Textile raw material:
Raw material has been defined as “material that has not been subjected to a specific process of manufacture.” Textile raw materials are materials that can be converted into yarns and fabrics of any nature or character. Fiber is a raw material used in textile manufacturing.
Fiber:
The material, which consists fibrous structure and length is thousand times higher than its width is called fiber. It is also the generic term used to describe the basic element of the material from which yarns, textile, knits other substances are made. Most apparel fiber ranges in length from 15 to 150 mm and thickness ranges from 10 mm to 50 mm.
What is textile fiber?
Textile Fiber:
The materials which consist fibrous structure
and length is thousand times higher than its width/diameter and can be spun
into yearn, sui
for weaving or knitting and easily colored by suitable dye
stuff are known as textile fiber. So a textile fiber have to contain the
following characteristics.
- Fibrous structure.
- Length is thousand times higher than it's width / diameter.
- Spun able i.e. It has spinning quality.
- Sufficient strength.
- Elasticity and flexibility.
- Fineness.
- Color.
- Dye ability i.e. affinity to dye, etc.
Mono filament
Multi filament
Monofilament: This filament is made only of a single filament.
Multi-filament: These filaments are made of more than one filament.
 |
| Classification of fiber |
What is the difference between the natural fiber and man made fiber?
Natural Fiber |
Man-Made Fiber |
| 1. Number of molecules is not limited. | 1. Number of molecules limited. |
| 2. Get from nature. | 2. Made by synthetic system. |
| 3. The Number of molecules controlled by nature. | 3. The Number of molecule controlled by man. |
| 4. The length can not be controlled. | 4. The length can be controlled. |
| 5. Hygienic. | 5. Some are not hygienic. |
Write down the merits and demerits of natural fiber and man made fiber.
1. Length / Fiber structure: Microscopic structure.
(a) The length of NF is limited for different fibers but the length of MMF fiber is unlimited because the length of man made fiber is depended on wishes of manufacturer.
(b) Most of the MMF is crystalline than natural fibers and structure is partially different such as follow and natural strands cotton.
(C) Crimps and schwas in wool and felt such characteristics are the great advantages of natural fiber which are absent in MMF.
2. Strength:
(a) The strength of man-made fibers is higher than natural fibers because of it’s crystalline and orientation.
(b)The amorphousness is higher in NF than MMF.
3. Scope of weariness
• In clothing, natural fibers are demandable due to its merit point of touch, softness, hygienic characteristics, that’s why the dresses of NF are more comfortable than MMF.
4. Production:
• The production of NF is affected by natural calamities and production may fall down.
• The man made fiber’s production is not dependent on natural climates.
What is the difference between staple fiber and filament?
• Staple fibers are mainly shorter in length and filaments are continuous in length
• Staple fibers are normally related to natural fibers but filaments are related to man made fibers
Write down the properties of textile fibers.
Properties of Textile Fibers:
A. Physical properties.
B. Thermal properties.
C. Chemical properties.
A) Physical properties:
a) Length:
It depends upon the types of fibers. It is fine in case of man-made fiber but varies largely in case of natural fibers. The lengths are measured in three ways –
- Average length
- Effective length
- Staple length.
b) Strength and extension:
The capability of a fiber to support a load is known as its strength. In case of a fiber, the strength is described as tenacity.
Tenacity = Strength / linear density.
It is expressed in terms of CN/Tex or N/Tex. The tensile strength is commonly described as the force required to reach break the increase in the length before breaking is known as extension.
c) Flexibility:
Flexibility is that property to resist repeated bending and folding.
d) Cohesiveness:
It is the ability of the fibers to cling together during spinning depends on crimp and twist.
e) Fineness:
The term ‘fineness’ describes the quality of a fiber. By this, we can know how fine a fiber is. It is expressed by the terms count, tex, denier, Tex per unit length etc.
1 tex = 1 gm wt/1000 m.
1 denier = wt. in gm/900 m.
Fineness affects some fiber properties. Such as yarn count, yarn strength, yarn regularity etc.
f) Cross section:
The cross section of a fiber determines the physical properties of the fiber. It gives idea about strength, fineness that varies from fiber to fiber. The cross-section shape of a fiber is important because it contributes to the surface appearance of the fiber. It helps to give properties of luster, bulk and body of the fibers, yarn and fabrics. It has effect in twisting, bending or shunning.
g) Crimp:
It refers to the waves or bends that take place along the length of a fiber. It increases cohesiveness & resilience, resistance to abortion and gives increased bulk or warmth to fabrics. It also helps fabrics to maintain their softness or thickness, increase absorbency and show contact comforts bid reduce lusture. A fiber may have one of the three types of crimp. Namely – mechanical crimp, natural crimp or inherent crimp and chemical crimp.
h.) Elasticity:
It is the power of recovery from deformation. The fiber may be plastic or elastic which depends upon fiber condition and surrounding environment.
i) Resiliency:
It is the property of a fiber, which enables it to recover from a certain load or stretch over a period of time.
j) Toughness:
The ability of a fiber to endure large permanent deformations without rupture is called toughness
k.) Work of rupture:
The area below the stress-strain curves provides a measure of the work required to break the fiber. It is called work of rupture and it commonly expressed in CN/Tex.
l.) Appearance:
It is expressed by length, fineness, cross-section cleanness and lusture of a fabric. Generally short fibers are bulky and loss lustrous.
m) Density:
The density indicates the mass per unit volume. The specific gravity of a fiber indicates the density relative to that of water at 40c.
n) Elongation:
It is the ability to be stretched, extended or lengthened. Elongations vary at different temperatures and when wet or dry.
B) Thermal properties:
a) Amorphousness:
Amorphous orientation of polymers within the polymer system of any fiber is called the amorphous region. In amorphous regions, the polymers are oriented or aligned at random.
b) Crystallinity:
Crystalline orientation of polymers within the polymer system of any fiber is called the crystalline region.In crystalline regions the polymers are oriented or aligned longitudinally into more or less parallel order.It is in the crystalline areas that hydrogen bonding and Vandars-Wals forces occur.
c) Flammability:
It is the ability to ignite and burn.
d) Dye ability:
It is the ability of fibers to be dyed.
C) Chemical properties:
a) Water:
Water is very important to determine the properties of fibers. According to the behavior of fibers with water, fibers are classified into two groups –hydrophobic and hydrophilic. Water is used in process like scouring, dyeing, etc.
b) Absorbency:
It is the ability of fiber to take up moisture and is expressed in therms of moisture regain. It depends upon the polarity of the polymers and the ratio of its amorphous and crystalline region. There are some terms, such as
c) Acid:
Textile fibers and materials are subjected to acids in various processing like bleaching. The different kinds of fibers react differently with acids. The acid must be chosen properly to use different process so that it doesn’t make any harm to the fiber but brings the required change perfectly.
d) Alkali:
Different kinds of fibers behave differently with different alkalis in different situations. For example, Caustic soda in dilute solution and low temperature dissolved the wool fibers, whereas mild alkalis have no injurious effect on wool at ordinary concentration. It is used to many presses as dyeing, sizing and finishing.
e) Heat:
Textile fibers are subjected to heat in dyeing, drying, steaming, calendaring, pressuring and other operations. Some fibers become tough under heat such as Rayon, resin, where as some burn under heat such as flax, cotton, jute, etc.
f) Sunlight:
Sunlight reacts differently with different fibers and fabrics. For example, white fabrics become faded in various degrees. Again black absorbs more suns heat than the white one.
g) Biological agent:
If the fibers are attacked by bacteria’s, black spots are seen on the fibers as a result of which the strength of fiber is reduced. Its importance whether fibers attached by micro-organisms or not upon which strength of products depends
h) Moisture Regain:
Moisture regain is defined as the weight of water in a material expressed as a percentage of the over dry weight of the material or the ratio of water in a material to the oven dry weight of this material is called moisture regain. It is donated by R.
Let, oven dry weight of a material =D
Weight of water in this material =W
Moisture Regain, R =W/D X 100
i) Moisture Content:
Moisture content is defined as the weight of water in a material express as a percentage of the total weight of the material or the ratio of water in a material to the total weight of the material is called moisture content. It is denoted by C.
