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Fifteen new difluorinated phosphonic and sulfophosphonic acids have been synthesized and characterized by 1H, 13C, 31P and 19F n.m.r. spectroscopy. The results are discussed in relation to previous work on monofluorinated acids.

Microemulsions, or their precursors, are proposed for improving the quality of dyed fabrics. The investigated substrates are polyamide (nylon 6 and 6.6) polyester, and a secondary cellulose acetate-nylon 6 blend. Besides conventional fibers, also nylon 6 and polyester microfibers are studied. It has been possible to ascertain that suitable organized systems allowed to obtain a better uniformity of coloration without depressing dyebaths exhaustion. Furthermore, in some cases, satisfactory results have been obtained at halved liquor ratios with consequent energy saving during the tinctorial cycles.

The use of a double-tailed cationic surfactant as additive in the dyeing of polyacrylonitrile with cationic dyes is proposed. Single-tailed colorless cations usually compete with the dyes for the anionic sites within the fibre and at the fibre surface, thus retarding and giving levelness to the dyeings. A set of comparative tests has shown that di-methyl-di-dodecylammonium chloride (DDDAC) behaves better by far, as retarding and levelling agent, than commercially well known single-tailed cations.