Bamboo Fiber Production Process

By Eman Abdallah Kamel

Eman is a writer and engineer. She received her bachelor’s degree in textile science from the College of Applied Arts.

Bamboo fiber is an environmentally friendly, recycled cellulose fiber. In this article, you will learn about the manufacturing process of bamboo fiber.

Image source: istockphotos.com

Bamboo Fiber

Bamboo fiber is a recycled cellulose fiber. Pests rarely feed on its fibers, nor are they susceptible to pathogens. Bamboo fiber has high tensile strength but a low modulus of elasticity. Bamboo is a valuable, multipurpose crop that belongs to the family Bambooceidae.

A bamboo plant grows naturally without pesticides. Bamboo plants are characterized by their robust structure and extremely rapid growth, yielding within 4 to 5 years of planting. This plant can reach a height of 60 meters in just three months. Bamboo is primarily produced in Asia and in Central and South America.

There are currently technologies that help to use bamboo fibers in a wide range of textile applications. Examples include shirts, trousers, and socks, as well as bedding such as sheets and pillowcases. Bamboo fibers can also be blended with other textile fibers, such as hemp.

What is cellulose?

Cellulose is an organic compound with the chemical formula (C6H10O5)n. It is a polysaccharide consisting of a linear chain of hundreds to thousands of D-glucose units linked by β(1→4) bonds. Cellulose is an important structural component of the cell walls of green plants. Cellulose is the most abundant organic polymer on Earth. Cotton fibers contain 90% cellulose, wood 40-50%, and dried hemp about 57%.

Why Bamboo Fiber

Bamboo possesses numerous beneficial properties for producing eco-friendly textiles.

Its rapid growth (100-250 cm/day or 39-98 in/day) produces a significant amount of bulk for fiber processing.
Its robust root system eliminates the need for replanting, and its antibacterial properties reduce the need for pesticides and fertilizers.
Bamboo plants, typically between 6 months and 3 years old, can be harvested for fiber extraction, yielding ten times the amount of fiber per unit area.
Textiles produced from mechanically extracted bamboo fibers are uniquely breathable, comfortable to wear, moisture-wicking, and antibacterial.
Bamboo fibers can absorb moisture and dry quickly.
It has anti-static properties and the ability to provide warmth.
Another distinctive characteristic attributed to naturally produced bamboo fibers is their natural, silky sheen.
Bamboo fibers have excellent dyeing properties and colorfastness.

Production Process

There are 4 ways to extract bamboo fibers.

Mechanical Treatment
Chemical Treatment
Combined Treatment
Enzymatic Treatment

1. Mechanical Treatment

Mechanical processing can be carried out in two ways:

A series of mechanical operations: In the general mechanical process, bamboo strips prepared from bamboo stalks are immersed in water for 3 to 7 days, or they can be boiled for 10 to 15 hours at 90°C. The strips are then beaten to separate the fibers from the outer green layer. Suitable bamboo fibers for spinning can be obtained by repeatedly scraping with sharp-edged tools.
A Steam Explosion: A steam explosion chamber can be used to quickly separate the fibrous and non-fibrous parts of a bamboo stalk. This method is used in biomass production and has been proposed as a means of producing bamboo fibers, particularly for use in composite materials. However, few studies have been conducted using steam explosion to extract spinnable fibers for textile production.

Did You Know?

In one study, steam explosion was carried out by a batch reactor at 205°C and 17 bar for 5 minutes, after which the fibers were washed with water. The researchers were able to extract bamboo fibers ranging in length from 5 to 135 mm from two distinct bamboo species. The variation in bamboo fiber length is an issue that must be addressed if consistent fibers are required for yarn spinning.

2. Chemical Treatment

Bast fibers are extracted using caustic chemicals such as sodium hydroxide (NaOH), sodium triphosphate (Na₅P₃O₁₀), sodium sulfate, sodium carbonate (Na₂CO₃), sodium hydrogen phosphate (Na₂HPO₄), sodium silicate (Na₂SiO₃), and sodium citrate.

In this process, bamboo sheets are cut into strips that are treated with a 1–4% sodium hydroxide solution for 7–12 hours at 70–80°C. This is followed by washing, neutralization, and drying to obtain the final fiber.

Advantage,

The cost of equipment and energy consumption is lower, and the fiber properties can be controlled. Consequently, chemically extracted bamboo fiber is significantly cheaper than mechanically or biologically produced fiber.

Disadvantage,

Bamboo’s antibacterial properties, strength, and UV resistance cannot be preserved using this method.
This process produces highly acidic wastewater, necessitating neutralization with a range of other strong chemicals, such as sulfuric acid, hydrochloric acid, nitric acid, and carbon dioxide. Carbon dioxide is considered the optimal choice for pH control due to its low environmental impact and cost.

To maximize yield, it may be beneficial to use multiple processing methods at different stages of bamboo fiber extraction.

3. Combined Treatment

Combining pre- or post-treatment of bamboo fibers with chemicals or enzymes with steam blasting (explosion) is one type of integrated processing for fiber production. In 2013, fibers were extracted using semi-automated mechanical processing (beating and crushing), enzymatic treatment, a series of water washes, and hydrogen peroxide bleaching. The resulting fibers were used to prepare NM10-NM401 yarns through sorting, carding, double carding, and cleaning. Sometimes, steam blasting is used, followed by treatment of the extracted fibers with alkalis for cleaning and hydrogen peroxide for bleaching.

4. Enzymatic Treatment

Biological treatments are typically applied to cellulose fibers in two different ways: exposure to appropriate enzymes or microbial culture.

1. Enzymes include,

Hemicellulase,
Pectinase,
Xylanase.

Lignin-oxidizing enzymes such as

Manganese peroxidase,
Lignin peroxidase,
Lactase.

Remember

Fibers collected using enzymatic methods are coarse and cannot be easily spun without further processing.

2. Microbial Culture

In this technique, microbial cultures, such as white mold fungi, are added to plant material. Microbes consume the plant’s resinous parts and secrete enzymes that break down lignin, hemicellulose, and pectin into water-soluble molecules, while leaving cellulose unaffected, thereby promoting fiber extraction. In this method, time, temperature, oxygen, and pH all play important roles during the fermentation process. Time, temperature, oxygen, and pH are all crucial factors in this fermentation method.

Did You Know?

Microbial culture is a slow and laborious process that produces coarse, stiff fibers that are difficult to spin. As a result, despite its environmental benefits, microbial cultivation is not economically viable.

Sources

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