Properties, Processing and Uses of Kenaf Fiber

What is Kenaf Fiber?

Kenaf is natural plant fiber. The scientific name of kenaf is Hibiscuscannabinus. It’s allied with jute fiber. Kenaf shows similar characteristics with jute. It has a unique combination of long bast and short core fibers. That makes kenaf suitable for a range of textile uses as well as paper and cardboard industries.

kenaf plant and fiber
Fig: Kenaf plant and fiber

The commercial uses of kenaf continue to diversify from its historical role. Once a cordage crop kenaf used for making rope, twine, sackcloth, and so on. But now, kenaf fiber has various new applications including paper products, grass mats, fiber glass substitutes, animal bedding, building materials, chicken and cat litter, animal forage, particle board, and potting soil, oil absorbents, and the like.

Kenaf Producing Countries:

There are more than 130+ names in kenaf producing countries all over the world. Some of them are as follow according to the country:

Producing Country Known as
French Chanvre de Bombay, chanvre du Deccan, chanvre de Guinée, chanvre de Gambo, chanvre de roselle, kénaf, roselle, jute de Java, jute de Siam.
Belgium Ketmie à feuilles de chanvre
German Ambari, Gambohanf, Hanfeibisch, Javajute, Kenaf, Rosellahanf, Roselle, Siamjute, Dekkanhanf.
Portuguese Cânhamo rosella, juta-do-sião, quenafe, juta-de-java.
Spanish Cáñamo de la India, cáñamo de gambo, pavona encendida, yute de Java, yute de Siam,cáñamo Rosella.
Brazilian Papoula-de-são-francisco, cânhamo-brasileiro, quenafe.
Afrikaans Stokroos.
Egypt & Northern Africa  Til, teel, teal.
West Africa Dah, gambo, and rama
India Ambaadi, Sunn, Shougri, Kudrum, Pundi Palle, pulicha keerai, Palungu, Gongura, Puntikura
Iran Kanaff
Taiwan Ambari.
China Yang Ma (foreign hemp).
Bangladesh Mesta, Bimli, Ambary, Sunn, Deccan Hemp, Bimlipatum Jute.

Kenaf Fiber Properties:

Chemical composition of kenaf:
The chemical composition of kenaf fiber is as follows:

  • Cellulose – 51-52%.
  • Hemicellulose – Nil.
  • Water – 7-10%.
  • Lignin – 17%
  • Ash – 2.9% to 4.2%.
  • Others – 5% to 15%.

Physical properties of kenaf:

  • Strong.
  • Soft Handle.
  • Aesthetically pleasing.
  • Linen look.
  • Can be either lightweight or heavyweight.
  • Brittle.
  • Very little elasticity.
  • Degradable.
  • Absorbent.
  • Can be lustrous.
  • Eco-friendly, etc.

Mechanical properties of kenaf:

Mechanical Properties Characteristics
Density g/cm3 1 1.4
Tensile Strength, MPa 283- 800
Modulus, GPa 21-60
Specific (E/d)
Elongation at failure, % 1.6
Moisture absorption, % 18

Processing of Kenaf Fiber:

Kenaf could be blended with cotton and made into yarn & woven into fabrics. These textile products are aesthetically pleasing, strong, lightweight, and have an excellent soft feel. Textile products made from kenaf, have an appearance of linen.

Kenaf is the most sustainable fabrics, due to its growth rate, and ability to replenish. It does not require much water for its cultivation and processing. Almost no fertilizer or pesticides used in the cultivation processes.

Kenaf can grow to its full length in about 145-150 days. It’s produced by separating the core of kenaf from its fibrous outer layers. The extracted layers can be chemically or naturally retted to convert them into fibers. Retting is a process is done by wetting. In this process, bundles of cells in the outer layer of stalk are separated from non-fibrous materials. Then it’s separated into strands through carding.

Basically, two types of retting are in practice for kenaf. One is bacterial retting using microorganisms under controlled water temperature and flow producing pollutants. Another is chemical retting using alkali solutions. Then the retted kenaf is blended with cotton and spun into yarns which are woven or knitted.

End Uses of Kenaf Fibre:

  1. Ropes.
  2. Twine.
  3. Sackcloth.
  4. Newsprint paper
  5. Garments that do not require lining.
  6. Sacking.
  7. Cordage.
  8. Hessian.
  9. Upholstery, and so on.

Kenaf Fibre Applications:

1. Kenaf paper uses: Kenaf pulping techniques are used to make several grades of paper including newsprint, bond, coating raw stock and surfaced sized. In particular terms of paper quality, durability, print quality and ink absorption it shows better result from any other fabric. News print papers made from kenaf pulp have been shown to be brighter and better looking, with better ink laydown, reduced rub-off, richer color photo reproduction and good print contrast. The commercialization uses of kenaf are in its final stages in newsprint manufacturing industry.

2. Social revolution: Kenaf fabric manufacturing requires less energy and chemicals for processing. A book named “Forest Revolution,” are started kenaf paper use and explained its many advantages over wood pulp. The first edition of the book was printed on kenaf paper.

3. Forage uses: The top leafy portion of the kenaf plant is not useful for pulping or making textile materials. Therefore, this part of the plant could be useful as forage.

4. Food and medicinal uses: Kenaf fruits have significant medicinal properties. Its seeds are a good source of fat-soluble antioxidants. In particular, its fruit have helped lowering blood pressure by helping increase nitric oxide and reducing oxidized lipids in the blood. It has very high in vitamin-C, antioxidants and phytochemicals. Kenaf fruits have been found useful in treating metabolic diseases such as atherosclerosis, liver disease, cancer and diabetes.

5. Textile industry applications: Kenaf Fiber is the thinnest and longest are used in the textile industry. Kenaf spin yarns have metric count from 12,000 to 25,000.Fibres spun from kenaf are extremely long. It is fond useful applications in making knit and woven textiles. Kenaf fiber can be blended very well with cotton and other fiber. It has commercial and healthy applications in making outerwear owing to its natural absorbency, and fire-retardant abilities.

Conclusion:

Many kenaf crop varieties has developed, released and used at farmer’s level for textile industrial uses. All those varieties had high fibre and biomass yielding values. In future, research should have to be continued for searching kenaf varieties tolerance to problem soil, diseases, and pests.

References:

  1. Kenaf Fibers and Composites Edited by S.M. Sapuan, J. Sahari, M.R. Ishak and M.L. Sanyang
  2. Kenaf (Hibiscus cannabinus L., Malvaceae) Research and Development Advances in Bangladesh: A Review by Md. Mahbubul Islam
  3. https://hort.purdue.edu/newcrop/afcm/kenaf.html
  4. https://www.fibre2fashion.com/industry-article/6856/ecology-economy-amp-equity-kenaf-fibre-fabrics
  5. http://www.catwalkyourself.com/fashion-dictionary/kenaf/

Author of this Article:
Md. Mahedi Hasan
B.Sc. in Textile Engineering
Textile Engineering College, Noakhali.
Email: mh18.bd@gmail.com

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