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Those
Terrific Synthetic Fibers!
Are
you one of the adults today with fond memories
of E.B.
White's Charlotte's Web?
Don't worry, you're not alone. And believe
it or not, this really does tie in with fabric
and textile care.
There was
a pig named Wilbur, and a girl named Fern who
loved him very much. Trouble was, Wilbur
was destined for the table... if you know what
I mean... and Fern was most distressed about
it, as were the other animals around the barnyard
(well, most of them.) Wilbur was friendly,
and one of the animals he'd befriended was Charlotte,
the spider who spun webs in the corner of his
pen. Together with the sometimes-reluctant
help of other animals, she got hold of fancy
words that described Wilbur, and spun them in
her web -- "Terrific," she wrote, and "Some
Pig."
Suddenly,
Wilbur wasn't destined for the table, he was
off to the state fair, where he won so many
blue ribbons for his miraculous signs that he
never had to worry about breakfast, lunch or
dinner (his or anyone else's) again.
The fiber
that saved the day for Wilbur may eventually
save the day for many of us. It was Spider
Silk. Unlike silkworms and their cocoons
which can be unraveled by machines, it is very
impractical to try to "harvest" spider silk.
Who
wants it?
Everybody!
The fact is that Dragline Silk (the heavier
lines you see in a spider web that go out like
spokes in a wheel) is strong stuff. It's
stronger than Kevlar, the material used in bullet-proof
vests -- and Kevlar is several times stronger
than steel. Spider
Silk is estimated to be five times stronger
than steel and yet it stretches (twice the elasticity
of nylon) and is waterproof.
There's nothing else like it, and no limit to
the kinds of things that could be made with
it if a synthetic version can be engineered.
How
do they do that?
It's called
a bioengineered polymer. Scientists mix
the genes that are involved in spider silk production
with a bacteria (like the dreaded but useful e.
coli ) and the bacteria clones itself,
producing the desired protein to make our own
spider silk in labs. It's complicated,
of course, using recombinant DNA technology
that you'd never expect to have applications
to this kind of thing, but it should work eventually.
It's been discovered that spider silk is made
up of the two simplest amino acids, and if aligned
correctly, they give spider silk its strength.
And
this relates to real life how?
We've been
copying the spider for almost 100 years.
Modern synthetic fibers are created by extruding
either a liquid or a solid through something
that looks like a shower head (but with much
smaller holes, of course) and it's called a
Spinneret -- just like spiders.
Some synthetic
fibers are made by "spun solution", which involves
having the textile substance mixed with a solution
and forced through the spinnerets. The
solvent evaporates, leaving the fiber.
This is how we get
Rayon and Orlon. Another
method is to force a molten mass through
spinnerets, resulting in Nylon
and Dacron. Coloring of
the fibers is often done before the extrusion
process, so the fibers come out whatever color
was added to the mix. This is why they
don't take dye well later, as you know if you've
ever tried to home-dye a garment with a cotton
blend exterior, but nylon thread and lining.
What a mess!)
The
third method produces the "glamour" fibers,
and is called "flash spinning."
It is also a solution process, but the solution
is taken away in a flash at high temperature
and pressure. This creates a web of randomly
oriented interconnected filaments. One
product you're no doubt familiar with is Tyvek
(R) --
as fabric or packaging. Kevlar
(R) is
made this way, as is fire and heat-resistant
Nomex (R),
which is used in protective clothing for firefighters.
(These are classified as glamorous because of
the uses to which they are put.)
What's
next?
We've only
been experimenting with man-made fibers since
1910 when Rayon was invented. The first
totally synthetic fiber was Nylon, in 1939 (made
directly from petrochemicals, not using fiber
from plants as original Rayon was made.)
We haven't even achieved the Spider Silk breakthrough.
Yet
there are incredible uses for synthetics on
the horizon, aside from garments.
For instance, offshore drilling platforms utilize
a lot of steel rope and chains to keep the platforms
from wandering or breaking away in high seas.
But work being done now has shown that polyester
cables can do the job with about 70% less "rope"
and a great deal less weight. Such
ropes may eventually anchor such exotic things
as floating airports and traveling hotels much
like cruise ships -- but bigger.
Caring
for Synthetics
When synthetics
first hit the market, it was a real breakthrough
for the American consumer. Less ironing!
Faster drying! Less wrinkling! And
those claims had to be repeated in ads many
times, because in the '60s, clothes didn't come
with care labels. The government stepped
in to mandate them, to reduce consumer confusion.
Synthetic
fibers have come a long way since then. The
old wash-and-wear mentality has sometimes given
way to more intricate cleaning instructions. If
you want to keep your synthetics looking great,
read the care label. We
do. (It's the #1 secret of textile
care professionals.) The labels are required
to be accurate, so you can depend on them to
give you a method of cleaning the garment or
home textile safely. |
