What is Jute Fabric: Structure, Composition, Properties, Manufacturing and Applications

Jute at a glance

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Botanical name	Corchorus olitorius and Corchorus capsularis
Common name(s) of fabric	Burlap, Hessian fabric
Fibre type	Natural – Cellulosic – Bast
Source	The bark of the white jute plant
Major producing regions	India and Bangladesh
Composition (in %)	Cellulose: 60.0-63.0 Hemicellulose: 21.0-24.0 Lignin: 12.0-13.0 Fats and waxes: 0.4-1.0 Pectin: 0.2-1.5 Nitrogenous matter: 0.8-1.9 Ash: 0.7-1.2
Identification	Feel: Stiff and rough Burning: Fibre burns easily with burning paper odour Chemical: Dissolves in 70% sulphuric acid
Structure	Cross-section: Polygonal with rounded corners Longitudinal: Smooth with occasional nodes
Colour	Varies from yellow to brown to grey
Appearance	Natural silky lustre
Tactile property	Coarse, but its best qualities are soft
Length	101.5 to 254 mm long
Tenacity	Single: 0.29-0.48 N/tex Bundle: 0.18-0.34 N/tex
Initial modulus	17-30 N/tex
Breaking extension	1.80%
Moisture regain at 65 RH 20˚C	11-13%
Fabric breathability	High
Moisture wicking ability	High
Heat retention ability	Moderate
Stretching ability	Low
Resistance to abrasion/ pilling	High
Resistance to staining	High
Advantages	Renewable sources and biodegradable High strength and initial modulus, moderate moisture regain Good dyeing ability Sound insulation, antistatic, low thermal conductivity Low cost
Limitations	Coarseness, stiffness, harsh feel, hairiness and high fibre shedding, photo-yellowing Low wet strength, moderate wash shrinkage, poor crease recovery
Applications	Sacks (packaging), geotextiles (landfill covering, embankment reinforcement), ropes, home décor, bags, apparel, footwear

Major jute Producing Regions

Among all bast fibres, jute is one of the most significant and versatile fibres of commercial and technical importance. It is mainly cultivated in the equatorial, tropical and sub-tropical zones. India and Bangladesh are the leading producers of jute in the world. The other major jute-producing countries are China, Uzbekistan, Nepal, Myanmar, Thailand, and Vietnam. India contributes to over 50 per cent of global raw jute production and over 40 per cent of global jute goods production.

The cultivation of Jute in India is mainly confined to the eastern region that includes Bihar, West Bengal, Andhra Pradesh, Assam, Odisha and Chhattisgarh. In the year 2022-23, raw jute production was estimated to be close to 9 lakh bales, which was about 6-7 per cent higher than that in 2021-22. The National Jute Board, Government of India, Ministry of Textiles acts as the apex body for promoting and popularising jute in the country and abroad.


Figure 1: Major jute-producing states of India

Jute Fibre Structure

Jute fibre is a multicellular fibre, cemented laterally and longitudinally by intercellular non-cellulosic materials. The fibre thus forms a cylindrical sheath, which is joined together in such a way as to form a three-dimensional network from top to bottom of the stem. An individual jute fibre cell is spindle-shaped. Its size can vary in length from 1.52 mm to 5.1 mm and the width in the middle can range from 20 microns to 25 microns.

The longitudinal surface of the cell is smooth with nodes or cross-markings appearing occasionally. The cross-sectional view of the cell is polygonal with rounded corners. Each cell is surrounded by a thin to medium layer of lignin. The lumen is large and oval. The lumen is irregular along the length of the fibre with occasional sharp constrictions. It thickens towards the end of the call resulting in thin cell walls and tapering ends. The cell wall is composed of a thick outer (primary) wall and a thick inner (secondary) wall. These walls comprise ultra-fine microfibrils.


Figure 2: Jute fibre morphology

Composition of jute fibre

Jute fibres are composed primarily of polysaccharides (cellulose and hemicellulose) and lignin. The fibre also contains a small percentage of fats and waxes, pectin, nitrogenous, colouring and inorganic matters. The chemical composition of jute is given in the table below.


Figure 3: Chemical composition of jute

Cellulose/alpha-cellulose forms the skeletal structure of the jute fibre. It is a long-chain polymer. The chemical structure of alpha-cellulose is shown below.

Figure 4: Chemical structure of alpha-cellulose

The hemicellulose in jute is a complex mixture of polysaccharides and polyuronides. It is a short-chain polymer. The chemical structure of hemicellulose is shown below.

 

Figure 5: Chemical structure of hemicellulose

Lignin and pectin function as support materials in the plant body. Lignin is a complex non-crystalline polymeric constituent that gives structural support, while pectin holds the fibre bundles together. Small quantities of nitrogenous and inorganic components are also present. The colouring matter and pigment present in jute fibre consist of xanthophyll, carotene and tannin. These can be removed by chemical treatments.

