Bamboo Fiber.pdf

Bamboo Fiber
It is a regenerated cellulose fibre. Bamboo is a plant with high cellulose
content in their barks. With suitable technology, the cellulose from the bamboo
barks are extracted and made into fibre. The specialty of this fibre is its natural
antibacterial properties.
The advantages of these fibres are the UV protection capacity, gentle drape,
luxurious softness and antibacterial property which are all inherent. They are
environmentally friendly because the garments using these fibres needs no special
chemical treatments to achieve these properties. The antibacterial properties make
the fibres preferred for under garments, but it is also used for socks, shirts and other
summer clothing’s.
Bamboo Plant and History
Bamboo botanically categorized as a grass and not a tree, bamboo just might
be the world’s most sustainable resource. It is the fastest growing grass and can
shoot up a yard or more a yard. The first patents for bamboo paper occurred in 1864
and 1869. Modern bamboo clothing was first introduced by Beijing University, but
commercial use increased during 2004-2010.
Md. Abdul Alim, Asst. Prof., Dept. of Textile Engineering, KUET. 2

Bamboo Fiber
Features
1. Naturally antibacterial and hygienic effect
2. Biodegradable and sustainable material
3. Breathable and moisture absorbing character
4. Soft and cool fabric hand feel
5. Smooth fabric drape
6. Luxurious and shiny appearance
7. Low tensile strength (wet strength 60% lower compared with dry tensile
strength)
8. Natural UV protection capacity

Bamboo Fiber
Physical parameters:
Dry tensile strength: 2.2–2.4 cN/dtex
Wet tensile strength: 1.2–1.4 cN/dtex
Dry elongation at break: 18–25%
Moisture regain approximately: 8–9%
Test conditions:
Temperature: 20°C
Relative humidity: 65%

Bamboo Fiber
Manufacture
Two types of processing are done to obtain bamboo fibres: mechanical
processing and chemical processing.
Chemical processing is based on hydrolysis alkalization. The crushed bamboo is
‘cooked’ with the help of sodium hydroxide (NaOH) which is also known as caustic
soda or lye into a form of regenerated cellulose fibre. Hydrolysis alkalization is then
done through carbon disulphide combined with multi-phase bleaching. Although
chemical processing is not environmentally friendly, it is preferred by many
manufacturers as it is a less time-consuming process.
In mechanical processing, the crushed bamboo is treated with biological enzymes.
This breaks the bamboo into a mushy mass, and individual fibres later combed out.
Although expensive, this process is eco-friendly.
Bamboo
Bamboo
Sheet
Refined
Bamboo
Pulp
Bamboo
Cellulose
Bamboo
fiber

Bamboo Fiber
Processing
Bamboo fibre being a regenerated cellulosic fibre, it can be processed same
way as the viscose materials. But certain precautions have to be taken due to special
physical and chemical characteristics of the fibre.
Enzyme desizing, moderate bleaching and semi mercerizing should be applied to the
bamboo fabric during its dyeing and finishing process. Avoid drastic conditions and
use small mechanical tension. Bamboo fabric can be signed in moderate condition.
Desizing rate should be over 80%.
Scouring: Pure bamboo normally needs no scouring; sometimes washing with a
little alkaline soap may serve the purpose. The scouring process should be made in
terms, if fibre blend contains cotton. When pure bamboo fabrics are scoured, the
alkali should not be over 10 g/l but can be applied in accordance with the thickness
of fabrics.

Bamboo Fiber
Bleaching/mercerizing: The processing should be made in terms of the
specification and thickness of fabrics. Fabrics of bamboo fibres normally should not
need mercerizing due to their sound luster and poor anti-alkaline properties.
However, in some cases, to increase their absorbance capacity to dyestuff, it can be
mercerized.
Dyeing: Reactive dyestuffs are used during dyeing process – alkali should not be
over 20 g/l; temperature should not be over 100°C. During drying process, low
temperature and light tension are applied. In yarn dyeing, alkali should not be over 8
g/l. Chemically manufactured bamboo rayon has some wonderful properties which
are adored by conventional and eco-aware designers and consumers involved in
towel sector.

