KR20150076672A - Thermosensitive polymer prous sheet composition and manufacturing method for thermosensitive polymer sheet using the same - Google Patents

Abstract

The present invention relates to a thermosensitive polymer porous sheet composition and a method for manufacturing a thermosensitive polymer porous sheet using the same, and more specifically, to a thermosensitive polymer porous sheet composition which has a high deformation rate due to a change in temperature to be suitably used as a temperature sensor, an actuator or the like, and to a method for manufacturing a thermosensitive polymer porous sheet using the same. The thermosensitive polymer porous sheet composition according to the present invention may comprise a cationic polyelectrolyte, an anionic polyelectrolyte, and a carbon nanotube.

Description

TECHNICAL FIELD [0001] The present invention relates to a thermosensitive polymer porous sheet composition and a thermosensitive polymer porous sheet using the thermosensitive polymer sheet,

The present invention relates to a thermosensitive polymer porous sheet composition and a method for producing a thermosensitive polymer porous sheet using the same. More particularly, the present invention relates to a thermosensitive polymer composition suitable for use as a temperature sensor or an actuator, And a method for producing a thermosensitive polymer porous sheet using the same.

Since the discovery of carbon nanotubes (CNTs) for the first time by Iijima using electric discharge methods, there has been much research on this new carbon material, which is growing in domestic and international interest. The first carbon nanotube discovered by Iijima is 200 times stronger than steel and has excellent mechanical properties, excellent elasticity, heat resistance to withstand 2800 ° C in vacuum, nearly twice the thermal conductivity of diamond, and about 1000 times that of copper High current transfer capability, etc., and is considered to be highly applicable in all engineering fields.

Carbon nanotubes are carbon materials having a high aspect ratio, usually having a diameter of 1 to 100 nanometers (nm) and a length of several nanometers (nm) to several tens of micrometers (占 퐉). Carbon nanotubes have a tubular shape with a honeycomb flat carbon structure in which one carbon atom is combined with three other carbon atoms. There are various kinds of carbon nanotubes. Depending on the number of walls constituting the nanotubes, they can be divided into multi-walled nanotubes (MWNTs) and single-walled nanotubes (SWNTs) Walled nanotube, and a single-walled nanotube is referred to as a multi-walled nanotube.

Further, due to the high surface area and the aspect ratio, the carbon nanotube has a percolation threshold (the carbon nanotube / polymer complex exhibits the minimum electrical conductivity of carbon nanotubes Content) can be achieved. In the case of conventional carbon fibers, the critical content in conventional electrical properties is 8 to 20 wt%, whereas when carbon nanotubes are used, the critical content is reduced. Potschke's study of polycarbonate shows that the critical content of carbon nanotubes 2% by weight (European Polymer Journal 40 (2004) 137-148). However, there was a problem that this value was not too small.

In addition, carbon nanotubes are being utilized as additives for various composites due to their high electrical conductivity, thermal stability, tensile strength and stability. It is important to effectively disperse the bundles of carbon nanotubes in a solvent in order to form a functional composite material to which carbon nanotubes are added. For example, in order to produce a polymer composite in which carbon nanotubes are dispersed, it is necessary to uniformly disperse carbon nanotubes in a polymer matrix. However, the carbon nanotubes have a problem of having a very low dispersion degree with respect to the solvent due to the long length and the strong attractive force between the carbon nanotubes.

To solve these problems, techniques for mixing carbon nanotubes with a polymer material by providing a dispersion force through a chemical and physical pre-treatment process have been studied.

In order to increase the dispersibility of the carbon nanotube itself, there is a known method for oxidizing the surface of the carbon nanotube with strong acidic solution such as sulfuric acid, hydrochloric acid or nitric acid. However, And there is a problem that when the carbon nanotubes treated with the acidic solution are thermally dried, the dispersibility of the carbon nanotubes is not sufficient.

On the other hand, as a material of the temperature sensor, a metal, a ceramic, a complex thereof, a polymer, or the like is generally used. Among them, a polymeric sensor material has been developed which is provided with a temperature-sensitive function that reacts with temperature using a polymer material.

Regarding this, in regard to a temperature sensor using a conductive material obtained by synthesizing with a polymer using carbon black having conductivity as a medium, reference is made to Patent Document 10-0094261 (published on May 20, 1994) .

Conventionally, a conductive material is forcedly mixed in a polymer to impart temperature functionality to the polymer material, and the temperature sensor function is imparted by the change in resistance due to heat shrinkage or expansion of the polymer depending on the temperature. However, the temperature sensor manufactured by the above-described conventional method has the following problems.

First, when a conductive material is mixed into a polymer, the rate of change in resistance with temperature changes must be a constant function. In general, the resistance increases suddenly at a certain temperature or suddenly decreases in resistance. There is a problem that is difficult to match.

Secondly, polymer and conductive material are destroyed in the process of forcibly mixing a large amount of conductive material into a polymer, so that basic characteristics are often not obtained.

