The Preparation And Characterization Of Carbon Nanotubes Filled With Potassium Nitrate

Carbon nanotubes with the antioxidants filled in their cavity could be made as flammable agent,which could form a new class of nanocomposite energetic materials.The paper selected KNO₃ as antioxidants,and filled it into the cavity of the carbon nanotubes through the one-step method and two-step method by the capillary action.One-step method was to open and fill the carbon nanotubes at the same time.The two-step method was to open the mouth of the carbon nanotubes firstly,and then filled them.The two-step method includes stirring at room temperature,ultrasonic,melting.The samples were characterized by XRD,TEM,IR, DSC and TG.The influence of KNO₃ solution concentration,reaction time and vacuum conditions of the different preparation methods to the efficiency of the filling was studied.The main research results showed that:(1) Hydrophilic groups such as hydroxyl were added to the surface of the carbon nanotubes after treating with nitric acid,and thus improved the dispersion in aqueous solution, it was better for the KNO₃ solution to enter the inner cavity of the carbon nanotubes by capillary action.(2) The concentration of KNO₃ solution and the reaction time were the most important influencing factors to the efficiency of filling.The efficiency of the filling was higher when the concentration of KNO₃ solution was higher and the reaction time was longer.The vacuum condition had no obvious influence.(3) The analysis of XRD,TEM and IR showed that the filling materials inside the nanotubes filled in the saturated KNO₃ solution by one-step method were KNO₃ possessing good crystals.The carbon nanotubes were filled with not only discrete particles but also continuous nanolines.The length of the longest nanoline was about 250 nm.The filling materials inside the nanotubes filled in the saturated KNO₃ solution by stirring at room temperature were KNO₃ possessing good crystals,and the length of the longest nanoline was about 60 nm.The efficiency of the filling of the samples which were made by ultrasonic and melting was much lesser than by the one-step method and stirring at room temperature.(4) The analysis of DSC showed that the value of the reaction heat enthalpy of the sample made in the saturated KNO₃ solution by one-step method was 15738.82 J·g^-1,and the value of the reaction heat enthalpy of the sample made in the saturated KNO₃ solution for 48h reaction by stirring at room temperature was 9583.76 J'g^-1.The analysis of TG showed that the samples had a weightlessness rate of 30%because of oxidation-reduction reaction.(5) The efficiency of the filling of the sample which were made in the saturated KNO₃ solution by one-step method and the sample which were made in the saturated KNO₃ solution for 48h reaction by stirring at room temperature was higher.