Preparation and characterization of long-term stable pullulan nanofibers via in situ cross-linking electrospinning

Abstract

Pullulan nanofibers with long-term stabilization were fabricated by using glutaraldehyde as the cross-linking agent and sulfuric acid as the catalyzer via in situ cross-linking electrospinning. The structural, chemical, and thermal analyses have been conducted by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and differential scanning calorimetry. Cross-linked pullulan nanofibers were found thermally more stable. More importantly, the water absorption and water solubility of the cross-linked pullulan nanofiber membranes were evaluated. The results showed that the water absorption rate increased significantly (from 327% to 651%) and the weight loss rate decreased (from 19.0% to 4.1%) with the increase of glutaraldehyde content. Overall, this in situ cross-linking electrospinning technique provides a method to cross-link pullulan during electrospinning.

Cross-linking electrospinning

“…85 Because both PVA and HEC contain a large number of hydroxyl groups, the cross-linking reaction is mainly the aldol condensation. Similarly, the cross-linking reaction of e-spun nanofibers of individual dextran, 86 starch, 87,88 and PVA/starch mixture 89 is also dominated by aldol condensation. Another type of polysaccharide, CS, contains a large number of amino groups, which can undergo a Schiff base reaction with the aldehyde groups on GA.…”

Electrospinning based on benign solvents: current definitions, implications and strategies

“…216 Similarly, recent work has shown that this method is valid also for polysaccharides. 217 Specifically, sulfuric acid was added to the formulation with glutaraldehyde to obtain in situ cross-linking of pullulan fibers. The cross-linking kinetic is even slower when glyoxal instead of glutaraldehyde is utilized as di-aldehyde cross-linker, similar to what was observed when reacting it with amines.…”

Fractal-like multiple jets in electrospinning process

“…However, the output of traditional single-needle electrospinning technology is about 0.01-0.05 g/h, which greatly restricts its development and industrial applications. In order to solve the problem, much effort has been made, the focus was put on various needleless electrospinning technology [8][9][10][11], multinozzle electrospinning technology [12], bubble electrospinning [13,14], and macromolecular electrospinning [15][16][17].…”