Bast fibre
Bast fibre (fiber) or skin fibre is
fibre collected from the Phloem (the "inner bark" or the
skin) or
bast surrounding the stem of a certain, mainly dicotyledonic,
plants. Most of the technically important bast fibers are
obtained from herbs cultivated in agriculture, as for instance
flax, hemp or rhamie, but also bast fibers from wild plants, as
stinging nettle, and trees as the lime tree, have been used to
some extent. Since the valuable fibers are located in the
phloem, they must often be separated from the xylem material
("woody core"), and sometimes also from epidermis. The process
for this is called
retting, and can be performed by microoganisms either on
land (nowadays the most important) or in water, or by chemicals
(for instance high pH and chelating agents) or by pectinolytic
enzymes.
In the phloem bast fibers occur in bundles that are
glued together by pectin and calcium ions. More intense retting
separate the fiber bundles into elementary fibers, that can be
several cm long. The bast fibres have often higher
tensile strength than other kinds, and are therefore used
for textiles (not seldom very exclusive textiles, sometimes in
blends with cotton or synthetic fibers)
ropes,
yarn,
paper,
composites and
burlap. A special property of bast fibers are that the fiber
contain a special structure, the fiber node, that
represents a weak point. Fiber nodes seems not to be present in
seed hairs as cotton.
Examples are:
-
Jute
-
Industrial hemp
-
Flax (Linen)
-
Ramie
-
Kenaf
-
Roselle Hemp
-
Rattan
-
Soybean fibre
-
Okra fibre
-
Vine fibre
-
Banana fibre
Use of bast fibre
Bast fibres are processed for use in carpet
yarn,
rope,
geotextile (netting or matting), traditional
carpets,
hessian or burlap,
paper,
sacks, etc. Bast fibers are also used in the non-woven,
moulding, and composite technology industries for the
manufacturing of non-woven mats and carpets, composite boards as
furniture materials, automobile door pannels and headliners,
etc. From prehistoric times through at least the early 20th
century,
Bast shoes were woven from bast strips in the forest areas
of Eastern Europe.
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