Relationship between Integral Diffusion Coefficient and Rate Constant in Dyeing Poly(ethyleneterephthalate)

Practical methods of computing the diffusion coefficient D and rate constant K from the Cegarra-Puente equation for dyeing poly (ethylene terephthalate) fibre with disperse dyes are given. A simple approximate relationship has been derived enabling the corresponding D to be found when K is known. A general technique is also described for approximation of complicated diffusion equations by means of simpler relationships