Thirdly, since it is a mixture, it is difficult to process a product having a thin thickness, so that it is difficult to measure an instant at a very sensitive region.

The present invention has been made in order to solve the above-mentioned problems, and unlike a conventional polymer sensor, the present invention provides a thermosensitive polymer A porous sheet composition and a method for manufacturing a thermosensitive polymer porous sheet using the same are provided.

The present invention also provides a thermosensitive polymer porous sheet composition suitable for use as a temperature sensor, an actuator, or the like due to its high strain rate due to a change in temperature, and a method for manufacturing a thermosensitive polymer porous sheet using the same.

The present invention provides a thermosensitive polymer porous sheet composition comprising a cationic polymer electrolyte, an anionic polymer electrolyte and carbon nanotubes.

According to a preferred embodiment of the present invention, the cationic polymer electrolyte is selected from the group consisting of polyallylamine hydrochloride (PAH), polyethylenimine (PEI), polydiallyldimethylammonium chloride, But are not limited to, polymethacryloxyethyltrialkyl ammonium halides, polyallylamine chlorides, polyacrylamides, aminoethylated polyacrylamides, polyvinylamines, And may include at least one member selected from the group consisting of Hofman-degradated polyacrylamide, polyethyleamine, cationized starch, and chitosan.

According to another preferred embodiment of the present invention, the anionic polyelectrolyte is selected from the group consisting of polystyrenesulfonic acid-co-maleic acid, polyacrylic acid, polystyrenesulfonic acid, polystyrenesulfonic acid, And at least one member selected from the group consisting of polymethacrylic acid, polyvinylphosphate, and poly4-ammonium styrenesulfonic acid.

According to another preferred embodiment of the present invention, the carbon nanotube may be a multi-walled nanotube (MWNT).

According to another preferred embodiment of the present invention, the carbon nanotubes may have an average diameter of 1 to 20 nm and an average length of 1 to 300 μm.

According to another preferred embodiment of the present invention, the carbon nanotubes may not be physically and chemically modified.

According to another embodiment of the present invention, the composition may include 10 to 1,000 parts by weight of the cationic polymer electrolyte and 10 to 2,000 parts by weight of the anionic polymer electrolyte based on 100 parts by weight of the carbon nanotubes.

The present invention also provides a method for preparing a thermosensitive polymer porous sheet, comprising the steps of: preparing a mixture by mixing the thermosensitive polymer porous sheet composition as described above; Filtering the mixture with a hydrophilic polymer porous support to prepare a polymer sheet comprising a hydrophilic polymer porous support; And drying and heat-treating the polymer sheet to produce a thermosensitive polymer porous sheet; Sensitive porous polymeric porous sheet.

According to a preferred embodiment of the present invention, the hydrophilic polymer porous support may include at least one member selected from the group consisting of cellulose, regenerated cellulose, aramid, polyisophthalon, and nylon.

According to another preferred embodiment of the present invention, the filtration may include at least one of the group consisting of vacuum filtration, pressure filtration, gravity filtration and heat filtration.

According to another preferred embodiment of the present invention, the heat treatment may be performed at 5 to 100 MPa and 90 to 300 ° C for 30 minutes to 1 hour.

Further, the present invention provides a fuel cell comprising a first layer comprising a carbon nanotube, a cationic polymer electrolyte and an anionic polymer electrolyte; A second layer formed below the first layer and including a carbon nanotube and a porous hydrophilic polymer; And a third layer formed below the second layer, the third layer comprising a porous hydrophilic polymer; The present invention also provides a thermosensitive polymer porous porous sheet comprising the thermosensitive polymer porous porous sheet.

According to a preferred embodiment of the present invention, the cationic polymer electrolyte is selected from the group consisting of polyallylamine hydrochloride (PAH), polyethylenimine (PEI), polydiallyldimethylammonium chloride, But are not limited to, polymethacryloxyethyltrialkyl ammonium halides, polyallylamine chlorides, polyacrylamides, aminoethylated polyacrylamides, polyvinylamines, And may include at least one member selected from the group consisting of Hofman-degradated polyacrylamide, polyethyleamine, cationized starch, and chitosan.

According to another preferred embodiment of the present invention, the anionic polyelectrolyte is selected from the group consisting of polystyrenesulfonic acid-co-maleic acid, polyacrylic acid, polystyrenesulfonic acid, And at least one member selected from the group consisting of polymethacrylic acid, polyvinylphosphate, and poly4-ammoniumstyrenesulfonic acid.

According to another preferred embodiment of the present invention, the carbon nanotube may be a multi-walled nanotube (MWNT).

According to another preferred embodiment of the present invention, the carbon nanotubes may have an average diameter of 1 to 20 nm and an average length of 1 to 300 μm.

According to another preferred embodiment of the present invention, the hydrophilic polymer may include at least one selected from the group consisting of cellulose, regenerated cellulose, aramid, polyisophthalon, and nylon.

According to another preferred embodiment of the present invention, the thermosensitive polymer porous porous sheet may have a strain of 0.1 to 50% measured at one side heating on a sheet at 25 to 120 ° C.

