Fibers
Dyes
Tannins
Ferry Slik – Economic Botany - UBD
What are fibers?
Threads of plant or animal material,
used to make ropes or lines
Why are they important?
They are used for making
- Textiles
- Paper
- Filling materials
- Baskets and nets
- Ropes
- Mats
How do you get fibers?
Originally: Strips of bark and leaves
Later: Use individual fibers to weave textiles
What is the difference between animal and plant fibers?
Animal fibers are composed of proteins
Hairs, Silk, Feathers
Plant fibers are composed of cellulose
Bark, stems, leaves, fruits, seeds
What is the difference between animal and plant fibers?
Animal fibers
- Sensitive to heat
- Easy to dye
- Attacked by animal pests (moths, silverfish)
- Elastic
- Generally water repellent
Plant fibers
- Not sensitive to heat
- Need elaborate treatment for dying
- Attacked by fungi, molds and termites
- Not elastic
- Generally water absorbant
Vegetable fibers used for textiles
Fiber types
- Seed and fruit fibers
- Soft (or bast) fibers (mostly dicotyls)
- Hard (or leaf) fibers (mostly monocotyls)
Fibers are further divided into
- Those that can be plaited, twined, woven or spun into threads
- Those that cannot (too short, brittle or slippery)
Fiber characteristics
- Look and feel are determined by length (long/short) and structure (flat/round)
- Strength is determined by diameter, cell length, and cell arrangement
- Elasticity is determined by curliness, cell arrangement, and cell number per fiber
- Textile shape (drape) is determined by fiber weight and density
- Endurance is determined by the fiber chemistry
Fiber extraction
Step 1. Retting (bacterial decomposition of plant tissue)
Fiber extraction
Step 2. Washing, drying, rolling and scutching
- Washing removes soft material
- Drying makes the material breakable
- Rolling breaks the woody parts, but does not affect the flexible fibers
- Scutching (beating and scraping) then leaves mostly the fibers
Fiber extraction
Step 3. Hackling (sort of combing) to separate the fibers
Fiber extraction
Step 4 (optional). Bleaching (heating in an alkali solution)
Without bleaching, dying is less effective
Seed and fruit fibers
Seed and fruit fibers
Cotton the most important fiber today!
- Large amount of fiber produced by each plant
- Production is cheap (mechanization is easy)
- Cotton produces fine textiles that dye and withstand washing well
Old World
2n
Gossypium arboreum
Versus
Versus
New World
4n
Each cotton fiber is a single,
long, epidermal seed coat
cell
Seed and fruit fibers
Cotton is originally a perennial (producing flowers & fruits every second year),
but people have bred an annual variety (producing fruits every year)
Cotton is a small shrub, making mechanized harvest easy
Before harvest the crop is usually defoliated with chemicals
The Cotton Gin – The machine that revolutionized cotton production
Seed and fruit fibers
Fiber production
- Mixing of different length fibers
- Plucking and beating with steel spikes to remove debris
- Carding (combing) of fibers
- Weaving fibers into slivers
- Pulling to produce different diameter lines
- Stretching and Spinning
Seed and fruit fibers
Cleaning of cotton threads of waxes and pectins
- Boiling with caustic soda for 8 hours
- Bleaching with hydrogen peroxide
Mercerizing (John Mercer 1844) increases the luster, dye uptake and durability
- Stretch the threads under pressure
- Place in a cold bath of caustic soda for several hours
The fibers will swell and deform, creating more circular, swollen fibers
Seed and fruit fibers
Sizing of cotton threads for increased strength
- Addition of a thick substance (starch or a gel) on the surface of the threads
- This stiffens the thread and makes it more smooth
The sizing materials are washed out after the weaving or garment manufacture
Sanforization (since 1970) prevents shrinkage of cotton after washing
- Based on addition of ammonium that swells the fibers
- The process prevents the shrinking of the fibers after washing
Seed and fruit fibers
Permanent press, to prevent wrinkling in cotton fabrics
- Use of chemicals to cross-link the cellulose polymers of cotton cloth
- The fabric then retains the shape it had when chemicals were applied
This process can also be used to add patterns to cotton fabrics!
