Why Carbon Fiber Needs DMSO
Over 90% of high-performance carbon fiber is made by carbonizing polyacrylonitrile (PAN) precursor fibers. PAN is a stiff polymer that will not dissolve in ordinary solvents. To dissolve it and spin it into uniform, defect-free filaments, a highly polar, powerful solvent is required. DMSO, with its molecular structure, is the solvent that fits.
Three Core Advantages
Superior Dissolving and Homogenization
DMSO dissolves high-molecular-weight PAN well. During polymerization it keeps monomers mixed evenly, producing a narrow molecular-weight distribution and a well-ordered polymer, which is the foundation for strong, high-modulus fiber.
Control of Precursor Micro-Defects
In wet or dry-jet wet spinning, DMSO leaches out into the coagulation bath as water moves in. DMSO allows precise control of this two-way diffusion, so the precursor stays denser, smoother, and with less fuzz.
Relatively Environmentally Friendly
Compared with highly toxic sodium thiocyanate or the mutagen DMF, DMSO is low-toxic and nearly odorless. In the push for green chemistry, this makes it the practical choice for large modern plants.
From Liquid to Fiber
In a carbon fiber plant, DMSO is present from the start: solution polymerization of acrylonitrile in DMSO forms the spinning dope; degassing and filtration remove micro-bubbles and particles; spinning and coagulation push the dope through spinnerets into a DMSO-water bath; post-processing draws, washes, sizes, and dries the filament into the final PAN precursor.
Industry Challenge: DMSO Recovery
Spinning sends a large volume of DMSO into the wastewater. Boiling at 189 C and highly hygroscopic, DMSO requires multi-effect evaporation and vacuum distillation to recover. Raising recovery rates, cutting energy use, and preventing impurity buildup are core technologies that separate cost leaders from the rest.