Wool is extracted from sheep. There are various types of wool. Marino wool is the best wool.

Physical properties:

1. Length: length of wool fibre varies from 2 to 12 depending on type of fibre and the interval length of time of collection.

2. Fineness: normally longer the fibre coarser the fibre fineness varies from 3-15 dtex that is coarser than cotton fibre.

3. Strength & extension: wool is weak fibre, its tenacity is 1 to 1.5 g/dtex & break 35%.

4. Elastic property: wool is the best natural fibre in respect of good recovery from deformation.

5. Cross-sectional shape: roughly circular or elliptical in cross-section.

6. Appearance: characterized by crimp & scales. Due to scales and extensibility its felling property is good. Color varies depending on type of wool fibre.

7. Effect of chemical:

· Water: moisture regain of wool is 19% & when wet strength reduces about 20%.

· Alkali: alkali degrades the wool fibre, changes color & reduces strength.

· Acid: wool is safe in acid. In carbonizing wool 5% sulphuric acid solution is used to remove vegetable & cellulosic materials.

· Solvent: wool is safe in solvent, hence dry-cleaning is popular for woolen garments.

8. Effect of heat: burns with burning hair smell with specific sound.

9. End use: area of use depends on variety of wool.e.g.

· Merino: suiting dress materials

· Fine cross bread: blanket, knitwear, linht wear outings.

· Coarse cross bread: blanket, tweed, carpet.

· Carpet wool carpet, rags etc.

Silk is a natural protein fibre. It is produced by the silk worm which produces cocoon. Silk fiber is extracted from cocoon. Silk are mainly two types i.e. cultivated silk and wild silk. Cultivated silk is better than wild silk. Main properties of silk fibre are as follows:

1. Length: Length of silk fibre varies from 400 to 700 meters.

2. Fineness: It is very fine fibre. Fineness varies from 11 to 12 microns.

3. Cross-section: Its cross-section is triangular.

4. Strength: Strength of silk fibre is reasonably good. Its tenacity varies from 2.4 to 5.1 g/den.

5. Stretch and elasticity: Extensibility is 15% when at break. Recovery from stretch is 90% when extension is up to 2%.

6. Resiliency: resiliency is moderate.

7. Abrasion Resistance: Resiliency good.

8. Moisture Regain: 11%.

9. Effect Chemical properties:

· Effect of bleaches: Damages by the effects of strong bleaching agents. Hence, perfectly white silk fabric is not seen.

· Effect off acid & alkali: Strong mineral acid damages silk fibre & strong alkali also damages silk.

· Effect of organic solvent: Silk is unaffected by the organic solvent hence dry cleaning is safe.

· Dye-ability: Dyeing at low temperature by direct, acid, basic, vat & reactive dyes could be done.

· Biological properties: Normally unaffected by fungus, moths & insects.

· Flammability: Burns slowly when contact with flame. It also self extinguishes.

· Electrical & thermal conductivity: Heat and current flow rate is slow.

· Use: silk is widely used all over the world. It is used for children’s wear, ladies wears, tie, suits etc purposes.