Let, Oven dry weight of a material =D
Weight of water in this material =W
Moisture Content, C =W/ W+D X 100
What is the botanical classification of cotton?
Botanical classification of Cotton:
• Cossypium harbaceum: Plant length: 3¢-6¢
Flower colour: yellow.
• Gossypium hirsutum: Plant length: 6¢
Flower colour: Red
• Both are mainly cultivated in America and India.
• Gossypium peruvianum:
They are mainly produced in Peru and other South American countries.
• Gossypum barbedense: Plant length: 6¢-15¢
Flower colour: Yellow.
• They produce fine silky Sea Island cotton.
Mention some important/major cotton cultivating country?
Major cotton cultivating countries:
• The main cotton producing countries are USA, India, Russia, Egypt, Brazil, USSR, China, Mexico, Pakistan, Turkey, Argentina Peru etc. The USA produces almost one-fifth the total crop
Environment of cotton cultivation:
• Cotton cultivation mainly takes place in tropical and sub tropical climates sunshine heavy rainfall; higher humidity is required for cotton cultivation.
• Sufficient sunshine is necessary for cultivation while frost will kill the plants
• Cotton plants can survive in dry but best cultivation can be done in place where rain fall is 20” to 60” per year.
• Irrigation is necessary when rainfall is less.
Cultivation of cotton:
• Seed planted.
• Two weeks later two leaves appear on the plant.
• At five or six weeks later, the first flower appears.
• At eight to nine weeks the first flower blooms.
• Seed hairs start to grow inside the bolls.
• For 16-18 days, fiber length and perimeter achieved.
• For the next 22-50 days, cellulose is deposited inside the fibers.
• When cellulose deposition stops, the bolls dry and cracks to open.
• These bolls are picked up manually or by machine. This picking period is continue for 1-3 months.
• Then ginning is done to collect the cotton fibers.
Consequence process of cotton fiber production:
• The cotton seeds are usually shown by machine is continuous stream in raw three to four apart.
• When the plants are a few inches high, the rows must be thinned by cutting out the undesired plants (chopping).
• Upland cotton goods to a height of about four feet and blooms two to the three months after planting.
• The blossoms last but a days and when they fall of the boll begins to develop.
• These seeds pods or bolls contain the seeds to which the fibers are attached.
• When the cotton is ripe, the bolls burst exposing a soft, fluffy mass of fibers.
• The cotton must be picked soon after the bolls open to prevent the fibers from
beaming discolored and dirty from exposure to the sun and weather.
What is ginning?
Ginning:
The freshly picked cotton has seeds in it, this cotton is called seed cotton. The treading is done in this condition also, but normally the treading is done after separation of the fibers from their seed. So, the process, involves to separate the cotton fibers from seeds is called ginning.
What is the objective of ginning?
Objects of ginning:
• To separate fibers fully from its seeds.
• To collect seeds and waste together.
• To collect fiber without any faults.
• To separate whole fiber.
Write down the types of ginning?
Types of ginning:
• Saw ginning
• Roller ginning
• Macarthy ginning
Saw ginning: →
What is procedure of saw ginning?
Procedure of saw ginning:
● The cotton with seed is stored in hopper feeder by feed table or air flow.
• Spiked roller throws the cotton with seed on grid bar.
• The discs of saw gin permits to entry of seed free fiber through the hole of bar.
• The empty path of bars (both sides of saw teeth) permits to entry the fibers but not seeds.
• The separated seeds fall on conveyors.
• The cotton lints are separated from saw teeth by proper air flow.
• The separated cotton lints is transported by conveyor pipe.
What is roller ginning?
Roller ginning: → 1. Feed hooper.
2. Feed roller.
3. Spiker drum.
4. Net.
5. In clined net.
6. Drum.
7. Ejecting drum.
. 8. Accelerating drum.
9. Functional roller
10. Backing of roller.
11. Doffing roller.
12. Perforated sheet.
• The seeded fiber comes in contact with feed roller by the help of feed hooper.
● The seeded fibers are embedded on the two feed roller and are feed to spiked
roller.
• The trash are removed by the action of spike and are stored on trash chamber by perforated sheet.
• Then seeded fiber pass through inclined net by air flow and attached to the spiked drum. Here accelerating drum separates the cotton fiber and pass it.
• The accelerating drum transports the cotton fibers.
• Rough surface of functional roller takes only fibers and the seeds are retained on backing roller.
• The doffing roller separates the fibers from functional roller and transports through delivery pipe and the seeds fall on conveyor.
Classification of cotton fiber according to maturity:
1) Mature fiber: Well-developed secondary sell wall and very small humen.
2) Immature fiber: Fibbers with thinner secondary sell wall, larger lumen.They can not exhaust the dye molecules properlyin dyeung or printingthats why they produce paler shade in dyeing.
3) Dead fiber: So called dead fibers have essentially only the primary cell wall .The lumen occupied the bulk of fiber .They remain undyed in dying.
Bangladeshi cotton:
Mainly American cotton are produced in Bangladesh, Commercially hybrid cotton are producing at Meherpur, Jessore,Kustia and Gazipur.The quality or Bangladeshi cotton is improving now. Length, colour, maturity are also very good. It is possible to produce minimum 60s yarn from Bangladeshi cotton fibers.
Chemical composition of raw cotton:
|
Component |
Main location |
Relative amount (%) |
|
Cellulose |
Secondary wall |
86.8 |
|
Oil and waxes |
Cuticle |
0.7 |
|
Pectins |
Primary was |
1.0 |
|
Carbohydrate |
Primary was |
0.5 |
|
Proteins |
Lumen |
1.2 |
|
Salts |
Lumen |
1.0 |
|
Water |
|
6.8 |
|
Others |
|
2.0 |
The oils and waxes of cotton consists of:
1) Glycerides, which are readily saponifiable oils and fats.
2) Waxes which are difficult to saponify.
3) Unsaponifiable oils
4) Free fatty acids.
5) Traces of soaps.
Grading of cotton:
In order to grade the quality of raw cotton, the rating is done according to the level of the length, fineness, strength, colour, lusture, natural strands and impurities in the fiber. These are divided in different ways according to the production land.
Quality of cotton: Quality of cotton depends on-
· Colour.
· Staple length.
· Fineness.
· Strength.
· Maturity.
· Trash content.
· Uniformity ratio.
Considerable points of grading of cotton:
The assessment of cotton is carried out traditionally by the cotton ‘classer’ who depends upon personal skill and long experience in judging cotton quality by inspection and feel.
In arriving at his assessment, the classer takes note of (1)The staple length,(2)The colour and (3)The amount of impurity in the cotton and the quality of its preparation.
Grading of cotton of different countries:
(From high grade to low grade)
|
American cotton |
Egyptian cotton |
Indian cotton |
|
Middling fair |
Extra fine |
Super choice |
|
Strict good middling |
Fine |
Choice |
|
Good middling |
Good |
Super fine |
|
Strict middling |
Fully good fair |
Fine |
|
Middling |
Good fair |
Fully good |
|
Strict low middling |
Fair |
Good |
|
Low middling |
|
Fully good fair |
|
Strict good middling |
|
|
|
Ordinary |
|
|
|
Good ordinary |
|
|
Polymer system of cotton fiber:
Cotton is a crystalline fiber, cellulosic polymer. The repeating unit in the cotton polymer is cellubiose which consists of two glucose units. Its polymer system is about 65-70%crystalline and corresponding about 35-30%amorphous.
Degree of polymerization: 2000+
Functional group: OH, Cell-CH2OH
Cross sectional structure of cotton fiber:
 |
1. Cuticle: the outermost layer of cotton is known as the cuticle and is a thin film of fats, pectines and waxes.
2. Primary cell wall: Inside the cuticle the primary wall is composed mainly of cellulose in which the fibers are arranged in a criss-cross pattern.
3. Secondary cell wall:
- Under primary wall, secondary wall is composed of cellulose which constitutes the balk of the fiber.
unknown.