The present invention relates to a thermosensitive polymer porous porous sheet composition which can be processed to a thin thickness without destroying the polymer and the conductive material because the polymer is not mixed with the conductive material forcibly, unlike the conventional polymer sensor, and the thermosensitive polymer porous There is an effect of providing a porous sheet production method.

The present invention also provides a thermosensitive polymer porous porous sheet composition suitable for use as a temperature sensor, an actuator, or the like due to a high strain rate due to a change in temperature, and a method for manufacturing a temperature responsive polymer porous porous sheet using the same.

1 is a flowchart illustrating a method for manufacturing a porous thermosensitive polymer porous sheet according to a preferred embodiment of the present invention.
2 is a cross-sectional SEM photograph of the thermosensitive polymer porous sheet prepared in Example 1. Fig.
3 is a cross-sectional SEM photograph of the first layer of the thermosensitive polymer porous sheet produced in Example 1. Fig.
4 is a sectional SEM photograph of the second layer of the thermosensitive polymer porous sheet produced in Example 1. Fig.
5 is a cross-sectional SEM photograph of the third layer of the thermosensitive polymer porous sheet prepared in Example 1. Fig.
6 is a polymer sheet prepared in Experimental Example 1 by using the polymer sheet composition of Example 1. Fig.
7 is a polymer sheet prepared by using the polymer sheet composition of Comparative Example 1 in Experimental Example 1. Fig.
Fig. 8 is a polymer sheet prepared using the polymer sheet composition of Comparative Example 2 in Experimental Example 1. Fig.
FIG. 9 is a graph of strain according to the temperature measured in Experimental Example 2. FIG.
10 is a photograph of a polymer sheet on a hot plate at 29 DEG C measured in Experimental Example 2. FIG.
11 is a photograph of a polymer sheet on a hot plate at 122 DEG C measured in Experimental Example 2. Fig.
12 is a photograph of a polymer sheet on a hot plate at 84 DEG C measured in Experimental Example 2. FIG.
13 is a photograph of a polymer sheet on a hot plate at 30 DEG C measured in Experimental Example 2. Fig.

Hereinafter, the present invention will be described in detail.

As described above, the polymer sensor produced by forcibly mixing a conductive material into a polymer has a problem that the resistance suddenly rises suddenly at a certain temperature or abruptly decreases in resistance, which makes it difficult to adjust the coefficient of the accurate temperature-resistance. There is a problem that it is difficult to process a thin part of the product because it is a problem and a mixture in which the polymer and the conductive material are broken and the basic characteristics are not exhibited in the process of forcibly mixing a large amount of the conductive material into the conductive material .

Accordingly, the present invention has been made to solve the above-mentioned problems by providing a thermosensitive polymer porous sheet composition comprising a cationic polymer electrolyte, an anionic polymer electrolyte, and a carbon nanotube. Unlike a conventional polymer sensor, a conductive material is not forcedly mixed into a polymer so that the polymer and the conductive material are not destroyed. The polymer can be processed to have a small thickness, and the strain due to the temperature change is high. The present invention provides a thermosensitive polymer porous sheet composition suitable for use as a thermosensitive polymer porous sheet, and a method of manufacturing a thermosensitive polymer porous sheet using the same.

The present invention provides a thermosensitive polymer porous sheet composition comprising a cationic polymer electrolyte, an anionic polymer electrolyte and carbon nanotubes.

The cationic polyelectrolyte is not particularly limited as long as it is a conventional polymer electrolyte having a cationic property, but is preferably a polyallylamine hydrochloride (PAH), a polyethyleneimine (PEI), a polydiaryldimethylammonium chloride polydiallyldimethylammonium chloride, polymethacryloxyethyltrialkyl ammonium halide, polyallylamine chloride, polyacrylamide, aminoethylated polyacrylamide, polyvinylamine and may include at least one member selected from the group consisting of polyvinylamine, Hofman-degradated polyacrylamide, polyethyleamine, cationized starch, and chitosan.

The anionic polyelectrolyte is not particularly limited as long as it is an ordinary polymer electrolyte having an anionic property, but is preferably a polystyrenesulfonic acid-co-maleic acid, a polyacrylic acid, a polystyrene surfactant, And at least one member selected from the group consisting of polystyrenesulfonic acid, polymethacrylic acid, polyvinylphosphate and poly4-ammoniumstyrenesulfonic acid.

The carbon nanotube is not particularly limited as long as it is a carbon nanotube that can be conventionally purchased and / or manufactured, but preferably a multiwalled nanotube (MWNT) can be used.

The carbon nanotubes may be carbon nanotubes that are not physically and chemically modified, but may be physically and chemically modified. Examples of the carbon nanotubes include, but are not limited to, Carbon nanotubes that are not chemically modified and have an average diameter of 1 to 20 nm and an average length of 1 to 300 占 퐉 can be used.

