Dyeing properties of monoazo disperse dyes derived from 4-alkylamidosalicylic acids: equilibrium study

The dyeing equilibria of a set of monoazo dyes derived from 4-alkylamidosalicylic acids on nylon 6.6 have been studied. A Nemst distribution has been obtained indicating the prevailing mechanism of solution of the dye in the fibre Equilibrium depends on the length of the alkyl chain of the dye and on the concentration of dispersant. The latter affects the equilibrium differently according to the hydrophobicity of the dye. Linear relationships between the chain length and ΔHd? and ΔSd? have been found.     

Monoazo dyes for polyamide derived from 4-alkylamido-2-hydroxybenzoic acids

Data on a series of 65 azo dyes derived from 4-alkylamido-2-hydroxybenzoic acids are reported. The dyes are suitable for application to polyamide fibres.Many correlations between the nature of substituents and the physical, spectroscopic or tinctorial properties of dyes were established. Correlations between structure and colour of dyed fabrics were also found.     

Design of high fastness acid dyes for silk: a chemometric approach

A chemometric strategy tor the design of acid dyes for silk is reported. A small set of representative dyes was selected by the technique of fractional factorial design, using the principal properties of the substituents as design variables. The selected dyes were synthesised and fastness properties on silk were measured. Wash fastness and light fastness values were related to the chemical structure by the partial least squares (PLS) method. The models were used to predict the fastness of new dyes of the same class and to optimise the structure.     

Model dyes for optimizing the dyeing of polyamide

Model disperse azo dyes, containing a salicylic moiety, hydrophobic alkyl chains and usual substituents, allowed the investigation of the effects of these structural variations on dyeing properties. By combining the results of both equilibrium and rate studies, some interesting structures for practical purposes could be identified.     

Integrated optofluidic microsystem based on vertical high-order one-dimensional silicon photonic crystals

In this work, fabrication and testing of an optofluidic microsystem exploiting high aspect-ratio, vertical, silicon/air one-dimensional (1D) photonic crystals (PhC) are reported. The microsystem is composed of an electrochemically micromachined silicon substrate integrating a 1D PhC featuring high-order bandgaps in the near-infrared region, bonded to a glass cover provided with inlet/outlet holes for liquid injection/extraction in/out the PhC-itself. Wavelength shifts of the reflectivity spectrum of the photonic crystal, in the range 1.0–1.7?μm, induced by flow of different liquids through the PhC air gaps are successfully measured using an in-plane all-fibre setup, thanks to the PhC high aspect-ratio value. Experimental results well agree with theoretical predictions and highlight the good linearity and high sensitivity of such an optofluidic microsystem in measuring refractive index changes. The sensitivity value is estimated to be 1,049?nm/RIU around 1.55?μm, which is among the highest reported in the literature for integrated refractive index sensors, and explained in terms of enhanced interaction between light and liquid within the PhC.     

Quantitative relationships between chemical structure and technical properties of 4-aminoazobenzene sulphonic acid dyes

A series of new 4-aminoazobenzene dyes was synthesised. Absorption maxima and some important technical properties (lightfastness and fastness to washing) on nylon-6.6 and on wool were measured. A number of similar previously described structures were also prepared and characterised. Colour and constitution relationships in this series of dyes were established.A statistical analysis of their fastness properties by a modified Free-Wilson method was carried out. The validity of the additive model was confirmed and quantification of substituent contributions was obtained.     

Monoazo dyes for polyamide derived from 2-(4-alkylamido-2-hydroxyphenyl)benz-X-azoles

A series of 51 azo dyes derived from 2-(4-alkylamido-2-hydroxy-phenyl)benz-X-azoles was prepared. The dyes were used as disperse dyes for polyamide fibres. Physical, chemical, spectroscopic and technical properties of the dyes are discussed. A ‘spectroscopic constant’ is introduced to account for the colour of dyes in solution and of dyed fabrics.     

Technical properties and photofading of disperse heterocyclic azo dyes

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.     

Developments in the Application of Quantitative Structure-Property Relationships of Dyes

Presented at the 13th Congress of the International Federation of Associations of Textile Chemists and Colourists in London on 20 September 1984. A major aim of current research in dye chemistry is the detection of quantitative relationships between structure and technical properties in order to design new compounds. In the study reported here the light fastness of a set of azo dyes was analysed by some of the methods of chemometrics.