Abstract:
The invention provides a carbon nanotube compound and method for producing the same. The method of the invention comprises the following steps. Firstly, Aniline-trimer and DMAc (dimethyl acetamide) solution are mixed to form a first solution. Secondly, Dianhydride and DMAc solution are mixed to form a second solution. The first solution and the second are mixed to form a third solution. Additionally, carboxyl-multiwall carbon nanotubes (c-MWNT), Diaminodiphenylether and DMAc solution are mixed to form a fourth solution. The third solution and the fourth are mixed to form a polyamic acid/CNT solution. Some polyamic acid/CNT solution is spread on a substrate and processed by a thermal treatment, and a carbon nanotube compound is eventually produced.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to a carbon nanotube compound, and particularly, the invention relates to a compound having carboxylic-multiwall carbon nanotubes (c-MWNTs). 
         [0003]    2. Description of the Prior Art 
         [0004]    Because of the development of high technology, the influence of the electromagnetic wave to the instrument and the human body is deeply concerned. 
         [0005]    The casing of the electronic device nowadays is mostly made of plastics having the characteristics such as light weight, low cost, easy design, and isolation, so that the static electricity is easily charged and the noise could not be eliminated to cause huge influences to the instrument, the environment, and the person. Many countries have announced the standard for the electromagnetic compatibility and the device which does not conform to the standard is not arrowed to be sold. Therefore, the skill for the electromagnetic compatibility and the shielding material becomes the key point of the design of the electronic product. Because of the superior electric conductivity and the dielectric feather, the conductive polymer is emphasized in the application of the electric shielding materials. 
       SUMMARY OF THE INVENTION 
       [0006]    Therefore, the invention provides a method for producing a carbon nanotube compound, which has the anti-electromagnetic-radiation effect, provided as a shielding material for the electric product. 
         [0007]    A scope of the invention is to provide a method for producing a carbon nanotube compound. 
         [0008]    According to an embodiment of the invention, the method for producing the carbon nanotube compound includes the following steps. Firstly, an Aniline-trimer and a first DMAc (dimethyl acetamide) solution are mixed to form a first solution. And then, a Dianlydride and a second DMAc solution are mixed to form a second solution. And then, the second solution and the first solution are mixed to form a third solution. Afterwards, carboxyl-multiwall carbon nanotubes (c-MWNTs), a Diaminodiphenylether, and a third DMAc solution are mixed to form a fourth solution. 
         [0009]    Furthermore, the fourth solution and the third solution are mixed to obtain a polyamic acid/CNT solution. Finally, a part of the polyamic acid/CNT solution is spread on a substrate and then the part of the polyamic acid/CNT solution spread on the substrate is processed by a thermal treatment to form the carbon nanotube compound on the substrate. 
         [0010]    Another scope of the invention is to provide a carbon nanotube compound, and the carbon nanotube compound could be a polyamic acid/CNT compound. 
         [0011]    According to another embodiment of the invention, the carbon nanotube compound includes a polyamic acid polymer and a plurality of carboxyl-multiwall carbon nanotubes distributed in the polyamic acid polymer uniformly. 
         [0012]    Because the carbon nanotubes have weak van der waals forces to easily gathering and there are no interactive force between the carbon nanotubes and the polymer materials, the carbon nanotubes could not be distributed in the polymer materials. Compared to the prior art, the advantage of the invention is to bring the carbon nanotube a dissolving character for being distributed in the polymer uniformly through a surface functional group transformation to generate a carboxylic acid (—COOH) on the surface of the carbon nanotube. 
