Preparation Of Graphene Oxide Nanoribbons And Their Reinforcement On Poly(Vinyl Alcohol) Fibers

Polyvinyl alcohol(PVA)fiber has high strength,high modulus,and non-toxic,no harmless to the human body and the environment,and is one of the new generation of green materials.In industry,it is often used in transport belts,filter cloth,fishing nets,cables,etc.However,in some special fields,its strength and modulus still can not satisfy the demand of application.In recent years,the addition of the nano-carbon material has become a new hot topic of high performance fiber research.However,whether carbon nanotubes(CNTs)or graphene,although excellent in performance,are still subject to a number of limitations in fiber applications.The researchers tried to convert CNTs,mostly multi-walled carbon nanotubes(MWCNTs),into nanoribbons and applied them to the reinforcement of composite fibers,resulting in good results.In this paper,graphene oxide nanoribbons(GONRs)were prepared via unzipping single-walled carbon nanotubes(SWCNTs)through long-time freeze-drying after oxidation.GONRs derived from SWCNTs(SGONRs)did not need any modification and could be directly added to PVA to form uniform dispersions and then continuous fibers were fabricated using wet spinning and hot-drawing.And the structure and properties of the fibers were studied.The main contents and conclusions of this paper are as follows:1.SGONRs with complete morphology were prepared via unzipping SWCNTs through long-time freeze-drying after oxidation and the morphology,structure and dispersion of SGONRs were analyzed.The results showed that the SGONRs obtained by longitudinal unzipping of SWCNTs contained a relatively complete morphology,and there were more oxygen-containing functional groups on the surface of SGONRs over SWCNTs.The dispersibility of SGONRs was better than that of SWCNTs in both DMSO/H2O and PVA,and the interaction of SGONRs with PVA was much stronger than SWCNTs with PVA.2.SGONRs were added into the PVA matrix,and the PVA/SGONRs composite fibers were obtained through wet spinning followed by hot drawing.The dispersibility of SGONRs in fibers was studied and the results showed that when the amount of SGONRs added to the fibers was low,the dispersibility was uniform,but with the increase of the content of SGONRs,the dispersibility of SGONRs in the fibers decreased gradually.Compared with the same content of SWCNTs in the fibers,the dispersibility of SGONRs was obviously better.3.The effects of the addition of SGONRs on the mechanical and thermal properties of the fibers were investigated.The results showed that the larger length to diameter ratio of SGONRs was favorable to their orientation along the fiber axis,and the largely increased surface area of provided more chances for the interaction between PVA and SGONRs.When the content of SGONRs increased gradually,the strength and modulus of PVA/SGONRs composite fibers increased at first and then decreased.As the amount of SGONRs was 0.4 wt%,the best enhancement effect could be achieved,and the tensile strength and Young's modulus were higher than those of pure PVA fibers by 200%and 153%,respectively,and higher than those of PVA/SWCNTs(0.4 wt%)composite fibers by 121%and 24%,respectively.In addition,the thermal properties of the PVA/SGONRs composite fibers were also improved.