ISO 3071 pdf download – Textiles – Determination of pH of aqueous extract.
6 Apparatus
6.1 Stoppered glass or polypropylen. flasks, chemically resistant, for preparation of tbe aqueous extract. NOTE It is recommended that the glassware used for this test be set aside br this purpose only and filled with distiled water between tests.
62 MechanIcal shaker, providing ro(ational or reciprocating movement sufficient to ottain a ready exchange of liquid between the interior of the textile material and the solution used in piepahng the extract. A to-and-Ira movement at a rate of 60 min1 or a rotational frequency 0130 min1 has been found satisfactory.
6.3 Beakers, chemically resistant, with a capacity of 150 ml (see Note to 6.1).
6.4 Rods, chemicaly resistant (see Note to 6.1),
6.5 pH-meter, with a glass electrode, capable of measuring to at least 0.1 p1-I–units.
6.6 Balance accurate to 001 g.
6.7 II volumetric flasks, of grade A quaIity
7 Preparation of test samples
7.1 Take a laboratory sample representative of the bulk of the textile material and sufficient to provide all
the test samples requed, Cut the laboratory sample iota pieces having approximately 5 mm sides or of such
a size as to allow the test samples to wet out rapidly.
7.2 To avoid contamination, handle the material as little as possible. Take from the laboratory sample three lest samples of (2.00 ± 0.05)9 each.
8 Procedure
8.1 Preparation of the aqueous extract
Prepare the extract In triplicate at room temperature, as follows.
Place each test sample and 100 ml of extracting solution [either water (5.1) or potassium chloride solution (5.2)] Into a sloppered flask (6.1). AgItate the flask for a short penod by hand to ensure that the textile material is properly wetted out, then shake it mechanically for 2 h ± 5 mm.
Record the temperahire of the extracting solution used.
8.2 Measurement of the pH of the aqueous extract
Calibrate the pH-meter at the temperatte of the extract to be measured. Check the calibration of the pH-meter using two buffer sOlutions.
Immerse the electrode several times I, the same solution (water or KCI solution) used to prepare the extract until the indicated pH-value stabilizes.
Decant the first extract into a beaker, immechately immerse the electrode to a depth of at least 10 mm and stir gently with a rod until the pH-value stabilizes (do not record the pH-value of this solution).
Decant the second extract into another beaker, immediately Immerse the electrode, without washing. In the beaker to a depth of at least 10 mm and allow to stand without stirring until the p1-I-value stabilizes, Record this value.
A.l General
Use only reagents of recognized analytical reagent grade. Prepare the buffer solutions using water of at least grade 3 as defined In Iso 3696 and renew them at least once a month.
A.2 pH 4,0 potassium hydrogen phthalate solution (0,05 moIIl)
Dissolve 10.21 g of potassium hydrogen phthalate (KHC8H4O4) in dlstled or deionized water in a II volumetric flask and dilute to the mark The pH of this solution is 4,00 at 20 C and 4,01 at 25 C.
A.3 pH 6,9 potassium dihydrogen orthophosphate and disodium hydrogen orthophosphate solution (0,08 molIl)
Dissolve 3,9 g of potassium dihydrogen orthophosphate (KH2PO4) and 3,54 g of disodium hydrogen orihophosphate (Na2HPO4) m distilled or deionized water ii a ii volumetric flask and dilute to the mark.
The pH of thés solution is 6,87 at 20 C and 6,86 at 25 C,
A.4 pH 9,2 dlsodlum tetraborate solution (0,01 molll)
Dissolve 3.80 g of disodium tetraborate decahydrate (Na284010H2O) in distilled or deionized water ii a II volumetric flask and dilute to the mark. The pH of this solution is 9,23 at 20 C and 9.18 at 25 C.
ISO 3071 pdf download – Textiles – Determination of pH of aqueous extract
