What is Determination of De-Aerating Effect
De-Aerating Effect Principle :
A cheese of grey-state cotton yarn is immersed in a solution containing a de-aerating agent and the volume of air expelled is measured at given intervals of time.
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Equipment and material required :
| Substrate | grey-state cotton yarn, |
| Metal tube | Geidner system spindle, 15 mm |
| Loading weight | 5 g (is attached to metal tube) |
| Winding device | developed in-house |
| Measuring cylinder | 250-ml |
| Time measurement | stopwatch |
| Water | de-ionized water |
| Test temperature | 25°C |
Procedure
| Preparation of cheese | o o o o | weigh empty spindle, note weight mount spindle on package support and fix on winding device wind 15 g yarn onto spindle (ca. 45 s winding time) attach 5 g “loading weight” to one end of the metal tube |
| Preparation of test liquor | o o o | make up 5% stock solution / emulsion make up 200 ml test liquor with a concentration of 2 g/l and 4 g/l product to be tested temperature 25°C |
| Testing routine | o o o o o o o | pour 200 ml test liquor into 250-ml measuring cylinder have stopwatch ready drop package (cheese) into measuring cylinder When the package is totally immersed in the liquor, start the stopwatch note the volume on the 250-ml measuring cylinder every 10 seconds i.e. difference between liquor level and 250-ml graduation. Maximum testing time 2 min. |
| Assessment | 1 ml volume difference = 3% de-aeration * Calculation example: measured volume difference x 3% —————————————————– = % de-aeration 1 ml Plot a graph of the volumes noted at 10-second intervals. |
| Note | Attaching a 5 g “loading weight” to the tube ensures that the package (cheese) becomes totally immersed in the liquor immediately. “Instantaneous air displacement” is hence invariably achieved, and this is particularly important with products which have poor wetting and de-aerating properties. |
