Introduction
Kenaf is a plant, also known as Hibiscus Cannabinus, which has been around for thousands of years and used in ancient cultures of the world. As a close relative to cotton and okra, kenaf contains two types of fibers. One being a bast fiber bark used for burlap and carpet padding. The second fiber is the spongy, absorbent core fiber. While many people in the Western countries may not be as familiar with kenaf, the plant is used in animal bedding, packing materials, paper, and oil absorbent mats. Since kenaf is an extremely niche market, there are very few processing plants.5
KENAF PAPER
Although Kenaf is still relatively new to most people, it is considered one of the most promising alternatives to non-wood paper production. Major companies such as Apple, Sony, Warner Bros., and many others alike are starting to use kenaf for printing catalogues and other purposes.
ADVANTAGES AND DISADVANTAGES OF KENAF PAPER
The USDA has identified kenaf as the best non-wood paper alternative for many reasons including: rapid growth, high yield, and exceptional papermaking characteristics. Kenaf can reach 12-18 feet in only 150 days, while other species of trees must grow at least 14 years before it can be harvested. Kenaf has a much higher yield than other tree species as well, approximately 3 to 5 times as much as southern pine trees. This means that kenaf produces 5-10 tons of dry fiber per acre. Finally, an advantage that kenaf has over other wood paper is its exceptional papermaking characteristics. Kenaf requires less chemicals, less time, and less heat to pulp the fibers as they are not quite as tough as wood pulp. Toxic chemicals are also used to remove lignin, a resin that is used to bind together fibers in trees or plants, and to bleach wood pulp. Using kenaf as an alternative allows for producers to pulp and bleach without the harsh chemicals.
Although kenaf has vast advantages over its competition, it still has its disadvantages. The kenaf industry is severely underdeveloped. “As of August 1995, New Mexico’s Vision Paper was the only company commercially producing kenaf paper in the U.S. Vision Paper manufactured 200 tons of kenaf paper in 1994. Due to significant industry start up costs, smaller economies of scale and government subsidies to the pulp, paper and timber industries, kenaf paper is more expensive than virgin wood-based papers.”2,3
KENAF TEXTILES
According to a study from The Journal of Cotton Science, kenaf can produce fibers that can be made into textiles. To do so, the fibers must be either chemically or bacterially retted. In the article from The Journal of Cotton Science researchers blended kenaf with cotton to make a more wearable textile as kenaf was quite stiff because of the lignin resin in it.3 Although kenaf is starting to show up more in the apparel industry, some believe that it would be best for industrial wear or home furnishings as the yarn itself can be pretty rough.
KENAF TEXTILES ADVANTAGES AND DISADVANTAGES
The main advantages of kenaf being a great fiber for the textile industry are that it’s renewable, local, eco-friendly, and a high quality fabric. Kenaf grows very quickly, thus there is a much less danger of extinction or over-harvesting in order to keep up with production demands. Depending on where kenaf is planted, it can also be grown year round in warmer climates. Speaking on the topic of bringing more production to the U.S.A., kenaf can be grown in the U.S., making it a great choice for local producers. One of the hugest advantages for using kenaf is its sustainability. Kenaf leaves almost no carbon footprint and also can improve the area that it grows in by absorbing CO2. Kenaf requires little water and pesticides and fertilizer are barely used. Kenaf in textiles, paper and plastics is biodegradable as well. Lastly, kenaf fibers are known as being of high quality. The fibers produced have long staple, which in turn produces a strong yarn that can be spun. Although the hand is bit coarser than linen, the textiles are absorbent and fire-retardant, making outerwear or shoes the ideal selection for kenaf production.
