Method for preparing carbon nanotube/polyacrylic acid hydrogel, product and application thereof

A method for preparing a carbon nanotube/polyacrylic acid hydrogel, comprising following steps:

• step 1:
• adding a carboxylated carbon nanotube, acrylic acid and an alkali into water to obtain mixed materials and performing a dispersion treatment on the mixed materials to obtain a carbon nanotube/acrylic acid aqueous dispersion;
• step 2:
• adding a crosslinking agent, an initiator and a co-initiator into the carbon nanotube/acrylic acid aqueous dispersion, and performing in-situ polymerization to obtain the carbon nanotube/polyacrylic acid hydrogel;
• wherein in the step 1, the alkali is sodium hydroxide, and a mass ratio of the carboxylated carbon nanotube:the acrylic acid:the sodium hydroxide:the water is 0.1-2.5:10-20:5-10:80-120;
• and
• wherein in the step 2, the crosslinking agent is N, N-methylenebisacrylamide, the initiator is ammonium persulfate, the co-initiator is triethanolamine, a mass ratio of the acrylic acid:the ammonium persulfate:the triethanolamine:the N, N-methylenebisacrylamide is 10-20:0.05-0.15:0.05-0.15:0.002-0.02, a temperature of the in-situ polymerization is in a range of 30 degrees Celsius (° C.) to 85° C., and a time of the in-situ polymerization is in a range of 10 minutes (min) to 80 min;
• and
• wherein before the step 1, the method further comprises:
• mixing concentrated sulfuric acid and concentrated nitric acid to obtain a hyper-concentrated acid solution;
• mixing a carbon nanotube with the hyper-concentrated acid solution to obtain a mixture;
• and
• performing an oxidation on the mixture to obtain a product, and washing the product, thereby preparing the carboxylated carbon nanotube;
• wherein a volume ratio of the concentrated sulfuric acid:the concentrated nitric acid is 3:1, a mass ratio of the carbon nanotube:the hyper-concentrated acid solution is 1:200-400, a temperature for the oxidation is in a range of 50° C. to 95° C., a time for the oxidation is in a range of 2 hours (h) to 8 h, and after the oxidation is completed, the carboxylated carbon nanotube is washed until a pH value of the carboxylated carbon nanotube is in a range of 6 to 8.