Physical Properties of Jute fibre

Jute fibre appears pale in colour with a natural silky shine. Thus, jute is also called the “golden fibre”. The colour of commercial jute ranges from pale cream to golden yellow and from light brown to a dirty grey. The hand feel of jute is relatively coarse. It is stiff, inelastic and moderately rigid.

The fibre has a high coefficient of friction, high tenacity, high modulus and low elongation at break. Jute fibre exhibits increasing friction with an increase in moisture regain. The tenacity value of a single fibre is 0.29-0.48 N/tex, and that of a bundle is 0.18-0.34 N/tex. The initial modulus value is 17-30 N/tex. The breaking elongation ranges between 1.0% and 1.8%.

The moisture regain of jute is 11-13%, which is slightly higher than that of cotton (7-8%). It is a hygroscopic fibre and the wetted filaments may swell up to 23% in diameter. The flexural and torsional rigidities of jute fibre are quite high due to its coarseness and inelastic structure. For this, jute textile material develops wrinkles and creases easily.

Jute fibre shows good thermal insulation. However, the ignition temperature is not very high (about 193˚C), which may be a reason that makes jute susceptible to catching fire. At very high temperatures, jute fibre chars and burns without melting.

Dry jute fibre has high electrical resistance but in moist conditions, the electrical resistance drops by about 10000 times.

Chemical Properties of jute fibre

Jute fibre after retting primarily contains alpha-cellulose, hemicellulose and lignin. These comprise more than 97% of the total jute constituents. Hemicellulose has acidic groups, making jute an acidic fibre. The presence of the carboxylic acid group gives jute a strong affinity for basic dyes.

An alkali treatment on jute weakens the intercellular cementing material and considerably reduces its wet strength. It also makes the fibre develop crimps due to irregular swelling. This crimping process is known as the ‘woolenisation’ of jute.

Inorganic acids weaken jute fibres by hydrolysing cellulose chains rapidly.

Bleaching agents such as sodium chlorite and hypochlorite are used to decolourise jute fibres. The bleaching agent dissolves lignin. While jute becomes whiter, the treatment makes it weaker and finer due to partial disintegration of the multicellular structure.

Manufacturing

Jute is an annual crop and is generally sown from March to May depending on the nature of the land and atmospheric condition. It is a rain-fed crop, requiring little fertiliser or pesticide. The plant grows up to 8 to 12 feet high in about 90 to 100 days after sowing.

The main objective of the mechanical processing of bast fibrous plants like jute is extracting the maximum amount of the fibre which is of the highest possible quality to allow for further processing. The steps involved to obtain jute fibre are shown below.

Figure 6: Steps to obtain jute fibre

Harvesting

Harvesting jute at the right time is important as an early harvest would have weak fibres while a late harvest would yield coarse fibres lacking lustre. The crop age, height and flowering stage are the parameters that decide the harvesting time. Usually, 110-120 days are required for the jute to mature for harvesting.

Jute is generally ready for cutting when the flowers begin to fade. The stalk of the plant is cut close to the ground. The cut stalks are then sorted out by height and diameter. These are tied into bundles, each weighing about 8-10 kg. The bundles are left on the field for 3-4 days. This helps in defoliation and desiccation.

Figure 7: Harvested jute tied in bundles

Retting

Retting refers to the process of controlled rotting away of the non-fibrous material in the stem to yield the fibrous material of jute alone. It can be done through biological or chemical processes.

Traditionally, retting of jute plants involves submerging the plants in water for 15–18 days and extracting the fibre manually. As a result of being submerged in water for days, the bark of the stem swells and forms cracks and crevices in the cortex. Through these openings, bacteria and fungi from the surrounding water, soil or plant enter the soft tissues around the fibre bundles and fibres. The fibres are loosened due to the microbial attack on the binding matter – pectin. This also releases other matter such as soluble tannin and fatty acids into the water. The water left after retting contains nutrients which could be a supplemental source for the growth of paddy.

Retting is complete when the bark separates easily from the core. The end-point of retting is a critical stage that largely determines the quality of the fibre. Fibre extraction becomes difficult if the bundles are taken out from the water too early, while, the fibre becomes weak if it is submerged for a prolonged duration. Before extraction, the farmers make frequent checks to determine the end-point of retting.

The limitations of traditional retting are:

• Objectionable gases such as methane and carbon monoxide are released into the air
• Open water retting pollutes the water bodies and the surrounding air becomes fouled
• Inconsistency in fibre quality as a result of uncontrolled batch process
• Impacts fish cultivation.