Although kenaf has many advantages, it also has a few disadvantages. While kenaf may look like linen, the untreated fabric is very rough, and not suitable for everyday wear. Also, to harvest kenaf for fiber use, moisture content and the equipment used for harvesting are important considerations. Kenaf needs to be dried by either a frost or just drying in the field once cut. This means that certain climates and soil type may delay harvesting and drying, which in turn would cause problems for certain shipping dates for manufacturers.2,3,6
PROPERTIES OF KENAF
Kenaf is made up of approximately 65.7% cellulose, 21.6% lignin and pectin, and other composition. Lignin must be extracted so that the fibers may be separated. Chemical retting or bacterial retting is usually done to kenaf and both yield different properties for the plant. When chemical retting was applied, the fiber had less residual gum content but the bundle breaking tenacity was lower and the color and luster were not quite as good when bacterial retting was involved. Elongation at break was the same for both processes. Some studies show that cotton can be combined with kenaf to make a better fiber. With kenaf not exceeding more than 30% of the blend, the yarn strength was weaker, stiffer, and less recoverable than 100% cotton, however displayed high air permeability. The higher the kenaf percentage, the lower elongation.3,4
NOVELTY
While kenaf the plant is not new to our world, the textile aspect of the plant is. The cotton industry is having sustainability issues while kenaf is an option for designers to consider for sourcing sustainable materials. Kenaf should be considered a novelty fiber because of its ability to be eco-friendly and renewable. Because sustainability is such an important aspect of the fashion industry right now, kenaf could be a great addition to textiles that are environmentally friendly. Another novelty aspect of kenaf is that producers of the plant are able to use the entire plant, not just the stalk. The plant composition allows for producers to use some parts of the plant for paper and textiles and the other parts can be used for livestock feed as they contain a relatively high amount of protein. Kenaf’s strength and resistance to rot and mildew make the cotton and kenaf blend very unique in end uses. The diversity of the kenaf textiles makes it an interesting addition to the apparel industry.
PRODUCTION
Kenaf is to be planted in the spring once soil temperature has warmed to 13 degrees Celsius and there isn’t a threat of another frost. Standard planting equipment can be used to plant the kenaf seed 1.25 to 2.5 cm deep. Hand harvesting of the kenaf seed is labor intensive as there are many loosely held spiny hairs on the seed capsules. Because of this, studies show that an all crop header on a rotary combine is the best option for harvesting. It was also noted that the plant itself must be dried first before production can start. Seeds must then be properly cleaned and conditioned as the seed contains about 20% oil. The next step in the production process is retting. This process involves removing the unwanted bark material from the fiber strands within the bark. Retting can be done by either a natural process or chemical process. Natural retting is more simple and inexpensive yet quite lengthy in process. Chemical retting involves soaking the fibers in a wetting agent for one hour, and then bark is removed and immersed in a solution. The fibers go through many other solution soakings until the neutralized fibers are washed and air dried. The process is quicker than the natural way but affects properties like tenacity and color. The fibers are usually packed in bales for shipment to be spun. After fibers have been loosened from the bales, they are sent to carding machines that further divide the fiber clumps and remove impurities. If blended with cotton, kenaf can then be spun like other staple fibers.3,7 Once the fibers are blended, softening treatments still need to take place as the fabric is still too rough to wear. Such treatments can include enzymes, bleaching and mercerization. Once treatments have taken place, the fabric had looked better and had a softer hand, which in turn made it suitable for use in apparel. In the end, cotton enhances the kenaf fibers and results in a higher value end product.
COST COMPARISON
I visited the site, alibaba.com, to find the different prices that kenaf is selling for, as well as compare the prices of kenaf to that of its close relation, hemp. The prices of kenaf varied greatly on the site. This I feel attributes to possibly where the kenaf was produced and what retting process was used, along with how high of quality the kenaf fiber is. The prices listed ranged from $250-$700 per ton. When looking up hemp fibers on the website, I noticed that hemp was drastically more expensive than kenaf. This just gives another reason as to why kenaf should be produced more. Hemp started at a price of about $200 and sold for as high as $1,000 per ton.8
Conclusion
Kenaf isn’t new to the world, but its different uses are. The plant can produce end results such as animal bedding, paper products, building materials, absorbents, and even livestock feed. Some setbacks for this fiber are that the industry is very underdeveloped, and unless combined with a different fiber, the result of a 100% kenaf made shirt is very rough to the touch. This however could mean that kenaf would be best for more industrial apparel like shoes. While there are some setbacks, there are far more advantages to kenaf. With properties like, sustainability, high quality, and the fact that it can be grown locally, kenaf is a new textile that many researchers are looking to know more about.
With only minor disadvantages, kenaf seems to be one of the best choices for new textile production. With more testing and blends with different fibers, I believe more designers will produce clothing with this cost effective new fiber.
“Keep kenaf fabric on your radar and you’ll be the coolest kid on the block. It is much much better than bamboo because bamboo is very chemical intensive -it’s rayon. Kenaf is much cleaner and more sustainable. Now we have to find a way to make it cool.” 1