KR101554650B1 - Nanocomposite and Method of Preparing the Nanocomposite - Google Patents

Abstract

The present invention relates to a nanocomposite and a nanocomposite, and more particularly, to a nanocomposite which improves the dispersibility of the nanoclay and strengthens the interface between the nanoclay and the PP powder, and a method of manufacturing the nanocomposite.
To this end, the nanocomposite of the present invention comprises a polymeric synthetic resin powder, a nanoclay added to the polymer synthetic resin powder, a polypropylene-grafted maleic acid copolymer (PP-g-MA) which is a coupling agent added to strengthen the interface between the polymeric synthetic resin powder and the nano- wherein the nanoclay is surface-treated with a cationic surfactant so as to serve as a site for nucleation in a dispersed state, the content of the coupling agent added is 5% by weight, and the polymer The content of the nanoclays surface-treated with the cationic surfactant is 3% by weight in order to relatively increase the crystallinity of the synthetic resin powder.

Description

TECHNICAL FIELD The present invention relates to a nanocomposite and a nanocomposite,

The present invention relates to a nanocomposite and nanocomposite manufacturing method, and more particularly, to a nanocomposite which improves the dispersibility of nanoclay and strengthens the interface between the nanoclay and the PP (polypropylene) powder and a method of manufacturing the nanocomposite .

Since metal materials are excellent in heat resistance and mechanical properties, they are currently used in various fields such as automobiles, aircraft, and construction.

However, the metal material has a disadvantage that it is heavy because of its high specific gravity. On the other hand, polymeric materials have a low specific gravity, which is advantageous in that products of the same size can be made several times lighter than metal materials. In particular, due to recent high oil prices, the automobile and aircraft industries are actively developing lightweight parts to reduce costs.

On the other hand, it is very difficult to realize a performance comparable to that of a metal material as a polymer material that has been commercialized so far. Therefore, research and development for replacing metal materials using a polymer composite in which different materials are mixed with a polymer material is being steadily under way. The most widely used polymer complexes are composites using thermosetting polymers.

The thermosetting polymer composite is prepared by impregnating a thermosetting monomer such as an epoxy resin with a reinforcing material made of glass fiber or carbon fiber and partially curing the prepreg to prepare a prepreg. The prepreg is processed into a desired shape, Thereby manufacturing a product. The advantage of such a thermosetting polymer composite is that it has excellent heat resistance and mechanical properties because it does not melt again once cured. On the other hand, since the thermosetting polymer composite undergoes a heat curing process, it has a disadvantage that productivity is low and it is not recycled.

Another type of polymer complex is a thermoplastic polymer complex. The thermoplastic polymer composite is excellent in melt processability, and thus it is possible to process various types of products and it is also possible to recycle it.

The thermoplastic polymer composite is formed by mixing short fibers made of glass fiber or carbon fiber with a thermoplastic polymer capable of injection or extrusion processing. The thermoplastic polymer complex has a high melt viscosity because it uses a polymer having a high molecular weight. Therefore, when the short fibers are combined, the melt viscosity is further increased, and the processability is lowered. Therefore, the content of the short fibers can not be increased, so that there is a limit to the mechanical properties and the shortened fibers are randomly oriented. It can not be used for a product which requires the use of the above-mentioned method.

Korean Patent Publication No. 2011-0009505 entitled Clay Nanoparticles and Method for Producing Thermoplastic Polymer Composite Containing Matte Stiffener is a method for producing a carbon nanotube mixture by melt-mixing a carbon nanotube with a matrix polymer, A second step of high-shear molding the carbon nanotube mixture to produce a carbon nanotube composite material, a third step of melt-mixing the carbon nanotube composite material and the nanoclay to produce a nanoclay mixture, And a fourth step of preparing a carbon nanotube-nano-clay composite by high shear molding to produce a polymer nanocomposite.

In order to improve the properties of the nanocomposite, nanocomposites having various additives including nanoclay are being developed.

A problem to be solved by the present invention is to propose a nanocomposite in which a nanoclay is added to a polymer.

Another problem to be solved by the present invention is to propose a nanocomposite having a high degree of polymer crystallization.

Another object to be solved by the present invention is to propose a nanocomposite having relatively good tensile properties.

To this end, the nanocomposite of the present invention comprises a polymeric synthetic resin powder, a nanoclay added to the polymer synthetic resin powder, a polypropylene-grafted maleic acid copolymer (PP-g-MA) which is a coupling agent added to strengthen the interface between the polymeric synthetic resin powder and the nano- wherein the nanoclay is surface-treated with a cationic surfactant so as to serve as a site for nucleation in a dispersed state, the content of the coupling agent added is 5% by weight, and the polymer The content of the nanoclays surface-treated with the cationic surfactant is 3% by weight in order to relatively increase the crystallinity of the synthetic resin powder.

