Vegitable Fibres

8/7/2019 Vegitable Fibres

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Vegetable Fibres:

Vegetable or plant based natural fibres are made up of cellulose microfibrils in an amorphous

matrix of lignin and hemicellulose. They consist of several hollow fibrils which run all along

their length. Each fibril exhibits a complex layered structure, with a thin primary wall encircling

a thicker secondary layer. The primary cell walls are usually very thin (< 1m) and thesecondary layer is made up of three distinct layers.

The different types of Vegetable Fibres are as follows:

1. Bast

2. Leaf

3. Seed

4. Cereal Straw

5. Grass

BAST:

Bast fibres exist in inner bark of many flowering plants to provide structural rigidity to the stem.

These fibres are in bundles and parallel to stems in between nodes. The fibre strands are

composed of many smaller cells called ultimate fibres. The common Bast vegetable fibres are

Jute, Hemp, Kenaf, Flax etc.

Jute: Jute is a long, soft, shiny vegetable fibre that can be spun into coarse, strong threads. It is

produced from plants in the genus Corchorus, which has been classified in the family Tiliaceae,

or more recently in Malvaceae. It is the most affordable natural fibre and is produced second to

cotton in amount. Jute fibres are composed of cellulose and lignin. Thus it is a partially a textilefibre and partially a wood. The fibres are white to brown and of length 1-4 metres.

Fig 1: Jute Plant Fig 2: Jute cloth Pattern


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Properties of Jute:

y Ultimate Jute length: 1.5-4 mm

y Ultimate diameter : 0.015 to 0.002 mm

y Jute fibre length: 1 to 4 m

y Jute color: white, yellow, brown or gray.

y Strength of jute: 3.5to 5 G/Den

y Specific Gravity: 1.48

y Moisture Regain of Jute: 13.75%

y Elastic recovery is very low

y Bad resilience

y Dimensional stability: Good

Uses:

y Jute is used for making cloths for wrapping bales of raw cotton.

y Can be used as natural biodegradable containers for planting young trees.

y To make ropes and pulp and paper.

y For floor covering.

y Jute bag is a good alternative for polythene bags.

Hemp:

Hemp is soft, durable fibre cultivated from plants of the Cannabis genus. Hemp fibre is one ofthe strongest and most durable natural textile fibres.Hemp is the one of the faster growing

biomasses known, producing up to 25 tonnes per hectare per year. It is very environmentally

friendly as it requires few pesticides and no herbicides. Hemp is one of the ermost domesticated

plants known.

Fig 3: Hemp Plant Fig 4: Hemp stem showing fibre


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Properties:

y Hemp fibre is one of the strongest and most durable natural textile fibres.

y Lowest percentage of elongation as compared to most of the natural fibres.

y Hemp has the best ratio of heat capacity of all fibres which serves as superiorinsulation.

y Lightweight.

y As a fabric, hemp provides all the warmth and softness of other natural textiles

but with superior durability.

y It is biodegradable.

y Cost effective.

y Hemp fibre is longer, stronger , more absorbent and more insulative than cotton

fibre.

y Hemp is excellent biomass fuel producer.y Youngs modulus: 88000 to 90000MPa.

y Tensile strength: 690 to 696MPa.

y Elongation: 1 to 6%.

y Thermal conductivity: 0.048 W/m.K.

y Density: 1.48 to 1.49 kg/m3.

Uses: It is used for a wide variety of purposes.

y Industrial textile use, being one of the most interesting fibres to build ropes.

y In the painting industry as well as to produce soaps and plastics.

y As fuel, as a substitute of petrol, being more ecological.

y As food, specially to feed cattle and birds but also for human consumption.

Kenaf:

Kenaf is a plant in the Malvaceae family. It is an annual plant , originating from Africa,

has traditionally been a source of bast fibre in India, Iran, China, Bangladesh, Nigeria and

Thailand. The name kenaf is also used for the fibre obtained from this plant. Kenaf is one

of the allied fibres of Jute and shows similar characteristics.


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Properties:

y Bundle strength (kg/mg):

o Mean: 5.02

o Range: 3.10 to 6.34

y Fineness diameter (width): 41.7

y Tensile strength: 55.8 MPa

y Tensile strain modulus: 2.36

y Flexural modulus: 5.91 MPa

y Breaking elongation:

o Mean: 1.17o Range: 0.40 to 2.20

y Linear density:

o Mean: 3.00

o Range: 1.25 to 5.33

Uses:

y Pulp, paper and cardboard (from wet way process).

y String, rope and cord

y Material for mattresses and furniture.

y Compression insulation panels.

y As a packing material.

y Natural fuels.

y Animal fodder and feed.

Fig 5: Kenaf Tree Fig 6: Kenaf Fibre


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Flax:

Flax is a member of the genus Linum in the family Linaceae. Flax is an erect annual plant

growing to 1.2m tall with slender stem. The leaves are glaucous green, slenderlanceolate, 20-40mm long and 3mm broad.

