Method of preparation for carbon nanotube material

A method for preparing a carbon nanotube material, comprising the steps of:

• (a) preparing a modified montmorillonite by an ion exchange reaction comprising the substeps of:
• i) acidifying an alkylamine with equal mole of a concentrated HCl;
• ii) mixing the resulting acidified alkylamine with a montmorillonite dispersion in 1:1˜2 volume ratio of the acidified alkylamine to the montmorillonite dispersion;
• and
• iii) precipitating, filtering and pulverizing to obtain a modified montmorillonite;
• (b) preparing a catalyst by a hydrogenation reduction method, comprising the substeps of:
• i) mixing an aqueous solution of nickel nitrate and an alumina-silica hybrid in a weight ratio of 35-45 parts of nickel to 55-65 parts of alumina-silica hydrid, wherein the alumina-silica hydrid contains 10 wt % of alumina and has a particle size of 10-30 μm;
• ii) drying and calcining the resulting product;
• and
• iii) reducing the product with a reducing gas containing hydrogen to produce a nickel-supported catalyst;
• (c) preparing a polyolefin mixture of a polyolefin, the modified montmorillonite prepared in step a) and the catalyst prepared in step b) in a mixer in the weight ratio of 75˜97.5:0˜20:0˜5 provided that the amounts of the modified montmorillonite and the catalyst are not both 0;
• (d) preparing and purifying a nanotube, comprising the substeps of:
• i) placing the polyolefin mixture obtained in step (c) in a crucible and heating the temperature inside crucible up to 550° C.˜650° C., wherein the heating time begins from the burning of the polymer and ends when no flame can be observed and cooling the polyolefin mixture to obtain a mixture of carbon nanotube, nickel catalyst and montmorillonite;
• ii) adding a hydrofluoric acid with a concentration of 20-50% to the mixture, mixing, and separating to obtain a carbon powder;
• and
• iii) adding a mixture of a concentrated sulfuric acid and a concentrated nitric acid, refluxing, and separating to obtain a purified carbon nanotube.