Fabrication and Characterization of Electrospun Poly(acrylonitrile- co-Methyl Acrylate)/Lignin Nanofibers: Effects of Lignin Type and Total Polymer Concentration

Suchitha Devadas; Saja M Nabat Al-Ajrash; Donald A Klosterman; Kenya M Crosson; Garry S Crosson; Erick S Vasquez

doi:10.3390/polym13070992

Fabrication and Characterization of Electrospun Poly(acrylonitrile- co-Methyl Acrylate)/Lignin Nanofibers: Effects of Lignin Type and Total Polymer Concentration

Polymers (Basel). 2021 Mar 24;13(7):992. doi: 10.3390/polym13070992.

Authors

Suchitha Devadas¹, Saja M Nabat Al-Ajrash¹, Donald A Klosterman¹, Kenya M Crosson^{2

3}, Garry S Crosson⁴, Erick S Vasquez^{1

3}

Affiliations

¹ Department of Chemical and Materials Engineering, University of Dayton, Dayton, OH 45469, USA.
² Department of Civil and Environmental Engineering and Engineering Mechanics, University of Dayton, Dayton, OH 45469, USA.
³ Integrative Science and Engineering Center, University of Dayton, Dayton, OH 45469, USA.
⁴ Department of Chemistry, University of Dayton, Dayton, OH 45469, USA.

Abstract

Lignin macromolecules are potential precursor materials for producing electrospun nanofibers for composite applications. However, little is known about the effect of lignin type and blend ratios with synthetic polymers. This study analyzed blends of poly(acrylonitrile-co-methyl acrylate) (PAN-MA) with two types of commercially available lignin, low sulfonate (LSL) and alkali, kraft lignin (AL), in DMF solvent. The electrospinning and polymer blend solution conditions were optimized to produce thermally stable, smooth lignin-based nanofibers with total polymer content of up to 20 wt % in solution and a 50/50 blend weight ratio. Microscopy studies revealed that AL blends possess good solubility, miscibility, and dispersibility compared to LSL blends. Despite the lignin content or type, rheological studies demonstrated that PAN-MA concentration in solution dictated the blend's viscosity. Smooth electrospun nanofibers were fabricated using AL depending upon the total polymer content and blend ratio. AL's addition to PAN-MA did not affect the glass transition or degradation temperatures of the nanofibers compared to neat PAN-MA. We confirmed the presence of each lignin type within PAN-MA nanofibers through infrared spectroscopy. PAN-MA/AL nanofibers possessed similar morphological and thermal properties as PAN-MA; thus, these lignin-based nanofibers can replace PAN in future applications, including production of carbon fibers and supercapacitors.

Keywords: alkali; electrospinning; kraft lignin; lignin-based nanofibers; low sulfonate lignin; modulated DSC; nanofibers; poly(acrylonitrile-co-methyl acrylate).