Carbon nanotubes added to sheets or separation membranes generally serve to increase the hydrophilicity by adding acid or plasma modified surface, but in the present invention, by manufacturing using carbon nanotubes that are not physically and chemically modified, The effect of improving the thermal and electrical properties inherent to the carbon nanotubes can be confirmed by preventing the decrease in the length of the carbon nanotubes and the surface defects caused by the carbon nanotubes.

If carbon nanotubes having an average diameter exceeding 20 nm are used, the tunneling distance between the carbon nanotubes may increase, which may result in a decrease in heat conduction performance.

Further, if carbon nanotubes having an average length exceeding 300 μm are used, there is a difficulty in manufacturing and supplying the carbon nanotubes, which may cause economically disadvantageous problems.

The content of the thermosensitive polymer porous sheet composition is not particularly limited as long as it contains carbon nanotubes, a cationic polymer electrolyte, and an anionic polymer electrolyte. Preferably, the thermosensitive polymer porous sheet composition contains 10 to 1,000 weight parts per 100 weight parts of carbon nanotubes A negative cationic polymer electrolyte and 10 to 2,000 parts by weight of an anionic polyelectrolyte.

If the cationic polymer electrolyte is contained in an amount of less than 10 parts by weight based on 100 parts by weight of the carbon nanotubes, uneven carbon nanotube layer having weak mechanical strength may be generated due to weak coagulation and crosslinking between the anionic electrolytes, If the cationic polymer electrolyte is contained in an amount exceeding 1,000 parts by weight based on 100 parts by weight, an economically disadvantageous problem may arise.

In addition, if the anionic polymer electrolyte contains less than 10 parts by weight of the anionic polymer electrolyte based on 100 parts by weight of the carbon nanotubes, the pi-phyta interaction between the carbon nanotube and the anionic electrolyte may be weak, , And an anionic polyelectrolyte in an amount exceeding 2,000 parts by weight based on 100 parts by weight of the carbon nanotubes, it is economically advantageous to use an excess amount of water to clean excess anionic electrolytic polymer after bonding between the cation electrolytes Disadvantages can arise.

On the other hand, when only the carbon nanotubes and the cationic polymer electrolyte or the anionic polymer electrolyte were included, it was confirmed that they were not suitable for the production of a polymer sheet because of poor moldability as seen in Comparative Examples 1 and 2 To 8).

FIG. 1 is a flow chart illustrating a method of manufacturing a thermosensitive polymer porous sheet according to a preferred embodiment of the present invention, and a method of manufacturing the thermosensitive polymer porous sheet of the present invention will be described with reference to FIG.

First, a mixture is prepared by mixing the thermosensitive polymer porous sheet composition as described above (S1).

The mixing is not particularly limited as long as it is a method for mixing a solid and a liquid, but it can be preferably stirred.

The agitation can be carried out for uniform interaction between the anion electrolytes and uniform agitation between the cation electrolytes. The agitation speed is not particularly limited, but may be preferably 5 to 30 minutes at 100 to 1,000 rpm.

If the stirring speed is less than 100 rpm, it is difficult to uniformly aggregate the carbon nanotubes with the anion and the cation electrolyte, and a part of the carbon nanotubes may fall off during the production of the sheet. If the stirring speed is 1,000 rpm If it is exceeded, there may be disadvantages of normal manufacturing process.

If the agitation time is less than 5 minutes, it is difficult to uniformly aggregate the carbon nanotubes with the anion and the cation electrolyte, and a part of the carbon nanotubes may fall off during the production of the sheet. If the agitation time is 30 minutes If it is exceeded, there may be disadvantages of normal manufacturing process.

Next, the mixture is filtered with a hydrophilic polymer porous support to produce a polymer sheet comprising a hydrophilic polymer porous support (S2).

The hydrophilic polymer porous support may be at least one member selected from the group consisting of cellulose, regenerated cellulose, aramid, polyisophthalon, and nylon, although it is not particularly limited as long as it is a porous sheet or membrane including a common hydrophilic polymer. , More preferably a sheet or a film containing at least one of the above-mentioned groups and having an average thickness of 100 to 400 mu m.

If a hydrophilic polymer porous support having an average thickness of less than 100 탆 is used, mechanical strength may be weak and leakage may occur during filtration. If a hydrophilic polymer porous support having an average thickness exceeding 400 탆 is used, Which may cause economically disadvantageous problems.

In addition, the hydrophilic polymer porous support usually has pores, but the porosity is not particularly limited, but a hydrophilic polymer porous support having a porosity of 20 to 85% can be used.

If a hydrophilic polymer porous support having a porosity of less than 20% is used, the filtration time increases, which is economically disadvantageous, and a part of the carbon nanotube is hardly inserted into the porous support layer, When a hydrophilic polymer porous support having a porosity of more than 85% is used, a non-uniform sheet may be produced due to a low mechanical strength, or a part of the carbon nanotubes may be excessively inserted, resulting in a problem of low heat strain.

The filtration is not particularly limited as long as it is a method of filtering the mixture with a porous sheet (or membrane), but it may preferably include at least one kind selected from the group consisting of vacuum filtration, pressure filtration, gravity filtration and heat filtration.