         [0013]    The advantage and spirit of the invention may be understood by the following recitations together with the appended drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE APPENDED DRAWINGS 
         [0014]      FIG. 1  is a flow chart illustrating the method for producing a carbon nanotube compound according to an embodiment of the invention. 
           [0015]      FIG. 2  is a flow chart illustrating the method for producing the Aniline-trimer in  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]    The invention is to provide a method for producing a carbon nanotube compound, and the carbon nanotube compound could be a polyamic acid/CNT compound, wherein the carbon nanotubes could be carboxylic-multiwall carbon nanotubes distributed in the polyamic acid polymer uniformly. The embodiments of the invention are described as the following. 
         [0017]    Please refer to  FIG. 1 .  FIG. 1  is a flow chart illustrating the method according to an embodiment of the invention. 
         [0018]    As shown in  FIG. 1 , the method of the embodiment includes the following steps: firstly, in step S 110  of the method, an Aniline-trimer and a first DMAc (dimethyl acetamide) solution are mixed to form a first solution. And then, in step S 112  of the method, a Dianlydride and a second DMAc solution are mixed to form a second solution. And then, in step S 114  of the method, the second solution and the first solution are mixed to form a third solution. Afterwards, in step S 116  of the method, carboxyl-multiwall carbon nanotubes (c-MWNTs), a Diaminodiphenylether, and a third DMAc solution are mixed to form a fourth solution. In practice, the ratio of the components of the fourth solution could be adjusted by conditions. 
         [0019]    Furthermore, in step S 118  of the method, the fourth solution and the third solution are mixed to obtain a polyamic acid/CNT solution. Finally, in step S 120  of the method, a part of the polyamic acid/CNT solution is spread on a substrate and then the part of the polyamic acid/CNT solution spread on the substrate is processed by a thermal treatment to form the carbon nanotube compound on the substrate. 
         [0020]    The conditions for executing the method of the invention will be described in the following. It should be noted that the process, the materials, the parameter, and the data are the embodiments for explaining but not the limiting the invention. 
         [0021]    Firstly, 0.1363 g (0.47 mmole) Aniline-trimer is dissolved in 6 g DMAc (dimethyl acetamide) and the mixture is stirred at the room temperature for 24 hours to form a first solution. And then, 0.5205 g (1 mmole) Dianlydride is dissolved in 1.5 g DMAc and the mixture is stirred at the room temperature for 30 minutes to form a second solution. And then, the second solution is mixed with the first solution and the mixture is stirred at the room temperature for 24 hours to form a third solution. And then, carboxyl-multiwall carbon nanotubes (c-MWNTs) and 0.2002 g (1 mmole) Diaminodiphenylether are dissolved in 2.5 g DMAc and the mixture is stirred at the room temperature for 24 hours to form a fourth solution, wherein the carboxyl-multiwall carbon nanotubes occupies 0.5-3 weight percents of the fourth solution. 
         [0022]    Furthermore, the fourth solution is mixed with the third solution, and the mixed solution is stirred at the room temperature for 24 hours to obtain a polyamic acid/CNT solution. Finally, a suitable quantity of the polyamic acid/CNT solution is spread on a glass plate and the part of the polyamic acid/CNT solution spread on the glass plate is processed by a thermal treatment to form the carbon nanotube compound on the glass plate. 
         [0023]    The temperature of the processes of the thermal treatment is increased from the room temperature to 300° C. stage by stage, and then decreased from 300° C. to the room temperature stage by stage. The details of the processes of the thermal treatment for forming the carbon nanotube compound are shown in Table. 1. 
         [0000]    
       
