Interaction of dyes used for foods with food packaging polyester fibers

The effect of pH, temperature, dye concentration, and additives on the absorption of the dyes FD & C (Food, Drugs and Cosmetics) Blue 1 and Blue 2 upon poly(ethylene terephalate) (PET) and poly(butylene terephthalate) (PBT) subjected to different draw ratios (and, thus, resulting in different percentage crystallinities determined with DSC and wide-angle X-ray diffraction patterns) was investigated and a correlation between these parameters and the dye uptake was suggested. The absorption kinetics of the dyes on the polyesters were studied and a mechanism based upon the development of hydrogen bonds between the dyes and the end groups (? COOH,? OH) of the polyesters and the swelling of the network was proposed. Finally, an indirect measurement of the T_g values of the polyesters was suggested based upon the different dyeing diffusion rates. © 1994 John Wiley & Sons, Inc.     

Synthesis and characterisation of 3-ketocoumarins: substituent effects on colour

Two series of 3-ketocoumarin dyes, the methyI-3-coumarinoylacetates and 3,3-carbonylbiscoumarins, were synthesised by condensation of salicylaldehyde derivatives with dimethyl-1,3-acetonedicarboxylate. The preparation of the corresponding cyanated derivatives of the above compounds is also reported. All compounds are characterised by their ¹H-NMR and mass spectra. Electronic spectra are also recorded and discussed.     

Colour and fastness of natural dyes: revival of traditional dyeing techniques

Cotton and wool fabrics were dyed with nine natural dyes obtained by aqueous extraction of the original plants/insect in an attempt to reconstruct traditional textile dyeing recipes, to optimise the methodology at all stages, i.e. extraction, mordanting and dyeing, and to standardise it. Cochineal, madder, alkanna, henna, brazilwood, red sandalwood, safflower, indigo and logwood were used for the dyeings, which were carried out directly and after mordanting of the textile material. A variety of mordants, namely, aluminium potassium sulphate, potassium dichromate, copper sulphate, zinc chloride, iron(iii ) chloride, iron(ii ) sulphate and tin chloride, is anticipated to meet both early and recent requirements and options. The dyeings were evaluated through colour measurements and standard wash, light and rub fastness tests. Generally, the mordanting process known for many centuries and connected with the textile dyeing resulted in an improvement in dye absorption and fastness properties mainly for the cotton samples, as is concluded from the tests and measurement assessments.     

Cellulose mercerization: Use of amino acid‐glycerol ethers as wetting agents

The action of a new nonconventional series of (tryptophan‐phenylalanine‐histidine and tyrosine)‐glycerol‐ether surfactants as wetting agents in hot cotton mercerization was studied. The mercerization result was evaluated with the barium hydroxide absorption number, water absorbency and moisture regain, and mechanical properties of fibers; the dyeability of the mercerized samples with a direct and reactive dye was also studied. An improvement was observed for all the above parameters in the presence of the aforementioned wetting agents despite their being used in very low concentrations. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Ink‐jet printing of cotton with natural dyes

Four natural dyes, annatto, cutch, pomegranate fruit rind, and golden dock, were used as colorants for the preparation of water‐based ink‐jet inks for digital textile printing. The physical and rheological properties (pH, conductivity, surface tension, and viscosity) of the inks were measured over a period of 90 days for the evaluation of ink stability and suitability for ink‐jet printing. The inks were found to be suitable and were used for the digital printing of cotton fabrics. The prints were subjected to wash, light, and rub fastness tests and colour measurements. Colour consistency and fastness results, especially after fixation, are comparable with those of synthetic dyes, which paves the way for the production of environmentally friendly ink‐jet inks using natural dyes for the digital printing of cotton through the formulation of suitable printing techniques.     

Synthesis and characterization of hetarylazo disperse dyes derived from substituted N‐β‐acetoxyethylanilines—Application on cellulose acetate

The heterocyclic amines 2‐amino‐6‐methoxy‐ and 2‐amino‐6‐nitrobenzothiazole, 3‐amino‐5‐nitro‐[2,1]‐benzisothiazole, and 2‐amino‐3,5‐dinitrothiophene were diazotized and coupled to substituted N‐β‐acetoxyethylanilines to give dyes which colored cellulose acetate in red to deep blue hues. The color of the dyes is discussed with respect to the nature of the heterocyclic ring and to the substituents in the diazo and coupling component. Dyeing and fastness properties of the dyes on cellulose acetate are also reported. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3479–3483, 2004     

Effect of Surfactants as Dispersing Agents on the Properties of Microemulsified Inkjet Inks for Polyester Fibers

The preparation of microemulsified disperse inkjet inks was carried out and the effect of the surfactant used as dispersing agents on the properties of the inks was studied. The dispersing agents used were anionic conventional and non-conventional surfactants and a gemini type surfactant. The properties studied were surface tension, pH, conductivity, viscosity and the particle size distribution. The use of the gemini type and the two non conventional surfactants even in submultiple amounts resulted in a significant increase in the ink stability.     

Disperse ink‐jet inks: properties and application to polyester fibre

Water‐based ink‐jet inks were prepared using press cake samples of two commercially available azo disperse dyes. The suitability of the inks for printing polyester fabric was evaluated via measurement of surface tension, conductivity, viscosity, pH and particle size distribution. Inks prepared by the proposed method fulfill most requirements for an ink‐jet ink depending on the colorant structure, the dispersing agent and the alcohol used. The inks were applied to polyester fabric by both printing and dyeing and the fastness of the ensuing coloured samples was assessed. The fastness properties of the dyed and printed polyester samples were found to be very good to excellent and generally meet accepted customer requirements. Oil‐in‐water microemulsions containing the same colorants were also prepared. Their properties, which are crucial to the suitability for ink‐jet ink, were compared with those of the conventionally prepared inks and were found to be improved, with the exception of conductivity, while surface tension remained within acceptable values.     

Interaction of dyes used for foods with food packaging polyamides

The effect of pH, temperature, dye concentration, and additives on the adsorption of the dyes FD & C (Food, Drugs & Cosmetics) Blue 1 and Blue 2 upon the polyamides nylon 4–7,9, and 10–12 was studied and a correlation between these parameters and the dye uptake was found. The adsorption kinetics of the dyes on the polyamides were studied and a mechanism based on the interaction of the acid groups of the dyes and the positively charged groups of the polyamides was suggested. © 1993 John Wiley & Sons, Inc.     

Synthesis and properties of new cationic surfactants. II. Odd homologous members

In connection with our previous work on the synthesis and study of new pyrimidinium cationic surfactants, some new members of the N-alkyl-pyrimidinium salts homologous series were prepared. The above compounds contain long-chain alkyl groups of 7, 9, 11, 13, 15, 16, 17 and 18 carbon atoms. The series of these compounds having an alkyl chain of C₇–C₁₈ has been completed, and a correlation between their constitution and some properties has been made. The structural assignment of these compounds was made on the basis of the elemental analysis and IR, NMR, MS spectroscopic data. Surface tension, water solubility and antimicrobial activities were determined for these surfactants. The wet fastness of direct dyed cotton fabrics after-treated with these cationics also was studied.