Next, the polymer sheet is dried and heat-treated to produce a thermosensitive polymer porous sheet (S3).

The drying is not particularly limited as long as it is a condition for drying the polymer sheet, but it is preferably dehydrated and dried, and more preferably from 20 to 80 ° C for 30 minutes to 1 hour.

If it is dried for less than 30 hours, excessive water may be contained and it may be difficult to produce a sheet of the desired shape upon heat treatment, which may cause a problem of normal manufacturing. If drying is performed for more than 1 hour, Economic problems can arise.

If drying is carried out at a temperature lower than 20 ° C, the drying is insufficient and excessive water is contained, so that it is difficult to produce a sheet having a desired shape at the time of heat treatment. , There may arise a problem that sheet shape such as shrinkage becomes uneven due to rapid decrease of moisture.

The heat treatment is not particularly limited as long as it is a temperature condition of a heat treatment process used in a process of producing a polymer sheet, but it may preferably be performed at 5 to 100 MPa and at 90 to 300 ° C for 30 minutes to 1 hour.

If treated at a temperature of less than 90 ° C., the electrochemical cross-linking between the cation and the anion electrolyte is not sufficient, and formation of a uniform carbon nanotube layer may be a problem. When treated at a temperature exceeding 300 ° C., The thermal deformation of the electrolyte, the porous support, and the interfacial adhesion between the porous support and the porous support may reduce the thermal deformation of the sheet due to the temperature.

If the heat treatment is performed for less than 30 minutes, interfacial adhesion between the carbon nanotube layer and the porous support layer may not be sufficient, resulting in difficulty in forming a uniform sheet, and heat treatment may be performed for more than 1 hour This can lead to economically disadvantageous problems.

If the heat treatment is performed at a pressure of less than 5 MPa, insertion of the carbon nanotubes into the porous support layer may not be sufficient, and heat strain may be reduced. If the heat treatment is performed at a pressure exceeding 100 MPa, And the thermal deformation rate may also be poor.

The thickness of the thermosensitive polymer porous sheet is not particularly limited as long as it is the thickness of a conventional polymer sheet, but it may preferably be 200 to 600 탆 thick.

When a polymer sheet having a thickness of less than 200 μm is produced, the distinction between the carbon nanotube layer and the porous support layer is unclear and the thermal strain difference between the respective layers is not large, When the polymer sheet is produced at a thickness exceeding 占 퐉, the thickness of the sheet is too thick, so that the thermal deformation according to the temperature may be suppressed.

FIG. 2 is a SEM photograph showing a thermosensitive polymer porous sheet according to a preferred embodiment of the present invention, and the thermosensitive polymer porous sheet of the present invention will be described with reference to FIG.

First, a first layer 210 including a carbon nanotube, a cationic polymer electrolyte, and an anionic polymer electrolyte will be described.

The carbon nanotube is not particularly limited as long as it is a carbon nanotube that can be conventionally purchased and / or manufactured, but preferably a multiwalled nanotube (MWNT) can be used.

Further, the carbon nanotube is not particularly limited as long as it is a carbon nanotube that can be conventionally purchased and / or manufactured, but it is preferable to use carbon nanotubes that are not physically and chemically modified, Carbon nanotubes that are not chemically modified and have an average diameter of 1 to 20 nm and an average length of 1 to 300 占 퐉 can be used.

Carbon nanotubes added to sheets or separation membranes generally serve to increase the hydrophilicity by adding acid or plasma modified surface, but in the present invention, by manufacturing using carbon nanotubes that are not physically and chemically modified, The effect of improving the thermal and electrical properties inherent to the carbon nanotubes can be confirmed by preventing the decrease in the length of the carbon nanotubes and the surface defects caused by the carbon nanotubes.

If carbon nanotubes having an average diameter exceeding 1 nm are used, the tunneling distance between the carbon nanotubes may increase, resulting in a decrease in the thermal conductivity.

Further, if carbon nanotubes having an average length exceeding 300 μm are used, there is a difficulty in manufacturing and supplying the carbon nanotubes, which may cause economically disadvantageous problems.

The cationic polyelectrolyte is not particularly limited as long as it is a conventional polymer electrolyte having a cationic property, but is preferably a polyallylamine hydrochloride (PAH), a polyethyleneimine (PEI), a polydiaryldimethylammonium chloride polydiallyldimethylammonium chloride, polymethacryloxyethyltrialkyl ammonium halide, polyallylamine chloride, polyacrylamide, aminoethylated polyacrylamide, polyvinylamine and may include at least one member selected from the group consisting of polyvinylamine, Hofman-degradated polyacrylamide, polyethyleamine, cationized starch, and chitosan.

The anionic polyelectrolyte is not particularly limited as long as it is an ordinary polymer electrolyte having an anionic property, but is preferably a polystyrenesulfonic acid-co-maleic acid, a polyacrylic acid, a polystyrene surfactant, And at least one member selected from the group consisting of polystyrenesulfonic acid, polymethacrylic acid, polyvinylphosphate and poly4-ammoniumstyrenesulfonic acid.

