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Plasticization for melt viscosity reduction of melt processable carbon fiber precursor
Batchelor, B.L.,Mahmood, S.F.,Jung, M.,Shin, H.,Kulikov, O.V.,Voit, W.,Novak, B.M.,Yang, D.J. Pergamon Press ; Elsevier Science Ltd 2016 Carbon Vol.98 No.-
<P>Fibers of polyacrylonitrile (PAN), or commonly referred to as acrylic fibers, are found to have many applications. Acrylic fibers are used as a textile medium for high quality and high performance yarns and fabrics, and also as the main supply of precursors for carbon fibers. The main reason of its use as carbon fiber precursor is that the polymer gives high mechanical properties with high carbon yield compared to other polymers. However, a major issue with current carbon fiber production from PAN is the use of a solvent spinning process for the preparation of polymer fiber precursor with hazardous solvents, and its safe reclamation. This study presents a solution by a solvent-free melt-spinning process with a copolymer produced from acrylonitrile (AN) with 1-vinylimidazole (VIM). A further significant improvement of the melt-spinning process is found with the additional use of a new oligomer as a plasticizer; the oligomer was prepared by polymerizing AN and methyl-2-(1H-imidazol-1-yl) acrylate (IA). The AN/VIM copolymer has glass transition temperature (T-g) of 115 degrees C but the plasticizer use lowers it to 75 degrees C. Thus, the oligomer plasticizer broadens the temperature range of melt-spinning processability. A carbon fiber prepared utilizing 8 wt% of the synthesized oligomer (Mn = 5 KDa) and high molecular weight base copolymer (Mn - 47 KDa), tensile strength of 1.9 GPa and modulus of 190 GPa have been achieved. (C) 2015 Elsevier Ltd. All rights reserved.</P>
Reduction of perchlorate using zero-valent titanium (ZVT) anode: reaction mechanism
Lee, Chunwoo,Batchelor, Bill,Park, Sung Hyuk,Han, Dong Suk,Abdel-Wahab, Ahmed,Kramer, Timothy A. Techno-Press 2012 Advances in environmental research Vol.1 No.1
Here we show that perchlorate reduction during pitting corrosion of zero-valent titanium (ZVT) is likely caused by dissolved titanium species, especially Ti(II). Several possible mechanisms were suggested based on the literature and were evaluated based on experimental observations. Direct reduction of perchlorate on the bare metal of the ZVT electrode was thermodynamically infeasible due to the high anodic potential that was applied. Other potential mechanisms were considered such as reduction by small ZVT metal particles released from the electrode and direct reduction on the oxide layer of the electrode where potential was sufficiently reduced by a high ohmic potential drop. However, these mechanisms were not supported by experimental results. The most likely mechanism for perchlorate reduction was that during pitting corrosion, in which ZVT is partially oxidized to form dissolved ions such as Ti(II), which diffuse from the electrode surface and react with perchlorate in solution. This mechanism is supported by measurements of the dissolution valence and the molar ratio of ZVT consumed to perchlorate reduced (${\Delta}Ti(0)/{\Delta}ClO_4{^-}$). The results shown in this study demonstrate that ZVT undergoing pitting corrosion has the capability to chemically reduce perchlorate by producing dissolved Ti(II) and therefore, it has the potential to be applied in treatment systems. On the other hand, the results of this research imply that the application of ZVT undergoing pitting corrosion in treatment systems may not be feasible now due to several factors, including material and electricity costs and possible chloride oxidation.
Study of a melt processable polymer precursor for carbon fiber
Mahmood Samsuddin F.,Batchelor Benjamin L.,정민혜,박규순,Voit Walter E.,Novak Bruce M.,Yang Duck 한국탄소학회 2019 Carbon Letters Vol.29 No.6
Carbon fibers (CF) are predominantly being manufactured from polyacrylonitrile (PAN) based precursors which require solution spinning utilizing health hazardous organic solvent. This also adds to the cost of production due to the investment for the solvent recovery. Study of melt processable precursors has long been sought as a solution for health and environmental problems associated with the use of hazardous solvent. No use of solvent for spinning will also reduce the cost of manufacturing. Our coworker Deng et al. reported the possibility of using acrylonitrile-co-1-vinylimidazole (AN/VIM) copolymer as melt processable CF precursor. Here we report a successful preparation of carbon fiber from the co-polymer. We successfully demonstrated the preparation of thinner precursor fibers and carbon fibers through our optimization study of melt spinning, annealing, stabilization and carbonization.
Lin, Qianqi,Li, Qian,Batchelor-McAuley, Christopher,Compton, Richard G. The Korean Electrochemical Society 2013 Journal of electrochemical science and technology Vol.4 No.2
The study of methyl viologen ($MV^{2+}$) mediated oxygen reduction in electrolytic ethanol media possesses potential application in the electrochemical synthesis of hydrogen peroxide mainly due to the advantages of the much increased solubility of molecular oxygen ($O_2$) and high degree of reversibility of $MV^{2+/{\bullet}+}$ redox couple. The diffusion coefficients of both $MV^{2+}$ and $O_2$ were investigated via electrochemical techniques. For the first time, $MV^{2+}$ mediated $O_2$ reduction in electrolytic ethanol solution has been proved to be feasible on both boron-doped diamond and micro-carbon disc electrodes. The electrocatalytic response is demonstrated to be due to the radical cation, $MV^{{\bullet}+}$. The homogeneous electron transfer step is suggested to be the rate determining step with a rate constant of $(1{\pm}0.1){\times}10^5M^{-1}s^{-1}$. With the aid of a simulation program describing the EC' mechanism, by increasing the concentration ratio of $MV^{2+}$ to $O_2$ electrochemical catalysis can be switched from a partial to a 'total catalysis' regime.