Identification of wool Pract class 1.ppt

Included identification of wool practical

2. Sampling techniques for wool

3. Wool sampling techniques
What is sample ?
Sample is a relatively modest fraction selected from a
population; the sample is supposed to move a
truthful representative of the population

4. What is purpose of taking sample
To draw conclusion about populations from samples,
we must use inferential statistics which enables us to
determine a populations characteristics by directly
observing only a portion (or sample) of the population

5. Types of sample
Sample are 3 types. They are:
1. Random sample:
 
In this type of sample every individual
in the population has an equal chance of being included in
it.
2. Numerical sample:
 
A sample in which proportion of long
medium and short fibre would be same in sample as
population

3. Biased sample:
 
When the alternative of an private is
influenced past times factors other than chance, a sample
ceases to move genuinely representative of the mass in
addition to leads to bias inward results.

6. Causes of bias inward sampling
1.Bias due to physical characteristics:
 
Longer fibers
possess got a greater take away a chance of beingness
selected.
2.Position relative to the person:
 
Lab assistant may
pick samples from the top layer of a representative of
yarn (just to brand his task easier or may move because
of his ignorance), biased due to their position.
3.Subconscious bias:
 
Person selecting sample that are
best-looking ones that are costless. This affects the
examine results

7. Sampling methods depends on the next
factors
•Form of the sample
•Amount of sample available
•Nature of the examine
•Information required
•Degree of accuracy required

8. Sampling for textile testing:
•Fiber phase
•Yarn phase
•Fabric phase
•Garment stage

9. Sampling methods for fibre :
From bulk there are two methods:
1.Zone technique
2.Core sampling
From combed / silver roving:
1.Numerical sample
2.Length biased sample
3.Random draw method (for silver)
4.Cut square method (for yarn)

10. Zone technique
Is popular technigues for testing of fibre, where the property
may vary considerably from place to place
Procedure:
1.Collect handful of fibre randomly from at east 40 bales.
2.Each handful id divided into 2 parts out of which one is
discarded and other is retain
3.Again divide the retain part into half
4.Repeat the process until about 5 grams of fibre remain in
handful.
5.Treat each handful in similar manner and collect all the
fibre from 40 zone to have the final sample 5 gram.

11. Zone technique
 Sample from each zone

12. Core sampling
•This method is used to evaluate the amount of grease, vegetable matter
present in the sample taken from unopened bales of raw wool.
•It means half way into the bale i.e. samples from centre. The tube enters in
the direction of compression, so perpendicular to the layers of fleece.
Procedure:
1.A core position is selected at random. Positions vary from bale to bale
within a sale lot in accordance with the sampling requirements.
2.The core tube starts to penetrate the bale and the initial plug of core
sample material containing the pack material is ejected as core waste.
3.The core tubes continue to penetrate to the required depth and the
remaining core sample material is retained.
4.The core sample material is evacuated through flexible hoses connected to
the core tube and is deposited into the plastic sample bag at the core
collection point.
5.Completed core samples are sealed and placed in a second plastic bag,
which is also sealed.
•This is important for the correctdetermination of yield.

13. Core sampling
Core sample material is tested to determine the yield
and mean fibre diameter of the wool in the sale lot.

14. Fibre sampling from combed
sliver/Roving & yarn :-
1.Numerical sample :- the removal of one sample
does not effect the composition of remaining sample
then it can be considered as numerical sample and
each segment is representative of whole.
2.Length-biased :-
Prepare a length-biased sample in such way that
the bias can be allowed for in any calculation (based
on some assumptions).

15. RANDOM DRAW METHOD
•The random sampling technique is the most widely used
technique. Take out fibre (2mm at each stage) and discard
until a distance equal to that of the longest fiber. After each
draw will be numerical sample.
Stratified random sampling:
 
This is done past times dividing
the population into several mutually exclusive regions.
Cluster sampling:
 
This is done past times subdividing the
population into groups or clusters in addition to taking a
sample from each.
Selected sampling:
 
In this type, the samples are collected from
one purpose of the population.
Systematic sampling:
 This is performed systematically at a
regular interval.
Acceptance sampling:
 
This is used to convey the incoming
raw stuff or for character assurance of outgoing consignments.