Convolution:
The mature fiber can be recognized by the Under the microscope, the cotton fiber looks a twisted ribbon or a collapsed and twisted tube. These twists are called convolution. Convolution of Egyptian cotton: 230 /cm and of Indian cotton: 60/cm.
Chemical structure of cotton fiber:
Features (structural) of cellulose:
- Cellulose is a polymer of ₿– D glucose.
- Branchless linear large polymer.
- ₿-D glucose are linked by ₿-glycocydic bond.
· Bond is made between C1 and C4 atom of ₿ -D glucose.
· Molecular weight is above 5,00,000.
· One cellulose polymer contains 300-1500 glucose polymer.
Chemical Characteristics:
- Water insoluble but soluble in NaOH and CS2 mixture, Ammoniacal Cu (OH) 2 etc.
- Do not react with I2.
Properties of cotton fiber:
1. Molecular structure: Cellulosic.
2. Physical properties:
i) Length: .3 cm to 5.5 cm.
ii) Diameter: 16 to 20 microns.
iii) Cross section: Kidney shape
iv) Colour: White, grey, cream.
3. Tensile properties:
i) Tenacity(gm/den): 3.0-5.0 (In dry state)
3.6-6.0 (In wet state)
ii) Elasticity: Elongation at break 3.0-7.0%
iii) Resiliency: Low.
iv) Moisture regain: 8.5%and raised to around
25-30% water at 100% Relative humidity.
v) Specific gravity: 1.54
4.. Chemical properties of cotton fiber:
i) Effects of bleaches: – Resistance to bleach, but H2O2, NaOCl, NaOCl2, Ca (OCl)Cl are used as bleaching agents for cotton processing.
ii) Effects of acids and alkalis: Dissolved in high concentrated mineral acids such as HCl, H2SO4 but high resistant to alkalis that’s why NaOH, Na2CO3, and used for scouring of cotton. Concentrated NaOH is also used for cotton mercerizing.
iii) Effect of organic solvents: Have resistant ability to most organic solvents such as dry cleaning agents.
v) Effect of heat: Cotton has an excellent resistance to degradation by heat. It begins to turn yellow after several hours at 1200c and decomposes markedly at 1500c as a result of oxidation.
vi) Effect of sunlight: There is a gradual loll of strength when cotton is expressed to sunlight and the fiber turns yellow.
vii) Effect of insects: Cotton is not attacked by moth grubs or beetles.
viii) Micro-organism: Cotton is attacked by fungi and bacteria.
ix) Dye ability: Direct, Reactive, Sulfur and Vat dye.
Faults of cotton fiber:
Þ Neps : Small groups of entangled fibers, which form at cotton processing. In spinning neps are difficult to eliminated or to comb. They impair the quality and outward appearance of yarns.
Þ Fiber strings: Strongly roped groups of fibers of different shapes. The same as neps, fiber strings appear at cotton processing. They can be well combed in spinning but as neps may appear which are difficult to eliminate.
Þ Coils: Slightly roped groups of fibers. Their presence is undesirable as they easily form neps and strings. Mainly short fibers and ill fibers are form this type of faults. This presence renders difficult yarn production and impairs the quality.
Þ Trash: Trash is defined as particles above 500 micro meters trash typically accounts for 1%to 5% of baled cotton. Mainly bits of leaves, boll parts, and stems are defined as trash.
Þ Motes: Small and immature seeds and their fragments which fall through the grates in grains.
Þ Crushed seed: Parts of seeds crushed during primary cotton processing.
Þ Bearded motes: Small bits of seed hull with fibers. Formed at seed crushing during primary cotton processing and at further seed cult to eliminate.
Þ Dust: Defined as representing particles between 50 and 500 micrometer, dust maybe exhausted into a waste collector.
Chemical reaction of cellulose:
Cellulose is an active chemical with three hydroxyl groups attached to each glucose residue. Those in the 2 and 3 positions behave as secondary alcohols; the hydroxyl ion the 6 positron acts as a primary alcohol.
These hydroxyl groups take part in normal chemical reactions and a great number of cellulose esters and ethers have been made.
Oxidation of cellulose gives rise to oxycellulose.
Increased strength of cotton fiber for wetting:
When water molecules penetrate into the interior of fiber, it lies between the fibrils and into the amorphous regions of the fiber polymer where they can easily form hydrogen bonds with free cellulose hydroxyl groups and the water absorption causes the swelling of the secondary sell was but little fiber elongation. Although absorbed water acts as a plasticizer, it also cements the cellulose chains and fibrils together by hydrogen bonding .These are the reasons of increasing the strength of cotton fiber for wetting.
Chemically Modified cotton:
1. PA cotton: Treatment of cotton with acetic anhydride in acetic acid converts it to partially acetylated cotton (PA cotton). This material looks like original cotton. It has no smell and is non-toxic. But in many of its properties, PA cotton differs from the normal cotton fibers. Most important of all, it has a great resistance to heat than cotton. At 250° C, cotton looses one-third of its strength in three minutes where as PA cotton in similar yarn looses one third of its strength after twenty-five minutes at the same temperature. For these properties of PA cotton it can be used to make laundry press cover and lasts for long time.
- It also withstands the attacks of micro-organism of mildew and rotting.
- It has chemical resistance. In 20% HCl, it looses its one-third of its strength in eight hours, where as ordinary cotton looses about two-thirds.
- Better electrical insulator.
Uses:
Sand bags, fishing nets and lines, weather resistance fabric etc.
2. AM COTTON: When cotton is treated with 2-aminoethylsulphuric acid in sodium hydroxide, another form of chemical modification takes place. The fiber retains its essential structure, but its properties have changed. The new fiber is known as AM cotton.
3. CM cotton: Cotton treated with monochloroacetic acid and then sodium hydroxide is converted into CM cotton.
4. CN Cotton: Treatment of cotton with acrylonitrile yields a chemically modified cotton described as cyanoethylated(CN).
5. PL cotton: Treatment with propiolactone converts cotton into a modified cotton described as PL cotton.
Average maturity of cotton fiber:
The proportion of immature fiber to mature fiber is called average maturity, which is an important factor in determining the quality of the cotton.
In ordinary commercial cotton, about one quarter of the fibers will be immature. Sometimes, the proportion of mature cotton reaches 90 per cent, but such high ‘maturity count’s are rare. In commercial upland cotton, maturity counts of more that 84 per cent are described as ‘hard-bodied’. Average maturities like between 68 and 78 percent and cotton with maturity counts below about 67 percent are regarded as immature.
Absorbency of cotton fiber:
The molecules are called hygroscopic nature. Cotton is very absorbent fiber. Cotton consists – OH group, which is polar. Its positive portion affects the negative portion of water and negative portion affect the H+ of H2O. So, cotton can absorb easily in water.
The amorphous polymer system also liable for its being absorbent. It is the crystalline regions are too small for the water molecules. The amorphous region, which has enough empty places, permits easy entry of water and this it is more absorbent.
Lingo cellulose & Pecto-celloulose:
Pecto cellulose: Cellulose fiber containing cotton and pectin is called pecto – cellulose.
Ligno-cellulose: Cellulose fiber containing lignin is called ligno cellulose.
Diference between pecto and lingo-cellulose:
|
Properties |
Pecto-celloulose |
Ligno-cellulose |
|
Strength in all condition |
Stronger |
Weak |
|
Stiffness |
Moderate |
High |
|
Resiliency |
Good |
Bad |
|
Alkali |
Non resistant |
Resistance to alkali |
|
Bleach |
Affected by it |
No Affected by it |
|
Cellulose |
High |
Medium |
|
lusture |
Low |
High |
Ultimate:
The unit cell beyond which subdivision is not possible without loss of fiber’s identity.
End uses of cotton:
- Cotton fabrics combine remarkable durability with attractive wearing qualities. Cotton fabrics have a pleasant feel or handle. They are cool in hot weather.
- Cotton is used in great quantity as a fabric for hot-weather wear; it is able to provide warmth as well.
- Cotton garments are therefore comfortable and cool, passing on the perspiration from the body into the surrounding air.
- The absorbency of cotton makes it an excellent material for house-hold fabrics such as sheets and towels too.
- Cotton is widely used in making rain wear fabrics.