The average thickness of the first layer is not particularly limited as long as it is usually the thickness of the polymer sheet to be used, but it may preferably be 60 to 120 탆.

If the average thickness of the first layer is less than 60 占 퐉, there may arise a problem that the thermal strain rate decreases. If the average thickness of the first layer exceeds 120 占 퐉, the problem that the thermal strain rate decreases due to the rigidity of the carbon nanotube May occur.

Next, the second layer 220 formed at the bottom of the first layer and including the carbon nanotubes and the hydrophilic polymer will be described.

The carbon nanotube is not particularly limited as long as it is a carbon nanotube that can be conventionally purchased and / or manufactured, but preferably a multiwalled nanotube (MWNT) can be used.

In addition, the carbon nanotube is not particularly limited as long as it is a carbon nanotube that can be conventionally purchased and / or manufactured, but it is preferable to use carbon nanotubes that are not physically and chemically modified, Carbon nanotubes that are not chemically modified and have an average diameter of 1 to 20 nm and an average length of 1 to 300 占 퐉 can be used.

Carbon nanotubes added to sheets or separation membranes generally serve to increase the hydrophilicity by adding acid or plasma modified surface, but in the present invention, by manufacturing using carbon nanotubes that are not physically and chemically modified, The effect of improving the thermal and electrical properties inherent to the carbon nanotubes can be confirmed by preventing the decrease in the length of the carbon nanotubes and the surface defects caused by the carbon nanotubes.

If carbon nanotubes having an average diameter exceeding 20 nm are used, the tunneling distance between the carbon nanotubes may increase, resulting in a decrease in heat conduction performance.

Further, if carbon nanotubes having an average length exceeding 300 μm are used, there is a difficulty in manufacturing and supplying the carbon nanotubes, which may cause economically disadvantageous problems.

The hydrophilic polymer is not particularly limited as long as it can be used in the production of a polymer sheet, but may preferably include at least one member selected from the group consisting of cellulose, regenerated cellulose, aramid, polyisapharm, and nylon.

The average thickness of the second layer is not particularly limited as long as it is the thickness of the polymer sheet to be used, but it may preferably be 80 to 150 탆.

If the average thickness of the second layer is less than 80 占 퐉, the thermal deformation rate may decrease and a problem of peeling between the carbon nanotube layer and the porous support layer may occur during thermal deformation. If the average thickness of the second layer exceeds 150 占 퐉 , There may arise a problem that the thermal strain rate decreases due to the increase in thickness.

Next, the third layer 230 formed below the second layer and including the hydrophilic polymer will be described.

The hydrophilic polymer is not particularly limited as long as it can be used in the production of a polymer sheet, but may preferably include at least one member selected from the group consisting of cellulose, regenerated cellulose, aramid, polyisapharm, and nylon.

The average thickness of the third layer is not particularly limited as long as it is usually the thickness of the polymer sheet to be used, but it may preferably be 150 to 250 탆.

If the average thickness of the third layer is less than 150 占 퐉, the difference in thermal strain between the first and second layers is insignificant and the thermal strain rate is not good. If the average thickness of the third layer exceeds 250 占 퐉, A problem that the strain rate is not good may occur.

Further, the thickness of the thermosensitive polymer porous sheet is not particularly limited as long as the thickness of the conventional polymer sheet is 20 to 600 μm.

When a polymer sheet having a thickness of less than 200 μm is produced, the distinction between the carbon nanotube layer and the porous support layer is unclear and the thermal strain difference between the respective layers is not large, When the polymer sheet is produced at a thickness exceeding 占 퐉, the thickness of the sheet is too thick, so that the thermal deformation according to the temperature may be suppressed.

In addition, the thermosensitive polymer porous sheet may have a calculated deformation rate of 0.1 to 50% after measuring the length deformation of the thermosensitive polymer porous sheet at 25 to 120 ° C with temperature increase.

Specifically, as can be seen in Experimental Example 2 and FIG. 9, the deformation rate according to the temperature change was high, and it was confirmed that it was suitable for use as a temperature sensor or an actuator.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[ Example ]

Example  One.

1 g of a multiwall carbon nanotube (Hanwha Chemical, CM250, average diameter 10 to 15 nm, average length 200 탆) and 10 g of polystyrene sulfonic acid-maleic acid (Mw: 20,000) were added to 500 L of distilled water The mixture was stirred at a stirring speed of 500 rpm for 3 minutes. To this, 5 g of polydiallyldimethylammonium chloride (Aldrich, MW 350,000) was further added to disperse uniformly. Thereafter, the mixture was further stirred for about 10 minutes to prepare a thermosensitive polymer sheet composition. Then, a porous cellulose sheet (whatman, 5B, 185 mm in diameter) was mounted in a funnel connected with a vacuum flask equipped with an aspirator, and the sheet composition was placed in a funnel to decompress the temperature sensitive polymer sheet composition Followed by filtration to prepare a polymer sheet.

