Bamboo, the wonder plant in nature, has many uses which include but not limited to erosion control, watershed protection, soil remediation,environmental greening and medicinal application. Bamboo is an incredibly
Bamboo is a high-yield renewable natural resource: ply bamboo is now being used for wall paneling, floor tiles; bamboo pulp for paper making,briquettes for fuel, raw material for housing construction, and rebar for reinforced concrete beams. Bamboo is a mystical plant as a symbol of strength,flexibility, tenacity, endurance, luck and compromise. Throughout Asia, bamboo has been an integral part to religions ceremonies, art, music and daily life for centuries. Among the earliest historical records, in 2nd century B.C., it was written on green bamboo strips strung together in a bundle with silk thread.Instruments made of bamboo create unique resonance.
Bamboo shoots provide nutrition for million of people worldwide. In Japan, the antioxidant
Many Asian countries overall development policy is to make limited use of natural resources, concentrating on the renewable ones. This policy recognizes the importance of rural activities, such as agriculture,forestry and handicrafts production. Bamboo is involved in all of these. The demand for bamboo is bound to increase over time, particularly for use asfodder and other multipurpose uses. There is ample scope for greater bamboo production, especially in the higher areas where communities are widely dispersed and agriculture is less profitable.
Bamboo fiber and starchy pulp are made from bamboo that grows widely throughout Asian countries. Starchy pulp is a refined product of bamboo stems and leaves through a process of hydrolysis-alkalization and multi-phasebleaching. Chemical fiber factories then process it into bamboo fiber.
Manufacturing process:
There are two ways to process bamboo to make the plant into a textile substrate: mechanically and chemically.
Mechanical process: The woody parts of the bamboo plant are crushed and then natural enzymes are used to break the bamboo walls into a mushy mass so that the natural fibers can be mechanically combed out andspun into yarn. This is treated as an eco-friendly manufacturing process.Bamboo fiber product made from this process is sometimes called bamboo linen.Very little bamboo linen is manufactured for clothing because it is more labor intensive and costly.
Chemical process: Chemically manufactured bamboo fiber is a regenerated cellulose fiber similar to rayon or modal. Chemically manufactured bamboo is sometimes called bamboo rayon because of the manysimilarities in the way it is chemically manufactured and similarities in itsfeel and hand.
Bamboo fiber is chemically manufactured by cooking the bamboo leaves and woody shoots in strong chemical solvents such as sodium hydroxide and carbon disulfide in a process also known as hydrolysis alkalization combined with multi-phase bleaching. This is basically the same process used to make rayon from wood or cotton waste by products. The general process for producing regenerated bamboo fiber using hydrolysis alkalization withmulti-phase bleaching technology is furnished below:
Preparation : Bamboo leaves and the soft, inner pith from the hard bamboo trunk are extracted and crushed;
Steeping : The crushed bamboo cellulose is soaked in asolution of 15% to 20% sodium hydroxide at a temperature between 20 degrees Cto 25 degrees C for one to three hours to form alkali cellulose.
Pressing: The bamboo alkali cellulose is then squeezedmechanically to remove excess sodium hydroxide solution.
Shreeding: The alkali cellulose is mechanically shreddedto increase surface area and make the cellulose easier to process.
Ageing: It is then left to dry for 24 hours. During this process, the shredded alkali cellulose is allowed to stand in contact with the oxygen of the ambient air. Because of high alkalinity, the alkali cellulose is partially oxidized and degraded to lower molecular weights. This degradation is to be controlled to produce chain lengths shorter enough to give proper viscosities in the spinning solution.
Xanthation: Carbon disulfide is added to the bamboo alkali cellulose to sulfurize the compound causing it to jell. Any remaining carbon disulfide is removed by evaporation due to decompression and cellulose sodium xanthate is the result.
Dissolving: A diluted solution of sodium hydroxide is added to the cellulose sodium xanthate dissolving it to create a viscose solution consisting of about 5% sodium hydroxide and 7% to 15% bamboo fiber cellulose.
Spinning: After subsequent ripening, filtering and degassing, the viscose bamboo cellulose is forced through spinneret nozzles into a large container of a diluted sulfuric acid solution which hardens the viscose bamboo cellulose sodium xanthate and reconverts it to cellulose bamboo fiber threads which are spun into bamboo fiber yarns to be woven into reconstructed and regenerated textile product of bamboo.
