Free Textile Article

All about textile & Fiber

Free Textile Article

All about textile & Fiber

ANTISTATIC AND ANTISOILING FIBERS

These topics are related because the origins of the problems are interrelated. Synthetic fibers
in general, and PET in particular, are hydrophobic materials—PET has a moisture regain of
0.4% at 60% RH. PET fibers are difficult to wet and rapidly build up static electrical charges
by friction because as water effectively leaks away, voltage is produced. It is possible to build
up potentials as high as 50 kV by rubbing a polyester fabric, e.g., by walking on a polyester
carpet when the relative humidity is low (5%). Such a potential, discharged by grasping a
grounded door handle, would give a very unpleasant electric shock. Static charges also lead to
attraction of dust and dirt.
To avoid these problems, the moisture uptake of the polyester should be increased by
combining it with hydrophilic materials that are wash-fast. One additive that has been used
20 Handbook of Fiber Chemistry
repeatedly is polyethylene oxide (PEG), a stable, functional, highly hydrophilic, watersoluble,
and humectant polymer (see below):

HO_CH2CH2O[CH2CH2O__]n_H


The MW can be from a few hundred to many millions. Copolymers of PET with PEG having
a molecular weight of approximately 500–2000 Da were made, and it was possible to
incorporate permanently enough PEG without drastic reduction of the PET properties to
greatly improve the fiber moisture uptake, but at the expense of severe reduction in the light
stability of dyed fibers [58]. Other processes used a PET=PEG block copolymer in aqueous
dispersion that was padded and baked onto the fiber as a textile finish. This relied on
cocrystallization of the PET segments with the polymer to make the treatment wash-fast
[59]. The most satisfactory technique is probably to make a bicomponent fiber with a thin
coating of a PET=PEG copolymer on a PET core in a core–sheath configuration. This does
not affect fiber properties and minimizes the light fastness issue [60].

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