- The versatility of cotton has made it into the most widely used of all textile fibers. Cotton is made into every type of garment and house-hold fabric. It goes into boots and shoes, carpets and curtains, clothing and hats. Heavy cotton yarns and materials are used for tyre cords and marquees, tarpaulins and industrial fabrics of all description.
SILK
(The Queen of the fiber)
Introduction
Silk is the filament spun by the caterpillars of various butter flies. Silk is a natural protein filament. Its filament density is 1.34g/cm3 which make it a medium weight fiber. Very light weight silk textile materials may be manufactured form silk filaments.
Different types of silk
Types of silk:
a) Silk: It refers to cultivate silk.
b) Wild or Tussah Silk: Wild or Tussah silk is a tan-colored fibre from the cultivated silk worm which feeds on sorub oak. As the cocoon are always pierced the fibres are shorter than reeled silk. It is different both physically and chemically from ordinary silk. It is brown in color, considerably stiffer and coarser. It is less reactive towards chemical. It is used in the shantung, pongee fabrics.
c) Thrown silk or greg: Thrown silk consists of two or more threads of raw silk reeled tighter and given a slight twist.
d) Organzine silk: Organzine silk is produced from best cocoons. It contains tow or more strands each composed of a number of greges twisted together slightly. These threads are then doubled and retwisted in the opposite direction to the original twist in the strands (Strands mean a number of flexible strings twisted together into a rope). Organzine is used for warp threads when high tensile strength is required.
e) Tram silk: Tram silk si usually made from cocoons of lower grade, like organzine. It is composed of two or more strands of thrown silk lightly twisted together and then doubled.
f) Chapple silk: When silk which is still in the green is spun, the yarn is known as chapple.
The manufacturing steps of silk
The manufacturing steps of silk are:
i) Sericulture,
ii) Sorting cocoons,
iii) Softening the sericin,
iv) Reeling,
v) Throwing.
i) Sericulture: Sericulture the care and nurture of the silk caterpillar is a tedious painstaking business. The silk worm cultivation is called sericulture. The process starts with the silk moth, which lays eggs on specially prepared paper. The eggs are kept in cold storage until the mulberry frees start to bud. Then they are placed in incubators for a ten days period.
The next stage is one of the phenomenal growths. When hatched the silk worm is about one quarter of an inch long. When it ahs reached maximum growth it has increased in length to about 3inches and in weight from 3milligrams to 5grms. It eats only fresh, young, tender, dry mulberry leaves. The worms are fed and placed on clean trays several times a day.
When the silk worm is grown it spins a fibre cocoon around itself. The cocoon is spun in an almost continuous session of 24 or 72hours. The caterpillar extrudes from two holes in its hard two strands of fibroin (called brins), which are glued together by the ‘secicin’ selected by adjacent glands. The silk worm winds the thread in figures of eight round its body forming an egg-shaped case the cocoon.
Sometimes later a moth emerges from this cocoon, bursting the cocoons. In order to obtain the silk thread undamaged the charysales are destroyed by that before they emerge. The cocoons are beaten in hot water to disentangle the filaments. The filaments of several cocoons from a silk thread which is wound up on a reel.
ii) Sorting cocoons: The cocoons are shorted according to colour, shape and texture.
iii) Softening the sericin: (What is sericin: when the silk worm is grown it spins a double strand of silk fibres surrounded by water soluble substance is called sericin)
After the cocoons have been sorted they are put through a series of hot and cold immersions as the sericin must be softened to permit the unwinding of the filament as one continuous thread. Raw silk consists of about 80% fibroin and 20% sericin. At this time only about 1% of sericin is removed, because this silk gum is a needed protection during the further handing of the delicate filament.
iv) Reeling: The process by which filament is taken up from the cocoon is called reeling. The diameter of the filament is so little that if it is reeled, its commercial value will be decrease. More-over double filament is too delicate to handle alone. So several of these double strands from as many cocoons are joined and wound in a skein. The gum which holds the strands of silk together in the cocoons is softened but not removed before reeling. Only about 16% of the weight of the cocoon is silk fibre. About half of which can be reeled. These fibre vary in length 300 to 1000yds.
v) Throwing: The production of yarn from reeled silk know as throwing consists adding twist or of doubling and further twisting these strands into the desired size. When two or three of silk multifilament are twisted together to form heavier threads, this process is called throwing.
It is an operation of making a twisted yarn from reeled silk or putting additional twist into filament yarns of man made fibres or in some cases combining and twisting two separate yarns into one piled yarn.
Thrown or reeled silk yarn are classified as follows:
a) Singles, g) Compensne
b) Tram silk, h) Crepe.
c) Organzine silk,
d) Voile,
e) Georgetle
f) Two by two (Grenadine)
The common diseases of silk worms
Silk worms’ disease: The silk worm the particularly susceptible to various disease which become more or less epidemic in character. The principle diseases of the silk worm are as follows:
i) Pebrine: This disease is cased by protozoa parasites worm affected with these disease devel9op slowly, irregularly and very unequally and show black spot on their skin.
ii) Flachesie: Flachesie is caused by digestive deraugment due to atmospheric conditions and lack of ventilation in rearing rooms.
iii) Grasseric: This disease shows itself by the worms becoming restlen, bleated and yellow in coloru and caused by uneven feeding.
iv) Muscardine: This disease is caused by minute fungus. The body becomes raddish in color and dead often 20hors.
v) Fly paraside: The silk worm is affected by pest (hest). Pest lays eggs on the silk worm.
Weighting of silk
Silk is rarely used without degumming which causes loss in weight 22-25%. To replace this lose by causing the fibre to absorb and retain suitable organic or inorganic substances. This procedure is knows as weighting of silk.
It is a process of adding weight or body to fabric or yarn by addition of various materials either chemically or mechanically. The degummed silk is first immersed in an acid solution of tetrachloride of tin. The fibres are permeated to absorb the salt to the point of saturation. Excess solution is now removed by centrifugal hydro extraction. The material is then thoroughly washed with cold water which hydrolise the tetrachloride of tin into stannic oxide and hydrochloride acid. The insoluble oxide remains precipitated in the fibre while the acid carried off in the wash water. A treatment in a hot solution of disodium phosphate radical to the tin, already present in the silk.
Degumming
The process of which the natural gum or sericin is removed from the raw silk is called degumming.
Degumming is needed in order to make a silk fabric soft and glossy. It is basically a scouring operation. The gum is removed from the finished yarns or fabrics usually by boiling with soap at a temperature 200-2050F. Without degumming silk can not absorb dye.
Scroop
Scroop refer to the cracking sound emitted when the fibre is squeezed or pressed. The scroop of silk does not appear to be an inherent property of silk fibre itself but is acquired when the silk is worked in a bath of dilute acid (acetic or tannic) and dried without washing. This produces the resulting property of silk. Scroop does not change the true quality or real value of silk.
Chemical composition of Silk:
Silk gum or Sericin ® 22-25%
Silk or Fibroin ® 62.5-67%
Water ® 10-11%
Salts ® 1-1.5%
Fibrion is composed of a number of 
-amino acids in which the most important are;
Glycine ® 38%
Alanine ® 22%
Serine ® 15%
Tyrocine ® 9%
Other amino acids with bulky subtituents ® 16%
Polymer System of Silk:
Silk polymer is a linear, fibroin polymer. It is composed of sixteen different amino acid, so the repeating unit of silk polymer is amino acids. The silk polymer is created only by the beta-configuration. It is 140nm long and 0.9nm thick. Functional groups of silk polymer are -COOH, -NH2, -CONH. Hydrogen bonds are formed by peptide bond and salt linkage by carboxyl and amine groups. Silk is composed by 65-70% crystalline and 30-35% amorphous region.
Physical properties of Silk:
i) Specific gravity: 1.34 gm/cm3.
ii) Moisture: MR%= 11
iii) Strength:
a) Tenacity = 3-6gm/dtex.
b) Elongation = 13-20%,
c) Dry = 4.3gm/d,
d) Wet = dry ´ 0.92 gm/d.
iv) Elasticity: Breaking extension = 23.4%, Recovery = 52% at 5%
v) Appearance and color:
Shinning appearance, slipy fabric, and creamy white, browny color etc. Wild silk shinning as natural.
vi) Effect of light:
Changes color by sunshine, silk losses weight by degumming about 20%, compensate by weighing.
vii) Resiliency: Moderate.
viii) Absorption resistance: Good.
ix) Dimensional stability: Good.
