Automatic identification of ramie and cotton fibers based on iodine blue reaction,Part I: the optimum conditions for the iodine blue reaction of cellulose

Abstract

A new iodine blue staining technique to distinguish ramie fibers from cotton fibers was presented. The influencing factors on staining color, including temperature, concentration of iodide anions in I₂-YI solution, ratio of the volumes of added I₂-YI solution and saturated LiX solution, time, and concentrations of alkali metal cation Y⁺ and halide anion X^–, were investigated to maximize the difference in color between stained cotton and ramie fibers. The optimum conditions were as follows: temperature: –15℃; concentration of iodide anion in colorant: 1/5; volume ratio: 1/20; colorant: I₂-LiI solution; swelling reagent: saturated LiCl solution. The experimental results showed that the new staining technique can be useful for automatic identification of cotton and ramie fibers.