Seed and fruit fibers
Coir (coconut fiber)
The fibers found in the
fibrous mesocarp surrounding
the coconut
Coir fibers are longer than
cotton fibers, but still shorter
than most bast or leaf fibers
The best fibers come from the
young fruits
Seed and fruit fibers
Retting takes about 8-10 months
(using brackish water)
Washing and beating to remove all
pulpy remains
The clean pure fibers are spun into
yarns that are used for
- Ropes
- Matting
Seed and fruit fibers
Often old coconut fibers are used, producing
- Short (mattress) fibers for stuffing
- Longer (bristle) fibers for brushes, brooms and rough door mats
Coir is often used for netting as they are salt water resistant
Bast fibers
Bast fibers are also known as soft fibers
(thick walled phloem cells)
Individual fibers can be over 5 m long
Fibers are removed from the stems by Retting
Most bast fibers can be bleached and dyed
Bast fibers
Jute (Corchorus capsularis – Tiliaceae)
After Cotton, the most produced fiber
Primary use is sacking
Jute problems
- Cannot be dyed
- Inelastic
- Rough to the feel
- Disintegrate in water
Jute is still popular because of its ease
of production
Most is produced in India
Bast fibers
Flax (or Linen) (Linum usitatissimum – Linaceae)
The oldest textile fiber used by humans
The plants also yield linseed oil
Flax fibers are
- Smooth
- from 0.3 to 1 m long
- Two to three times as strong as cotton!
Because of its strength, linen is often used for buttonholes and button thread, as well as
hoses and mail-bags.
Linen is less popular than cotton because it
needs Retting, which makes it more expensive
Bast fibers
Hemp (Cannabis sativa – Cannabaceae)
Similar to Linen, but stiffer and with more
dark colour
Hemp fibers are up to 5 m in length
Hemp fibers are generally a bit rough and dark and mostly used for
- Cordage
- Rope
- Canvas
- Sailcloth
- Jeans (Levi’s)…….
Bast fibers
Ramie (Boehmeria nivea – Urticaceae)
Problems
- Difficult production because plants have uneven heights
- Fibers contain gum and pectins
Advantages
- Strong, durable fibers
- Among the longest fibers
- Silky
Used mostly in fabrics that need exceptional strength
Leaf fibers
Leaf fibers are also known as hard fibers
From the phloem in the leaf vascular bundles (veins)
Mostly coming from fast growing tropical monocots
Generally the fibers are too stiff for textiles (hence the name ‘hard fibers’)
Most fibers are between 2 and 4 m in length
Generally used in ropes
Leaf fibers
Sisal & Henequen (Agave – Agavaceae)
From the America’s where the fibers were used
for clothing, while the spines were used as needles!
Fiber production
- Old leaves are cut from the plant
- These are squeezed to pulp
- After washing the fibers are sun dried
These fibers can be dyed, but they also have a nice
natural colour
Agave grows in arid regions were little else can be
grown, and is thus an important crop
Leaf fibers
Abaca (Musa textilis – Musaceae)
The fibers are extracted from the leaf bases (stems)
of the banana trees
Very diverse use:
- Tea bags
- Dollar bills
- Wrappings
- Cigarette filters
- Ropes (water resistant!)
- Clothes
Fiber production like the Sisal
Dyeing and Dye Plants
Primates (including humans) are an exception among
mammals because they can see in colour!
Many plant parts produce dyes, but most of them fade
in the sun or do not adhere to fabrics very well
Mordants
Chemicals (mostly metals) that bind the dye to the fibers
- Iron salts ‘sadden’ colours
- Tin & Chrome salts ‘brighten’ colours
- Copper salts ‘enhance bluish hues’
The Mordants form an insoluble compound with the dye
which is bound to the fibers at molecular level
In ancient time the Mordants would have come from
- Metal vessels in which the dying was done
- Urine
- Dung
Dyeing and Dye Plants
Some famous dye plants
- Henna (Lawsonia inermis – Lythraceae), to dye hair and skin, or wool
- Safflower (Carthamus tinctorius – Asteraceae), for fabrics
Dyeing and Dye Plants
Some famous dye plants
- Indigo (Indigofera tinctoria – Fabaceae), for jeans!
- Saffron (Crocus sativus – Iridiaceae), royal orange-red from the red stigmas!
Dyeing and Dye Plants
Some famous dye plants
- Annato (Bixa orellana – Bixaceae)
- Black logwood (Haematoxylum campechianum – Fabaceae)
Tannins & Tanning
Tannins are secondary plant compounds used
for processing skins into leather
Tannins are present in all plants, but more
common in:
- In plant parts attacked by insects
- Perennial plants
- Evergreen trees
Tannins likely play a role in plant defense
Tanning makes skins resistant to
- Heat
- Water
- Microorganisms
Tannins & Tanning
Steps taken for tanning leather
1. Remove hair from outer surface (Calcium Oxide solution)
2. Combine the skins with tannins in water
3. Add oil or grease to the leather for softness
4. Coating the leather with a layer of gum, resin or wax
Tannins & Tanning
Tannins are still mainly harvested from wild trees such as
Rhuss -Anacardiaceae
Punica garnatum - Punicaceae
Quercus - Fagaceae
Acacia - Fabaceae
Picea - Pinaceae
Rhizophora - Rhizophoraceae