Thereafter, the polymer sheet separated from the funnel was dried at 30 ° C. for 40 minutes, and then subjected to pressure heat treatment at 170 ° C. and 20 MPa for 1 hour to prepare a thermosensitive polymer sheet.

The cross section of the manufactured thermosensitive polymer sheet was photographed with a scanning electron microscope (SEM, SNE-3000M) and shown in Fig. 2. The first layer 210 of the section of Fig. 2 was photographed by SEM, The second layer 220 of the cross section of the second layer 220 is photographed by SEM, and the third layer 230 of the cross section of FIG. 2 is photographed by SEM and is shown in FIG.

As can be seen from Figs. 3 to 4, carbon nanotubes existing in the first layer and the second layer could be identified. Also, as can be seen from FIG. 5, it was confirmed that carbon nanotubes were not present in the third layer.

Comparative Example  One.

A polymer sheet composition was prepared in the same manner as in Example 1, except that an anionic polymer electrolyte was not used.

Comparative Example  2.

A polymer sheet composition was prepared in the same manner as in Example 1, except that the cationic polymer electrolyte was not used.

Experimental Example  1. Formability Evaluation

A polymer sheet was prepared using the polymer sheet composition prepared in Example 1 and Comparative Examples 1 and 2, and the moldability of the polymer sheet was evaluated.

Specifically, the polymer sheet compositions prepared in Example 1 and Comparative Examples 1 and 2 were respectively poured into a vacuum flask and dehydrated in vacuo to prepare a polymer sheet. The polymer sheet thus prepared was dried under the condition of 30 캜 for 40 minutes and then subjected to pressure heat treatment at 170 캜 and 20 MPa for 1 hour.

6 to 8 show a polymer sheet prepared using the polymer sheet composition of Example 1, FIG. 7 shows a polymer sheet prepared by using the polymer sheet composition of Comparative Example 1, 8 is a polymer sheet prepared using the polymer sheet composition of Comparative Example 2. Fig.

6, it was found that the polymer sheet composition comprising the cationic polymer electrolyte and the anionic polyelectrolyte of Example 1 was excellent in moldability.

As shown in FIGS. 7 to 8, the polymer sheet composition including only the cationic polymer electrolyte of Comparative Example 1 and the polymer sheet composition including the anionic polymer electrolyte of Comparative Example 2 had a low formability, resulting in a uniform and flat sheet form It was confirmed that it was not suitable for production.

As a result, it was confirmed that the thermosensitive polymer porous sheet composition of the present invention is excellent in moldability and suitable for the production of a polymer sheet.

Experimental Example  2. Measurement of strain according to temperature

The strain of the thermosensitive polymer porous sheet prepared in Example 1 was measured according to the temperature change.

Specifically, the thermosensitive polymer porous sheet (diameter 15 cm) prepared in Example 1 was cut to 8.6 cm x 2.0 cm x 0.423 cm (width x length x thickness), the cut polymer sheet was placed on a hot plate, The change in the transverse length of the polymer sheet was measured while the temperature was elevated to 125 ° C, and the change in the transverse length of the polymer sheet was measured while the temperature was lowered from 125 ° C to 30 ° C. The strain rate of the polymer sheet was calculated using the transverse length of the measured polymer sheet and the following equation (1), and the calculation results are shown in FIG.

The polymer sheet on the hot plate at 29 ° C, which is the temperature for starting the heating, is shown in FIG. 10, and the polymer sheet on the hot plate at 122 ° C for the temperature for starting the temperature sensing is shown in FIG. 12 is a photograph of a polymer sheet on a hot plate, and FIG. 13 is a photograph of a polymer sheet on a hot plate at a final temperature of 30 ° C during a warming process.

As can be seen from Figs. 9 to 13, it was confirmed that the polymer sheet of Example 1 was deformed according to the temperature change such as the temperature increase and the temperature decrease. Particularly, the temperature rise from 125 deg. C to 80 deg. C, And it was confirmed that it showed a large strain rate.

As can be seen from Examples, Comparative Examples and Experimental Examples, it was confirmed that the thermosensitive polymer porous sheet composition of the present invention can be processed to a thin thickness and has high moldability. In addition, the temperature responsive polymer porous sheet of the present invention has a high strain rate due to a change in temperature, which is suitable for use as a temperature sensor or an actuator.

