ISO 3073:1975 pdf download.Wool — Determination of acid content.
ISO 3073:1975 is applicable to undyed wool in any form, for example loose fibre, sliver, yarn or fabric. It is also applicable to dyed wool when the amount of dye extracted during the test does not interfere with the determination of the end-point of the titration. The determined value is expressed as a percentage by mass.
1 SCOPE AND FIELD OF APPLICATION
This International Standard specifies a method for determining the acid content of a wool sample, expressed as a percentage by mass.
This method is applicable to undyed wool in any form, for example loose fibre, sliver, yarn or fabric. It is also applicable to dyed wool when the amount of dye cxtracted during the test does not interfere with the determination of the end-point of the titration.
2 PRINCIPLE
Immersion of a known amount of the wool in a dilute solution of pyridine which extracts the acid from the wool Determination of the amount of acid extracted, by titration with standard sodium hydroxide solution.
3 REFERENCE
ISO 1130, Textile fibres – Some methods of sampling for testing.
4 REAGENTS
4.1 Pyridine, 5 g/l solution
Dissolve 5 g of pyridine (analytical grade) in 1 I of distilled water
4.2 Sodium hydroxide, 0, 1 N solution
Standardize this solution by titration with standard otassium hydrogen phthalate solution
4.3 Phenolphthalein, 5 g/l ethanolic solution
Dissolve 0, 5 g of phenolphthalein in 95 %(V/V) ethanol and dilute to 100 ml with the same ethanol.ISO 3073:1975 pdf download.