Chemistry Reference
In-Depth Information
of this spectrum, resulting in a decrease in the inner temperature of the
clothing and thus indirectly of the body temperature (cooling effect). All
these new functional textiles are in one way (heating or cooling) thermo-
regulated heat-insulating materials
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.
More interesting are those materials that show two-way thermo-
regulated properties. Such textiles are obtained by impregnation, coating,
development of composite materials or microencapsulation. The active
material for the thermoregulation is often a phase-change material (see
section 8.2.1.), such as polyethylene glycol; this is one of the most impor-
tant phase-change materials.
Heat storage and thermo-regulated textiles can be manufactured by
filling hollow fibres or impregnating non-hollow fibres with phase-change
materials and plastic crystals. They can also be manufactured by coating
fabric surfaces with phase-change materials, plastic crystals or micro-
capsules. Embedding the microcapsules directly within the fibre increases
durability as the phase-change material is protected by a dual wall, the first
being the wall of the microcapsule and the second being the surrounding
fibre itself. Thus the phase-change material is less likely to leak from the
fibre during its liquid phase, enhancing its life and the repeatability of the
thermal response. Additionally, the PCM-coated fabrics can gain anti-
bacterial properties as is the case for polyethylene glycol-coated fibres
40
.If
particles of ZrC are added to a heat-storage and thermo-regulated textile,
they can absorb near infra-red rays of sunlight and convert it into heat, which
allows phase-change materials to melt (to change phase)
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.So, in this way,
an excess of energy uptake is compensated for by using it for the melting
process of the phase-change material, thereby ensuring that the inner cloth-
ing temperature (and thus the body temperature) remains almost constant.
8.4
Electrotextiles
8.4.1
Introduction
Electrotextiles are a novel category of textiles, offering a unique way to fab-
ricate flexible clothing for use in military and medical applications as well
as for novel large-area, commercial systems. For that reason, there is unique
research and development in basic yarn components, textile circuits, CAD
device manufacturing and simulation, fabric-based system simulation,
design and modelling. The term electrotextiles encompasses a very impor-
tant condition - the possibility of conducting an electrical current. In this
section, different methods of producing such fibres, yarns and garments will
be discussed.
However, electrotextiles are not expected to compete with high-density,
high-performance electronic systems typified by current computer or
