Page 12 - Mario Bigon "The Morrow Guide to Knots"

Polyamide fibers
(commonly known as nylon)
These fibers offer excellent characteristics for rope, as they
combine strength and elasticity, enabling them to absorb
shock loads better than any other material. They do not rot or
float. The fibers can be modified chemically to produce other
products which vary slightly from one another (nylon 6, nylon
66, and nylon 11 ) and are used in climbing rope. Fishing line is
also made of polyamide fibers, as it has to be both tough and
flexible and must allow knots to be made in it and to hold well.

Polyester fibers
Polyester fibers have the best mechanical qualities combined
with low elasticity and so are agood choice for rope to be used
in sailing. They are highly resistant to wear and atmospheric
agents and can be pre-stretched to reduce deformation under
strain. They do not float.

Polyethylene fibers
Ropes made of polyethylene fibers should be avoided. They
are very cheap, but they are not very strong, and they stretch
and slip easily, so they do not hold aknot well. Added to this is
the fact that they are difficult to handle. They are, however,
very resistant to atmospheric agents and also float. They are
used for lifelines on rowboats and rafts, as tow ropes for water
skiing, and as rescue lines.

Aramid fibers
These are the newest of the synthetic fibers used for ropes.
They are manufactured by Dupont under the name Kevlar. The
product has characteristics which are more comparable to
those of steel than to the common synthetic fibers. In fact, this
material does not melt. but decomposes at about 500°C
(932°F) and has a breaking strain equal to that of steel of the
same section, although it is slightly more elastic. It is not very
resistant to light and does not float. It is used to a limited

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