Properties:

y Youngs modulus: 28000 to 40000MPa.


y Elongation: 1.5 to 4%.

y Thermal conductivity: 0.055 W/m.K.

y Density: 1400 to 1600 kg/m3.

y It is amongst the oldest fibre crop in the world.

y Flax fibre is soft, lustrous and flexible.

y It is stronger than cotton fibre but less elastic

Uses:

y Flax is grown both for its seeds and fibre.

y In ancient times of Neolithic flax fibre was used for manufacturing cloths.

LEAF:

Leaf fibres are coarser than bast fibres and commonly used as cordage, mats, rugs and

carpet backing rather than clothing fabrics. Common examples of these materials are

Manila hemp (abaca), Sisal, Pineapple leaf, Henequen etc.

Fig 7: Flax Plant Fig 8: Flax fibre


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Sisal:

Sisal is an agave that yields a stiff fibre traditionally used in making twine, rope and also

dartboards. Sisal is a natural fibre fully biodegradable. It is highly renewable source of

energy. Sisal fibre is exceptionally durable and a low maintenance with minimum wear

and tear. Its fibre is too tough for textiles and fabrics. It is not suitable for a smooth wallfinish and also not recommended for wet areas. The fine texture of Sisal takes dyes easily

and offers the largest range of dyed colors of all natural fibres. Sisal fibre is exceptionally

durable and biodegradable.

Properties:

y Youngs modulus: 26000 to 32000MPa.


y Elongation: 4.3%.

y Density: 1200 to 1450 kg/m3.

y Sisal fibre is exceptionally durable with a low maintenance with minimal wear

and tear.

y It is recyclable.

Uses:

y From ancient times Sisal has been the leading material for agricultural twine

because of its strength, durability, ability to stretch.

y Apart from ropes, twine Sisal is used in low cost and specialty paper.

y Dartboards, buffing cloths, filters.

y Geotextiles, mattresses, carpets, handicrafts, wire rope cores and Macrame.

y It is a good alternative for plastic.

Fig 9: Sisal Plant Fig 10: Sisal Fibres


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SEED-HAIRFIBERS:

Unlike the bast and leaf fibers, seed-hair fibers are single celled. These fibers are attached to the

seeds of certain plants for aid in wind-dispersal. One exception to this is coir, a fiber produced

from the husk of coconuts. The more typical seed-hair fibers are all similar in morphology to

cotton, with long lengths (20 mm) and small diameters (20 mm). Cotton fibers consist of the

unicellular seed hairs of the bolls of the cotton plant. Innumerable products are made from

cotton, primarily textile and yarn goods, cordage and automobile tire cords. Short fibers that are

left on the seed after processing are termed linters. Cotton linters are commercially available and

are currently use as rag content in fine papers. These waste fibers have similar diameters to the

textile cotton, with much shorter lengths (less than 7 mm).

Cotton:

Cotton is a soft, fluffy staple fiber that grows in a protective capsule, around the seeds of cotton

plants of the genus Gossypium. The plant is grown in more than 70 countries. The fiber most

often is spun into yarn or thread and used to make a soft, breathable textile, which is the most

widely used natural-fiber cloth today.

Fig 1: Cotton boll ready for harvest

Source:Wikipedia.org

Fig 2: Cotton modules in Australia

Source:Wikipedia.org


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Properties:

y Length varies from 1 cm to 6 cm; typical length is 2.2 cm to 3.3 cm.

y Fairly uniform in width (12-20 m).

y Youngs modulus: 5300 to 8000 MPa.

y Tensile strength: 400 to 850 MPa.

y Elongation: 3-8 %

y Density: 1540 kg/m3

y Water absorption: 20 100 %

Uses:

y Cotton fibre is used as yarn and threads in a wide range of clothing, most notably in

shirts, T-shirts and jeans, but also in coats, jackets, underwear and foundation garments.

y Cotton is also used to make home furnishings, such as draperies, bedspreads and window

blinds

y cotton is used in fishnets, coffee filters, tents, gunpowder, cotton paper, and bookbinding.

y It is also used in cordage and automobile tire cords.

Coir:

Coir is the fibrous material found between the hard, internal shell and the outer coat of a coconut.

Like bast fibers, coir is produced by separation technique after husks undergo retting. The

individual fibre cells are narrow and hollow, with thick walls made of cellulose. They are pale

when immature but later become hardened and yellowed as a layer of lignin is deposited on their

walls. Each cell is about 1 m long and 10 - 20 m in diameter. Fibres are typically 10 to 30 cm

long.

