Effect of liquid ammonia treatment on the pore structure of mercerized cotton and its uptake of reactive dyes

Abstract

Structural changes in mercerized cotton by liquid ammonia (LA) treatment were investigated and correlated with changes in dyeability of cotton fabrics with reactive dyes. The pore structures of mercerized cotton and mercerized-liquid ammonia (M-LA) treated cotton were characterized by inverse size exclusion chromatography (ISEC). Results showed that when the mercerized cotton was subjected to LA treatment, cumulative accessible volume of smaller pores (e.g., 25.2 Å) increased, whereas that of the larger pores (e.g., 56.7 Å) decreased. These results might be related to the changes in the amorphous region of cotton fiber. The decrease in crystallinity of cotton fiber would increase accessible volume of smaller pores. The larger pores might be compressed by extrusion during swelling of microfibrils or elementary fibrils in water. The change in dyeability of fabrics with reactive dyes of various molecular weights could be rationalized using the observed changes in pore structure. Results also showed that ISEC was more suitable than the method employing Chrastil's diffusion equation for analyzing the pore structure of cotton fiber.

Established an eco-friendly cotton fabric treating process with enhancing anti-wrinkle performance

“…Consequently, the resilience of the fiber is enhanced by this natural crosslinking, and this crosslinking effect is further strengthened by chemical crosslinking. 26,35,44 Therefore, the value of WRA, DP, and softness of MLC before and after anti-wrinkle finishing shown in Figure 1(a)–(c) are superior to those of MC.…”

“…24,48,49 The swelling with liquid ammonia results in a product having more evenly distributed due to smaller pore size and smaller pore size distribution, which makes it has less inner external stress and so that has greater strength. 44,49 For WI shown in Figure 1(e), there is no difference between the MC and MLC before and after anti-wrinkle finishing. But it should be noticed that the sharp whiteness loss after CA treatment was due to the production of unsaturated acids during CA crosslinking finishing.…”

“…Consequently, the resilience of the fiber is enhanced by this natural crosslinking, and this crosslinking effect is further strengthened by chemical crosslinking. 26,35,44 Therefore, the value of WRA, DP, and softness of MLC before and after anti-wrinkle finishing shown in Figure 1 Secondly, the cotton fiber under concentrated NaOH solution and liquid ammonia treated would go through swelling states and form Na-cellulose complex and ammonia-cellulose complex, respectively, after that the decomposition of the complex by removing NaOH or liquid ammonia leads to the cellulose crystalline structure changes from its initial cellulose I to cellulose II or cellulose III. 28 Meanwhile, these crystalline transformations and reformations are strictly related to the specific conditions, therefore, may be accompanied by decrystallization in general resulting in a decrease in mechanical properties.…”

Influence of Sequential Liquid Ammonia and Caustic Mercerization Pre-Treatment on Dyeing Performance of Knit Cotton Fabric

“…However, the CM treatment expands the fiber pores, while the LA treatment compacts the fiber pores. Thus, the LA-treated cotton fiber only exhibits a poorer dyeability in using big reactive dyes [ 11 ].…”

Dyeing Ramie Fabrics With Curcumin in NaOH/Urea Solution at Low Temperature

“…Recently, some methods of improving the dyeing property of ramie fibers have been developed, including liquid ammonia treatment (Wakida et al, 2001), cation modification (Choudhury, 2014), alkylation, and acetylation; these methods modify the aggregate structure and molecular structure of the ramie fibers. Sun, Zhou, and Xing (2016) introduced a liquid ammonia treatment before dyeing the ramie fibers, resulting in a reduction of the fibers' crystallinity and an improvement of coloration. However, the liquid ammonia treatment was expensive to perform.…”