Textile materials have a certain pH value due to the properties arising from their structures and as a result of the chemical processes they undergo.
In textile, especially in the clothing sector, the pH value of the textile material is very important in terms of human health.
The purpose of this test is to determine the pH value of textile materials, which is associated with their natural structure and chemical treatments applied during production processes.
This test is applied to every textile material.
The pH value in the aqueous extract of textile materials gives useful information about the processes they have seen in the past.
pH can also be defined as the minus logarithm of the hydrogen ion concentration in an aqueous solution. (TS EN ISO 3071 )
Used materials
All reagents used must be of analytical purity.
pH meter,
distilled water,
0,1 mol/L potassium chloride solution,
Buffer solutions for the calibration of the pH meter,
pH 4, pH 7 and pH 10,
Each,
Balloon,
Capped Erlen,
Mechanical shaker (Features; rotation frequency should be 30 revolutions per minute or 60 reciprocating movements per minute),
Precision scales.
Sample preparation
The test samples are cut into pieces of approximately 5 mm from the fabric conditioned under standard atmospheric conditions.
The cut pieces are weighed in a flask and adjusted to 2,00 g each, or first adjusted to 2 g and then transferred to the flask.
In this way, three samples are prepared.
During all these procedures, it is recommended to use gloves so that the sample does not come into contact with the hand.
Experimental Procedure
The calibration of the pH meter takes the first place in the execution of the experiment.
The pH meter should be calibrated with buffer solutions before each use.
A 0,1 M KCl solution is prepared.
First, the molecular weight of the KCl compound is calculated and found to be 74,6 g/mol.
This is the value in one mole, but because our solution is 0,1 M, the value in 0,1 mole is required.
For this, 74,6/10=7,46 g of the substance is weighed. It is taken into a beaker and dissolved in distilled water by mixing with a baguette, then transferred to the balloon.
The bottom of the beaker is rinsed with distilled water and added to the balloon and the solution is completed to 1 liter.
The pH and temperature of the solution are recorded.
100 mL of solution is added to each test sample in the flask.
The flask is shaken by hand for a short time until it is ensured that the sample is properly wet, then shaken for 2 hours on a mechanical shaker.
Then, the solutions filtered with the help of filter paper are taken into a beaker and their pH is measured.
The electrode is immersed in the first extract to a depth of at least 10 mm and mixed gently with a glass rod until a stable pH value is observed.
The pH value of this extract is not recorded.
Without washing the electrode, it is immersed in the second extract and left without stirring until a stable pH value is observed.
This value is saved.
Again, without washing the electrode, this time it is dipped in the third extract and waited without stirring until a stable pH value is observed, and this value is recorded.
The pH values of the second and third extracts are recorded as the first and second measurements.
The difference between these two pH values should not be greater than 0,2, otherwise the experiment is repeated.
As a result of the experiment, the arithmetic mean of these two measurements is given.
