Liquid ammonia treatment

Thus, further experiments were performed with two hydrolytically degraded linters powders subsequently disintegrated to different particle sizes (Filtrak, FNA and FND, VEB Spezialpapierfabrik Niederschlag, GDR), the lateral order of these samples being varied by liquid ammonia treatment or by mercerization with 18% aqueous NaOH. A posthydrolysis of these samples with aqueous acid (5% HC1, 2 hr, 100°C) resulted in changes in DP and in residue as indicated in Table IX and as to be expected from previous publications (11,16). 

Figure 14. Adsorption isotherms at 32° C for boards with or without liquid ammonia treatment before water sorption. Severe and mild refer to cooking steam pressures.

Variety Temperature Scouring and bleaching Caustic mercerization Liquid ammonia treatment Removal techniques... 

These techniques have been used to elucidate the effects of variety [289], temperature [287], scouring-bleaching [290], caustic mercerization [290-292], liquid ammonia treatment [290,292,293], cross-linking with different agents under varying conditions [294-298], dye-ability [296,299], and treatment with cellulases [300-302], on the cotton. The trends observed are summarized in Table 5.8. 

It has been suggested that the great depth of color or dye yield found with mercerized cotton is due to the caustic treatment inducing an abundance of large pores in the fiber. In contrast, the high level of resilience associated with liquid ammonia treatment has been ascribed to a low level of large pores in the fiber [292]. 

Stevens, C.V. and Roldan-Gonzalez, L.G., Liquid ammonia treatment of textiles, in Handbook of Fiber Science and Technology, Vol. 1, Part A, Lewin, M. and Sello, S.B., Eds., Marcel Dekker, New York, 1983, pp. 167-203. 

Loss of abrasion, tear and ripping strength Wet condensation, liquid ammonia treatment, addition of silicones and other auxiliaries for example polyvinyl acetate, polyurethane... 

R. M. Gaily, Conf. Proc. in Liquid Ammonia Treatment of Cellulose Textiles, Shirley Institute, Manchester, England, Nov 19,1970, pp 34. 

The discussion of cellulose dissolution must recognize that cellulose can exist in four polymorphic forms native cellulose known as cellulose I polymorph cellulose II obtained by regeneration of cellulose I cellulose III, which is derived from the liquid ammonia treatment of cellulose I or cellulose II and cellulose IV, which refers to the thermal treatment of cellulose I or cellulose 111 [2]. It is important to recognize these distinctions because the respective cellulose polymorphs can have different solubility characteristics in particular solvents, as will become evident further in this chapter. 

Sanfor-set trademark. A trademark of Cluett, Peabody Co. Inc., denoting a controlled standard of shrinkage performance originally developed for denims. Fabrics bearing this trademark will not shrink under home-wash, tumble-dry conditions because they have been subjected to a liquid ammonia treatment and compressive shrinkage. 

Recent developments in the synthesis of dibenzopyrrocolines have centered mainly on variations of the benzyne approach. Potassium amide in liquid ammonia treatment of the bromobenzylisoquinoline 1 affords the dibenzopyrrocoline 2 along with the corresponding aporphine 3. " ... 

Conversion to cellulose II and cellulose III via caustic mercerization and liquid ammonia treatment are commercial textile processes that are discussed later. Figure 7 shows the characteristic diffractograms (Cu Ka radiation) of native cellulose, cellulose mercerized with sodium hydroxide, and cellulose treated with liquid ammonia. 

Scouring and bleaching slightly increase the accessible internal volume, liquid ammonia treatment of the scoured-bleached cotton decreases it slightly, caustic mercerization substantially enhances accessibility, and cross-linking to impart durable press properties reduces the accessible internal pore volume substantially. 

The application of 2-3% omf (on mass of fibre) fixed resin appears to be optimal for easy-care properties, dependant on the fabric constmction and weight. Application levels of 2% omf are needed to stop fibrillation on domestic washing. In addition to the resin, the choice of softener can have a large effect on the easy-care performance of fabrics, and it is important to consider the whole formulation and build it up to give the required performance. Silicone micro-emulsions penetrate yams more than the macro-emulsions. Polyethylene dispersions aid sewing and build the handle of the fabric, whilst some soft acrylic-based chemicals can increase the abrasion resistance. It is also worth remembering that caustic soda or liquid ammonia treatment in preparation will help to increase the easy-care rating of lyocell fabrics. 

Bertoniere, N. R., King, W. D. (1989), Effect of scouring/bleaching, canstic mercerization, and liquid ammonia treatment on the pore stmcture of cotton textile fibers. Textile Res. J.,59(2), 114-21. 

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