Comparative studies targeting the best dyeing conditions for pure, blend and modified fabrics with novel nano-disperse reactive dyes and their biological activity.

Here, in the current work, three different types of novel nano-disperse reactive dyes (3a, 3b, and 4) based on the pyrazolone moiety with one or two reactive centers were synthesized and used to study the effect of the kind and number of reactive groups on dyeing performance. The structure of the synthesized nano-disperse dyes was confirmed using different spectroscopic techniques. The dyeing properties of newly synthesized dyes have been investigated for dyeing different fabrics under traditional conditions. On the other hand, we studied the effect of changes in pH, dyeing bath temperature, and dyeing time through statistically designed experiments to determine the optimal conditions for achieving high fixation and good color fastness. After careful investigation, we found that dye 3a, which has a vinyl sulfone group as a reactive group center in its structure, gave the best and highest value of fixation (K/S%) ranging from (12.17-50.85) in almost all of the examined fabrics (polyester, cotton, polyester/wool, polyester/cotton and polyester/chitosan) except wool, taking into consideration the change of suitable temperature, pH level, and dyeing time for each type of fabric. Critically, the synthesized dyes exhibited significant and structure-dependent antimicrobial activity against the Gram-positive (S. epidermidis, S. haemolyticus, MRSA) and Gram-negative (E. coli, K. pneumoniae, P. aeruginosa) bacteria and the pathogenic yeast C. albicans. Data revealed that dye 3b possessed exceptional broad-spectrum potency, specifically against S. haemolyticus, MRSA, K. pneumoniae, and C. albicans.