title: Rheological Properties and Electrospinnability of High-Amylose Starch in Formic Acid.
abstract: Starch derivatives, such as starch-esters, are commonly used as alternatives to pure starch due to their enhanced mechanical properties. However, simple and efficient processing routes are still being sought out. In the present article, we report on a straightforward method for electrospinning high-amylose starch-formate nanofibers from 17 wt % aqueous formic acid (FA) dispersions. The diameter of the electrospun starch-formate fibers ranged from 80 to 300 nm. The electrospinnability window between starch gelatinization and phase separation was determined using optical microscopy and rheological studies. This window was shown to strongly depend on the water content in the FA dispersions. While pure FA rapidly gelatinized starch, yielding solutions suitable for electrospinning within a few hours at room temperature, the presence of water (80 and 90 vol % FA) significantly delayed gelatinization and dissolution, which deteriorated fiber quality. A complete destabilization of the electrospinning process was observed in 70 vol % FA dispersions. Optical micrographs showed that FA induced a disruption of starch granule with a loss of crystallinity confirmed by X-ray diffraction. As a result, starch fiber mats exhibited a higher elongation at break when compared to brittle starch films.
authors.affiliation: †NanoEngineering Group, Faculty of Mechanical Engineering, Technion Israel Institute of Technology, 32000 Haifa, Israel.
authors.forename: Anica
authors.initials: A
authors.lastname: Lancuški
authors.affiliation: †NanoEngineering Group, Faculty of Mechanical Engineering, Technion Israel Institute of Technology, 32000 Haifa, Israel.
authors.forename: Gleb
authors.initials: G
authors.lastname: Vasilyev
authors.affiliation: ‡Université Grenoble Alpes, Centre de Recherches sur les Macromolécules Végétales (CERMAV), F-38000 Grenoble, France.|§CNRS, CERMAV, F-38000 Grenoble, France.
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Putaux
authors.affiliation: †NanoEngineering Group, Faculty of Mechanical Engineering, Technion Israel Institute of Technology, 32000 Haifa, Israel.
authors.forename: Eyal
authors.initials: E
authors.lastname: Zussman
mesh_terms: D000688:Amylose / Q000737:chemistry* / Q000648:ultrastructure; D005561:Formates / Q000737:chemistry; D057139:Nanofibers / Q000737:chemistry* / Q000648:ultrastructure; D012212:Rheology; D013213:Starch / Q000737:chemistry* / Q000648:ultrastructure; D014783:Viscosity; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D005561:Formates; D014867:Water; C030544:formic acid; D013213:Starch; D000688:Amylose