Guido Alberti

Thermodynamic Features in Acrylic Fiber Dyeing with Basic Dyes

The dyeing affinity of some pyridine basic azo dyes for Leacril 16 acrylic fiber was measured from the Langmuir isotherms. Results show a dependance of affinity on dye structure. Comparison with previous results supports the hypothesis of constant group contributions to dyeing standard free energy.

Technical properties and photofading of disperse heterocyclic azo dyes

Abstract A series of heter acyclic azo dyes derived from aminophenyl-benzothiazoles and substituted dialkylanilines was prepared and tested on polyamide and polyester. The overall properties were satisfactory and compared favourably with related dyes previously described. Several correlations between structure and physical, spectroscopic (VIS and NMR) and fastness properties were found. An investigation of the photofading of the dyes on substrates as a function of time, checked with colourimetric techniques, proved a close time-dependent feature for colour parameters.

Easy access to trans-2,3-disubstituted cyclobutanones, 2,4,5-trisubstituted 3,6-dihydro-2H-pyrans and cis-substituted phenylcyclopropylsulfones by using the highly versatile 1-phenylsulfenyl- or 1-phenylsulfonyl-cyclopropylketones

The high versatility of 1-phenylsulfenyl- or 1-phenylsulfonyl-cyclopropylketones has been exploited for the regioselective synthesis of trans-2,3-disubstituted cyclobutanones, 2,4,5-trisubstituted 3,6-dihydro-2H-pyrans and cis-2-alkyl- or cis-2-aryl-cyclopropylphenylsulfones.

Pyridyl-substituted azobenzene disperse dyes

Abstract N,N-Disubstituted aminoazobenzene dyes containing a 2-pyridyl substituent were prepared and used for the dyeing, as disperse dyes, of polyamide, polyester and cellulose acetate. The dyeings and the fastness tests gave very satisfactory results. Correlations of physico-chemical constants and spectroscopic parameters, as well as of colour parameters of dyed fabrics, with the structure of the present set of dyes and of previous ones were found. A detailed 1 H and 13 C nuclear magnetic resonance (NMR) analysis of dyes, including correlation techniques, was performed.

Effect of Electrolytes on the Dyeing of Polyacrylonitrile Fiber with Anthraquinone Cation Dyes

The effect of various electrolytes on the dyeing rate and on the adsorption isotherms of two anthraquinone cation dyes was studied. The relative synthesis and fastness tests are reported. The results clearly indicate that the retarding effect of the various elec trolytes is related to the ionic radius of the cation of the electrolyte. A linear correlation was found between the saturation values, calculated with the Langmuir isotherms, and the radius of the hydrated ions.

Solvent Effects on Short Time Dyeings of Acrylics

The absorption of CI basic green 4 by acrylic yam in the presence of different solvents is studied by means of the short dyeing time method. The quantity of absorbed dye is related to the dyeing temperature through an equation of the Williams-Landel- Ferry type. Using the theory of fractional contribution to the solubility parameter, linear correlations are found between the ratio of polar to nonpolar contributions to the solubility parameter and the lowering of the dyeing transition temperature of polyacrylonitrile caused by the solvents, and between the same and the quantity of absorbed dye. Increases in temperature level the effect of the different solvents on dye absorption.