Electrospun lignin-PVP nanofibers and their ability for structuring oil

• Main Authors: Borrego, M. (Author), Franco, J.M (Author), Martín-Alfonso, J.E (Author), Sánchez, M.C (Author), Valencia, C. (Author)
• Format: Article
• Language: English
• Published: Elsevier B.V. 2021
• Subjects: Article; castor oil; Castor Oil; chemical structure; chemistry; concentration (parameter); Dimethylformamide; elasticity; Elasticity; electric conductivity; Electrospinning; flow kinetics; Kraft lignin; lignin; Lignin; Lubricants; lubricating agent; Molecular Structure; morphology; n,n dimethylformamide; nanofiber; Nanofiber; Nanofibers; nanoparticle; Oil structuring; Oleogel; oleogels; Organic Chemicals; organic compound; particle size; Particle Size; physical chemistry; povidone; Povidone; Rheology; shear stress; solution and solubility; Solutions; surface tension; thin filament; viscoelasticity; viscosity; Viscosity
• Online Access: View Fulltext in Publisher

 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 solutions were prepared at different concentrations (8–15 wt%) 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 filaments were obtained from solutions with low LSL/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 by modifying 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 structuring. © 2021 Elsevier B.V.