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 24 hours, at a rate of almost 40 mm (1 1⁄2 in) an hour (growth of around 1 mm every 90 seconds, or 1 inch every 40 minutes). Giant bamboos are the largest members of the grass family.

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

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

Morphological Structure of Bamboo

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

Polymeric Structure

Bamboo Fibre Processing

There are two manufacturing methods for bamboo fibers:

Chemical Process
Mechanical Process

Depending upon the type of fabric bamboo fiber can be produced by two different chemical methods. The majority of the bamboo fibers are produced by the viscose rayon processing method. Which is cheap to produce but it has some environmental downsides. Actually, this method is a regenerated or semi-synthetic fiber 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 an 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
The 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 fiber 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 fiber 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 of spinning process. It is an eco-friendly process also. Unlike the process used for viscose rayon, closed-loop rayon production does not chemically alter the structure of the cellulose that is used, resulting in a fabric that is purely organic. While the solvent used to make traditional viscose processing is wasted and usually ends 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 fiber 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	Overlength staple fibers (%)	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 fiber can be processed through a regenerated or natural process. As it is 100% cellulosic it is biodegradable in nature. Bamboo fiber 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 fiber is finer & softer than cotton. Cross sections of bamboo fibers are filled with micro gaps and micropores. So it has better moisture absorption and ventilation. In summer bamboo fabric can evaporate sweat from the human body very fast just like breathing, such types of garments give aesthetically pleasant and cool to the human body. According to authoritative testing figures, apparel made from bamboo fibers is 1-2 lower than normal apparel in hot summer. Apparel made from bamboo fiber is crowned as an Air Conditioning Dress.

Natural Anti-Bacterial Property:

Many scientists prove that bamboo fiber has an inherent natural antibacterial property. Bamboo viscose-made fabric had a significant effect on the 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 fiber. The ‘Kun’ bamboo fabric is sometimes said to be naturally antibacterial, antifungal, and odor-resistant.

UV protection property:

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

Uses of bamboo yarn & fabric:

Intimate Apparel uses:

Undergarments including socks, bath suits, underwear, towel, etc.

Sanitary purpose & medical uses:

Sanitary materials: bandages, masks, surgical cloths, nurses wear, and so on. It has an incomparably wide foreground on application in sanitary materials such as sanitary towels, gauze masks, 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 napkins, masks, mattresses, food-packing, and bags.

UV-resistant product:

Due to its UV-resistant properties, it is used for making apparel for pregnant women and children.

Household uses:

Television cover, wallpaper, 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 fiber has already gained popularity in the textile market due to its aesthetic properties, fineness, flexibility, inherent antimicrobial properties, and UV-resistant properties. Moreover, it is an eco-friendly green textile material that would be the future of the 21stcentury for sustainable textile solutions.