This work explores the electrospinnability of low-sulfonate Kraft lignin (LSL)/polyvinylpyrrolidone (PVP) solutions
in N,N-dimethylformamide (DMF) and the ability of the different micro- and nano-architectures generated
to structure castor oil. LSL/PVP solutionswere prepared at different concentrations (8–15wt%) and LSL:PVP ratios
(90:10–0:100) and physico-chemically and rheologically characterized. The morphology of electrospun nanostructures
mainly depends on the rheological properties of the solution. Electrosprayed nanoparticles or
micro-sized particles connected by thin filamentswere obtained fromsolutionswith lowLSL/PVP concentrations
and/or high LSL:PVP ratios,whereas beaded or bead-free nanofibers were produced by increasing concentration
and/or decreasing LSL:PVP ratio, due to enhanced extensional viscoelastic properties and non-Newtonian characteristics.
Electrospun LSL/PVP nanofibers are able to form oleogels by simply dispersing them into castor oil
at concentrations between 10 and 30 wt%. The rheological properties of the oleogels may be tailored bymodifying
the LSL:PVP ratio and nanofibers content. The potential application of these oleogels as bio-based lubricants
was also explored in a tribological cell. Satisfactory friction and wear results are achieved when using oleogels
structured by nanofibers mats with enhanced gel-like properties as lubricants. Overall, electrospinning of lignin/
PVP solutions can be proposed as a simple and effective method to produce nanofibers for oil structuringThis work is part of a research project (RTI2018-096080-B-C21) sponsored by the MICINN-FEDER I+D+i Spanish ProgrammeFunding for open access charge: Universidad de Huelva / CBU
