Studies On The Preparation And Properties Of Fluorpolymers/CNTs Composites

Multi-walled carbon nanotubes (MWCNTs) have received much attention due to the highmechanical strength, good electric conductivity and heat transfer and other features. AlthoughMWCNTs have emerged as an exciting and promising strategy in the field of electronic devices andcomposites in recent years, their development in viable disperse systems has faced challenges due totheir form bundles and easily reunification. Therefore, suitable functional surface of MWCNTs isneeded to develop for effectively improving dispersion in water and organic solvents. In this paper,the dispersion of MWCNTs in the solvent is improved by chemical modification, thepolymer/MWCNTs composites materials can be obtained by the MWCNTs blend with thefluorpolymers gel solution in order to improve the mechanical properties and electrical properties ofcomposite materials.1. N-ethyl-3,6-diamino-carbazole-modified MWCNTs:During the alkylation-nitration-reduction step, the carbazole was first treated in a alkylationprocess in dibromoethane, and followed by nitration in nitric acid, in the final step to prepareN-ethyl-3,6-diamino-carbazole,-NO2was reduced to-NH2by stannum particles in concentratedhydrochloric acid to reflux. MWCNTs-COCl has been prepared using purification in hydrochloricacid, carboxyl in nitric and sulfuric mixure, acyl chloride reaction in thionyl chloride with startingmaterial MWCNTs, and N-ethyl-3,6-diamino was finally to generate N-ethyl-3,6-diaminocarbazole-modified MWCNTs in a solvent react. FT-IR, UV-Vis spectroscopy showed that theN-ethyl-3,6-diamino-carbazole was successfully grafted on MWCNTs. Raman spectroscopy presentedan intact structure of MWCNTs.2.2,5-di(4-aminophenyl)-1,3,4-oxadiazole-modified MWCNTs:The2,5-di(4-aminophenyl)-1,3,4-oxadiazole was synthesized by p-aminobenzoic acid andhydrazine hydrate, and then followed by a reflux reaction with treated MWCNTs to prepare2,5-(4’-aminophenyl)-1,3,4-oxadiazole-modified MWCNTs. The dispersion of MWCNTs by chemicalmodification had been significantly improved in DMF and other organic solvents.3. PVDF-HFP/MWCNTs compositesPVDF-HFP was this paper selected as the representative for the PVDF-HFP matrix ofcomposites because of its high dielectric properties. The ionic liquid [bmim][BF4] was overlaid intoPVDF-HFP, in the same time as well as adding N-ethyl-3,6-diamino-carbazole-modified MWCNTs.The composite was made by the method of solution blending method in form of DMF preparation"Polymer-in-salt" form of the polymer gel. When the weight ratio of [bmim][BF4] and PVDF-HFP weight ratio of was1:1, the conductivity of the polymer gel was reached to9.22×10-4S/cm. When1wt%MWCNTs dosage was added, the tensile strength of was up to9.27MPa, which was increasedby22.78%compared with that without increase MWCNTs composites tensile strength.