A new method for stabilizing softwood kraft lignin fibers for carbon fiber production

Abstract

Renewable resources, such as kraft lignin, have shown great potential as precursors for carbon fiber production. This manuscript reports an investigation into the stabilization of softwood kraft lignin (SKL) fibers and the determination of the difference in stabilization between hardwood‐ and softwood‐based kraft lignin fibers. The stabilization was achieved either thermally by using only heat or oxidatively in the presence of air, at various heating rates. A heating rate of 4°C min−1 and a holding time of 30 min at 250°C were successfully used for the thermal stabilization experiments. Faster stabilization was achieved using oxidative conditions at a heating rate of 15°C min−1 and 30 min holding time at 250°C. Furthermore, stabilization and carbonization in a one‐step process was performed on SKL fibers, which show great potential to reduce both production time and costs. The stabilized and carbonized fibers were evaluated using thermal, spectroscopic, and microscopic methods. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

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“…Therefore, the direct use of industrial lignin is the most favorable option because it is a relatively cheap raw material. Unmodified lignin has poor stability [141] and difficult melt processing [142], which make its direct use uncompetitive. However, many studies have …”

Utilization of wood cell wall components

“…The SKLbased fibers could be thermostabilized at a heating rate of 3°C/min. In addition, this research group successfully spun fibers from SKL alone, which was a low-molecularmass fraction of SKL prepared by ultrafiltration, and the thermostabilization of the resulting fibers was achieved at a heating rate of 15°C/min [54]. Last year, CF with a tensile strength of more than 1 GPa, was first prepared from partially acetylated SKL through dry spinning [55].…”

Strategies towards Novel Carbon Fiber Precursors: the Research Results on the Synthesis of PAN Copolymers via AGET ATRP and on Lignin as a Precursor

“…polyethylene oxide, PEO). Moreover, the phenomena taking place during stabilization are not yet fully understood [2,5,7,8].…”

“…Since the normal ATRP is sensitive to air lignin is not always the same, but it varies depending on the type (and origin) of initial wood, as well as the method used for separating lignin from the wood pulp; depending on the wood used two major categories are recognized: softwoodand hardwood-originating lignin, whereas depending on the wood pulp separation method used there are several categories like Kraft, Organosolv (Alcell, Acetosolv) etc. ; however, the vast majority of lignin originates from the Kraft process [1][2][3][4].…”

“…One of the reasons that the aforementioned proposal has not been yet applied is the high CFs price. Table 1 depicts the mean estimated cost for manufacturing CFs out of different feedstock (actual or proposed) and Figure 1 presents the cost breakdown per each production step [2,5]. The reference value is the special grade PAN which is currently the dominant precursor material for CF production.…”