Chemical properties of silk:
Silk is a protein fibre of animal origin. The major composing part of silk is silk gum or sericin and silk or fibroin. The fibroin molecules contain only carbon, hydrogen, nitrogen and oxygen. There is no Sulphur in it.
Effect of bleaches:
Silk fibrion is attacked by oxidizing agents; bleaches such as H2O2, NaOCl, calcium hypo- chlorite Ca(OCl)2 , KMnO4, K2Cr2O7, O3, NaCl . Silk becomes yellowish in sodium hypochlorite (NaOCl) and dissolve. It is less harmed by reducing agents; bleaches such as ZnO, SnCl2, SO2, H2S and FeSO4.
Effect of acid:
Silk is readily soluble in cold concentrated mineral acids. The solubility in cold concentrated HCl may be made use of to determine the percentage of silk present when it is in a mixture. In moderate concentrated acids cause contraction in silk; this shrinkage is used to bring about crape effect in silk fabrics; called ‘scroop of handle’. Dilute acids do not attack silk under mild condition. Acids are readily absorbed into silk filaments and are not easily removed.
Effect of alkalis:
Silk is less readily damaged by alkali than is wool. Cold concentrated solutions of caustic alkalis appear to have little effect when contact in short duration and when rinsing follows immediately. More concentrated solution of caustic alkalis will destroy the lustre and causes loss of strength. Silk dissolve in solution of concentration caustic alkalis. More resistance than wool dissolves in hot concentrated solution.
Effect of water:
Silk does not dissolve in water and it withstands the effect of boiling water better than wool. Prolonged boiling tends to cause a loss of strength.
Effect of inorganic solvent:
Silk dissolves in solution of ZnCl2, CaCl2 and alkali thiocyanates and ammoniacal solution of copper or nickel.
Effect of organic solvents:
Silk is insoluble in the dry-cleaning solvents in common use.
Effect of sunlight and weather:
The resistance to silk to the environment is not as good as of wool. This power resistance is due mainly to the lack of covalent cross links in the polymer system of silk.
Thermal properties of Silk:
Silk is more sensitive to heat than wool. The existing peptide bonds, salts, linkage and hydrogen bonds to the silk polymer system tend to break down once the temperature exceeds 1000C.
Electrical properties of Silk:
Silk is a poor conductor of electricity and tend to acquire a static charge when it is handled. This causes difficulties during manufacture in a dry atmosphere. Silk is valuable for insulating materials.
JUTE
Jute fiber: It is a member of bast fibres. Jute is derived from plant and in the plant it forms continuous strand and run the entire length of the plant stem. Among all bast fibres jute is top of the list.
Why jute is called bast fiber: Bast fibers are obtained from stem, bark or leaf of certain vegetable plants. Jute fibre is also obtained from the bark of jute plants. So it is called bast fibre.
Examples of bast fibers: Jute, Flax
Jute growing countries: Jute is cultivated on a large scale in Bangladesh (Mymensingh, Rangpur, Dhaka, Faridpur, Jessore, Pabna and Comilla etc), India (East Bengal, West Bengal, Coochbihar, Tripura, Bihar, Assam and Orissa). Jute is also cultivated in the Nile Valley, Nigeria and other parts of Africa, Brazil, Indo-china, Japan and Myanmar. But the quantities produced in these countries are very small and quality is not good.
Botanical Classification of jute plant
- Corchorus Capsularis,
- Corchorus Olitorius,
- Corchorus Fuscus,
- Corchorus Decurnanglatus,
- Corchorus Monpoxensis.
- Corchorus Japanicus.
Among above the first two types are cultivated the most. There are about 40 species of jute, plants. Jute fibre is obtained from the two types of jute plants.
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Corchorus Capsularies |
Corchorus Olitorius |
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a) The leaves are thin and light green in colour with serrated edges. |
a) The leaves are lovely green in colour. |
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b) The leaves taste better, hence the name “TEETA PAT” in some localities. |
b) The taste of the leaves is not better, hence the name “Mitha pat” in some localities. |
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c) The bark of the stem is brown to green in colour. |
c) The bark of the stem tends to be purple in colour. |
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d) Colour of flowers is yellow. |
d) Colour of flowers is depper yellow and the flowers are large in size. |
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e) Seed pods are short and almost circular in shape. |
e) The seed pods are long and cucumber like in shape. |
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f) Seeds when matured are brownish in colour. |
f) Seeds when matured are grey in colour with a bluish tinge. |
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g) The plants flowers in the monsoon reason and the fruits ripes in September and October. |
g) The plants flower in the monsoon reason and fruits ripes during October and November. |
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h) Fibres from this variety are known as “white jute” in the trade. |
h) Fibres from this variety are known as Tossa in the trade. |
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i) Locally it is known as “Sutipat”. |
i) Locally it is known as “Bogipat”. |
Difference between Corchorus capsularies (white jute) and Corchorus Olitorius (Tossa jute).
Requirement for successful cultivation and growth of jute
i) Temperature: High temperature up to 950 F with a minimum 800F during the period of growth.
ii) Soil: Well penetrative soil of fairly fine texture.
iii) Seeds: The seeds should be suitable or suitable seeds should be select.
iv) Rainfall: Rainfall should be over 40inches. This rainfall should be so distributed that while the young plants have sufficient moisture, the bulk of the fall should take place when the crop is more matured.
v) Supply of water: A sufficient supply of water for retting the plants and washing the stripped fibres.
vi) Supply of labor: There should be sufficient and suitable supply of labour to handle the crop at the proper time.
vii) Facilities for placing the fibres in the market.
Character of soil:
- The rich sandy soil of high lands is the best quality for the cultivation of jute in respect to strength and colour. In this type of land corchrous olitorius variety is cultivated. Preparation of land begins often winter crops and sowing in March and April.
- The bulk of jute crops is cultivated in char land.
- Low lying lands are the best, for jute can be prepared in large quantity.
Cultivation of jute
a) Preparation of land: Jute seeds are small; therefore a very fine preparation of land is necessary. The country plough made of wood is used generally for ploughing the land. The land should be ploughed and cross-ploughed at least 6 to 8 times to break down the lumbs of earth and level the ground.
b) Sowing methods: There are generally two methods of sowing. i) Broad cost sowing, ii) Line sowing.
c) Time of sowing: Chorchorus capsularus variety can be sowing any time after January. But depends upon the position of lands and weather conditions. Chorchorus olitorius variety should be sown before March.
d) Weeding and thinning: When the plants are about 1-2inches high first weeding carried out. When plants are 3-4 inches high, weeding and thinning are carried together and again carried out when plants are 2-3 feet high. In between this period weeding is carried out if necessary.
e) Jute posts and diseases: A small insect known as “Jute aplam” bores hole in jute stem and lay eggs. Also other insects feed on leaves of plant “Flingus” also causes stem and root of plant decay. “Chlerosis” or “Yellowing” of leaves is also observed.
f) Harvesting time: Jute plants may be harvested from the bud stage until the young fruits have just yet. It also may be harvested when fruits have fully formed.
g) Cutting: Cutting of jute plants is usually done by hand with a sickle. The stalks are tied into small bundles and stacked on the field for 2days. During which time the leaves full of the stalk on the ground.
h) Retting:Retting is the process in which the fibre in the bark are lossened and separated for the woody stalk due to the removal of pectins, gums etc. This is done by the combined action of water and micro-organism.
During retting, disintegration of the tissues starts from the interior of the stem and
extend to the outside, liberating the fibre bundles from the wood. The presence of periderm (a thin corky outer layer) on the stem surface hampers retting and lowers the fibre quanlity.
