Lignin fibers were developed from a commercial available soda hardwood lignin (SHL) with a melt-spinning approach. SHL showed spinnability to form the fine fibers when poly(ethylene oxide) was used as a plasticizer with lignin. The thermal properties of lignin provided valuable information to assist the processing steps of the lignin fiber formation. The guaiacyl/syringyl ratio in SHL was determined by 31P-NMR because it had great influence on the thermal mobility of lignin. A suitable temperature profile for the melt spinning was predicted through rheological studies of lignin. (c) 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013