| The breadth and range of research into carbon nanotubes and graphene has expanded greatly since their discovery. They exhibit extraordinary and unique electrical, physical, thermal and chemical properties benefiting from their nano-sized hexagonal array of carbon atoms. Carbon nanotubes(CNTs) and graphene received much attention in their many potential applications, such as energy accumulation, capacitors, composites and catalyst, and their functionalization was also researched extensively in some special applications. CNTs could be oxidized to introduce active hydrogen containing groups which could react with functional molecules. Graphene oxide(GO) is the intermediate of graphene produced through redox method,and it contains a range of reactive oxygen containing groups, such as carboxyl, hydroxyl and epoxy groups, which renders it a good candidate for chemical functionalization. Carbon nanomaterials applied on textiles to produce functional textiles has been reported.CNTs and GO were used for linking flame retardancy and hydrophobic moieties to produce multifunctional carbon nanomaterials which were dispersed and applied on cotton by dip-coating procedure. Since the multifunctional textile couldn't be developed simultaneously easily through traditional methods, multifunctional carbon nanomaterials produced in this research might introduce two or more function at one step.Amount of reactive groups should be introduced on the surface of carbon nanomaterials for the sake of organic functionalization. CNTs-COOH and CNTs-OH were then prepared by different oxidation methods. GO was synthesized from natural graphite by oxidation according to the modified Hummers' method, and the optimum conditions including oxidant concentration and reaction conditions for the oxidation were improved in this study. Ethanolamine was attached onto the basal plane by the ring-opening reaction of epoxy groups for increasing the amount of hydroxyl groups, and the effect of p H of the reaction system was studied.Aiming at environment-friendly multifunctional nanomaterials development, perfluoro-1-iodohexane was chosen as the hydrophobic moiety in this study to engage in the nucleophilic substitution with the hydroxyl groups on CNTs and GO to obtain CNTs-F and GO-F, respectively. Dimethy phosphite and cyanuric chloride were chosen as the flame retarding moiety. After grafted acryloyl chloride, C=C bond that could react with dimethyl phosphite was generated on the surface of CNTs or GO, then CNTs-P and GO-P were obtained after having that additive reaction. Finally, perfluoro-1-iodohexane, cyanuric chloride and dimethyl phosphite were grafted on the surface of CNTs and GO extensively to get CNTs-multi and GO-multi, respectively. The chemical composition and structure and thermal behavior of the CNTs-F, CNTs-P, CNTs-multi, GO-F, GO-P and GO-multi particles were characterized by XPS, FTIR and TGA. The optimized dispersed medium was studied by observing their homogeneous dispersion. The dispersions were applied on cotton by simple dip-drying process without using any additive agent.The flame retardancy of cotton was not improved after deposite CNTs. CNTs-multi/cotton sample could be lighted in the match test, but the amount of the char residue increased and the skeleton remained. MCC analysis showed that the peak heat release rate(PHRR) and total heat release(THR) of the CNTs-multi/cotton significantly reduced by more than 65% compared with the untreated cotton. TG analysis proved that the char residue of cotton component in CNTs-multi/cotton increased due to the existence of P element. After combustion, residue with tighter structure and the net-work of carbon materials retained emerged on the FE-SEM images of CNTs-P and CNTs-multi. Assumed reason for the improved fire resistance is the stabilizing ?-? electronic interactions between the unsaturated structure of the carbonaceous amorphous char and the carbon nanomaterials, which is developed by the intimate contact of the fiber and carbon nanomaterials caused by the crosslinking reaction between the cellulose and the phosphoric acid released by CNTs-P or GO-P in burning.Contact angle(CA) of CNTs-F/cotton and CNTs-multi/cotton are 149.1° and 67.5°, respectively. The CA decrease of CNTs-multi/cotton could be explained by the lower perfluorohexane content on the CNTs-multi. Meanwhile, the electrical conductivity and the anti-UV capability of CNTs-multi/cotton were determined. The squaure resistance is 225.6 k?/? and the UPF value is 121.GO-P/cotton and GO-multi/cotton could be lighted in the match test, but the amount of the char residue increased and the skeleton remained. The whole contact carbonaceous amorphous char and the shape of the surrounded GO-P or GO-multi could be seen on the FE-SEM images. MCC analysis showed that the PHRR and THR of the GO-multi/cotton decreased distinctively compared with the untreated cotton. TG analysis proved the char component of GO-multi/cotton increased after combusion which benefited from the introduced P and N elements.Compared with CNTs-multi/cotton, GO-multi/cotton had better hydrophobic property, with the CA data of 93.4o, which could be due to higher surface roughness might be constructed by layers of GO-multi than cylindrical tubes of CNTs-multi. The electrical conductivity and UV-resistance of GO-multi/cotton were also studied. The surface resistance highly increased, even beyond the four-probe tester's scale(105 k?/?), due to the higher density of defects of GO-multi. GO-multi/cotton showed good UV-resistance property, with its UPF data of 253.In either synthesis process of CNTs-multi or GO-multi, functional moieties competed for hydroxyl groups of carbon nanomaterials in both reactions, which limited their density. Thus, HCCP, containing P and N elements which had P-N synergistic effect and P-Cl which had high reactivity, was chosen as flame retardancy function components. HCCP could link GO and hydrophobic chain(3,3,4,4,5,5,6,6,7,7,8,8,8-Tridecafluoro-1-octanol in this study) and thus improved the reaction condition on the surface of GO. XPS?FTIR and TGA analysis showed that in GO-HCCP the constituent content of P element was 8.74% and N element 6.94%. In GO-HCCP-F, the constituent content of P was 6.18 wt%, N 4.76 wt% and F 33.0 wt%. Through AFM, the distribution of functional components on the surface of GO was monitored. GO-HCCP-F was dispersed into 1,1,1,3,3,3-hexafluoro-2-propanol and then applied onto cotton by dip-drying process. AFM analysis revealed that the bulk layer thickness of GO-HCCP-F was 12.31 nm and XRD indicated that the space between layers was 1.33 nm, which gave information that about 9-layer aggregates were obtained on the dispersion, and that could be the reason that higher weight gain was required for better hydrophobicity. The GO-HCCP-F/cotton had lower flame retardancy but much higher hydrophobicity, with its CA data of 131.3°. Its low flame retardancy could be caused by the perfluorohexane attaching on the very surface of GO-HCCP-F, which prevented the contact between cyclic phosphazene and cotton, even supported combustion when decomposed. The UPF data of GO-HCCP-F/cotton is 500, and TUVA and TUVB are both 0.01%, proving its extraordinary UV-resistance. |
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