Defects of jute
The following are the defects generally found in jute:
a) Specky jute:
Due to not rotted and washed properly.
b) Rooty:
Due to under rotting of the root ends of the fibre.
c) Croppy:
Due to careless steeping for rotting.
d) Knotly:
Due to punctures in the growing plants.
e) Dazed:
Due to over rotting or strong in moist condition.
f) Heart:
Due to excess moisture in jute while baled.
g) Hunka:
Due to non remove of hard bark from the fibre.
h) Weak:
Due to over rotting.
i) Mossy:
Due adhere to the fibre.
j) Glossy:
Due to denoting the quality of a jute fibre.
k) Sticky or woody:
Due to over retting of the lower part of the plant.
l) Runners:
Due to careless steeping and washing.
m) Flabby:
Due to over retting and careless stripping.
Grading of jute
By the term grading of jute we mean the assortment of raw jute according to their quality.
Fibre characteristics which influences grading of jute to higher or lower standard:
Length: Long fibres which allow removal of roots leaving a good length for manufacturing purposes command a higher price short fibres of the same character medium qualities 6 to 8 feet long and better qualities over 8 to 12 feet long.
Strength: Greater the strength, higher it is grading. When jute is stored in moist condition, its strength fails off. Therefore storage of jute in moisture reduces its strength as well as decreases it grading.
Lustre: Better qualities have fairly high lustre, malt and rough surface indicates weak fibre.
Uniformity in colour: This property is quite evident in better qualities. Inferior qualities are very irregular in their respect.
Color: Best qualities are pale, white or silvery grey, common qualities are brownish or greenish and inferior qualities and roots are usually darker without any lustre.
Roots: Base portion of the jute stems is more rigid and ahs a stronger supporting bark than the rest of the stem. This is due to longer exposure of this part to the action of the sun and water. In high grade sorting root portions are removed by cutting and baled separately known as bale cuttings.
Clearliness: Clearliness of fibres is an essential factor for high grade. Adhering portions of bark and specks are undesirable which affect grading according to their degree of presence.
Grading of jute (Pucca jute):
White jute
i) Bangla White Special (BW-S):
- This jute are finest texture,
- Very strong and very good luster,
- Completely free from any defects,
- Clean cut and well hackled (AvPuov‡bv) and entirely free from red ends.
ii) Bangla White –A (BW-A):
- Jute of fine texture,
- White to light cream color,
- Strong, very good luster,
- Completely free from any blemish(`vM),
- Free from red ends and fault.
iii) Bangla White-B (BW-B):
- Light cream to straw color,
- Jute of good texture,
- Strong and good luster, clean,
- Free from blemish,
- Well hackled and free from red ends.
iv) Bangla White –C (BW-C):
- Light grey to light reddish to straw color
- Jute of sound strength, avg. luster,
- Free from croppy or hard gummy(wPUwP‡U) tops,
- Well cut, free from black roots,
- Red soft end permissible.
v) Bangla White –D (BW-D):
- Jute of any colour.
- Average strength, occasional(gv‡Sg‡a¨)bark (Qvj) & specks are permissible,
- Slightly croppy and gummy tops are permissible,
- Red ends are permissible(MÖnY‡hvM¨Zv) .
vi) Bangla White –E (BW-E):
- Jute of any colour.
- Avg. strength, but free from prevished (cuPv) fibres,
- Free from unrotten jute & stick.
- Bark and hard jute permissible.
Tossa jute
i) Bangla Tossa special (BT-S):
- Uniform golden/reddish color,
- Finest texture,
- Very strong, very good luster,
- Clean cut & well hackled,
- Completely free from any defects.
ii) Bangla Tossa –A (BT-A):
- Uniform silver grey to golden color,
- Fine texture, strong and good lusture,
- Clean cut & well hackled.
- Completely free from any blemish.
iii) Bangla Tossa –B (BT-B):
- Light to medium grey color,
- Clean, good texture, avg. lustrue,
- Cleaned cut and well halked
- Free from any blemish.
iv) Bangla Tossa –C (BT-C):
- Mixed color
- Avg. strength,
- Occasional bark and soft speck allowable but free from runners.
- Slightly croppy and gummy tops permissible,
- well cut and halked
- Free from black root ends or tops.
v) Bangla Tossa –D (BT-D):
- Mixed color,
- Avg. strength,
- Occasional bark and specks allowable but free from runners.
- Croppy and gummy tops permissible.
- Rough cut and halked but free from black root ends.
vi) Bangla Tossa –E (BT-E):
- Avg. color,
- Avg. strength,
- Free from unrotten jute and stick and rotten fibres.
- Rough hackled,
- Bark & dark centre permissible.
Kutcha Bale is graded as follows
i) Tops:
- Very strong fibre,
- Excellent color & luster,
- Free from all defects.
ii) Middles:
- Strong and good color and luster,
- Free form specks, runners, harsh crop end.
iii) Bottoms:
- Medium strength,
- Free from hard centered jute.
iv) B-Bottoms:
- Medium strength
- Not suitable for higher grade yarn.
v) C-Bottoms:
- Medium strength
- Any color
- Free from runners and croppy ends.
vi) X-Bottoms:
- Weak, harsh,
- Free form entanglement jute and stick.
vii) Habi-jabi:
- Entangled jute of any sort
- Free from dust and cuttings.
Classification of jute
Classification of jute according to their suitability of spinning and weaving.
1. Jut: The fibers of this variety are generally hard, even and of well defined texture, spin into the first count and involve minimum waste, this is the best class of jute grown in parts of Mymensingh, Dhaka and Comilla.
2. District: The districts quality jute which is next to the jat a soft hairy and light. District jute of two types. i) Hard district, ii) Soft district.
The jute of hard district is better than the soft district. Hard district jute grows is the district of Faridpur and jute grow in the district of Noakhali, Pabna, Barishal, lower Comilla, part of Dhaka.
3. Northern:
This type of jute is grown in the district of Rajshahi, Dinajpur, Bogura and Pabna etc in between the river Gauges and Brahmaputra. This variety of jute is most hairy and soft and has very littlie lustre. Some qualities are heavily rooted and dark colour.
Physical structure of jute:
The jute stands is bundle of individual fibre, held together by gums waxes and lignin. The cross-section of the fibre is polygonal in shape with sharply defined angles. Cell are thick. The lumen is large and the cross-section is oval. Longitudinally the lumen is irregular.
Molecular structure:
Jute is a cellulosic fibre. It’s repeating unit also cellulosic. Jute is composed of 65 percent cellulose and 35 percent natural waxes, oils and cements (lignin).
Ultimates:
- Ultimates are connected each other to form a fibre structure.
- It is 1.5 to 4mm in length,
- 6-20 ultimates takes place in cross-section.
Lignin:
Lignin is a gum which joins ultimate one by one and gives a jat fibre. It harshes the fibre.
Pecto cellulose:
Cellulose fibre containing cotton and pectin is called pecto cellulose.
Ligno cellulose:
Cellulose fibre containing lignin is called ligno cellulose.
Macro-Structure of Jute:
The individual fibrils in the jute bundle are shortest. It is a weakest of the cellulosic fibre. Lumen is irregular in size.
i) Ultimate length: 1.5 to 4mm.
ii) Diameter: 0.015 to 0.002mm.
iii) Length: 150 to 300cm (5-12ft)
iv) Length width ratio: 90:1 contain 6 to 20 ultimate in cross-section.
v) Colour: Yellow to Brown to Grey
Chemical composition of jute:
Cellulose ® 65.2%
Hemicellulose ® 22.2%
Lignin ® 10.8%
Water soluble ® 1.5%
Fats and wax ® 0.3%
Draw the Anatomy (microscopic) of Jute fibre:
Properties of Jute
a) Physical Properties:
1. Specific gravity: 1.48
2. Moisture regain: 13.75% (Standard), jute can absorb 23% moisture at humid condition.
3. Tenacity: 3.5-5 g/d, loses strength during wet condition.
4. Elongation at break: 1.8%
5. Elastic recovery: Almost no recovery.
6. Resiliency: Bad.
7. Abrasion resistance: Moderate.
8. Dimensional stability: Good.
9. Effect of age: If kept at dry condition it will last for indefinite time. Moisture deteriorates jute and loses strength with age.
b) Chemical properties of jute:
1. Effect of Bleaching: Not affected by oxidizing and reducing agent. Bleachable with such bleaching agents that are used for cotton bleaching.
