The Effect Of Carbon Black On The Structure And Properties Of Lyocell Fiber

Lyocelll fiber is a new kind of regenerated cellulose fiber invented in the 1990s. It is expected to replace the rayon fiber in the future production of manmade cellulose fiber because Lyocell process is simple, advanced and environmentally friendly. Lyocell fiber has lots of excellent properties such as high strength, good hand-feeling and water-absorbing property, and so on. Therefore, it is widely used in the dress field. In addition, Lyocell fiber can be used as the precursor to produce cellulose-based carbon fiber since it has round cross-section, compact structure and high strength.To this day, few works have been reported on the investigation of modification of Lyocell fiber, and there is less research on Lyocell fiber modified with carbon black. In this paper, carbon black was added to Lyocell fiber and the effect of carbon black on the rheological behavior of cellulose/NMMO solution, the structure and properties of Lyocell fiberwas investigated. In addition, the application of Lyocell fiber modified with carbon black used as the precursor of carbon fiber was also studied.The paper studied the effect of carbon black on the rheological properties of the cellulose/NMMO solution at first. The results showed that the cellulose/NMMO solution with carbon black addition was a typical shear thinning solution. With the addition of small amount of carbon black (1%), the viscosity of the system decreased obviously, the non-newtonian index and the viscous activation energy increased. In addition, the structural viscosity index declined and the spinnability of solution improved. Then with the further increase of the carbon black, the viscosity of the solution increased gradually, the non-newtonian index and the viscous activation energy decreased.The study on the structure and properties of the carbon black filled Lyocell fiber showed that the tensile strength and initial modulus of carbon black filled Lyocell fiber decreased slightly while the elongation at break increased. With the same content of the carbon black, the smaller size the carbon black had, the less the mechanical properties of carbon black filled Lyocell fiber decreased. The experimental results showed carbon black filled Lyocell fiber still had the cellulose II crystal structure and remained the characteristic peak of carbon black at the same time. Compared to Lyocell fiber without carbon black, Lyocell fiber filled with nano-carbon black had the same round cross-section and more compactstructure. Moreover, the nano-carbon black addition could increase the carbon yield of Lyocell-based carbon fiber. Therefore, the nano-carbon black filled Lyocell fiber could be used as an excellent precursor.In addition, this study showed the characteristic diffraction peak of carbon black had been reserved in the nano-carbon black filled Lyocell fibers pre-oxided under different temperature and resulted carbon fiber. In the range of our experiments, the mechanical properties of carbon fiber filled with 5% nano-carbon black increased obviously. And the higher content of carbon black was filled, the better mechanical properties of resulted carbon fiber had.