Duncan Phillips

UV/Visible spectroscopic studies of the effects of common salt and urea upon reactive dye solutions

Abstract The absorption spectra of two reactive dyes were studied by UV/Visible spectrophotometry in the presence of sodium chloride and urea at varying concentrations. Evidence has been produced to show that the effect of adding common salt to a dyebath at neutral pH is to produce increased aggregation of the dye species. In contrast, the addition of urea to a dye liquor results in reduced dye aggregation and the generation of increased amounts of the monomeric species. ©

The development of a laboratory method for quantifying the bioelimination of anionic, water soluble dyes by a biomass

Abstract A simple and rapid laboratory-based method has been developed to enable measurement of the removal of anionic, water soluble dyestuffs from a typical wastewater treatment works by adsorption onto a biomass. The proposed screening test is robust and gives results that are highly reproducible and forms the basis of a correlation between molecular structure and colour bioelimination. A detailed description of the new method and a comparison with some previous methods is given.

A chemometric approach to understanding the bioelimination of anionic, water-soluble dyes by a biomass using empirical and semi-empirical molecular descriptors.

Single correlation and multiple linear regression analyses have been applied to understand the bioelimination of 103 anionic, water-soluble dyes by a biomass at a wastewater treatment works. The chemometric approach highlighted that anionic, water-soluble dyes with larger molecular size/ionic charge ratios and containing more primary aromatic amines and unsulphonated naphthalene nuclei and fewer aliphatic alcohol groups had superior levels of bioelimination.

The dyeing of cotton with hetero bi-functional reactive dyes containing both a monochlorotriazinyl and a chloroacetylamino reactive group

Water-soluble reactive dyes incorporating both a chloroacetylamino group and a monochlorotriazinyl group have been prepared. Under the alkaline application conditions employed, little or no additional fixation, via the desired nucleophilic displacement of chloride from the chloroacetylamino group, by cellulosate, was observed. The principal reaction was amide hydrolysis.

The influence of yarn-processing parameters on the tensile properties and structure of poly(l-lactic acid) fibres

Abstract This paper examines the influence of processing parameters on the physical properties and structure of yarns constructed from poly( l -lactic acid) (PLLA) fibres. Commercially produced spun- and false-twist texturised (FTT) PLLA yarns, and knitted fabrics derived there from were characterised in terms of their tensile properties, and structurally using differential scanning calorimetry (DSC) and wide angle X-ray diffraction. The effects of pre-dye heat-setting at 130 °C for varying times was assessed in terms of the resultant tensile properties of the yarns. The as-received FTT yarns (and hence their derived fabrics) differed in properties and fibre microstructure as compared to the spun yarns (and fabrics). More significantly, for both FTT and spun materials, differences in fibre properties and structure were observed between yarns removed from the fabrics and their respective feed-yarns. We associate this with possible thermomechanical influences experienced by the fibres during the knitting process. The duration of heat-setting influenced the tensile properties and DSC spectra for both types of yarn. Scouring following heat-setting was also carried out, and this produced no measurable additional effect on the spun yarns, but FTT yarns heat-set for less than ca 45 s showed instability to scouring.

4-Arylamino-6-chloro-1,3, 5-triazin-2(1H)-ones: nucleophilic substitution of a model compound in acid medium to produce novel fibre reactive triazinyl derivatives

A model 4-arylamino-6-chloro-1,3,5-triazin-2(1H)-one has been synthesised and reacted with a variety of nitrogen, oxygen and sulphur nucleophiles in an acidic medium. Unlike the parent compound, the products from reaction with pyridine, nicotinic acid and p-aminobenzene-β-sulphatoethylsulphone are capable of reaction with cellulose in an alkaline medium.

The dyeing performance on cotton of reactive dyes containing the α-bromoacrylamido group

Three reactive dyes containing the α-bromoacrylamido group have been synthesised and their performance assessed for the exhaust dyeing of cotton. The results indicate that, when situated in the appropriate electronic environment in the dyestuff molecule, this reactive grouping is compatible with the sulphatoethylsulphonyl (vinylsulphonyl) group in delivering warm dyeing (60°C) characteristics.

Novel fibre-reactive triazinyl betaines: a one step synthesis of 4-m-carboxypyridinium-s-triazine-2-oxides from dichloro-s-triazinyl derivatives

Five dichlorotriazinyl compounds have been reacted in turn, with nicotinic acid and one with pyridine, in acid medium. In each case either a carboxypyridinium or a pyridinium-triazine-2-oxide was formed cleanly. Ring opening of the pyridinium ring attached to the triazine did not occur. A limited study suggests that a bis-pyridinium-triazine is the penultimate species and chlorohydroxytriazines [6-chloro-1,3,5-triazin-2(1H)-ones] are not intermediates in the reaction sequence.

Synthesis and application of disperse dyes based on 1,4-bis(benzothiazol-2-yl)benzene to polyethylene terephthalate

Abstract Two novel water-insoluble dyes based on the 1,4-bis(benzothiazol-2-yl)benzene chromophore have been synthesised and applied to polyethylene terephthalate (PET) by exhaust dyeing. The dyes exhibited high levels of heat and wet-fastness but light fastness was very poor.

Interaction of oxidative bleach containing detergents with dyes. Part 1: Preparation and resistance of 1-amino-2-arylazonaphthalene-4-sulphonic acid dyes to hydrogen peroxide and m-chloroperbenzoic acid

A series of red water soluble azo dyes were prepared by coupling variously substituted phenyldiazonium salts onto 1-aminonaphthalene-4-sulphonic acid. In order to mimic the conditions experienced during domestic laundering, in presence of an oxidative-bleach containing detergent, the dyes were then subjected, separately, to treatment with m-chloroperbenzoic acid and with hydrogen peroxide. Experiments were conducted under alkaline conditions (pH 9.8) and pseudo first order rate constants were determined for dye destruction. The m-chloroperbenzoic acid was much more effective than hydrogen peroxide in bringing about loss of colour. The introduction of electron donating groups into the diazo component of the dyestuff, which would be expected to lead to an increased propensity to undergo attack by electrophilic species, resulted in increased levels of bleaching by the peracid. Additionally reduction in pH caused an increase in the rate of bleaching in presence of peracid, the rate increasing approximately tenfold per unit drop in pH. These observations are consistent with attack by m-chloroperbenzoic acid, a highly electrophilic species, rather than m-chloroperbenzoate (the major species present at pH 9.8).