Jute Fiber – the natural cellulose bast fibers from plants or vegetables

Jute is one of the cheapest natural fibers. Jute fibers are composed primarily of cellulose (a  major component of plant fiber) and lignin (major component wood fiber). It is thus a lignocellulosic fiber that is partially a textile fiber and partially wood. It falls into the bast fiber category (fiber collected from bast or skin of the plant) along with kenaf, industrial hemp, flax (linen), ramie, etc. The industrial term for jute fiber is raw jute. The fibers are off-white to brown, and 1–4 meters (3–12 feet) long. Jute is the common name given to the fiber extracted from the stems of plants belonging to the genus Corchorus, family Tiliaceae.

Depending on demand, price and climate, the annual production of jute and allied fibers in the
world remains around 3 million tonnes.

Sacking and Hessians (Burlap) constitute the bulk of the manufactured products. Sacking is
commonly used as packaging material for various agricultural commodities viz., rice, wheat,
vegetables, corn, coffee beans etc. Fine Hessian is used as carpet backing and often made
into big bags for packaging other fibers viz. cotton and wool.

Formation of Jute Fibers

Jute fiber develops in the phloem or bast region of the stem of the plants; in transverse
sections of the stem. They appear as wedge-shaped bundles of cells intermingled with
parenchyma cells and other soft tissue.

Extraction of Jute Fibers

The plants are harvested by hand with a sickle and cut close to the ground. The cut stems are then tied into bundles, the leaves removed as much as possible, and the bundles submerged in water for retting. This is the process by which the bundles of cells in the outer layers of the stem are separated from the woody core and form nonfibrous matter by the removal of pectins and other gummy substances.

The action involves water, microorganisms, and enzymes, and takes between 5 and 30 days to completion, depending on the temperature of the water. Constant supervision is required, and the time of removal is critical because if the degree of retting is insufficient, the fiber cannot easily be stripped from the woody core and may be contaminated with cortical cells, and if retting proceeds too far.

The fiber cells themselves may be attacked and weakened by microorganisms. Stripping the fiber from the stem is done by hand, after which the fibers are washed and dried. A difficulty in the retting procedure is that the thicker parts of the stem take longer to ret than the thinner parts do; consequently, if the butt ends of the stem are fully retted, the top ends are overrated and damaged. This can be avoided by stacking the bundles of stems upright with the butt ends in water for a few days before immersing the whole stem.

• Retting process: Retting is the bacterial decomposing of natural glues that adhere the bast fiber to the herd. Traditionally, this is accompanied in one of two ways; either dew retting or water retting. With the former, the swath of the stem material, after mechanical harvesting is left for about 4-6 weeks in the fields for dew and rainfall to affect the process; however, prolonged excessively wet conditions can turn retting to rotting.
• Scutching process: It is a process in which the retted plant is separated or ‘transformed’ into its basic parts: the hurd and the bast fiber. While transforming the plant, the fibers are kept at full length so at the end they can be cut to the length required for further processing.

Application of Jute Fibers

The large historic markets for jute in sacking, carpet backing, cordage, and textiles have decreased over the years as jute has been replaced by synthetics. Fiber from jute can be used in the handicraft industries, to make textiles, to make paper products, or to produce a wide variety of composites.

When the long fiber is separated, the byproduct is a large amount of short fiber and pith material that can be used for such products as sorbents, packing, light-weight composites, and insulation. By utilizing the byproduct of the long fiber isolation process, the overall cost of long-fiber utilization is reduced. The isolated long fiber can then be used to make mats which have value-added applications in filters, geotextiles, packaging,  molded composites, and structural and nonstructural composites.

1. Geotextiles

   The long bast fibers, like in jute, can be formed into flexible fiber mats, which can be made
   by physical entanglement, nonwovens needling, or thermoplastic fiber melt matrix
   technologies. The two most common types are carded and needle-punched mats. In
   carding, the fibers are combed, mixed, and physically entangled in a felted mat.

   Geotextiles derive their name from geo and textile and, therefore, mean fabrics in
   associated with the earth. Geotextiles have a large variety of uses. They can be used for
   mulch around newly planted seedlings. Jute fiber mats have good moisture retention and promote seed germination. Low and medium-density fiber mats can be used for soil stabilization around new or existing construction stop soileep slopes without roots to hold the soil erode and topsoil is lost. Medium and high-density fiber mats can also be used below ground in the road- and other types of construction as natural separators between different materials.

2. Filters

   Medium- and high-density fiber mats can be used for air filters. Air filters can be made to
   remove particulate and/or can be impregnated or reacted with various chemicals as air
   fresheners or cleansers.

3. Sorbents

   Medium and high-density mats can also be used for oil-spill clean-up pillows.

4. Structural Composites

   A structural composite is defined as one that is required to carry a load in use. In the
   housing industry, for example, structural composites are used in load-bearing walls, roof systems, subflooring, stairs, framing components, furniture, etc.

5. Nonstructural Composites

   As the name implies, nonstructural composites are not intended to carry a load in use. These can be made from a variety of materials such as thermoplastics, textiles, and wood particles, and are used for such products as doors, windows, furniture gaskets, ceiling tiles, automotive interior parts, molding, etc.

6. Molded Products

   Fiber mats are similar to the ones described for use as geotextiles except, during mat formation, an adhesive is added by dipping or spraying the fiber before mat formation, or it is added as a powder during mat formation. The mat is then shaped and densified by a thermoforming step. Within certain limits, any size, shape, thickness, and density is possible. These molded composites can be used for structural or non-structural applications as well as for packaging and can be combined with other materials to form new classes of composites.

7. Packaging

   “Gunny” bags made from jute have been used as sacking for products such as coffee, cocoa, nuts, cereals, dried fruits, and vegetables for many years. While there are still many applications for long fiber for sacking.

8. Combinations with Other Resources

   Composites of agro-based fiber and glass fiber can be made by using the glass as a surface material or combined, as a fiber, with lignocellulosic fiber. Composites of this type can have a very high stiffness-to-weight ratio. The long bast fibers can also be used in place of glass fiber in resin injection molding (RIM) or used to replace, or in combination with, glass fiber in resin-transfer-molding (RTM) technologies.

   One of the biggest new areas of research in the value-added area is in combining natural fibers with thermoplastics. Prices for plastics have risen sharply over the past few years, but adding a natural powder or fiber to plastics reduces cost (and in some cases increases performance as well). To the agro-based industry, this represents an increased value for the agro-based component.

9. Fibre Matrix Thermoplasticization

   The approach most often taken involves the chemical modification of cellulose, lignin, and the hemicelluloses to recrystallize/modify the cellulose and to thermoplastic the lignin and hemicellulose matrix in order to mold the entire lignocellulosic resource into films or thermoplastic composites.

   Thermoplastic alloys

   In this type of composite, the thermoplastic is bonded onto the lignocellulosic in such a way that there is only one continuous phase of the molecule.

10. Fashion Fabric

    Jute a versatile, eco-friendly, recyclable and economical fiber. Jute is also often blended with other fabrics like cotton (called JUCO) that are ideal for clothing, accessories and home furnishing. In order to make sophisticated products like fashion garments, jute needs to be
    blended with fibers like wool, nylon, rayon, acrylic or polypropylene. These blends enrich
    the fiber in feel, appearance, durability, resilience, and washability.

11. Fancy Bags and Handicrafts

    The versatile Jute fiber is now being used to create exciting new products, the most popular
    one is Hand Bags, Shopping Bags, Luggage Bags, Wallets, Casual Bags, and Fashion Bags.