Fig : Coir fibreFig : Coir mattress

source: apartmenttherapy .com


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Properties:

y Youngs modulus: 4000 to 5000 MPa.

y Tensile strength: 140 to 150 MPa.

y Elongation: 15 17.3 %

y Density: 1.15 1.33 kg/m3

y Water absorption: 10 %

Uses:

y Coir is used for making finer brushes, string, rope and fishing nets.

y It is utilized in Mattresses also.

y The major use of white coir is in rope manufacture

y Mats of woven coir fibre are made from the finer grades of bristle and white fibre using

hand or mechanical looms.

y It is also used for insulation and packaging.y Coconut coir from Mexico contains large numbers of colonies of the beneficial

fungus Aspergillus terreus which acts as a biological control against plant pathogenic

fungi.

CEREALSTRAW:

Straw is produced throughout the world in enormous quantities as a by-product of cereal

cultivation. Half the straw is simply burned on the fields just to get rid of it or else it is buried in

greater quantities than what is needed to replenish organic matter in the soil. Historically, straws

from wheat, rye, and rice were widely used as a pulp source for paper-making. Whereas this

practice became extinct in North America and much of Europe by 1960, it is still practiced in

southern and eastern Europe as well as many Asian, Mid-Eastern, and Southern American

countries. Although corn stalks are widely available and have been studied as a pulp source, their

commercial use has been limited.

Straw consists of less cellulose and lignin but more hemicelluloses as compared to wood. In

general, wheat straw and corn stalk fibers have small diameters and average lengths producing a

favorable aspect ratio of 110 as shown in Table 1. Fibers from rice straws typically have smaller

diameters (5 to 14 mm) with a long aspect ratio of 170. Straw offers some technological

advantages over wood because it allows better packing of the fibers or strands and the degree ofbonding between them is much better.


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Table 1: Cereal straw fiber dimensions

Property General Corn Rice Wheat

Length (mm) 0.68-3.12 1.0-1.5 0.65-3.48 1.5

Diameter (mm) 7-24 20 5-14 15

GRASS FIBERS:

Many other grasses have been and are considered as a fiber source. Because of limited

availability or processing difficulties, most of these fibers (except sugarcane bagasse) have never

become widely used; however, they are often common in certain localities. These fibers include

sugarcane bagasse, bamboo, esparto, and sabai grass.

In these grass fibers, sugarcane bagasse is the most common and widely studied among the

researchers. Sugarcane is grown as a source of sucrose in many tropical and sub-tropical

countries on many continents. Bagasse is the residue remaining after the sugar has beenextracted. Currently, this material is used for paper in India and Mexico and in boilers to

generate process steam for the sugar production

Bamboo fiber:

Bamboo fiber is a cellulose fiber extracted or fabricated from natural bamboo (and possibly other

additives) and is made from the pulp of bamboo plants. It is usually not made from the fibers of

the plant, but is a synthetic viscose made from bamboo cellulose.

Bamboo has gained popularity as a "green" fiber. Manufacturers tout the fact that bamboo can be

cultivated quickly, can be used as a cash crop to develop impoverished regions of the third

world, and is a natural fiber whose cultivation results in a decrease in greenhouse gases.

Fig:1 Bamboo fibre threads Fig: 2 Bamboo fibre babys pad


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Properties:

y Tensile strength is 368.1 MPa.

y Average diameter: 0.14 mm.

y Density: 1.31 g/m3.

y Softer than cotton, with a texture similar to a blend of cashmere and silk.

Because the cross-section of the fibre is filled with various micro-gaps and micro-holes, it

has much better moisture absorption and ventilation. Moisture absorbency is twice than

that of cotton with extraordinary soil release.

y Natural antibacterial elements in bamboo fibre keep bacteria away from bamboo fabrics.

y Garment of bamboo fibre can absorb and evaporate human sweat in a split of second just

like breathing. Such a garment makes people feel extremely cool, comfortable and never

sticking to skin even in hot summer.

y 100% bamboo yarns show a great elasticity i.e. nearly 20%. Even in 100% bamboo

woven fabrics a remarkable elasticity can be obtained.

y Anti-ultraviolet nature of bamboo fibre has made it suitable for summer clothing,especially for the protection of pregnant ladies and children from the effect of ultraviolet

radiation.

y Product of bamboo fibre is eco-friendly and bio-degradable.

Uses:

y Intimate apparels include sweaters, bath-suits, underwear, tight t-shirt, socks.

y Due to its anti-bacterial nature, non-woven fabric has wide prospects in the field of

hygiene materials such as sanitary napkin, masks, mattress, food-packing, bags.

y

Sanitary materials: bandage, mask, surgical clothes, nurses wears and so on. It hasincomparably wide foreground on application in sanitary material such as sanitary towel,

gauze mask, absorbent pads, and food packing.

y Decorating items: curtain, television cover, wall-paper and sofa slipcover.

y Bathroom products: towel and bath robe.

References:y http://www.matbase.com/material/fibres/natural

y http://www.wolframalpha.com

y http://www.wikipedia.com

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