Study On The Dispersion Of Noncovalent Functionalization Of Carbon Nanotubes In Solvents And Polymers

Carbon nanotubes(CNTs)have attracted extensive attention in academic and industrial fields since their discovery in 1991,owing to their outstanding mechanical,electrical and thermal properties.Adding CNTs into polymers not only can improve their physical properties,but also give them many new properties.However,the large aspect ratio,specific area,intertube strong van der Waals force and ?-? stacking of CNTs make them easy to reunite and hard to disperse.It becomes a critical obstacle for the composites to achieve their superior performance.The method of dispersing CNTs mainly includes: covalent and noncovalent functionalization.The covalent method is the introduction of oxidizing groups(carboxyl and hydroxyl)into CNTs through covalent bonds,but it destroyed the structure and unique properties of CNTs.On the basis of without destroying the structure,noncovalent method is making molecules adsorbed,wound or wrapped on the CNTs by ?-? stacking and van der Waals force.Therefore,in this paper,the noncovalent functionalized CNTs were used to study their dispersion in the solvent,and their Hansen solubility constants(HSPs)were calculated,and the intrinsic relationship between the dispersant,the dispersion and the HSPs of CNTs was researched.The compatibility of between CNTs,functionalized CNTs and polymers was predicted by HSPs,and the relationship of between compatibility and the dispersion of CNTs in the polymer was also studied.For the pre-simulation calculations,the surface modification of CNTs and dispersed method is more targeted,and then for its engineering applications to provide the necessary theoretical basis.Finally,the relationship between the dispersion and compatibility of CNTs and the properties of CNTs/polymer composites was studied.The main research contents are as follows:1.Adopt three types of surfactants(cetyl pyridinium chloride,sodium deoxycholate and Triton X-100),two kinds of biomacromolecules(chitosan and lysozyme)and two kinds of polymers(polyaniline and polyvinylpyrrolidone)to noncovalently functionalize MWCNTs.The MWCNTs were functionalized successfully,which were testified by FTIR,XRD,Raman,and SEM.2.The dispersion of pristine and functionalized MWCNTs in more than 20 single solvents was characterized by UV spectrophotometer(UV-Vis)or dynamic light scattering(DLS).Their HSPs were calculated based on the test results.It was found that the dispersion of MWCNTs in the solvent was improved in different degrees and their HSPs were also changed correspondingly.3.Based on the HSPs theory,many solvents mixture were prepared.The dispersion of MWCNTs in these solvents mixture was characterized by DLS.It was found that the solvent mixture not only improved the dispersion of MWCNTs to a certain extent,but also avoided the disadvantages of single solvent,such as high toxicity,high boiling point and expensive.4.In this paper,the dispersion of pristine and functionalized MWCNTs in polymer was observed by microscope.The compatibility of MWCNTs with polymer was analyzed by HSPs.It was found that the dispersion of MWCNTs in the composites prepared by the solution blending method was almost consistent with the dispersion of MWCNTs in the solvents.It was also found that the dispersion of CNTs in the polymer was consistent with that compatibility of HSPs prediction.5.The mechanical,electrical,thermal properties and biocompatibility of the composites were tested.These properties were found not only related to the dispersion and compatibility of MWCNTs in polymers,but also the instinct properties of dispersants.