In the nanocomposite prepared by the method of the present invention, the content of CTAB-MMT as a filler to be added is limited to 3 wt%, so that the crystallinity of the nanocomposite is increased and thus mechanical properties are improved. In addition, as the winding speed is also increased, the degree of polymer crystallization is increased, and accordingly, the mechanical properties in the extrusion direction are improved.

1 is a view illustrating a process of mixing a surfactant with a nanoclay according to an embodiment of the present invention.
FIG. 2 illustrates a process of adding a coupling agent to a nanoclay according to an embodiment of the present invention.
FIG. 3 illustrates a process of mixing a coupling agent and a surface-treated nano-clay with a surfactant in PP according to an embodiment of the present invention.
4 is a graph showing tensile properties of an extruded nanocomposite film according to an embodiment of the present invention.
5 is a view showing tensile properties of an extruded nanocomposite film according to another embodiment of the present invention.
FIG. 6 shows the degree of crystallization of each nanocomposite film according to an embodiment of the present invention.
FIG. 7 shows an example of measuring the degree of polymer crystallization using DSC according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and further aspects of the present invention will become more apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings.

The nanocomposite according to the present invention is intended to improve the inherent physical properties of a polymer resin by dispersing a nanometer-sized composition responsible for functionality in a polymer matrix or to impart new properties that have not been previously available, Any conventional complex of the art for nanocomposites corresponds to the nanocomposite of the present invention.

In a particular embodiment, the nanometer-sized composition comprises a nanometer-sized clay, i.e., a nanoclay.

Here, the nano-clay means a clay made of nanometer-sized particles.

In another specific embodiment, the nanocomposite refers to a product that is used for various purposes such as a product in which the nanocomposite composition is injection molded or extruded, for example, a film, a wall plate, a sheet, a pipe, etc. Preferably, It refers to pipes such as water / sewage pipes.

The clay according to the invention, specifically nanometer-sized clay, i.e. nanoclay, is dispersed in a nanocomposite composition, specifically a nanocomposite, to improve the physical properties of the nanocomposite.

Here, the size of the particles constituting the nanoclay is preferably in the range of 1 to several hundreds nm.

Specifically, it is preferable that the nano-clay is configured such that several tens to several thousands of plate-like structures having a thickness of 1 nm, a width of several hundreds of nm and a length of several hundred nm are stacked.

Particularly, the nanoclay is uniformly distributed in the nanocomposite, specifically, the vinyl chloride resin of the nanocomposite composition, thereby improving the tensile strength, the impact strength, the flexural modulus, and the thermal stability. For this purpose, The clay is not particularly limited, but it is preferable to use a layered compound, specifically a natural or synthetic layered compound, more preferably a layered silicate, and preferably montmorillonite, bentonite, But are not limited to, hectorite, fluorohectorite, saponite, beidelite, nontronite, stevensite, vermiculite, volkonskoite, Smect, such as sauconite, magadite, kenyalite and derivatives thereof, ite) or a mixture thereof.

On the other hand, since the nano-clay is formed in a laminated structure of the plate-like structure, when the laminated clay is separated and dispersed evenly among the polymer resin, various physical properties different from those of the conventional polymer resin are shown. It is very difficult to disperse in the composition because its size is in the nanometer scale.

The nano-clay should be used in consideration of its shape, ion exchange capacity, charge density and clay, affinity with an organic material penetrating between silicate layers in particular, and the like. In general, polar molecules include polar molecules , And nonpolar molecules have affinity with nonpolar molecules, making it difficult to disperse the clay easily.

Accordingly, in the nanocomposite manufacturing method according to the present invention, before the nanocomposite composition is prepared to improve the dispersibility of the nanoclay, the nanoclay is first mixed with the surfactant, and then mixed with the other nanocomposite composition , Allowing the nanoclay to be readily dispersed in the nanocomposite composition.

At this time, when the nanoclay is mixed with the surfactant, the surfactant penetrates and swells between the layers of the nanoclay, so that when the nanoclay is mixed with the other nanocomposite composition, the nanoclay is easily dispersed .

1 is a view illustrating a process of mixing a surfactant with a nanoclay according to an embodiment of the present invention. Hereinafter, a process of mixing a surfactant with a nanoclay according to an embodiment of the present invention will be described in detail with reference to FIG.

Referring to FIG. 1, the nanoclay is pulverized using an ultrasonic pulverizer and mixed with cationic surfactants. In this case, the mixture is pulverized for 3 hours using an ultrasonic pulverizer, and the pulverized nanoclay is mixed with the surfactant at 80 ° C for about 24 hours.

When the above-described process is carried out, as shown in Fig. 1, the surfactant penetrates between the layers of the nanoclay having the layered structure and is attached to the nanoclay.

An example of a surfactant includes cetyl trimethylammonium bromide (CTAB).

FIG. 2 illustrates a process of adding a coupling agent to a nanoclay according to an embodiment of the present invention. Hereinafter, the process of adding a coupling agent to a nanoclay according to an embodiment of the present invention will be described in detail with reference to FIG.