There are alternative methods to traditional retting. These include ribbon retting the outer skins of the stem manually or mechanical decorticators, enzymatic retting, chemical retting, etc. Chemical retting using acids and bases has been employed with some success; however, such processes tend to be more expensive than natural fermentation techniques.

Extreme care is required in retting, which would otherwise lead the fibre to become over-retted. Correct retting is essentially the first step in the production of good-quality jute fibre. After retting is completed, the fibrous material is rinsed and dried.

Figure 8: Biological retting in water

Extraction

After retting, the bundles are taken out of the water and the fibre is extracted. In this process, the non-fibrous matter is scraped off, leaving the fibres to be pulled out from within the stem.

Traditionally, the extraction is done by hand. This is done either by stripping fibre bundles from individual stalks or by a bundle of stalks being given a to-and-fro motion in water. Jute fibre extraction machines are also in use, where both retting and extraction are done mechanically. Novel processing techniques are being developed to improve the separation and extraction of fibres in terms of yield, homogeneity and cleanliness.


Figure 9: Extracting fibre bundles from the individual stalk

Figure 10: Extracting fibre bundles by a to-and-fro motion of stalk bundle in water


Figure 11: Extracting fibre mechanically

Washing

The extracted fibres are washed in clean water. This process removes dirt, gum, extraneous plant materials and retting residues.

The jute fibre is washed by holding the extracted fibre bundle is held at one end and tossed in the water. This motion is repeated until the entire bundle is cleaned thoroughly.

Figure 12: Washing jute fibre

Drying

As soon as the fibres are stripped and washed, they are up in sunlight to dry. The fibres are usually spread over a bamboo perch or bar. It is left for sun drying for about 4-7 days.

Along with the other fibre extraction processes, drying too needs care. Drying the fibres on bare ground is avoided as that can contaminate the fibres with dirt, sand, dust particles, etc. Additionally, a delay in drying the fibres after extraction could adversely affect the quality of the fibre.


Figure 13: Jute fibre drying on a bamboo bar under the sun

Bailing, Packing and Storing

After the jute fibres are dried, they can be separated and combed to get long silky fibre strips. The fibres are graded as per the quality and packed into bales accordingly. A kutcha bale usually weighs between 130 kg to 150 kg, and a pucca bale is hydraulically pressed with a net weight of 180 kg. The jute bales are stored and made ready to be supplied to spinning/ weaving mills or the jute market.


Figure 14: Kutcha bales of jute

Spinning

The jute spinning process involves batching, carding, drawing, spinning and winding. The jute fibres are batched according to the different counts and then treated with suitable additives such as oil emulsions and left for conditioning or piling for some time. The treated fibres are passed through the carding machine. In carding, the long lengths of fibre as a continuous mesh are broken into separate fragments. There are three different carding sections – breaker card, inner card, and finisher card. The gill pins help to control the fibre movement in drawing and the input sliver is doubled. Three drawing passages are mostly used. Two drawing passages are used for sacking fabric. The sliver is then spun into yarn and wound on spools. Jute yarn is made on automated machines or semi-automatic machines.

Figure 15: Drawing jute fibres


Figure 16: Jute yarn

Pre-treatment and dyeing

The ready yarn can be further subjected to pre-treatments, dyeing, and other functional finishes. Jute is scoured and bleached before dyeing. Since jute is sensitive to alkali and strong acids, the recipe of the treatment liquors should be carefully followed to retain the physical properties. Jute can be dyed using synthetic dyes and natural dyes. Jute has a good dyeing ability with different dyes such as basic, reactive, vat and sulphur dyes. 

The fibre has a special affinity for basic dyes, which provide brilliant effects even on an unbleached base. Some of the common functional finishes are to make jute water-resistant, fire-resistant, softening, etc. The finished reels of jute fibre are shipped out to textile production facilities to be woven into apparel or industrial textiles.

Figure 17: Jute dyed in vibrant colours

Weaving

Jute yarn can be woven on automatic power looms, shuttleless looms or hand looms. Warp yarns and weft yarns are interlaced to produce a fabric. The woven fabric is then subjected to damping by sprinkling water on the fabric continuously to provide the desired moisture. The moist fabric is calendered by passing it through pairs of heavy rollers. This process flattens the threads in the fabric and improves its appearance.


Figure 18: Jute weaving mill

Types of jute

There are four varieties of jute – white jute, dark jute or Tossa jute, Mesta jute and jute cuttings. Out of these, the two main types of jute, white jute (Corchorus Capsularies) and dark jute or Tossa (Corchorus Olitorius) are prominent.

White jute
It is also called “Bangla white” and is largely produced for consumer and industrial use. White jute is light in colour and less durable.