Eco friendly process to produce bamboo fiber
The chemical manufacturing process used to produce lyocell from wood cellulose can be modified to use bamboo cellulose. The lyocell process, also used to manufacture tencel, uses N-methylmorpholine-N-oxide (NMMO) as a solvent to dissolve the bamboo cellulose into a viscose solution. Hydrogen peroxide is added as a stabilizer and the solution is forced through spinnerets into a hardening bath which causes the thin streams of viscose bamboo solution to harden into bamboo cellulose fiber threads. The hardening bath is usually a solution of water and methanol, ethanol or a similar alcohol. The regenerated bamboo fiber threads can be spun into bamboo yarn for weaving into fabric. This lyocell processing is substantially healthier and more eco-friendly because N-methylmorpholine-N-oxide is supposedly non-toxic to humans and the chemical manufacturing processes are closed-loop so 99.5% of the chemicals used during the processing are captured and recycled to be used again. Only trace amounts escape into the atmosphere or into waste waters and waste products.
Other chemical manufacturing processes for bamboo fabric are appearing such as using acetic an hydride and acetic acid with sulfuric acid as a catalyst to form acetate fiber which is then spun into a yarn.
Nanotechnology in bamboo clothing industry
New nano-technologies are also being introduced into the bamboo clothing industry. It based on a bamboo clothing line made from nano-particles of bamboo charcoal. In this process, bamboo is dried and burned in 800 degree C ovens until it is reduced to charcoal. The bamboo is processed and converted into fine nano particles which are then embedded into cotton, polyester or nylon fibers. This conventional fiber yarn that contains trapped bamboo charcoal nano particles is then woven into fabrics mostly socks and blankets now.
It is reported that the active bamboo charcoal ingredients will only remain active in the clothing for about six months of active use.
Dyeing and Finishing
Light singeing, enzyme desizing, moderate bleaching and semi-mercerizing should be applied to the bamboo textile substrate prior to its dyeing and finishing process. It is better to avoid drastic conditions and use low mechanical tension.
Singeing: Bamboo fabric can be singed in moderate condition.
Desizing: Desizing rate should be over 80%.
Scouring: Pure bamboo normally needs no scouring; sometimes washing with a little alkaline soap may serve the purpose. The scouring process should be made in terms if fiber blend contains cotton. When pure bamboo fabrics are scoured, the alkali should not be over 10 g/liter but can be applied in accordance with the thickness of fabrics.
Bleaching: The processing should be made in terms of the specification and thickness of fabrics.
Mercerizing: Fabrics of bamboo fibers normally should not need mercerizing due to their sound luster and poor anti-alkaline properties. However, in some cases, to increase their absorbance capacity to dyestuff, it can be mercerized.
Dyeing: Reactive dyestuffs are used during dyeing process - alkali should not be over 20 g/liter; temperature should not be over 100 C. During drying process, low temperature and light tension are applied.
Yarn dyeing: Alkali should not be over 8 g/l in yarn dyeing.
Chemically-manufactured bamboo rayon has some wonderful properties which are adored by conventional and eco-aware designers and consumers involved in towel sector:
Water Absorbent
In textile form, bamboo retains many of the properties it has as a plant. Bamboo is highly water absorbent, able to take up three times its weight in water. In bamboo fiber towel, this translates to an excellent wicking ability that will pull moisture away from the skin so that it can evaporate.
Soft Feel
Bamboo fiber towel is softer and smoother than cotton and can be comfortable directly next to the skin. Many people who experience allergic reactions to other natural fibers, such as wool or hemp, do not complain of this issue with bamboo. The fiber is naturally smooth and round without chemical treatment, meaning that there are no sharp spurs to irritate the skin. Strong and stable strength both vertically and horizontally plus a good dependence which leads to natural look and elegance.
Breathable and Cool
Bamboo fiber towel has an unusual level of breatheability, making it incredibly cool and comfortable next to the human skin. This is because the cross-section of the bamboo fiber is filled with various micro-gaps and micro-holes, it has much better moisture absorption and ventilation. With this unique microstructure, bamboo fiber towel can absorb and evaporate human sweat very quickly. Bamboo fiber towel make people feel extremely cool and comfortable in hot conditions. The ability of moisture absorption is more superior to cotton.
Antistatic
A characteristic of bamboo fiber is such that it absorbs moisture due to micro-gaps and static electricity is hard to be generated. Bamboo fiber does not contain free electron and thus it is antistatic, so it fits very well next to the human skin but not clinging it. It flows lightly over the body.
