Modification Of Carbon Nanotubes And Research Of Their Composite Material Properties

In this paper, polyquaternary ammonium salts were synthesized by the reaction of diethylamine with epichlorohydrin, and then oxidation-treated carbon nanotubes (CNTs) with acids were modified using the resulting polyquaternary ammonium salts. Carboxyls in the tube wall of CNTs were produced via oxidizing CNTs under the action of mixed concentrated sulfuric acid and nitric acid, and lastly were converted to ester groups through reacting with polyquaternary ammonium salts using dicyclohexylcarbodiimide (DCC) as a catalyzer. Water solubility of the product was analyzed. Results indicated that the water solubility was greatly improved.Different polyvinyl alcohol/CNTs composite materials were prepared via altering the treating time of mixed acid, and the surface defect of CNTs was oxidized to carboxyl. Then the CNTs were dispersed in monomer under ultrasonic and polyvinyl alcohol/CNTs composite materials were obtained by mixing the solutions. The dispersed state and the structure of CNTs were characterized by transmission electron microscopy and scanning electron microscopy. Mechanical property and thermal characteristic of the composite materials were studied. In addition, effect of CNTs on the structure and the performance of the composite materials were researched.Based on our experiment results the oxidized CNTs dispersed well in the matrix, and the mechanical property of materials was improved. The effect of oxidation time on the mechanical property of materials was quite great. The optimal oxidation time was 0.5 h. The high temperature resistant capability of polyvinyl alcohol/CNTs composite materials was far more than polyvinyl alcohol. Besides, the longer of acidifying time for CNTs, the better of the high temperature resistant capability.