Chemistry Reference
In-Depth Information
They found that the electrospun webs of nylon 66, polybenzimidazole, polyacrylo-
nitrile (PAN), and polyurethane provided good aerosol particle protection, without
a considerable change in moisture vapor transport or breathability of the system [5].
While nanofi ber webs suggest exciting characteristics, it has been reported that they
have limited mechanical properties [8, 9]. To compensate this drawback in order to use
of them in protective clothing applications, electrospun nanofi ber webs could be lami-
nated via an adhesive into a multilayer fabric system [10, 11]. The protective clothing
made of this multilayer fabric will provide both protection against toxic aerosol and
thermal comfort for user.
The adhesives in the fabric lamination are as solvent/water-based adhesive or as
hot-melt adhesive. At the fi rst group, the adhesives are as solution in solvent or wa-
ter, and solidify by evaporating of the carrying liquid. Solvent-based adhesives could
“wet” the surfaces to be joined better than water-based adhesives, and also could so-
lidify faster. But unfortunately, they are environmentally unfriendly, usually fl amma-
ble and more expensive than those. Of course, it does not mean that the water-based
adhesives are always preferred for laminating, since in practice, drying off water in
terms of energy and time is expensive too. Besides, water-based adhesives are not re-
sisting to water or moisture because of their hydrophilic nature. At the second group,
hot-melt adhesives are environmentally friendly, inexpensive, require less heat and
energy, and so are now more preferred. Generally there are two procedures to melt
these adhesives; static hot-melt laminating that accomplish by fl at iron or Hoffman
press and continuous hot-melt laminating that uses the hot calendars. In addition, these
adhesives are available in several forms; as a web, as a continuous fi lm, or in powder
form. The adhesives in fi lm or web form are more expensive than the corresponding
adhesive powders. The web form are discontinuous and produce laminates which are
fl exible, porous, and breathable, whereas, continuous fi lm adhesives cause stiffening
and produce laminates which are not porous and permeable to both air and water va-
por. This behavior attributed to impervious nature of adhesive fi lm and its shrinkage
under the action of heat [12]. Thus, the knowledge of laminating skills and adhesive
types is very essential to producing an appropriate multilayer fabric. Specifi cally, this
subject becomes more highlight as we will laminate the ultrathin nanofi ber web into
multilayer fabric, because the laminating process may be adversely infl uenced on the
nanofi ber web properties. Lee et al. [7], without disclosure of laminating details, re-
ported that the hot-melt method is more suitable for nanofi ber web laminating. In
this method, laminating temperature is one of the most effective parameters. Incorrect
selection of this parameter may lead to change or damage ultrathin nanofi ber web.
Therefore, it is necessary to fi nd out a laminating temperature which has the least ef-
fect on nanofi ber web during process.
The purpose of this study is to consider the infl uence of laminating temperature
on the nanofi ber web/multilayer fabric properties to make protective fabric which is
resistance against aerosol pollutions. Multilayer fabrics were made by laminating of
nanofi ber web into cotton fabric via hot-melt method at different temperatures. Effects
of laminating temperature on the nanofi ber web morphology, air transport properties,
and the adhesive force were discussed.
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