Kenaf: Coming soon to a store near you?
It belongs to the hibiscus family. It grows tall like bamboo in warm climates. It can be made into yarn but has more strength than cotton. It’s kenaf, and Mary Warnock has spent some time in her laboratory seeing what she can make of it. It turns out that she can make quite a lot.
Warnock, professor and director of the School of Human Environmental Sciences, has spent her career experimenting with textiles. For a time she tested textiles for Wal-Mart Stores, Inc., and eventually she helped them establish their own laboratories in Northwest Arkansas, where some of her former students now work.
More recently, she became interested in kenaf when a company asked her to bury some.
She performed burial studies and soil analyses on the kenaf in different types of soil to see how well it decomposed. Many materials used in products today – such as polypropylene – do not break down in the soil. This can be problematic if these products end up in landfills.
“They stay there forever and ever,” Warnock said.
However, kenaf proved susceptible to mold and mildew, which broke down the fibers and deteriorated the material in about six weeks.
This biodegradability project piqued Warnock’s interest in the fiber. Kenaf was brought to the United States from Africa in the 1800s, but it never became a valued crop. She is now working with a group of Arkansas farmers who are looking at kenaf as a potential cash crop. They have asked her to develop and test potential products that could be created using kenaf.
She has embraced the project thoroughly: She tried growing kenaf by her house. After harvesting the stalks, she puts them through a “retting” process in the back yard, letting them soak in water for a few weeks.
“True grass-roots research,” she quips. After the retting process, she pulls the fibers off the stalk and boils them for 15 minutes in a 20 percent sodium hydroxide solution to get rid of the waxes, pectins and lignins that glue the fibers together. After rinsing, she has pliable fibers that can be made into products.
Warnock has a briefcase full of samples at the ready. She pulls out a piece of bark, strands of fibers, a skein of yarn made from the fiber and a small woven sample of a cotton-kenaf blend.
“Cotton gives comfort, kenaf gives strength,” she said.
She has taken kenaf and made doll hats, doilies, knitted samples, but she has also used kenaf to make other types of craft materials. The fibers take dye well and sport brilliant colors. The dyed fibers resemble raffia, often used to decorate presents. Because of its strength, it can be used in basket making. Warnock has also taken the fibers, ground them up, and made paper from them. The paper can be plain or marbleized with color.
And the fiber is not just decorative. Cows can eat kenaf. Warnock created a range cube with the hay-like fibers that the animals can munch on. Warnock also has shown that kenaf stiffens concrete mixtures, making the concrete go further, which may be useful in third world countries where resources are scarce.
Warnock concludes that kenaf may have many potential uses. And producers get paid more per acre for kenaf than for cotton. But one potential problem that remains is lack of infrastructure. Currently, very few factories can process this particular plant.
“There’s a system set up for cotton. There’s not a system set up for kenaf,” Warnock said.