Bamboo Fiber
Precautions:
1. Bamboo fibres are sensitive to alkaline conditions hence has to be pretreated at
lower alkali concentrations after trials. To achieve good whiteness, we need
higher concentrations of peroxide than other fibres.
2. Since the fibre is sensitive to alkali, it is preferred to be dyed with cold reactive
dyes (lower alkali requirement).
3. During finishing, it should be bear in mind that the fibre as such has a soft drape,
and the finishing agents has to carefully selected which can enhance the natural
feel unless otherwise required.
4. It has been found that the natural antibacterial properties are reduced during wet
processing. If necessary, they may be supported by antimicrobial treatments.

Bamboo Fiber
Specialties of bamboo fibre
Softness: It has a basic round surface which makes it very smooth. Bamboo fabric is
softer than the softest cotton, and it has a natural sheen like silk or cashmere.
Drape: Bamboo drapes like silk or satin yet is less expensive and more durable.
Bamboo/organic cotton blends are also extremely soft but heavier in weight.
Durability: Bamboo is durable and long wearing fabric. It is very sturdy and does
not spoil easily, even in the most severe conditions or environments.
Skin friendliness: Many people are allergic to natural fibres, such as wool. Bamboo
has had the smallest number of allergic reactions with people barely having any. It is
the best choice for people having allergy or skin problems.
Breathability: Bamboo fibre absorbs and evaporates sweat very quickly. Fabrics
made from bamboo fibre are highly breathable in hot weather and also keep the
wearer warmer in cold season.
Moisture absorbency: Bamboo is naturally cool to the touch. The cross-section of
the bamboo fibre is filled with various micro-gaps and micro-holes leading to much
better moisture absorption and ventilation.

Bamboo Fiber
Anti-bacterial: Pure bamboo fabric has a 99.8% bacterial kill rate. Most of the
varieties of bed sheets do not possess these qualities but bamboo bed sheets possess
specific antimicrobial and antibacterial properties, making them more odor and
bacteria resistant. This is because bamboo itself is highly resistant to the growth of
microorganisms and bacteria. With sweat, dead skin cells, oil and many other things
encountering our bed sheets every day, this reasoning makes the bamboo bed sheets
with antimicrobial properties even more appealing.
UV protection: Bamboo naturally provides added protection against the sun’s
harmful UV rays.
Antistatic property: Due to its high moisture absorption property, bamboo fabric
results in the enhancement of antistatic property.
Eco-friendliness: Bamboo is an environment friendly product. As a regenerated
cellulose fibre, bamboo fibre is made from 100% bamboo through high-tech
process. The whole distilling and producing process in the plant is green process
without any pollution. It produces natural and eco-friendly fibre without any
chemical additive.

Bamboo Fiber
Bio-degradability: As a natural cellulose fibre, it can be 100% bio-degraded in soil
by microorganism and sunshine. The decomposition process does not cause any
environmental pollution. Bamboo fibre is praised as ‘the natural, green and eco-
friendly new-type textile material of 21st century’.
Life span: Bamboo bed sheets are highly long lasting and do not demand any extra
care. They can easily be machine washed and dried. The threads of the bamboo bed
sheets are extremely soft and actually become softer the more they are washed and
the more they are used. This makes bamboo bed sheets an ideal choice for those
individuals who prefer bed sheets that have a longer life.
Cost: The cost differences range from 20% to 40% more expensive than cotton.
Bamboo bed sheets are slightly expensive than the other typical varieties of bed
sheets but their ability to last for a longer duration makes it highly cost-effective in
the long run. The cotton bed sheets begin to feel rougher as they are used but for the
bamboo bed sheets, it is completely opposite.