16. CUT SQUARE METHOD
1.Cut all the projected fibres and discarded.
2.The glass plate is then moved back few mm,
exposing more fibres with “natural length” without cut.
3.In each case projected fibre ends must be removed

17. Test for identification of wool

18. Testing for Identification
1.Non technical test
2.Technical test

19. Non technical test
Feeling test
1.The feeling test requires perception. Skilled perception is acquired only after
handling many different fabrics over a period of time.
2.Limitations of this test become apparent examining and comparing fabrics of
different fiber content.
3.Feeling test involves touching a fabric and feeling the fabric to know its
component fibers.
4.For example, wool fabrics will feel warm when touched because the heat
generated by wool, which is a nonconductor of heat, will remain in the touched
area itself.
5.On the other hand, the fabrics made up of plant fibers such as cotton fabrics,
linen fabrics and even the rayon, that are made from the cellulose of wood pulp
or cotton fiber, feel cool to touch.
6.As they are conductors of heat, the heat generated by the finger passes off
making the fabric cold.
7.However, it requires a long experience of handling different fabrics over a
period of time for such skillful perception.
8.Also, it is difficult to examine and compare the fabrics made of different fiber
contents with the feeling test.

20. Non technical test
2) Burning test:
Burn testing is a generally reliable way of identifying fibers. It is possible to
reliably determine whether a fiber is natural or man-made by burning fibers and
observing the behavior of the flame and the characteristics of the residue.
Procedure:
1.Hold fabric sample A over the flame with forceps until it ignites and then
remove it from the flame quickly. Observe the flame.
2.Hold the fabric sample over an evaporating dish with forceps if it continues to
burn.
3.Observe the nature of the burned end of the sample.
4.If it extinguishes, place it back in the flame and allow it to burn completely.
5.Put the burned residue in the evaporating dish. Try to crush the residue with
the tip of the forceps

21. Burning Test
Fibers can also be identified through the smell of the smoke it gives off in
burning and the ash or melted bead that remains after it has burned. Some of
the fabrics are blends, and the blend of fibers may make the burn test rather
unreliable test for fiber content.
Wool characteristics:
Wool is slow to ignite burns with a characteristic smell, flickering flame,
sizzles and curls.
It can be extinguished easily, as the fabric ceases flaming when the fire is
withdrawn.
Wool ash is dark and crisp, and it falls into an irregular shape that can be
crushed easily.
The ash has a strong animal odour resembling burning feathers and hair,
which indicates the presence of an animal substance or of a fibre obtained
from an animal.

The characteristic odour of burned wool is due to the sulphur in it.

22. Technical test
1.Microscopic Test:
Microscopic test is a technical test that involves identifying the fabric with
the help of a microscope with a magnification of minimum 100 powers.
The test can easily distinguish between fibers.
The test identifies the natural fibers more easily as compared to manmade
ones.
Synthetic fibers are very similar in appearance and the increase in the
number of varieties makes it a little tough to distinguish the fibers even
under a microscope

23. Microscopic test

24. Microscopic test

25. Microscopic test

26. Microscopic test

27. Microscopic test

28. Microscopic test

29. Technical test
2. Chemical Tests:
Chemical tests are another technical means of identifying fibers. But chemical
tests are not intended for the general consumers.
Different types of chemical tests are undertaken to establish the identity of
the fibers used.
These tests give accurate and precise analysis and conducted in research
laboratory.
Stain Test: Also known as the Double Barrel Fiber Identification (DBFI), the
test is based on the theory that each fiber has its own distinct two- color
reaction when treated with stain.
A fiber will turn to a particular color in the presence of dilute acetic acid and
to some other specific color when stained in the presence of a mild alkali

