Modification Of Carbon Nanotubes And Its Application In Viscose Fibers

In this paper, a kind of mixed acid system of concentrated nitric acid andconcentrated sulfuric acid was used to modify multi-walled carbon nanotubes (MWNTs)under ultrasound conditions, then, the modified MWNTs was obtained and the modifiedMWNTs was studied. NMMO solution was chosed as the dispersant for MWNTs todisperse MWNTs. The dispersion of modified MWNTs in the dispersant was explored.The viscose fiber was pretreated in different swelling agent, and the influence ofexperimental conditions on the swelling effect of viscose fibers was studied. TheMWNTs/viscose fibers composite fibers was prepared by Second Baptist Second rollingunder different concentrations of MWNTs after-finishing solution and the compositefibers was studied systematically.The structures and properties of the products were further characterized utilizingSEM, Polarizing microscope, TG thermal analysis, FTIR and XRD. The results show that:-COOH MWNTs functional groups were grafted on the surface of MWNTs in the mixedacid system, and the the surface activity of the MWNTs was improved. The crystalstructure of MWNTs was not damaged after the treatmen of mixed acid system. Viscosefiber had significant swelling phenomenon in distilled water and NMMO aqueous solutionunder heating conditions. The increasing rate of the diameter was affected by the heatingtemperature, the concentration of NMMO solution and the swelling time. The dispersionof MWNTs in aqueous solution of NMMO was better than that in distilled water andMWNTs could exist more stably. The MWNTs/viscose fiber composite fibers gainedmuch weight comparing with the original viscose fibers. Because of the addition ofMWNTs, the MWNTs formed a dense protective layer on the surface of viscose fibers. Itimproved the mechanical properties and flame retardancy of viscose fiber to a large extentand the fibers reached a level of flame retardant materials. The joining of MWNTs alsogave the fibers excellent conductive properties. The heat temperature of viscose fibersincreased from150℃to250℃because of the MWNTs. In the study, the MWNTs/viscose fiber composite fibers improved the performance of viscose fibers largely and provided a broader space for practical application of viscose fibers.