Colour dynamics and compatibility: A comparative analysis of reactive dyes on ramie and cotton fabrics

In this study, cotton and ramie knitted fabrics were dyed with reactive red 195, yellow 145 and blue 194 dyes and subsequent analyses were done. An exhaust method without alkali was followed and subsequently, spectrophotometric analysis was conducted to measure the values of substantivity% (S) of the dyes in both ramie and cotton knitted fabric dyeing. Solutions were prepared to measure the exhaustion% (E), fixation% (F) and reactivity% (R) of those dyes in cotton and ramie fabric dyeing using another exhaust method that comprises exhaustion, fixation (addition of alkali) and wash-off (treating with soaping agent) stages sequentially. Dye compatibility, colour strength (K/S), colour uniformity and colour fastness to washing and rubbing were assessed from the dyed cotton and ramie samples. All of these values were higher while dyeing cotton fabric samples. The average proportion of dye (%) of yellow, red and blue were 35.68%, 32.95% and 31.36% respectively for dyed ramie fabrics and in case of dyed cotton fabrics, the average proportion of dye (%) of yellow, red and blue were 41.45%, 33.22% and 25.33% respectively. Average K/S values of ramie and cotton were found 5.736 and 6.674 respectively and the colour uniformity was better for dyed cotton fabrics. Both cotton and ramie fabrics showed good to excellent results in terms of colour fastness to washing and rubbing. However, dyed ramie fabrics showed slightly inferior properties in case of staining to nylon-6, 6 and wet rubbing fastness. This research demonstrates the feasibility of dyeing both ramie and cotton with reactive red 195, yellow 145 and blue 194 in a union dyeing method.