This bachelor thesis aims to study the influence of the printing paste, the textile substrate, and the method of fixation on the pH sensitivity of the indicator dye bromocresol green, applied on polyamide and cotton fabric using the flat screen printing technique. The dye was applied in the form of pigment printing paste and printing paste for printing polyamide with acid dyes. Two types of fixations were used; heat fixation at 150°C for 5 minutes and normal steaming at 100 - 102°C, 30 minutes. The influence of the printing process on the change of mechanical and physical properties of the fabric was tested according to the valid SIST EN ISO standards. The colour of samples, before and after their immersion in the buffer solutions with different pH values, was evaluated spectrophotometrically. The colour fastness of the printed textiles to rubbing, washing and light was also investigated.
The pH sensitive textile was successfully developed by printing, which proved that the printing process could be one of the methods used to apply the indicator dye to the textile substrate. The application of printing paste on cotton and polyamide fabric caused a change in the mechanical and physical properties of the studied materials. The speed of response of printed fabrics to the change in pH depends on the types of fibres and the wetting ability of the fabric with buffer solutions. The colour fastness of printed fabrics to dry and wet rubbing is excellent. Printed polyamide fabric is more resistant to washing than printed cotton fabric. Both printed fabrics display poor colour fastness to light.
|