Studies On Modification Of MWCNTs And Preparation Of MWCNTs/SPEEK Composite Film

Carbon nanotubes(CNTs)are one-dimensional nanostructure materials and mainly composed of C-C covalent bond.They possess good mechanical,electrical, resistance-chemistry properties,and have been applied very widely.Because of small diameter and large specific area,they agglomerate easily and are difficult to disperse uniformly in polymer matrix,and the properties of their composite material have been affected.At present,studies on the modification of CNTs, improving the dispersibility of them in different solvents and the compatibility with the polymer matrix,have become hotspot.At first,multi-walled carbon nanotubes(MWCNTs)were treated with mixed acids, resulting in formation of many carboxyl and hydroxyl groups on their sides.With the action of N,N'-dicyclohexylcarbodiimide(DCC),p-aminobenzenesulfonic acid was grafted to MWCNTs.The FT-IR showed that the amino group of p-aminobenzenesulfonic acid reacted with the carboxyl on the sides of MWCNTs,and the process created an amide group.The FESEM showed that organic compounds deposited evenly on the surface of MWCNTs and grafted MWCNTs looked like vermicular.The TGA showed that the mass of the organic group was about 40%of the gross weight.The Raman spectrum showed that the ratio of I_D/I_G changed very slightly,which indicated that the content of graphite structure of MWCNTs had a little change.The dispersibility of grafted MWCNTs in water and ethanol were both better than the pristine MWCNTs.Secondly,ethanolamine was grafted to MWCNTs via the same method.The FT-IR spectrum showed that the hydroxyl of ethanolamine reacted with the carboxyl of the sides of MWCNTs,and the process created an ester group.The FESEM and TEM showed that organic compounds deposited evenly on the surface of carbon nanotubes.The dispersibility of graphed-MWCNTs in ethanol and DMF were both better.At last,MWCNTs/SPEEK composite film was prepared by the solution blending method.The surface and fracture of the film were observed by the light microscope and FESEM.The result showed that WMCNTs dispersed uniformly in the composite film and the resin gabled on the nanotube surface.The proton conductivity and mechanical property were determined by impedance spectrometry and universal testing machine.The result showed that the proton conductivity and the tensile strength of the composite film were both better than SPEEK pure film, and they improved with the increasing of grafted MWCNTs.