Antibacterial and Deodorized
Bamboo can thrive naturally without the use of pesticides as it is seldom eaten by pests or infected by pathogen. Scientists have found that bamboo contains a unique anti-bacteria and bacteriostasis bio-agent named "bamboo kun". This substance is maintained in the finished bamboo fabric as it is bound tightly to the bamboo cellulose molecule. Bacteria will propagate rapidly in cotton and other fibers obtained from wood pulp, forming bad smell and even cause early degradation of the fiber in some cases. But it will be killed 75% after 24 hours later in bamboo fiber.
Bamboo fiber towel has excellent natural functions. It is both anti-bacterial and deodorising in nature. It has been proven by studies conducted by the National Textile Inspection Association, China (NTIA), Shanghai Microorganism Research Institute and Japan Textile Inspection Association that even after bamboo fabric had been washed fifty times, it still possessed excellent anti-bacterial and bacteriostasis functions.
Bamboo fiber's natural anti-bacterial function differs greatly from that of chemical antimicrobial. The latter often tends to cause skin allergy when added to textile substrate.
Green and Biodegradable
Bamboo grows quickly, requiring few farming inputs and no pesticides. When compared to other fibres such as cotton, it is far more sustainable. Cotton requires huge amounts of water and extensive use of pesticides that pollute the environment. Bamboo takes up more greenhouse gasses and releases more oxygen and does not need replanting, or fertilisers and its roots are very good at stabilising erosion prone soil.
It produces natural and eco-friendly fiber without any chemical additives. More importantly, bamboo fiber is a unique biodegradable textile material. As a natural cellulose fiber, bamboo fiber can be 100% biodegraded in soil by micro organisms and sunlight. The decomposition process does not cause any pollution in the environment. "Bamboo fiber comes from nature and completely returns to nature in the end". Bamboo fiber is praised as "the natural, green and eco-friendly new-type textile material of the 21st century".
Care label hints of Bamboo towel
Towels can be machine washed in warm water. Do not bleach. Wash dark colors separately and avoid harsh detergents when washing
Wash Care Instructions:
It may be advised to launder towels before first use. Careful handling is recommended when washing a new Bamboo towel. To prevent snagging of the loops and towel shrinkage following steps can be followed:
> Placement of towels in a washing bag prior to its first laundering.
>Laundering of towels with warm water on delicate wash with like colors
>Do not bleach
>Tumble dry low
The use of fabric softeners is not often recommended as they tend to block the micro-gaps in the fibers leading to reduced absorbency.
Advantages over 100% cotton towel:
Anti-bacteria: 3 times effect than Cotton Products
Anti-static: 12 times effect than Cotton Products
Hygroscopic: 60% improvement in Comparison with Cotton Products
Deodorization: 30 % improvement in Comparison with Cotton Products
Microscopic view of Bamboo fiber :
About the Author:
Dr. Subrata Das has done his Ph.D (1997) and M.Tech (1986) from the Textile Technology Department of I.I.T.Delhi after the successful completion of B.Sc(Tech) in Textile Technology(1983) from Calcutta University. He has around two decades of work experience in Shop floor, Research & Development, Quality Assurance and Teaching. Dr. Das has been abroad several times and has received special training in Social Accountability, Laboratory Management Systems and Excellence in Retail Store Operations. He has performed more than 100 audits in Bangladesh as a lead auditor in Social Compliance for reputed garment buyers throughout the globe.
Dr. Das is currently heading the Consumer Testing Laboratories (India) Limited, Inc., Bangalore. He has around 75 publications in reputed national and international textile journals to his credit and has presented 20 technical papers in various national and international conferences. He is in the panel of referees of Indian Journal of Fibre and Textile Research. Dr Das has recently been empanelled as NABL assessor in Laboratory audit as per ISO/IEC 17025. You can contact him on: subratactl@gmail.com
Reference:
1) Facts about Bamboo Fabric, www.bamboofabricstore.com.au
2) Michael Lackman, Bamboo: Facts behind the Fiber, Organicclothing.blog.com, 18th September, 2007,
http://organicclothing.blogs.com/my_weblog/2007/09/bamboo-facts-be.html
3) Bamboo yarn fabrics dyeing and finishing, www.swicofil.com
4) Dr. Subrata Das, Properties of Bamboo Fiber, www.fibre2fashion.com, 21st May, 2007.
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