Oxidizing agents: H2O2, K2Cr2O7
Reducing agents: Na2S2O4(Hydrose)
2. Acids: Easily damaged by hot dilute and cold concentrated mineral acids.
3. Alkalis: Resistant to alkalis. It can be scoured by strong alkali such as NaOH, Na2CO3(Soda ash) in a suitable temperature.
4. Organic solvents: Resistant to organic solvents.
5. Resistant to sunlight and heat: Poor sunlight resistance, scorches at high temperature and burns rapidly and produce ashes.
6. Dye ability: Good affinity to Basic dye, but light fastness (Color fastness to light) and wash fastness is poor (color fastness to wash).
7. Biological properties: Scoured jute has good to excellent resistance to micro-organisms and insects.
8. Conductivity: Moderate conductor of heat and electricity.
Microscopical properties
a) Cross-sectional appearance:
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b)Longitudinally:
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Fine structure jute
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Why emulsion is add in the jute?
Ans: For high tenacity, less extension, high stiffness jute fibre is brittle and can holds less twist. So emulsion is added to make it soft.
Describe the present condition of jute in the world market?
Ans: Jute and jute products are one of the most important exporting things of a progressive country. Chat, Galicha, Carpet, Clothes etc are made from jute fibre. The districts of Mymensingh, Rangpur, Dhaka, Pabna, Jessore and Faridpur produce a large quality of jute.
A few years ago, jute and jute goods is the highed exporting thing in the world market from Bangladesh. By exporting it, the economic develops in the highest point.
But the exporting of jute and jute goods has gone to very low because jute is not produced in so much and the buyers of different countries are not so careful to buy jute and jute goods and they try to import another thins in place of it. So the present condition of jute in the world market is not expectable.
Uses of jute
Jute is cheap and reasonably strong and is available in large quantities. Familiar uses for jute include the following: Sacks, bags, bundle, clothes, wrappings, bedding, foundations, boot and shoe linings, cargo and other separation clothes, cables, plastics, filter clothes, fire curtains, hand bag, upholstery, wall covering. Jute can also form the backing cloth for floor covering. In world trade market increasing its demand as jute bags for cheap means of packaging, synthetic hags polluted the environment but jute fibres are friendly oriented to environment. So, day by day the demand of jute fibre is increasing rapidly.
Wool
Wool:
Wool is a natural fiber which we obtain from the fleece of domesticated sheep. It is a natural, protein, multicellular, staple fiber. Wool is a quality fiber and so it is unique and valuable in its properties. In a sheep under the layer of coarse hair fibers, there is an undercoat of finer hairs, much more delicate. This inner insulating layer has given us the textile fiber known as wool.
Wool producing countries:
Wool is generally produces in cool condition. The following are the wool producing country:
1) Spain, 5) New Zealand 9) France
2) Australia 6) Argentina 10) Brazil
3) U.S.A 7) South Africa 11) India
4) U.K 8) Uruguay 12) Turkey etc.
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Keratin ® 33%
Dirt ® 26%
Suint ® 28%
Fat ® 12%
Mineral materials ® 1%
Classification of wool:
Classification by sheep quality:
On the basis of sheep there are four types of wool. These classifications depending on fineness and length. These are:
i) Class I, Merino Wool,
ii) Class II Wool,
iii) Class III Wool,
iv) Class IV Wool.
i) Class I, Merino Wool:
It is mainly produce in Australia, New Zealand, South Africa, South America, Europe (Germany, France, Spain)
The staple length of:
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Features:
a) Fiber is fine and strong.
b) Highly elastic
c) Good working properties,
d) Greatest amount of crimp,
e) The scale of unit length is very high,
f) Maximum no. of scales about 8000 to the inch.
ii) Class II Wool:
This class of wool mainly produces in England, Scotland, and Ireland. It qualities are almost same to Class-I Wool but length is little but higher.
Staple length = 2// - 8//
Features:
a) This quality is not good as merino wool,
b) It has large no. of scale per inch.
c) Uses mainly in hosiery and knitting; suitable for coating and apparel
iii) Class-III Wool:
Origin of this wool is U.K.
Staple length = 4// - 8//
Features:
a) Coarse and less elastic,
b) Have fewer scale,
c) Have less crimp then merino and Class-II Wools.
d) Used for clothing.
iv) Class-IV Wool: (Cross-breed Wool)
This class is actually referred as cross breed wool.
Staple length = 1// - 16//
Features:
a) Coarse and hair like.
b) Have relatively fewer scales and very little crimp.
c) Smoother and have more lusture.
d) Used for carpet, rugs and low grades fabrics.
Classification by fleece:
These are of seven types:
i) Lambs wool, vi) Cotty wool,
ii) Hogget wool, vii) Taglocks.
iii) Wether wool,
iv) Pulled wool,
v) Dead wool,
i) Lambs wool:
Refers to the first fleece sheared from a lamb about 6 to 8 months old.
ii) Hogget wool:
Refers to the first fleece come from a sheep about 12 to 14 months old.
iii) Wether wool:
Any fleece clipped after the first shearing is called wether wool.
iv) Pulled wool:
When the sheep are slaughtered for meal, their wool is pull from the pelt by the use of chemicals.
v) Dead wool:
Wool has been covered from the sheep that have died on the range or have been accidently killed.
vi) Cotty wool:
Sheep that are exposed to severe weather conditions or lack of nourishment yield a wool is called cotty wool.
vii) Taglocks:
The torn, ragged or discoloured parts of a fleece are known as taglocks.
Classification by quality:
According to quality there are five types of wool.
These are:
i) Fine wool,
ii) Medium wool,
iii) Long wool,
iv) Cross breed,
v) Carpet or mixed wool.
i) Fine wool:
Length = 6// - 7//
Source = only the merino sheep produces this kind of fleece.
Producing sheep = the principle merino families of today are the Spanish, French, Australian,
American, South African.
ii) Medium wool:
Length = 4// - 6//
Source = It is proced from the firbst breed of sheep. Great England produce the largest
percentage of this type wool.
Producing sheep = South down, Hampshire, Dorest, Succex.
iii) Long wool:
Length = 3//- 4//
Source = Breeds of largest sheep.
Producing sheep = Lincoin, Cots wold, Leicester, Romney marsh.
iv) Cross breed wool:
Length = 4// - 6//
Source = Medium wool
Producing sheep = Columbia, Panama, Romledale, Polwarth & Targhee.
v) Carpet or mixed wool:
Length = 2//- 4//
Source = Primitive sheep (lower quality)
Producing = Mainly in Asiatic countries, America, Australian.
The manufacturing process of wool:
Shearing:
Wool is a natural, protein, multicellular, staple fiber which may be sheared form the living animal, domesticated sheep or pulled from the hide after the animal has been slaughtered for its meat. The sheared wool is called fleece or cup wool. Sheep are sheared once or twice a year. This shearing process is done by an expert shearer, who can clip as many as 100 to 200 sheep a day.
The sheep is sheared by early spring and the fleece removed in one piece by expert shares.
Sorting:
Wool sorting is done by skilled workers who sorts according to fineness, length and some times strength of fibers.
Scouring:
Following sorting, the wool is scouring. This involves washing in warm soapy water several times. It moves the natural grease in the fiber and saint dirt and dust.
Oiling:
The wool fiber is treated by various oil including animal, vegetable and mineral because of unmanageable.
Garneting:
The shredding process of recycled wool fiber is called garneting.
Carbonizing:
After garneting, the wool fibers are put through a dilute solution of HCl or H2SO4 which destroys any vegetable fibers. This process is known as carbonizing
A morphological diagram of a wool fiber:
The micro structure of wool consists of three main components:
i) The cuticle
ii) Cortex
iii) Fibrils.
i) The cuticle:
The cuticle is the layer of overlapping epithelial cells surrounding the wool fiber. It consists of the
epicuticle, exocuticle and endocuticle.
The epicuticle is the outermost layer which covers the wool fiber. It is only few molecules thick and
composed of a water repellent, wax-like substance.
