SCOPE: - This standard prescribes a method for determining the Water soluble matter of textiles.

PRINCIPLE: - Aqueous extraction of weighed sample is done by boiling it under reflux in an condenser for one hour. Following aqueous extraction of a prepared sample under specified conditions, the water-soluble matter is quantified by evaporation and drying at 110 °C.

REFERANCE: - IS 3456: 1966- Method for determination of water soluble matter in textiles materials.
1. Dessicator.
2. Reflux Condenser
3. Oven  - 105° to 110°C
4. Flat Bottom Flask- 250 ml
5. Heating element.
6. Filtration assembly

1. Distilled water.

Prior to test, test specimens shall be conditioned for 24 hours to moisture equilibrium in a standard atmosphere at 65±2 percent relative humidity and 27°± 2°C temperature

Preparation of evaporating dish:-
1. Heat the evaporating dish at 110°C in Hot air oven for one hour.
2. Remove the dish and cool in Dessicator.
3. Weigh quickly and note the dry weight of dish

1. Condition the rest specimens to moisture equilibrium in the standard atmosphere and weigh accurately 1 or 2 g of test specimen.
2. Put the specimen in the flask and add water to make the liquor to material ratio of 20:1(i.e. 20 ml of water for 1 g of test specimen) for all textiles, except wool.
Note - If the test specimen is wool, the liquor to material ratio should be, 50: 1
3. Connect the flask to condenser and rapidly bring to boiling.
4. Continue to boil the liquor under reflux for 60 minutes.
5. After one hour, disconnect and remove the flask while liquor is still boiling.
6. Immediately close the flask with glass stopper.
7. Rapidly cool the flask and its content to room temperature (27±2°C).
8. Filter the extracted liquid and wash the residue with amount of water.
9. Take the filtrate and washings in previously weighed evaporating dish and evaporate the extract to dryness on a hot plate or steam bath.
10. After evaporation, shift the evaporating dish into a hot air oven and dry the residue at 110°C for two hours.
11. Cool the dish in a Dessicator and weigh quickly.
12. Repeat the process of drying in oven till the weight change between two successive weighing is less than 0.005 gm.

Calculate the total water soluble matter as follows;-
Water soluble matter, percent = W2 x 100
Where, W2 = weight in gm of dry residue left after drying.
W1 = weight in gm, of the conditioned test specimen

Permissible Error - The results of a duplicate determination shall not differ from one another by more than 0.5 percent calculated on the original weight of the material taken for the test.

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