         
               
               
               
             
               
               
               
               
             
               
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 process 
                 temperature 
                 time 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 increasing 
                 Room temp.~80° C. 
                 30  
                 min 
               
               
                 increasing 
                  80° C.~150° C. 
                 6  
                 hrs 
               
               
                 increasing 
                 150° C.~200° C. 
                 6  
                 hrs 
               
               
                 increasing 
                 200° C.~250° C. 
                 2  
                 hrs 
               
               
                 increasing 
                 250° C.~300° C. 
                 3  
                 hrs 
               
               
                 holding 
                 300° C. 
                 3  
                 hrs 
               
               
                 decreasing 
                 300° C.~Room 
                 8  
                 hrs 
               
             
          
           
               
                   
                 temp. 
                   
               
               
                   
               
             
          
         
       
     
         [0024]    In this embodiment, the carbon nanotube compound is a polyamic acid/CNT compound, wherein the carbon nanotubes are carboxylic-multiwall carbon nanotubes and distributed in the polyamic acid polymer. Besides, the radio of mole of the Aniline-trimer to the Dianlydride to the Diaminodiphenylether is about, but not limited to, 0.47:1:1. In practice, the c-MWNTs occupy about 0.5-3 weight percents of the fourth solution. 
         [0025]    In practice, the c-MWNTs could be made by the following steps. Multiwall carbon nanotubes and a sulfuric acid/nitric acid mixed solution are mixed to perform a surface functional group transformation in the ultrasonic vibration conditions to obtain the c-MWNTs, wherein a carboxylation is acting to generate carboxylic acids on the surfaces of the multiwall carbon nanotubes when the multiwall carbon nanotubes are mixed with the sulfuric acid/nitric acid. The ratio of the sulfuric acid to the nitric acid of the sulfuric acid/nitric acid mixed solution could be 3:1, the purity of the sulfuric acid could be 90%, and the purity of the nitric acid could be 70%. In practice, it should be noted that the ratio and the purity of the sulfuric acid to the nitric acid could be adjusted by conditions. 
         [0026]    The conditions for the method to produce Aniline-trimer will be described in the following. It should be noted that the process, the materials, the parameter, and the data are the embodiments for explaining but not the limiting the invention. 
         [0027]    Firstly, the multiwall carbon nanotubes are mixed with a sulfuric acid/nitric acid mixed solution to perform a surface functional group transformation at the temperature of 20±5° C. in the ultrasonic vibration conditions for 23 hours, wherein the ratio of the sulfuric acid to the nitric acid of the sulfuric acid/nitric acid mixed solution is 3:1, the purity of the sulfuric acid is 90%, and the purity of the nitric acid is 70%. The product from the above processes is filtered in the air pumping condition and then is washed by deionized water and methanol for four times. The filtered c-MWNTs are place in air oven at the temperature of 60° C. for 24 hours to remove the unnecessary water to obtain the c-MWNT. 
         [0028]    Please refer to  FIG. 2 .  FIG. 2  is a flow chart illustrating the method for producing the Aniline-trimer in  FIG. 1 . Firstly, in step S 510  of the method, a p-Phenylenediamine, a chloride solution, and an ethanol solution are mixed to form a first mixed solution. And then, in step S 512  of the method, an ammonium persulfate and the first mixed solution are mixed to form a second mixed solution, and the second mixed solution is continuously stirred. And then, in step S 514  of the method, an aniline monomer is mixed with the second mixed solution to form a third mixed solution, and the third mixed solution is continuously stirred. And then, in step S 516  of the method, the third mixed solution is filtered in the low pressure condition to obtain a first product. And then, in step S 518  of the method, the first product is mixed with an ammonium hydroxide solution to form a fourth mixed solution, and the fourth mixed solution is continuously stirred. Furthermore, in step S 520  of the method, the fourth mixed solution is filtered in the low pressure condition to obtain a second product. Finally, in step S 522  of the method, the second product is purified by column chromatography to obtain the Aniline-trimer. 
         [0029]    The conditions for the method to produce Aniline-trimer will be described in the following. It should be noted that the process, the materials, the parameter, and the data are the embodiments for explaining but not the limiting the invention. 
         [0030]    Firstly, 0.86 g (8 mmol) p-Phenylenediamine, 100 ml chloride solution (1M), and 40 ml ethanol solution are mixed with each other, and the mixed solution reacts in the ice bath of −5° C. to form a first mixed solution. And then, 1.8 g (8 mmol) ammonium persulfate is mixed with the first mixed solution to form a second mixed solution, and the second mixed solution is continuously stirred. After 5 minutes, when the product becomes brown, 1.5 ml (16 mmol) aniline monomer is mixed with the mixed solution above-mentioned to form a third mixed solution, and the third mixed solution is continuously stirred. After several minutes, when the product becomes blue, the third mixed solution is stirred for 30 minutes. 
         [0031]    Afterwards, the product in the filtered in the air pumping condition and then the product is washed by 30 ml hydrogen chloride (1M) and 80 ml distilled water solution to obtain a first product. The first product is mixed with 40 ml ammonium hydroxide (1M) to form a fourth mixed solution, and the fourth mixed solution is stirred for 1-2 hours at the room temperature. Furthermore, the fourth mixed solution is filtered in the air pumping condition and then the product is washed by the distilled water until that the pH value of the product is close to 7 to obtain a second product, wherein the second product is blue-russet. Finally, the second product is purified by column chromatography to obtain the Aniline-trimer. 
         [0032]    Because the carbon nanotubes have weak van der waals forces to easily gathering and there are no interactive force between the carbon nanotubes and the polymer materials, the carbon nanotubes could not be distributed in the polymer materials uniformly. Compared to the prior art, the advantage of the invention is to bring the carbon nanotube a dissolving character for being distributed in the polymer uniformly through a surface functional group transformation to generate a carboxylic acid (—COOH) on the surface of the carbon nanotube. 
         [0033]    With the example and explanations above, the features and spirits of the invention will be hopefully well described. Those skilled in the art will readily observe that numerous modifications and alterations of the device may be made while retaining the teaching of the invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.