Bamboo textiles | History, characteristics, environmental impact, benefits

Plant fiber has always been a clear contributor to economic prosperity and sustainability in our lives because of its application in almost everything we use in our daily routines. There is a growing demand for more comfortable and eco-friendly products and to satisfy them, textile researchers are focusing on renewable and biodegradable sources and eco-friendly processes. Among natural fibrous plants, bamboo is by far the most popular, due to its versatile application and its significant contribution to the environment.

Bamboo textiles

Bamboo textiles are any fabric, yarn, or garment made from bamboo fiber. Although historically used only for structural elements, such as bustles and corset ribs, various technologies have been developed in recent years that allow bamboo fiber to be used for a wide range of textile and fashion applications. Different textile products are made from bamboo fabric like shirt tops, pants, and socks for adults and children, as well as sheets and pillow covers. Bamboo yarn can be mixed with other textile fibers such as hemp or spandex.

Bamboo is an alternative to plastic that is renewable and can be replenished at a faster rate. Modern clothing labeled bamboo is usually made of viscose rayon, a fiber that dissolves cellulose in bamboo and is then extracted to make fiber. This process removes the natural properties of bamboo fiber, making it identical to rayon from other cellulose sources.

The main components of bamboo fibers are cellulose, hemicellulose, and lignin. The secondary ingredients of bamboo fibers are resin, wax, and inorganic salt. It contains other organic matter besides cellulose and lignin. It contains cellulose(70-74)%, hemicellulose(12-14)%, lignin(10-12)%, and others like protein, pectin, and wax (2-3)%.

History of Bamboo Textiles

Bamboo has a deep connection with the culture of China and Southeast Asia. The Chinese planted and used bamboo about 7,000 years ago. It was used for food, clothing, transportation, shelter, musical instruments, and weapons. Bamboo strips were used as the most important writing medium for materials widely used with silk, animal fur, and other things like stone. The first books in China were made with bamboo strips on strings. The earliest record of a U.S. patent on bamboo fiber dates back to 1864 by Philipp Lichtenstadt. His idea was to introduce a useful process for breaking bamboo fibers to be used to make rope, fabric, mats, or paper pulp. In 1881, another patent included blending the bamboo fiber with wool, but it did not go into mass production due to the fact that it could include expensive processing methods. In the early 2000s, Beijing University published the results of the conversion of bamboo fiber into usable fabric. In 2002, bamboo fiber was first made by Hebei Jigao Chemical Fiber Company.

Bamboo textile characteristics

i. Bamboo fiber has many excellent properties that make it ideal for textile processing. This makes it breathable and cool to wear. It is incredibly hydrophilic, absorbing more water than other conventional fibers such as cotton and polyester.

ii. It is very durable to grow because it does not require the use of pesticides and grows very fast under favorable conditions. Its fabric may have an anti-bacterial property that maintains the fabric, which means the bamboo fabric does not require the use of chemically antibacterial agents.

iii. Bamboo textiles are more antistatic than other types of fabrics and have natural deodorizing properties when it comes to odors.

iv. It has a thin and whitish degree close to ordinary fine-bleached viscose and has strong durability, stability, and firmness.

v. Bamboo fiber textiles are made from bamboo pulp fiber. It is characterized by good hydrophilic properties, excellent permeability, soft feeling, ease of straightening and dyeing, and great coloring effect of pigmentation.

vi. It has strength like steel. It is a soft and beautiful fabric similar to rayon. This durable ingredient has a natural luster and inherent anti-microbial properties that help keep you odorless. Bamboo is an incredibly durable asset because it is fast-growing and resilient.

vii. The bamboo fiber resembles cotton in its unspun shape, light puffball, airy fibers. For making bamboo fiber, the bamboo is heavily pulped until it separates into a thread of thin material of fiber, which can be spun and dyed for weaving into fabric.

How is a bamboo textile made?

When regenerated bamboo viscose fiber is required for end-use, the stems of bamboo should be freed from lignin and hemicellulose. Several techniques such as acid or alkaline pretreatment, wet oxidation, steam pretreatment, and ammonia fiber blasting have been explored by various researchers. The basic idea is to cook bamboo leaves and woody stems in these powerful chemical solvents and then do alkaline hydrolysis combined with multi-phase bleaching. The process is similar to the conventional viscose production process.

i. Chemical process

To make regenerated bamboo or bamboo viscose fibers, hard bamboo stem leaves and inner pith are extracted, crushed, and soaked in sodium hydroxide (NaOH) solution. The alkali cellulose that is formed in the process is pressed by the excess solution to create more area for easy processing of cellulose. Then, the pieces of cellulose are kept open so that it dries in the presence of ambient oxygen. Subsequently, carbon disulfide is added to the cellulose so that gelling occurs; and its excess is removed by evaporation. Later, it is ripened, filtered, degassed, and finally, the bamboo viscose is wet-spun, i.e., through the tip of spinneret nozzles into a dilute sulfuric acid solution, where the cellulose sodium xanthate hardens and is re-converted-to-bamboo viscose. In other words, sulfuric acid behaves like a quenching solution that allows the strands to solidify into the fiber and is, therefore, able to spin into a yarn.