According to the present invention, a PP-g-MA (PP (polypropylene-grafted maleic anhydride) grafted with maleic anhydride (MA) as a coupling agent is added to a nanoclay .

FIG. 3 illustrates a process of mixing a coupling agent and a surface-treated nano-clay with a surfactant in PP according to an embodiment of the present invention. Hereinafter, a process of mixing the coupling agent and the surface-treated nano-clay with a surfactant in PP according to an embodiment of the present invention will be described in detail with reference to FIG.

According to Fig. 3, the coupling agent and the nanoclays surface-treated with a surface active agent are mixed with PP, and then extruded using an extruder. Of course, as described above, the nanoclay is surface-treated with a surfactant.

Hereinafter, the characteristics of the nanocomposite using various nanocomposite samples will be described. Of course, polymeric synthetic resin base material (powder) may include PE powder as well as PP powder.

Sample number Polymeric synthetic resin base material Nano filler type additive Filler content (% by weight) Extruder screw speed (RPM) Wrapping speed (%) (a) PP powder none none 0 12 10, 40, 90 (b) PP powder MMT none 3 12 10, 40, 90 (c) PP powder CTAB-MMT none 3 12 10, 40, 90 (d) PP powder CTAB-MMT PP-g-MA
(5% by weight) One 12 10, 40, 90 (e) PP powder CTAB-MMT PP-g-MA
(5% by weight) 5 12 10, 40, 90 (f) PP powder CTAB-MMT PP-g-MA
(5% by weight) 3 12 10, 40, 90

Winding speed: 21 rpm, 40 rpm, 90 rpm, 61 rpm

4 is a graph showing tensile properties of an extruded nanocomposite film according to an embodiment of the present invention. In particular, Figure 4 shows the tensile modulus and tensile strength of the nanocomposite film.

4, it can be seen that the sample sequence number f is relatively high in tensile modulus and tensile strength.

5 is a view showing tensile properties of an extruded nanocomposite film according to another embodiment of the present invention. In particular, Figure 5 shows the elongation and stress-strain of the nanocomposite film.

According to Fig. 5, the sample sequence number (f) shows a relatively good elongation and stress-strain.

FIG. 6 shows the degree of crystallization of each nanocomposite film according to an embodiment of the present invention. The crystallization degree of each nanocomposite film will be described below with reference to FIG.

In particular, the present invention measures the degree of crystallization of a polymer in a nanocomposite by measuring a thermogram using Differential Scanning Calorimetry (DSC). When nano-clay is added to PP powder, each particle serves as a nucleation site for nucleation, which increases the crystallinity of the polymer and thus improves the mechanical properties.

Take up speed % Crystallinity PP film Pb containing
CTAB-MMT (1%) / PP-g-MA Pb containing
CTAB-MMT (5%) / PP-g-MA Pb containing
CTAB-MMT (3%) / PP-g-MA 10% Take up speed 20.12 20.96 21.87 22.19 40% Take up speed 22.25 23.13 23.98 24.56 90% Take up speed 24.82 25.53 26.16 27.34

However, when the content of the nano clay is increased, the aggregation of the nano clay dominates the reinforcing effect, so that the optimum content for the reinforcing effect of the nano clay is 3 wt%.

It is also seen that as the winding speed increases, the degree of polymer crystallization increases and thus the mechanical properties in the direction of extrusion are increased. This can be seen from FIG.

FIG. 7 shows an example of measuring the degree of polymer crystallization using DSC according to an embodiment of the present invention.

Referring to FIG. 7, it can be seen that the melting temperature of the pure PP powder increases when the nanoclay is added. Also, it can be seen that the melting point increases as the winding speed increases.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the scope of the present invention .

Claims (5)

Polymeric synthetic resin powder;
A nanoclay added to the polymer synthetic resin powder;
And polypropylene-grafted maleic anhydride (PP-g-MA), which is a coupling agent added to strengthen the interface between the polymer synthetic resin powder and the nanoclay,
The nanoclays to be added are surface-treated with a cationic surfactant so as to serve as a site for nucleation in a dispersed state,
The content of the coupling agent added is 5% by weight,
Wherein the content of the nanoclays surface-treated with the cationic surfactant is 3 wt% to relatively increase the crystallinity of the polymer synthetic resin powder.
delete The method according to claim 1,
The nano-clay may be selected from the group consisting of montmorillonite, hectorite, saponite, sauconite, vermiculite, magadiite, kenyaite, kaolinite, kaolinite and thuringite. 2. The nanocomposite according to claim 1, wherein the nanocomposite is a mixture of one or more selected from kaolinite and kaolinite.
The method of claim 3,
Wherein the nanocomposite has a melting temperature of 167 캜 to 173 캜.
Pulverizing the polymeric synthetic resin powder using an ultrasonic mill;
A method for producing a nanocomposite according to claim 1, wherein the nanoclay is formed by adding a coupling agent to the polymeric synthetic resin powder to strengthen the interface between the nanoclay and the polymeric synthetic resin powder and the nanoclay.

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