ISO 4320:1977 pdf download.Non-ionic surface active agents - Determination of cloud point index - Volumetric method
1 SCOPE
ISO 4320:1977 pdf download specifies a volumetric method for the determination of the cloud point index of non-ionic surface active agents.
2 FIELD OF APPLICATION
The method is applicable to weakly alkoxylated non-ionic surface active agents (1 to 5 oxyethylene groups) the hydrophobic group of which Is provided by an alcohol, an alkylphenol or a fatty acid (provided that the last has a melting point lower than 30 °C). subject to the product being soluble in propan-1-ol to the extent of 1 g in 10 ml at 30 °C.
It is equally applicable to lipophilic bases derived from alcohols, alkyiphonols and fatty acids.
3 REFERENCE
ISO 807, Surface active agents -- Detergents — Methods of sample division.1)
4 DEFINITION
For the purposes of this International Standard, the following definition applies
cloud point Index : The number of millilitres of distilled water necessary to render cloudy, at a specified temperature, a solution containing a given mass of surface active agent in a given volume of solvent.
5 PRINCIPLE
Addition, at 30 °C, of distilled water to a propanol solution of the surface active agent until the appearance of cloudiness.
7.1 Beaker (see the figure) of height 80 mm and diameter 50 mm, with double walls permitting temperature stability,and having a mass less than 200 g, fitted with a poly-ethylene, polytetrafluoroethylene or an aluminium foil cover pierced with two holes allowing entry of the ther-mometer (7 .2) and the burette (7.4).
Fit the beaker (7.1) onto the water bath (7.7) and control the temperature at 30,0 ± 0,1 °C.
Start the water circulation and the stirrer (stir gently at first in order to avoid splashing the liquid on the walls of the beaker).
Ensure that the test portion is completely dissolved (the solution should be clear) and add, drop by drop, the water (6.1) from the burette (7.4) until the liquid remains cloudy.
Check that the temperature in the beaker is maintained at 30,0 ± 0,5 °C during the complete operation.
The results of the test depend upon the speed of introduction of the water. Hence, the period during which It is introduced should be between 20 and 30 mm, according to the quantity of water introduced.
Immediately after the cloud point is reached, allow the solution to equilibrate for 5 mm so as to verify that the turbidity does not desappear.
10.2 Repeatability
The maximum difference between the results of two deter-minations carried out in rapid succession on the same sample, by the same analyst using the same apparatus,should not exceed 2 % of the mean volume found.ISO 4320 pdf download.