Claims (20)

A thermosensitive polymer porous sheet composition comprising a cationic polymer electrolyte, an anionic polymer electrolyte, and a carbon nanotube. The method of claim 1, wherein the cationic polymer electrolyte is selected from the group consisting of polyallylamine hydrochloride (PAH), polyethylenimine (PEI), polydiallyldimethylammonium chloride, polymethacryloxyethyltrialkyl But are not limited to, polymethacryloxyethyltrialkyl ammonium halide, polyallylamine chloride, polyacrylamide, aminoethylated polyacrylamide, polyvinylamine, Hoffmann emulsion-polyacrylamide Wherein the thermally responsive polymeric porous sheet composition comprises at least one member selected from the group consisting of Hofman-degraded polyacrylamide, polyethylamine, cationized starch, and chitosan. The method of claim 1, wherein the anionic polyelectrolyte is selected from the group consisting of polystyrenesulfonic acid-co-maleic acid, polyacrylic acid, polystyrenesulfonic acid, polymethacrylic acid, wherein the thermally sensitive polymeric porous sheet composition comprises at least one member selected from the group consisting of polymethacrylic acid, polyvinylphosphate, and poly4-ammoniumstyrenesulfonic acid. The thermosensitive polymer porous sheet composition according to claim 1, wherein the carbon nanotubes are multi-wall nanotubes (MWNT). 5. The thermosensitive polymeric porous sheet composition according to claim 4, wherein the carbon nanotubes have an average diameter of 1 to 20 nm and an average length of 1 to 300 m. The thermosensitive polymer porous sheet composition according to claim 1, wherein the carbon nanotubes are not physically and chemically modified. The thermosensitive polymeric porous sheet composition according to claim 1, wherein the composition comprises 10 to 1,000 parts by weight of the cationic polymer electrolyte and 10 to 2,000 parts by weight of the anionic polyelectrolyte based on 100 parts by weight of the carbon nanotubes. 7. A method for preparing a thermosensitive polymer porous sheet composition, comprising: mixing a thermosensitive polymer porous sheet composition according to any one of claims 1 to 7 to prepare a mixture;
Filtering the mixture with a hydrophilic polymer porous support to prepare a polymer sheet comprising a hydrophilic polymer porous support; And
Drying and heat-treating the polymer sheet to produce a thermosensitive polymer porous sheet;
Wherein the thermally responsive polymer porous sheet comprises a thermally responsive polymer. The method of claim 8, wherein the hydrophilic polymer porous support comprises at least one member selected from the group consisting of cellulose, regenerated cellulose, aramid, polyisophthalon, and nylon. The method of claim 8, wherein the filtration includes at least one selected from the group consisting of vacuum filtration, pressure filtration, gravity filtration, and heat filtration. The method of claim 8, wherein the heat treatment is performed at 5 to 100 MPa and at 90 to 300 캜 for 30 minutes to 1 hour. The polymer sheet according to claim 8, wherein the polymer sheet
A first layer comprising carbon nanotubes;
A second layer formed below the first layer and including carbon nanotubes and a hydrophilic polymer; And
A third layer formed below the second layer and including a hydrophilic polymer;
Wherein the thermosensitive polymer porous sheet comprises a thermosensitive polymer. A first layer comprising a carbon nanotube, a cationic polymer electrolyte, and an anionic polymer electrolyte;
A second layer formed below the first layer and including carbon nanotubes and a hydrophilic polymer; And
A third layer formed below the second layer and including a hydrophilic polymer;
Wherein the temperature-sensitive polymer porous sheet is a thermosensitive polymer. 14. The method of claim 13, wherein the cationic polyelectrolyte is selected from the group consisting of polyallylamine hydrochloride (PAH), polyethylenimine (PEI), polydiallyldimethylammonium chloride, polymethacryloxyethyltrialkyl But are not limited to, polymethacryloxyethyltrialkyl ammonium halide, polyallylamine chloride, polyacrylamide, aminoethylated polyacrylamide, polyvinylamine, Hoffmann emulsion-polyacrylamide Wherein the thermally responsive polymeric porous sheet comprises at least one member selected from the group consisting of Hofman-degradated polyacrylamide, polyethylamine, cationized starch, and chitosan. 14. The method of claim 13, wherein the anionic polyelectrolyte is selected from the group consisting of polystyrenesulfonic acid-co-maleic acid, polyacrylic acid, polystyrenesulfonic acid, polymethacrylic acid, wherein the thermally sensitive polymeric porous sheet comprises at least one member selected from the group consisting of polymethacrylic acid, polyvinylphosphate, and poly4-ammoniumstyrenesulfonic acid. 14. The thermosensitive polymeric porous sheet as claimed in claim 13, wherein the carbon nanotubes are multi-wall nanotubes (MWNTs). 17. The thermosensitive polymeric porous sheet according to claim 16, wherein the carbon nanotubes of the first layer and the second layer have an average diameter of 1 to 20 nm and an average length of 1 to 300 m. The thermosensitive polymeric porous sheet according to claim 13, wherein the hydrophilic polymer of the second layer and the third layer comprises at least one selected from the group consisting of cellulose, regenerated cellulose, aramid, polyisophthalon and nylon. 19. The thermosensitive polymer porous sheet according to any one of claims 13 to 18, wherein the temperature sensitive polymer porous sheet has a strain rate of 0.1 to 50% measured at 25 to 120 DEG C, Sheet. 19. The thermosensitive polymeric porous sheet according to any one of claims 13 to 18, wherein the thermosensitive polymer porous sheet has an average thickness of 200 to 600 mu m.

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