invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims. .

Claims (3)

An organic agent for polyethylene terephthalate / clay nanocomposites of the following structural formula (I). [Structure Formula (I)]

Polyethylene terephthalate / clay nanocomposite comprising the organic agent of claim 1. The organic agent intermediate for nanocomposites characterized in that the organic compound intermediate (BrEth) synthesized by reacting 1,2-epoxy-3-phenoxypropane and 2-bromoethanol is reacted with 1,2-dimethylimidazole. Manufacturing method.

Images