Dyeing Mechanism of Natural Plant Dye R. Coptidis on Silk

摘要

The dyeing mechanism of silk fabric with natural plant dye R. coptidis was discussed in terms of the thermodynamic and kinetic factors, including standard affinity, enthalpy change, entropy change, dyeing rate, diffusion coefficient and activation energy of the diffusion. The results showed the adsorption isotherm of R. coptidis on silk fabric belonged to Langmuir type. And the analysis of dyeing thermodynamics showed adsorption of rhizoma coptidis on silk fabric was an exothermic process, when dyed at higher temperature, lower affinity and less dye uptake were obtained. However higher temperature increased the initial dyeing rate and increased the diffusion coefficient.