ISO 3073:1975 pdf download.Wool – Determination of acid content.
ISO 3073 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 whcn thc amount of dye extracted 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, Tex tile fibres — Some mnethuth of sampling for
5.2 Conical flasks, 250 ml capacity.
5.3 Pipettes, 50 and 100 ml capacity.
5.4 Burette, 25 ml capacity.
5.5 Stoppered weighing bottle.
5.6 Analytical balance, accurate to 0,000 5 g.
5.7 Desiccator.
5.8 Ventilated oven for drying samples at 105 ± 3 O(
5,9 Mechanical shaker (optional).
5.10 Glass beakers, 250 ml capacity.
5.11 Glass wool.
7.3 Place the other two test specimens in sepdldte glassstoppered conical flasks (5.1) and add 100 ml of pyridine solution (4.1) to each. Stopper each flask and shake on the mechanical shaker (5.9) for 1 h. Alternatively, allow each flask to stand overnight after initial shaking to ensure wetting of the specimen.
Decant the liquid from each flask into separate glass beakers (5.10), filtering through plugs of glass wool (5.11) Lu retain fibrous material. Fruiri each bedker, pipette 50 ml of the filtered liquid into separate conical flasks (5.2), add 3 drops of phenolphthalein solution (4.3) to each flask and titrate each extract with the sodium hydroxide solution (4.2) until a faint pink colour persists after a yen tie shaking by hand.
A potentiometric end-point determination is allowed.
T is the normality of the sodium hythoxide solution used for the titration;
V is the volume, in millilitres, of sodium hydroxide solution used for the titration;
k is a constant which has the tollowing values:
for calculating as hydrochloric acid: 3,65
for calculating as formic acid : 4,6
for calculating as sulphuric acid : 4,9
for calculating as acetic acid : 6,0
m is the dry mass, in grams. ot the test specimen ot mass approximately 1 g.
9 TEST REPORT
The test report shall include the following information a) the reference to ISO 3073.ISO-3073-1975