Bamboo Fiber || Properties || Processing || Applications

Amartya Ojha

Department Jute and Fibre Technology

Institute of Jute Technology,

University of Calcutta

Introduction

Bamboos are evergreen perennial flowering plants in the subfamily bambusoideae of the grass family. The word "bamboo" comes from the Dutch or Portuguese languages, which probably borrowed it from Malay.

Bamboo is one of the fastest growing plants in the world, due to a unique rhizome dependent system. Certain species of bamboo can grow 910 mm (36 in) within a 24-hour period, at a rate of almost 40 mm (1 1⁄2 in) an hour (a growth around 1 mm every 90 seconds, or 1 inch every 40 minutes).Giant bamboos are the largest members of the grass family.

As a fibre, bamboo is a natural cellulosic regenerated biodegradable environment friendly textile material. Not only a green fibre but it has also inherent property of anti- bacterial and UV protective property, which makes it a unique ecofriendly textile material in 21^st century.

It is not only used in conventional textile but also it is very useful for high performance end uses as a composite material due to high tensile strength, durability, stability.

Morphological Structure of Bamboo

Bamboo is bast fibre like jute, flax, ramie etc. Main components of bamboo are:

Rhizomes
Roots
Culms
Branches
Leaves
Flowers

Microscopic Appearance

longitudinal view

Cross Sectional view

Chemical Composition

Bamboo is a lingo-cellulosic bast fibre. Chemical composition and properties are similar to the other bast fibres like jute, flax. It contains cellulose(70-74)%, hemicellulose(12-14)%, lignin(10-12)%, extractives like protein, pectin,wax (2-3)%.

Polymeric Structure

Bamboo Fibre Processing

There are two manufacturing methods of bamboo fibres:

Chemical Process
Mechanical Process

Depending upon the type of fabric bamboo fibre can be produce two different chemical methods. Majority of the bamboo fibres are produced by viscose rayon processing method. Which is cheap to produce but it has some environmental downside. Actually this method is regenerated or semi synthetic fibre processing method.

Rayon Processing Method Wet Spinning:

Bamboo culms are extracted and crushed
Crushed bamboo is soaked in a solution of 20% NaOH at a temp of 20℃ for 3 hours to form alkali solution
Soda cellulose is crushed by a grinder and left to dry for 24 hours.
CS₂ is added to the soda cellulose to sulphurize the compound and become jelly
Remaining CS₂ is removed by evaporation & formation of Sodium Cellulose Xanthate
NaOH is added with sodium cellulose xanthate dissolving it to create a viscose solution consisting of about 5% NaOH and 7% to 15% bamboo fibre cellulose.
Then the highly viscous bamboo solution is forced through the spinneret nozzles into a large container of a diluted H₂SO₄solution.
It solidifies into the fibre which is spun into the fibre.
Carbon disulphide (CS₂) is a neurotoxin, and it also causes organ damage. Workers who are exposed to this chemical can develop psychosis, liver damage, coma, and blindness, and this chemical can also cause heart attacks.

Simplified Stages

Close loop solvent spinning process:

It is also known as Lyocell type spinning process. It is an eco-friendly process also. Unlike the process used to viscose rayon, closed loop rayon production does not chemically alter the structure of cellulose that is used, used results in a fabric purely organic. While solvent used to make traditional viscose processing is wasted and usually end up in a biosphere, the solvent (n-methylmorpholine n-oxide) used in closed-loop rayon production can be reused (99.5%) again and again.

Process sequence

Mechanical Process:

Bamboo fabric of the highest quality is made with production practices that do not extract cellulose. Instead, a natural enzyme is used on crushed bamboo wood fibers, and these fibers are then washed and spun into yarn. This yarn usually has a silky texture, and the fabric made by this process is sometimes called bamboo linen. It is actually true natural bamboo fibre processing.

When bamboo fabric is made with this method, it is not environmentally harmful, and the resulting textile is strong and long-lasting. However, most types of bamboo fabric are not made with this mechanical process; to ensure that you're getting high-quality bamboo fabric, make sure that it is manufactured with a mechanical rather than a chemical process.

Properties of Bamboo Fibre:

Table of physical Property of bamboo fibre

S/No	Properties	Data
1	Dry tensile strength (cN/dtex)	2.33
2	Wet tensile strength (cN/dtex)	1.37
3	Dry elongation at break (%)	23.8
4	Linear density (% deviation)	1.8
5	Percentage length deviation	1.8
6	Over length staple fibres (%)	0.2
7	Whiteness (%)	69.6
8	Moisture region	13.03
9	Oil content	0.17

(Note: Test done at 20 °C and 65% RH).

Advantages of Bamboo Fibre:

Green and eco-friendly:

Bamboo fibre can be processed through regenerated or natural process. As it is 100% cellulosic it is bio degradable in nature. Bamboo fibre decomposes without causing pollution. "Bamboo fiber comes from nature, and completely returns to nature in the end". As a green textile material bamboo has a great advantage over other natural textile materials. Bamboo can be grown without the use of pesticides, which together with other factors such as fast growing rate and low water consumption makes it a sustainable raw material for textiles.

Soft & Breathable:

Bamboo fibre is finer & softer than cotton. Cross section of bamboo fibres are filled with micro gaps and micro pores. So it has better moisture absorption and ventilation. In summer bamboo fabric can evaporate sweat from human body very fast just like breathing, such types garment gives aesthetically pleasant and cool to the human body. According to authoritative testing figures, apparels made from bamboo fibers are 1-2 lower than normal apparels in hot summer. Apparel made from bamboo fiber is crowned as Air Conditioning Dress.

Natural Anti-Bacterial Property:

Many scientists prove that bamboo fibre has inherent natural antibacterial property. Bamboo viscose made fabric had significant effect on odor of body sweat. There are claims that bamboo viscose fabrics have a unique antibacterial quality, due to an antimicrobial bio-agent called "bamboo Kun". Kun is found naturally in the living bamboo fibre. Due to the ‘Kun’ bamboo fabric is sometimes said to be naturally antibacterial, antifungal and odor resistant.

UV protection property:

Bamboo made fabric has UV absorption property. It protects human skin from UV rays. It can be used as a dress material of pregnant women and children.

Uses of bamboo yarn & fabric:

Intimate Apparel uses:

Under garments including socks, bath suit, under wear, towel etc.

Sanitary purpose & medical uses:

Sanitary materials: bandage, mask, surgical cloths, nurses wear and so on. It has incomparably wide foreground on application in sanitary material such as sanitary towel, gauze mask, absorbent pads, and food packing.

Due to its anti-bacterial nature, non-woven fabric has wide prospects in the field of hygiene materials such as sanitary napkin, masks, mattress, food-packing, bags.

UV resistant product:

Due to its’ UV resistant property, it is used for making of apparel of pregnant women and children.

Household uses:

Television cover, wall-paper and sofa slipcover.

Demand & cost of bamboo fabric

Viscose or similar semi-synthetic fabrics made from this type of wood are generally less expensive than cotton. In some cases, this decreased cost is passed on to the consumer. Genuine bamboo fabric that is made using mechanical methods, however, is almost always more expensive than cotton, but it may be more affordable than forms of luxury cotton like Egyptian cotton, Pima cotton etc.

Conclusion

Bamboo fibre has already gained popularity in textile market due its’ aesthetic property, fineness, flexibility, inherent antimicrobial property, UV resistant property. Moreover it is an ecofriendly green textile material which would be future of 21^thcentury for sustainable textile solution.