• Cotton 
• Viscose

• Drying Oven – It shall be capable of maintaining a temp of 105 ± 3°C .
• Analytical Balance – Capable of weighing an accuracy of 0.0002 g
• Conical Flask – 250 ml
• Desiccator
• Sieve

Reagent

• Sulphuric Acid solution Reagent grade, 75 % (m/m) specific gravity 1.67 at 27°C.
• Diluted Ammonia Solution – Adding 80 ml Concentrated Ammonia (Specific gravity 0.89 )  and making up to one litre with water.

• Sample weighing about 2.0 to 3.0 g. Cut the yarn into pieces and dissect the cloth into yarn pieces of about 10 mm length.
• Dry the sample in oven at 105 ± 3°C for 30 min.
• Cool in a Desiccator and weight them 1 gm sample (W)
• Treat the weighted out sample taken in a conical flask with 100 ml of 75% sulphuric acid solution.
• Stopper the flask and shake it carefully to wet out the sample completely.
• Maintain the flask at room temperature for 30 minutes.
• Filter the content of the flask through a sieve.
• wash the residue on the filter sieve with water, diluted ammonia solution and finally distilled water.
• Dry the residue in the drying oven at 105 ± 3°C to constant weight,
• Cool in a desiccator and weight them (W1)

Calculation