Tossa jute
The colour of Tossa jute varies from brown to off-white. It yields more fibre than white jute. The Tossa jute fibres are long and have more tensile strength as compared to white jute. It is mainly used for making gunny sacks and bags.

Mesta jute
Mesta jute is a blend of white jute and Tossa jute. Learn more about mesta jute. 

Jute cutting
Jute cuttings are the leftover pieces of jute production. They do not exhibit much strength and are rough in texture. Jute cuttings are used to make bags, ropes, paper products and basic textile materials.

Application of jute

Jute is one of the most affordable and largely produced natural fibres. As per tonnage, jute fibre’s world output is greater than that of all the other bast fibres combined. It has a variety of applications. Most of the jute produced is made into sacks and packing cloths. Due to its coarse nature, its use in clothing is limited. However, advancements in jute processing have increased the applications in apparel, especially for dresses, jackets and cardigans. Jute fibres are also used widely for making composites for automotive, construction, packaging and other industrial uses like cables, plastics reinforcement, filter cloths, fire curtains, etc.

The application of woven jute cloth can be broadly categorised under apparel and lifestyle, home textile, packaging textile and geotextile.


Figure 19: Application areas of jute fabric

Apparel and lifestyle

Jute is used to create fashionable garments and accessories. It is one of the eco-friendly fabric options in the fashion industry. To make fine-quality garments, jute fibre is used in combination with pure cotton and other natural fibres. This makes the fabric softer, lighter and more breathable. Jute is a very versatile fabric. It can be bleached and dyed in many colours and also treated to have other functionalities.

Uses- dresses, sweaters, cardigans, bags, shoes, fashion accessories, shoe linings, etc.

Related article: Lits of jute products   

Home textile

Jute has become a popular feature in rustic-style home décor, and it brings a natural, textured feel to the room. The finer qualities of jute fibres are used in furnishing cloth. Jute can also be combined with other softer fibres to create textiles for making pillows, throws, linens, and upholstery.

Uses- cushion covers, curtains, upholstery, backing for tufted carpets, foot rugs, table mats, table runners, bedding foundations, etc.

Packaging textile

The majority of jute produced is used for packaging. It serves as a reusable, recyclable, and long-lasting packaging material. Additionally, jute is cheap and reasonably strong. This makes jute an important fibre for sacks and packing cloths. The resistance of jute fibres to stretching forces has proved a valuable property when jute is used for storage and transport purposes. Sacks and bales remain firmly in place after stacking; they do not distort and shift position as they would if made from a fibre more elastic than jute.

Uses- sacks, bags, packaging material for rice, wheat, corn, and beans, baling and bundle cloths, wrappings, etc.

Geotextile and Agriculture

Jute geotextiles are woven or non-woven jute fabrics. They are useful for control, construction and reinforcement applications. Jute geotextiles are particularly advantageous because of their availability, moisture retention capacity, ease of installation, and bio-degradability which makes them a part of the soil after degradation, thus causing no pollution. The biodegradability also helps in the quick regrowth of displaced vegetation by coalescing with the soil, increasing its permeability, retaining the appropriate humidity as "mulch" and creating a micro-climate that is conducive to vegetative growth.

Uses- protective wrappings around sapling roots, cattle beddings, surface soil erosion control, construction of embankment on weak soil, strengthening road pavement and surface for separation, drainage, temporary reinforcement, etc.

For India, the versatile fibre – jute – could be the fabric of the future. Transfer of technology from research and development institutions plays a key role in the diversification and growth. Institutes like the Central Research Institute for Jute and Allied Fibers are helping towards such goals. Also, there are various government initiatives to support the jute industry in India. Some of these are Jute Integrated Development Scheme (JIDS), Jute Technology Mission (JTM), Jute Raw Material Bank (JRMB) Scheme, Incentive Scheme for Acquisition of Plants and Machinery (ISAPM).



References:

S. Roy, L.B. Lutfar, 3 - Bast fibres: Jute, Editor(s): Ryszard M. Kozłowski, In Woodhead Publishing Series in Textiles, Handbook of Natural Fibres, Woodhead Publishing, Volume 1, 2012.

https://www.jute.com/green-jute/agriculture-raw-jute
https://oceangeosynthetics.com/a-comprehensive-guide-on-what-is-jute-geotextile/

Image sources:

• https://m.theindependentbd.com/arcprint/details/56299/2016-08-18
• https://www.hawaii.edu/news/2017/02/23/jute-fiber-genomes-could-help-improve-production-of-natural-fiber/
• https://www.fibre2fashion.com/news/textile-news/59-domestic-indian-uk-investors-bid-to-run-closed-bangla-jute-mills-274976-newsdetails.htm
• https://mpbirlajute.com/jute-processing/