30. Chemical test
A specialty stain has been produced for the purpose of identifying fibers.
The color produced by the stain on a fiber or fabric is based on the chemical
and physical properties of the fibers in the fabric.
Stain testing can be conducted with several commercially available test kits.
Procedure:
Add 100 mL of tap water to a 150-mL beaker and set it aside until it is
needed to rinse the samples.
Warm 30 - 40 mL of the DuPont fiber identification stain solution to
approximately 70°C in a 100-mL beaker on a hot plate. Do not boil.
Soak fabric sample in the stain for 1 minute.
Remove the sample from the stain using forceps and rinse by dipping in a
beaker of water.
Remove the fabric sample from the beaker and record the color of the fabric
sample

31. Chemical test
Nitrogen Test:
Silk and wool contain amino acids (amide linkage), and nylon is a synthetic
polyamide.
All of these degrade in a caustic (alkali) environment (in this case created by
calcium hydroxide).
Nitrogen, in the form of ammonia gas (NH3), is released as a product of the
reaction.
Ammonia is identified if the red litmus turns blue
Procedure
Attach a test tube clamp to a ring stand.
Place sample in a 20 mm x 150 mm test tube. Push it to the bottom with a
clean glass stirring rod.
Use a spatula to dump a pea-size amount of calcium hydroxide powder on
the sample.
Place the test tube in the test tube clamp. Light the burner and place it
under the test tube.
Hold a piece of moistened litmus paper with forceps over the mouth of the
test tube without touching the side of the test tube.
Record the color of the litmus paper

32. Chemical test

Sulfur Test:
Wool contains sulfur-containing amino acids with disulfide (-S-8-) bonds.
The addition of wool to hot Sodium Hydroxide (NaOH) causes the wool to dissolve.
Lead (Pb2+) from the lead acetate and sulfur (S2-) from the wool bond to form lead sulfide
(PbS) which is a dark grey/black precipitate. Pb2+(aq) + S2(aq) -> PbS (s).
Procedure
Place a different fabric sample in each 15 mm x 125 mm test tube and add 5 mL
of 3.0 M Sodium Hydroxide (NaOH) to each.
 Label the test tubes with the letter of the fabric sample.
Add the test tubes to a hot water bath and turn up the heat so the bath heats to
a gentle boil.
Once the water in the bath begins to boil, leave the test tubes in the bath for 5
minutes.
Remove the test tubes with a test tube clamp and place them in a test tube
rack.
Allow the test tubes to cool to room temperature.
After the test tubes have cooled, add 2 drops of 0.25 M lead acetate to each test
tube.
A brown-black color indicates the presence of sulfur

33. Chemical test
Protein Test:
Silk and wool are natural animal fibers, which are made from proteins.
Proteins contain specific bonds called peptide bonds.
Exposing a substance to copper sulfate and Sodium Hydroxide (NaOH) results
in a purple color change if peptide bonds are present.
Procedure
Add 20 mL of 3.0 M Sodium Hydroxide (NaOH) to the 50-mL beaker.
Place sample in a watch glass (or spot plate) and drop 5 drops of 0.5 M copper
sulfate on the sample and allow it to sit for 5 minutes. (You may have to rub in
the solution with stirring rod if it does not absorb.)
Holding the sample with forceps, dip it in the 3 M Sodium Hydroxide (NaOH) for
10 seconds.
Remove the sample from the Sodium Hydroxide (NaOH). A purple color indicates
the presence of protein.
Observe and record the color of the sample

34. Chemical test
Solvent Test:
 The test involves treating the fibers in certain solvents for identifying them.
The technical test is becoming difficult to conduct as most of the
manufactured fibers and their blends are chemically similar.
There is no individual chemical or solvent test for separating or identifying
the fibers in combinations.

35. Chemical test

36. Chemical test

37. Chemical test

38. Chemical test

39. THANK YOU