Long Way Education

By Eman Abdallah Kamel

The fibers made from bamboo are natural, eco-friendly, and non-toxic. This article will discuss the chemical composition of bamboo fibers, the manufacturing process, properties, dyeing, and care of bamboo fibers

Bamboo

Bamboo is the fastest-growing plant on earth. Some types can grow up to 1 meter per day. Bamboo is a grass belonging to the Gramineae family. Bamboo grass grows from 1 foot (30 cm) to huge bamboo plants that can grow to over 100 feet (30 m). Bamboo plants are found in all regions around the world. It plays an important economic and cultural role.

Bamboo is classified according to its root types. Some types, called runners, are widely spread, while others are classified as sympodial, meaning they gradually expand from the original point of cultivation. Various types of root systems are a mixture of these types.

Generally, there are about 1,200 bamboo species in about 90 genera. Taxonomists are still debating the number of bamboo and ethnic species due to the long cycles of flowering plants.

Bamboo is not only used for furniture, construction, and musical instruments, but it is also used in the textile industry.

Bamboo fiber is extracted from bamboo stems via a hydrolysis-alkalization process and multiphase bleaching. There is an increasing interest in bamboo clothing among modern luxury fashion brands due to its silky feel and environmental benefits.

China and India are the two bamboo distribution centers in the world. The region includes 80 percent of the world’s bamboo species and 90 percent of the total area of bamboo forests.

The Netherlands, Britain, France, Germany, and other European countries began to grow bamboo. The plant also spreads rapidly to Africa and America.

A Brief History of Bamboo

In the cultures of China and Southeast Asia, bamboo has deep roots. The Chinese have been cultivating and using bamboo for 7,000 years. It was used for food, clothing, transportation, housing, musical instruments, and weapons. The first Chinese books were made of bamboo strips placed on strings. The oldest record of U.S. patents regarding bamboo fibers dates back to 1864, by Philipp Lichtenstadt. His idea was to introduce a new and useful process for breaking up bamboo fibers for use in making ropes, cloth, mats, or paper pulp.

In 1881, another patent included blending bamboo fibers with wool, but it did not go into mass production for reasons that might include ineffective or expensive processing methods.

In the early 2000s, Peking University released the results of converting bamboo fiber into usable fabric.

In 2002, Hebei Jigao Chemical Fiber Co., Ltd. manufactured renewable cellulosic bamboo.

Chemical Structure of Bamboo Fiber

A single bamboo fiber has a round cross-section with a small lumen. Bamboo has high breaking strength and good absorbency, but it has low elongation.

Bamboo is mainly composed of

1. Cellulose,
2. Hemicellulose,
3. and lignin.

Secondary components of bamboo include,

1. Resins,
2. Waxes,
3. and inorganic salts.

Besides cellulose and lignin, bamboo also contains other organic components. It contains about 2% oxidant polysaccharide, 2–4% fat, 2–6% starch, and 0.8–6% protein.

Bamboo’s carbohydrate content is a major factor contributing to its durability, and its chemical composition influences its resistance to mold and fungi.

Bamboo Fiber Properties

Bamboo fibers have a range of good properties, including

• Softness: Bamboo fiber is a renewable cellulose fiber, so it is as soft and healthy for the skin as cotton.
• Antibacterial: Pathogens rarely infect bamboo, and pests seldom eat it because it has a biological agent known as bamboo kun and an antibacterial substance.
  This substance binds tightly to the bamboo cellulose molecule during the bamboo fiber production process.
• Luster: Like silk, bamboo fiber has a beautiful color and luster.
• Moisture absorption: Bamboo fiber exhibits excellent absorbency and ventilation due to its cross-section, which is full of various micro-gaps and small holes. This gives a feeling of comfort, especially on hot summer days.
• Ultraviolet: There are many opinions about this property. At the 235th national meeting of the American Chemical Society, Appidi and Sarkar of Colorado State University stated that the raw bamboo fabric allows nearly all harmful UV rays to pass through and reach the skin. On the other hand, the viscose bamboo industry in China found that 100% bamboo fabrics did not allow ultraviolet rays to pass when the UV fabric test was completed using the GB/T 18830-2002 test method (Bambro Tex 2008).
• Durability: Bamboo fiber is as durable as jute fiber.
• Anti-static: Bamboo fiber has no free electrons. So it is anti-static and does not stick to the skin.
• Dyeing Ability: Bamboo fiber has good dyeing properties and colorfastness.
• Eco-friendliness: Textiles made from bamboo fiber are biodegradable. It can be 100% decomposed in the soil by microorganisms and sunlight.

Did You Know?

Japan Textile Inspection Association proved that even after 50 rounds of washing, bamboo fiber fabric still has an excellent anti-bacterial function.