The overlapping epithelial cells form the
exocuticle. An epithelial cell is about 1 
long and 36
wide. The epithelial
cells are largely responsible for the felting shrinkage of untreated wool
textile materials.
The endocuticle is an intermediate cementing layer bonding the epitheial cells to the cortex of the wool
fiber.
ii) Cortex:
The cortex of wool fiber forms about 90% of the fiber volume. It consists of countless long, spindle-
shaped cells. If a specially selected dye is applied to the fiber and the fiber cross-section examined,
the ortho and para cortex become apparent. The ortho cortex absorbs more dye than para cortex.The
cortex of the wool fiber is composed of two distinct sections.
Ortho-cortex, b) Para-cortex.
The ortho and para cortex spiral around one another, along the length of the wool fibre.
iii) Fibril:
The cortical cells of the wool fiber consists of a number of macro fibrils each about 100-200 nm in
diameter. The macro fibrils are held together by a protein matrix. Each macro fibrils consists of
hundreds of micro fibrils, each about 5nm in diameter. Each micro fibril consists of eleven photos
fibrils about 500nm in length and 2nm in diameter. Finally, each photo fibril consists of three wool
polymers, which also spiral around each other.
Why ortho-cortex absorbs more dye than the para-cortex?
The ortho-cortex absorbs more dye than the para-cortex. The reason for this different staining is the different composition of the para-cortex and the ortho-cortex. The chemical composition of the para-cortical cells shows a higher cystine (cystine is a sulpher containing amino acid, capable of forming disulphide cross-links) content than the ortho-cortical cells.
Since there is a greater amount of cystine in the para cortical cells, a greater number of disulphide cross links exist in the para-cortex. This increased cross-linking tends towards greater chemical stability resulting in less dye absorption.
Why wool is fine to wear?
Due to helical configuration of ortho and para cortex, wool fiber has a smoothness, flexibility, elasticity and more durability. So we can say that wool fiber has higher resiliency properties. That is why wool fiber is fine to wear.
General structure of protein fiber:
The wool polymer is linear, keratin polymer, with some very short side groups and it normally has a helical configuration. The repeating unit of the wool polymer is the amino acid which has the following general formula.
|
|
R --- C --- COOH (carboxyl group)
|
NH2 (Amino group)
(The steps in the formation of the wool polymer are not known. So the amino acid is considered the repeating unit of wool. As a result, it is not possible to determine the extent or degree of polymerization for wool.)
Amino acids are linked to each other by the peptide bond (i.e. --CO--NH--) to the wool polymer. The peptide bond is identical with the amide bond of the nylon polymer. The wool polymer is composed of twenty amino acids, but only a general formula can be given for the wool polymer.
It is known that, in general, the amino acids arginine, crystine and glutamic acid constitute at least one-third of the wool polymer. Wool is composed in 20 number of amino acid and silk is composed in 16 number of amino acid.
Polymer system:
The wool polymer is linear keratin polymer with some very short side groups and it normally has a helical configuration. A wool polymer is about 140nm long and about 1nm thick 25-30% crystalline. It has peptide bond (-CONH-), H-bond, cystine linkage (disulphide bond).
Keratin:
Keratin is an amphoteric substance i.e. reacts as both acids and bases. Keratin is made up of five
chemical elements-carbon, hydrogen, oxygen, nitrogen and sulpher.
alfa-Keratin:
When wool polymer is in its relaxed state
then it is spiral/helical. This spiral or helical configuration of wool polymer
is called 
-Keratin.
bita-Keratin:
When wool polymer is stretched, then it unfolds. The unfolded configuration of the wool polymer is called bita-Keratin.
Why wool fiber is easy to dye?
Wool is a protein fiber which has more amorphous region than crystalline region. So dye molecules can easily enter to the amorphous region of the fiber. Moreover wool is more absorbent in nature. So, wool is easy to dye.
Difference between ortho and para cortex/ common properties of ortho & para cortex:
|
Ortho Cortex |
Para Cortex |
|
1. Lower density. |
1. Higher density. |
|
2. More absorbent. |
2. Lower absorbent. |
|
3. Tends to be in the outer sides. |
3. Tends to be in the insides. |
|
4. Contains lower cystine content. |
4. Contains higher cystine content. |
|
5. Elastic & Flexible. |
5. Stable and rigid and tends to tighten the spiral. |
Macro structure of wool:
The wool fiber is a crimp, fine to thick, regular fiber. As the diameter of wool fiber increases, the number of crimps per unit length decreases. A single wool fiber is rod like and tapers from the root end to its tip.
1. Length: 5-35cm
2. Diameter:
Fine 14
Coarse 45
3. Length width ration:
Fine short- 2500:1
Long coarse- 75:1
4. Color:
Off white, light cream.
5. Crimp: 10 per centimeter
Physical Properties of Wool:
01. Tenacity:
8.8-15 CN/Tex (1.0-1.7gm/den) in dry state and 7-14 CN/Tex (0.8-1.6gm/den) in wet.
02. Elongation:
25-35% under standard conditions and 25-50% when wet.
03. Elastic properties:
It has an elastic recovery of 99% at 2% extension and 63% at 20% extension.
04. Specific Gravity of wool:
1.32 and so fabrics feel lighter than cellulose.
05. Resiliency:
Higher and so resist wrinkling.
06. Hygroscopisity:
Higher
07. Cross section:
Oval to roughly circular.
08. Appearance and colour:
Appearance depends on colour, long and smooth fiber characterized by two features. Sometimes microscopically shows dark in the middle. This kemp, which are hair like character. By selective breeding kemp can be minimized.
Chemical properties of Wool:
01. Effect of moisture:
Wool absorbs moisture to a greater extent than any other fiber and yield up readily to the atmosphere. Under ordinary conditions wool will hold 16-18% of it weight of moisture. Wool loses about 40% of its strength and silk loses about 15% in wet condition.
02. Effect of acids:
Wool is attacked by hot concentrated sulphuric acid and decomposes completely. It is in general resistant to other mineral acids of all strength. Even at high temperature, though nitric acid tends to cause damage by oxidation. Dilute acids are used for removing cotton from the mixture of two fibers.
03. Effect of alkalis:
The chemical nature of wool keratin is such that it is particularly sensitive to alkaline substances. Wool will dissolve in caustic soda solutions that would have little effect on cotton. The scouring and processing of wool is carried out under conditions low alkalinity (NaOH, NaCO3). Ammonium Carbonate, borax and sodium phosphate are mild alkalis that have a minimum effect on wool.
04. Effect of organic solvents:
Wool has a good resistance to dry cleaning and other common agents.
05. Effect of bleaches:
Wool fibrion is attacked by oxidizing agents or bleaches such as H2O2, NaOCl, calcium hypochlorite Ca(OCl)2 , KMnO4, K2Cr2O7, O3, NaCl. Wool becomes yellowish in sodium hypochloride (NaOCl) and dissolve. It is less harmed by reducing agents or bleaches such as ZnO, SnCl2, SO2, H2S and FeSO4.
06. Effect of sunlight:
The keratin of wool decomposes under the action of sunlight. The sulphur in wool is converted into sulphuric acid so the fiber becomes discolored and develops a harsh feel. It losses its strength and the dyeing properties are affected. Tends to yellow white or dull color or surface polymer degraded by ultraviolet radiation.
Thermal properties of Wool:
Wool becomes weak and losses its softness when heated at the temperature of boiling water for long periods of time. At 1300C, it decomposes and turns to yellow and it damages at 3000C. Wool doesn’t continue to burn when it is removed from a flame. Do not burns readily is self extinguishing, have odor of burning hair and have a black crushable ash.
Biological properties of Wool:
Wool is attacked by moth-grubs and by other insects. Wool has a poor resistance to mildews and bacteria and it is not advisable to leave for too long in a damp condition.
End uses of wool:
i) Knitted appeals,
ii) Suiting, over coat, sweater,
iii) Carpet, lining fabric,
iv) Lustrous dress,
v) Designs for kurtain,
vi) Blanket,
vii) Hosiery fabric,
vii) Home uses furnishing fabric
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