Preparation Of Carbon Nanotubes/Cellulose Composite Fiber And Their Conductivity

The conductive fibers with high flexibility,high strength and light weigh are widly used in sensors,capacitors,energy storage materials and so on.The macroscopic fibers assembled from carbon nanotubes(CNTs)can make full use of the super performance of CNTs,such as their high electrical conductivity,low density and high tensile strength.However,the pure CNTs fibers fabrication is complicated,such as spinning from a vertically aligned CNT array previously grown on a substrate,spinning from a CNT aerogel formed in a chemical vapor deposition(CVD)reactor,and twisting/rolling from a CNT film.Therefore,how to fabricate the CNTs fibers with excellent performances by a simple and environmentally friendly method is still a challenge,and it is still a hot research topic.This thesis aims at overcoming the shortcomings during the fabrication process of environment-friendly carbon based fibers,we put forward the effective template adsorption and wet spinning method to obtain the CNTs/cellulose composite fibers,respectively.The effects of fabrication conditions on the morphologies and structures of the composite fibers were discussed.Furthermore,the conductivity and mechanical properties of the composite fibers were also systematically investigated.Specific research contents are as follows:1.There exist strong Van der Waals interactions between individual CNTs,which can render the CNTs dispersion a challenging task.Firstly,Surfactants were used for single-walled carbon nanotubes(SWCNTs)dispersion via ultrasonic and centrifugation.UV-Vis absorption spectra and Zeta potentials were applied to characterize the dispersions of SWCNTs.The optimum dispersion conditions of SWCNTs were SWCNTs initial concentration of 0.8?1.2 mg/mL,SDS concentration of 5 mg/mL,ultrasonic power of 200 W,and ultrasonic time of 100 min.2.CNTs/cellulose composite fibers were fabricated by template adsorption method,and the cellulose fibers were taken as the adsorption template.Several kinds of the composite fibers were obtained by introducing the different types of CNTs.When the acidified carbon nanotubes(a-CNTs)with 2 wt%carboxyl content were introduced,the conductivity of the composite fibers can be as high as 3000 S/m.Hydrogen bond can be formed between a-CNTs and cellulose,which is benefit for the entanglement of a-CNTs to the surface of the cellulose fiber,and increase the conductivity of the composite fiber.3.A-CNTs/cellulose composite fibers with excellent mechanical and electrical performance can be reached by adjusting the fabrication conditions of the wet spinning,with introduction of cellulose as binder.Due to the formation of hydrogen bond between the a-CNTs and cellulose and ?-? interactions between the a-CNTs,the electrical conductivity of the composite fibers can be increased to 4020 S/m,and their tensile strength is as high as 70 MPa,which was improved 133%compared with the regenerated cellulose fiber.