Resumen de Synthesis, colorfastness evaluation and utilization of humic acid derived dyes / pigment
Saqib Nasir, Tahira B Sarfaraz, Khalid Khan, Ausaf Aleem, Rasheeda Parveen
Pakistan coal derived humic acid (HAL) salt was used to synthesize direct azo and acid dyes by coupling reaction with arylamines and its substituted derivatives (R1-R15) for dyeing industry as a reaction intermediates. A variety of color shades ranging from light to deep brown and yellowish were obtained by applying the dyes (D1-D15) to various fabrics. The dyes were noteworthy due to bio-organic in nature, excellent colorfastness to perspiration and washing. The presence of chromophoric groups in a humic acid will explore the utilization of such a natural polymer as potential candidate for the synthesis of dyes and pigments. Colorfastness tests had been studied and significant performance was observed for pure cotton, silk and wool fabrics with certain limitations. The dyed fabrics showed fair to good colorfastness to light and very good to excellent fastness to washing, perspiration, rubbing and seawater. Humic acid and its calcium salt were used to prepare anti-rust pigment using indigenous technique. The humic pigment (HAP) was successfully used for anti-rust purposes in marine paint composition and textile printing application for polyester-cotton fabric. The colorfastness features of printed fabrics were evaluated in comparison with commercially available carbon black pigment (CBP). The computational color data (CIELab) analysis for dyed and printed fabrics were exhibited a good performance of humic derivatives as UV-absorber for value added textile.