Bamboo Fiber
Advantages
Apart from above characteristics, bamboo also has the following benefits:
1. The fabric is light and strong.
2. It has the ability to take colors well.
3. It is an anti-fungal and hypoallergenic fabric– even after 50 washes.
4. It dries quickly – about twice as fast as most other fabrics.
5. Perfect travelling clothes – the wrinkles fall right out, so there is no need to iron.
6. Bamboo is less than half the price as compared to cashmere.
Disadvantages
1. Bamboo loses 60% of its strength when wet, so it may not be suitable for
industrial uniforms and washings.
2. It is not ideal for screen printing.
3. Expensive as compared to cotton.

Bamboo Fiber
End uses
Intimate apparels: Sweaters, bath-suits, underwear, tight t-shirt, socks.
Non-woven: Non-woven fabric has wide prospects in the field of hygiene materials
due to antibacterial nature napkin, masks, mattress, food-packing, bags, paper.
Sanitary materials: Bandage, mask, surgical clothes, nurses' wears, sanitary towel,
gauze mask, absorbent pads, and food packing and so on.

Wool Fiber
Wool fiber structure
Cuticle: A protective layer of scales on the outside of the wool fiber. The exposed
edges of the cells face away from the root end so there’s more friction when rub the
fiber in one direction than the other. This helps wool expel dirt and gives it the
ability to felt.
The cells have a waxy coating,
making the wool water repellent
whilst tiny pores in the cuticle
cells allow water vapor to pass
through the wool fiber, making
wool comfortable to wear in all
climates.

Wool Fiber
Cortex: The internal cells which make up 90% of the fibre. There are 2 main types
of cortical cells namely ortho-cortical and para-cortical.
In finer fibres, these two types of cells form in two distinct halves. The cells expand
differently when they absorb moisture, making the fibre bend - this creates the crimp
in wool.
In coarser fibres, the para-cortical and ortho-cortical cells form more randomly so
there’s less crimp. Fibre crimp makes wool feel springy and provides insulation by
trapping air.
Cortical cell: The cortical cells are surrounded and held together by a cell
membrane complex, acting similarly to mortar holding bricks together in a wall.
The cell membrane complex contains proteins and waxy lipids and runs through
the whole fibre.
The molecules in this region have fairly weak intermolecular bonds, which can
break down when exposed to continued abrasion and strong chemicals. The cell
membrane complex allows easy uptake of dye molecules.

Wool Fiber
Fig. Cellular structure of wool fibre (Source: University of Waikato).

Wool Fiber
Fig. Cellular structure of wool fibre.

Wool Fiber
The weak bonds also make this area susceptible to chemical attack, such as
strong alkaline conditions, which is why washing with a pH-neutral detergent is
recommended.
Macrofibril: These are made up of bundles of even finer filaments called
microfibrils, which are surrounded by a matrix region.
Matrix: The matrix consists of high sulphur proteins. This makes wool absorbent
because sulphur atoms attract water molecules. Wool can absorb up to 30% of its
weight in water and can also absorb and retain large amounts of dye. This region is
also responsible for wool’s fire-resistance and anti-static properties.
Microfibril: Within the matrix area, there are embedded smaller units called
microfibrils. The microfibrils in the matrix are rather like the steel rods embedded in
reinforced concrete to give strength and flexibility. The microfibrils contain pairs of
twisted molecular chains.

Wool Fiber
Twisted molecular chain: Within the twisted molecular chains are protein chains
that are coiled in a helical shape much like a spring. This structure is stiffened by
hydrogen bonds and disulphide bonds within the protein chain. They link each
coil of the helix, helping to prevent it stretching.
The helical coil: The smallest part of the fibre – gives wool its flexibility, elasticity
and resilience, which helps wool fabric keep its shape and remain wrinkle-free in
use.
Medulla: In brief, the central cavity inside the wool fibre is called the medulla. It is
generally, in medium and coarse wool fibre. Also, it is not found in fine fibres.

