Nanofiber Nonwovens

Aeeording to the statistical geometry of electrosprm nanofiber nonwovens, the pore size is dominantly determined by the fiber diameter, but other fiber variables, sueh as porosity, areal density, and fiber density, also have influence. 

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An electrospinning process was used to fabricate silk fibroin (SF) nanofiber nonwovens for wound dressing applications. The electrospinning of regenerated silk fibroin (SF) was performed with formic acid as a spinning solvent For ciystallization, as-spun SF nanofiber nonwovens were chemically treated with an... 

Hussain D., Loyal F, Greiner A., and Wendorff J. H., Structure property correlations for electrospun nanofiber nonwovens. Polymer, 2010,51, 3989-3997. 

Micrograph of electrospun nanofiber nonwoven web showing micropores with interconnected pore network. 

The reaction mixture can circulate around the fibers, as is the case, for example, in the continuously working microreaction technique, or the fibers fixed on a carrier can be immersed repeatedly into a reaction vessel to catalyze the content of the vessel. In addition to the short diffusion distances within nanofibers, the specific pore structures and high surface areas of nanofiber nonwovens allow a rapid access of the reaction components to the catalysts and of the products back into the reaction mixture. 

Combination of electrospinning of fibers and electrospraying of cells Scaffolds based on nanofiber nonwovens offer a lot of further advantages. One important prerequisite for a scaffold is a sufficient mechanical compatibility. Cartilage, for example, is characterized by a Young s modulus... 

Electrically conducting polymer Kang et al. (2005) nanofiber nonwoven web fabricated using tbe electrospirming tecbnique and the electrical conductivity of the fibers measured. 

The nanofiber nonwovens are able to produce cells in which the conductivity of the electrolyte is only barely reduced, from 4.4 x 10 S/cm to 4.0 x 10 S/cm, while retaining high wet strength of 14.3 MPa. 

Most nanofiber nonwoven separators are made through electrospinning. However, a few other approaches have been tried as well. 

Polyimide nanofiber nonwovens The separators showed better wettability with polar solvents, thermal stability to 500°C, better rate capability, and higher energy density when compared to conventional PP separators. 

Electrospun PET nanofiber nonwovens The nonwoven separators showed excellent thermal stability, thermal stability of the cell, and rate capability compared to conventional PE separators. 

Hegde, R.R., Dahiya, A., Kamath, M.G., 2005. Nanofiber nonwovens. In Material Sciraice and Engineering, Nonwovens Science and Technology II, The University of Tennessee, http // www.engr.utk.eduAnse/rextiles/Nanofiber% 20Nonwovens.htm (accessed 08.06.14.). 

Fig. 14.2 Comparison of SEM micrographs (a) mioroporous membrane, (b) layered fabric system with electrospun PU nanofiber web, and (c) spunbond nonwoven fabric, (d) SEM micrographs of electrospun PU nanofiber web. (e) Effects of area density of electrospun polyurethane web on air/moisture vapor transport properties of layered fabric systems, (f) Cross section of laminated nanofiber nonwoven web and (g) vapor permeability before/after wash (a-c Reprinted with permission from Lee and Obendorf [23]. Copyright 2007, The Korean Fiber Society, d, e Reprinted with permission from Lee and Obendorf [24]. Copyright 2007, SAGE Publications, f, g Reprinted with permission from Kimura et al. [25]. Copyright 2010, SAGE Publications)...

Fig. 20.14 Hysteresis loops of the polymer/Fe304 hybrids measured at 25 °C (the weight rate of Fe304-NPs/polymer in Fe304-NPs/PAA/PVA nanofiber nonwoven a 14.23 wt%, b 8.47 wt%, c 3.94 wt%, d PVA/PAA only) (Reproduced from Ref [51] by permission of SAGE Publications)...

Table 20.1 show that the magnetic nanofiber nonwoven has saturation magnetization of 1.72 to 6.77 emu/g, which is lower than that of the corresponding bulk (92 emu/g) resulting from the existence of polymer [63]. 

Production of nanofiber nonwovens using electrostatic spinning... 

Functions and applications Nanofibers Nonwovens Precision electrospinning... 

Fig. 5 Nanofiber nonwoven obtained by electrospinning shown at two different magnifications...

Fig. 18 Stress-strain experiments performed on polyamide 6/6T nanofiber nonwovens [89] with the fibers either parallel (blue, upper curve) or perpendicular (red, lower curve) to the deformation direction...

Figure 7.18. SEM images of PAN nanofiber nonwovens with different pore sizes. Spiimeret-coUector distance (A) 15 cm, and (B) 3 cm.

Hellmann C, Belardi J, Dersch R, Greiner A, Wendorff JH, Bahnmueller S (2009) High precision deposition electrospinning of nanofibers and nanofiber nonwovens. Polymer 50 1197-1205... 

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