Fiber crop

Fibre Crops are field crops grown their fibres, which are traditionally used to make paper, cloth, or rope. They are organized into 3 main groups- textile fibers (used in production of cloth), cordage fibers (used in production of rope), and filling fibers (used to stuff upholstery and mattresses). They are a type of natural fiber.[1]

Fiber crops are characterized by having a large concentration of cellulose, which is what gives them their strength. The fibers may be chemically modified, like in viscose (used to make rayon and cellophane). In recent years, materials scientists have begun exploring further use of these fibers in composite materials. Due to cellulose being the main factor of a plant fibers strength, this is what scientists are looking to manipulate to create different types of fibers.

Fiber crops are generally harvestable after a single growing season, as distinct from trees, which are typically grown for many years before being harvested for such materials as wood pulp fiber or lacebark. In specific circumstances, fiber crops can be superior to wood pulp fiber in terms of technical performance, environmental impact or cost.[2]

There are a number of issues regarding the use of fiber crops to make pulp.[3] One of these is seasonal availability. While trees can be harvested continuously, many field crops are harvested once during the year and must be stored such that the crop doesn't rot over a period of many months. Considering that many pulp mills require several thousand tonnes of fiber source per day, storage of the fiber source can be a major issue.These fiber mostly found in leaf ,seeds or in the body of a tree.

Botanically, the fibers harvested from many of these plants are bast fibers; the fibers come from the phloem tissue of the plant. The other fiber crop fibers are hard/leaf fibers (come from the entirety of plant vascular bundles) and surface fibers (come from plant epidermal tissue).[1]

Fiber sources

Ancient Sanskrit on Hemp based Paper. Hemp Fiber was commonly used in the production of paper from 200 BCE to the Late 1800's.

Before the industrialisation of the paper production the most common fibre source was recycled fibres from used textiles, called rags. The rags were from hemp, linen and cotton.[4] A process for removing printing inks from recycled paper was invented by German jurist Justus Claproth in 1774.[4] Today this method is called deinking. It was not until the introduction of wood pulp in 1843 that paper production was not dependent on recycled materials from ragpickers.[4]

To have a source of fiber to utilize in productuion, the fiber first must be extracted from the plant. This is done in different ways depending on the fiber classification. Bast fibers are harvested through retting which is where microbes are utilized to remove soft tissues from the plant and only the useful fibrous material remains. Hard fibers are harvested mainly through decortication which is where the non-fibrous tissues are removed by hand or machine. Lastly, surface fibers are harvested through ginning which is where a machine removes the fibers from other plant material.

Fiber crops

Fiber dimensions

Source of pulp Fiber length, mm Fiber diameter, µm
Softwood 3.1 30
Hardwood 1.0 16
Wheat straw 1.5 13
Rice straw 1.5 9
Esparto grass 1.1 10
Reed 1.5 13
Bagasse 1.7 20
Bamboo 2.7 14
Cotton 25.0 20

References

  1. 1 2 Levetin, Estelle; McMahon, Karen (2012). Plants and Society. New York, NY: McGraw-Hill. p. 297. ISBN 978-0-07-352422-1.
  2. ↑ "Agripulp: pulping agricultural crops". Retrieved 2007-10-03.
  3. ↑ "Nonwood Alternatives to Wood Fiber in Paper". Archived from the original on 2007-07-08. Retrieved 2007-10-03.
  4. 1 2 3 Göttsching, Lothar; Pakarinen, Heikki (2000), "1", Recycled Fiber and Deinking, Papermaking Science and Technology, 7, Finland: Fapet Oy, pp. 12–14, ISBN 952-5216-07-1
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