Study of the influence of formation conditions on dyeability of gel-fibers made from copolymers of acrylonitrile, methyl acrylate and itaconic acid

The aim of this work was to study the effect of the acid comonomer content and the spinning conditions on the coloring of gel fibers based on copolymers of acrylonitrile (AN), methyl acrylate (MA), and itaconic acid (ITA). Model copolymers AN, MA, and ITA with an acid comonomer content in the monomer mixture from 0 to 2 % (weight) due to a change in the MA fraction were synthesized. The correlation between the loading of the acid monomer into the reactor and the real amount of the same monomer that entered the copolymerization reaction was estimated by the sorption of methylene blue dye by films of model copolymers. It was found that the content of ITA in the copolymer is lower than the content of ITA in the initial polymerization mixture. Using a bench spinning machine based on the synthesized copolymers, samples of model fibers were obtained by the dimethylformamide method. The study of the coloring of polyacrylonitrile fibers in the gel state showed that the amount of sorbed dye is directly proportional to the content of ITA in the copolymer and does not depend on the temperature of the precipitation bath. It was found that the whiteness index (lightness) practically does not depend on the temperature of the precipitation bath, but to a greater extent is determined by the content of acidic comonomer in the copolymer. The maximum decrease in the whiteness index is observed with an increase in the content of ITA in the copolymer from 0 to 0.7 %. A further increase in this indicator to 1.79 % leads to an almost linear decrease in the whiteness index from 11-14 to 7.4-7.8 %.