Wool Fiber
The fiber surface of wool is water repellent
▪ The cuticle cells provide a tough exterior, protecting the fibre from damage.
▪ The cells have a waxy coating, making wool water repellent, but still allowing
absorption of water vapour.
▪ The water-repellent surface makes wool garments naturally shower-proof and also
reduces staining because spills don’t soak in easily.
Absorbency creates comfort
▪ When wool absorbs moisture, it produces heat, so if you go from a warm room
into a cold, damp night wearing a wool jersey, the wool picks up water vapour
from the air, keeping you warm.
▪ The reverse occurs when you go back into the warm room – the moisture in your
jersey passes into the atmosphere, cooling you down.
▪ Tiny pores in the cuticle cells allow water vapour to pass through the wool fibre.
▪ This makes wool comfortable to wear in both warm and cool conditions.

Wool Fiber
Arrangement of interior cells creates fibre crimp
▪ There are 2 main types of cell in the cortex – Ortho-cortical and paracortical – and
each has a slightly different chemical composition.
▪ In finer fibres, these cells are arranged in 2 distinct halves. In coarser fibres, the
arrangement is less distinct.
▪ These cells create the crimp in wool. The 2 types of cell expand differently when
they absorb moisture, causing the fibre to bend. When the cells are arranged in 2
halves, there is more crimp, and the more random arrangement in finer fibres and
in coarser fibres creates less crimp, so crimp relates directly to fibre diameter.

Wool Fiber
Fibre crimp affects wool’s properties
▪ The crimp in wool fibres makes it soft and springy to touch.
▪ It also adds bulk and traps a large volume of air between the fibres, giving it good
insulation properties.
▪ Finer fibres with more crimp such as Merino create fabrics that drape better than
coarser fibres.

Wool Fiber
Chemical composition of wool:
Raw wool contains a variety of different chemicals and dirt that must be
removed. These impurities may comprise as much as 60% of raw wool mass. They
include wool wax, suint and a range of vegetable and mineral debris.
Component %
Wool Keratin 45
Wool Wax 18
Suint 10
Water 12
Debris 15

Wool Fiber
Chemical composition of Keratin:
The wool fiber is chiefly composed of a protein called keratin. The basic
composition of wool keratin is more or less same in different types of wool. Wool
keratin contains the following elements.
Elements %
Carbon 50
Oxygen 22-25
Nitrogen 16-17
Hydrogen 7
Sulfur 3-4

Wool Fiber
Physical structure of wool
▪ Raw wool from sheep contains a number of constituents other than the fibre.
▪ The main ones are wool grease, water-soluble material derived from perspiration
(called suint) and contaminants such as dirt and vegetable matter picked up from
the pastures.
▪ Unlike cotton and the majority of synthetic fibres, wool does not have a
homogeneous structure.
▪ Wool fibres have highly complex physical and chemical compositions that have
evolved over millions of years to protect sheep from extremes of heat and cold.

Wool Fiber
Chemical structure of wool
▪ It has been estimated that wool contains more than 170 different proteins.
▪ These are not uniformly distributed throughout the fibre; proteins of different
structures are located in specific regions.
▪ This heterogeneous composition is responsible for the different physical and
chemical properties of the various regions of wool.
▪ The proteins in wool are composed of amino acids; so, called because they
contain basic amino (-NH ) and acidic carboxyl (-COOH) groups.
▪ Individual amino acids differ from each other in the nature of the side group
▪ Of the 22 naturally-occurring amino acids, wool contains 18.
▪ The side groups of amino acids vary in size and can be grouped, according to their
chemical properties: hydrocarbon, which are hydrophobic (water-hating);
hydrophilic (water-loving); acidic; basic; and amino acids that contain sulfur.

Wool Fiber
▪ In proteins, including wool, the amino acids are joined together to form long
polymer chains.
▪ These compounds can be regarded as polyamides because each structural unit is
joined by an amide group. When the polymer chain is a protein however, the
amide repeat unit (-NHCHRCO-) is called a peptide group.

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