Manufacturing Process of Bamboo Fiber

The processes for producing regenerated bamboo fiber are

• Mechanical,
• Chemical,
• Biological,
• Combined treatments.

1. The Mechanical Process

During mechanical processing, harvested and crushed bamboo wood is treated with enzymes that break down the bamboo into a soft material. Natural fibers are mechanically combed into individual fibers and then spun into yarn.

The fabric made through this process is often called bamboo linen. Chemicals are not used in this process. So it is environmentally friendly.

2. The Chemical Process

In the chemical process, bamboo leaves and inner cores are extracted from bamboo and crushed together to make bamboo cellulose. After that, the bamboo cellulose is soaked in a solution of 18% sodium hydroxide (NaOH) for 1 to 3 hours at 20°C to 25°C to form alkali cellulose. Alkaline cellulose is pressed to remove any excess sodium hydroxide. Then the alkaline cellulose is crushed by a mill and left for 24 hours to dry. Next, carbon disulfide (CS₂) is added to the alkaline cellulose mixture.

Bamboo cellulose, sodium hydroxide, and carbon disulfide mixtures are decompressed to remove carbon disulfide, resulting in cellulose sodium xanthogenate. A diluted sodium hydroxide solution is added to the cellulose sodium xanthogenate to dissolve it into a viscous solution. 

Through spinneret nozzles, the viscose bamboo cellulose is forced into a large container of the dilute sulfuric acid solution to harden the viscose bamboo cellulose sodium xanthogenate and convert it into bamboo cellulose fiber threads. Bamboo fibers are then spun into yarns to be woven into a fabric.

Did you know?

In chemical processing, chemicals like carbon disulfide and sodium hydroxide are used, which can pollute the environment as a result of chemical reactions. Also, some polluting chemicals are used, such as zinc, which makes the process harmful to the environment. Thus, research is underway to find more sustainable ways to obtain better-regenerated bamboo fibers.

3. Biological Treatment

Biological treatments are generally applied to cellulose fibers in two ways: exposure to appropriate enzymes and the use of microbial culture.

Enzymes such as hemicellulase, cellulase, pectinase, and xylanase are used to extract bamboo fiber. According to an article written on researchgate.net, these enzymes dissolve binding materials in bamboo fibers, such as lignin and pectin.

Pre-treatment with autoclave after splitting bamboo stalks can increase protein absorption and enzyme permeation, and as a result, there is greater weight loss by lignin removal to produce soft and spinnable fibers.

Microbial cultures, such as white mold fungi, are introduced into plant material. These microbes consume the plant’s resinous parts and secrete enzymes that convert lignin, hemicellulose, and pectin into water-soluble molecules. The cellulose remains intact, facilitating fiber extraction.

4. Combined Treatment

One type of integrated processing for fiber production is the use of chemicals or enzymes to pre- or post-treat bamboo fibers, followed by steam explosion. Steam blasting is sometimes followed by cleaning the extracted fibers with alkalis and bleaching with hydrogen peroxide.

Bamboo Dyeing

Reactive dyes are preferred for bamboo fibers; the alkali content should not exceed 20 g/L, and the temperature should not exceed 100°C. During the drying process, a low temperature and light tension should be applied.

Bamboo Fiber Uses

Among the many uses of bamboo fibers are bathrobes, towels, bedsheets, underwear, T-shirts, socks, sweaters, summer clothes, mats, and curtains.

Furthermore, bamboo non-woven fabrics are used to make sanitary napkins, masks, mattresses, food packaging bags, and surgical clothing.

Bamboo Fabric Care

1. You can use a gentle wash cycle or handwashing. As well as a good brand of mild soap.
2. Because chlorine bleach yellows colored fabrics, you can use oxygen bleach.
3. It is preferable to dry the bamboo fabrics in the sun. You can also use a low-temperature drying cycle because over-drying can damage the fabrics.
4. The bamboo fabric is easier to iron when it’s slightly damp. Use a dry iron on low heat because high temperatures can burn the bamboo fibers.

Sources

• fao.org... World bamboo resources: A thematic study prepared in the framework of the Global Forest Resources Assessment 2005.
• patents.google.com… Bamboo Fiber and Its Manufacture.
• EcoPlanet Bamboo aims to make alternative timber big business | GreenBiz. As anti-deforestation efforts ramp up, one bamboo supplier aims to take the industry from a “hippie business” to a serious, industrialized option for Fortune 500 companies.
• researchgate.net… Production of natural bamboo fibers experimental approaches to different processes and analyses.

©Eman Abdallah Kamel, 2022

About the author: Eman is a writer and textile engineer. She received her bachelor’s degree in textile science from the Faculty of Applied Arts, Egypt.

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