Process sequence-

i. At first, bamboo leaves and inner core are extracted from bamboo and crushed

ii. An alkaline solution is made by soaking crushed bamboo in a solution of 20% NaOH at 20℃ for 3 hours.

iii. Soda cellulose is crushed by a grinder and left to dry for 24 hours.

iv. CS₂ is added to soda cellulose to sulfurize the compound and turn it into jelly

v. The remaining CS₂ is evaporated and removed by making sodium cellulose Xanthate

vi. NaOH is added with sodium cellulose xanthate to make a viscose solution containing about 5% NaOH and 7% to 15% bamboo fiber cellulose.

vii. The high-viscosity bamboo solution is then pressed through the spinneret nozzles into a large container of a diluted H₂SO4 solution.

viii. It hardens into fibers that are spun into yarns.

ix. Then it is weaved into fabric/textile.

ii. Mechanical process

The highest quality bamboo fabric is made with production practices that do not extract cellulose. Instead, a natural enzyme is used in crushed bamboo wood fibers, and these fibers are washed to make yarn. These yarns usually have a silky texture, and the fabric made by this process is sometimes called bamboo linen. When bamboo fabric is made in this way, it is not environmentally harmful and the resulting textile is strong and durable. However, most types of bamboo fabric are not made by this mechanical process.

Bamboo textile's environmental impact

Concerns have been raised about the environmental friendliness of the chemical route of bamboo viscose fiber production. Carbon disulfide is known as toxic, resulting in a threat to factory workers, as well as polluting the environment through air emissions and wastewater. In most industries, its recovery is only about 50 percent. Also, sodium hydroxide and sulfuric acid also fall into the category of potentially hazardous chemicals. One remedy is to choose a process similar to the lyocell process used to make Tencel. Here, N-methyl morpholine-N-oxide is used as a solvent and hard baths are usually water-methanol solutions, both non-toxic. Also, since the process is closed-loop, 99.5 percent of the chemicals used are recycled, emitting only fraction marks in the environment.

However, bamboo fabrics have exploded in the market on the basis of false environmental claims that bamboo is an alternative to cotton, silk, and polyester. Customers were persuaded to spread fraudulent information about bamboo viscose fabric. Furthermore, soft touch and silk-like drapes tempted customers who were unaware of the use of toxic chemicals to process hard cellulose bamboo plants into soft fibers. Considering this information, the US Federal Trade Commission has imposed strict guidelines for manufacturers: A product cannot be labeled as bamboo unless it is made from mechanically processed bamboo. It should be called ‘bamboo viscose’ or ‘bamboo rayon’ if it is made with cellulose reproduced from bamboo stalks.

Bamboo textile benefits

i. Bamboo textile has moisture-wicking properties.  There is no chemically treated garment that can outperform a bamboo piece.  It is naturally moisture-wicking because of the natural bamboo fibers. As bamboo grows in hot and humid climates, the plant can retain moisture and help it grow. Bamboo is the fastest-growing tree in the world and requires a lot of water to grow that fast.

ii. Bamboo textiles are naturally odor-resistant. Because it is not treated with chemicals, natural fibers can prevent odors. Bamboo has antibacterial properties, which allow it to resist mold and mildew, which can otherwise ruin a part of the garment. Bamboo textile clothing will always smell fresh and clean no matter what kind of workout it is facing.

iii. Bamboo textile is naturally UV protective and has a safety rating of 50+ without the use of chemicals and this protection lasts no matter how often it is washed.

iv. Its fabric is hypoallergenic. When we make fabric from bamboo, we don’t have to use chemicals or mix it with lots of heavy synthetic fibers to create the functionality you need from your clothing. For example, you will not find ingredients in bamboo cloth that will irritate your sensitive skin.

v. Its fabric is a climate control wonder. Bamboo fibers are naturally very porous, and there are small gaps between the fibers that allow air to flow freely in and out. This natural ventilation system allows the bamboo fabric to be the best heat-regulating fabric in the world.

vi. It has a positive impact on global environmental concerns such as water scarcity, deforestation, soil erosion, and the greenhouse effect. It is a much more durable textile than cotton available to help create a developed world.