Studies on the Dyeing of Chitin and Chitosan with pre-metallised Dyes at Neutral pH
Journal Title: Progress on Chemistry and Application of Chitin and its Derivatives - Year 2010, Vol 0, Issue
Abstract
Both 1:1 pre-metallised acid dyes and pre-coppered direct dyes, but not 1:2 pre-metallised acid dyes, have been shown to readily dye chitin and chitosan from neutral dyebaths. With the 1:1 pre-metallised acid dyes the addition of neutral electrolyte increases the uptake of dye, indicating that electrostatic forces of attraction are not involved in the adsorption process. A mechanism of dyeing is proposed involving complex formation between the metal ion of the pre-metallised dye and the amine groups of the substrate. The wet fastness properties of the 1:1 pre-metallised acid dyeings carried out at neutral pH are at least equal to, and in many cases greater than, those obtained by the conventional dyeing process at pH values of 4.5 - 5. In the case of precoppered direct dyes a rigorous washing-off process is required in order to remove dye adsorbed on the substrate, but not complexed with the amine groups, if the maximum wet fastness is to be achieved.
Authors and Affiliations
Simon Mazengarb, George AF Roberts, Frances A. Wood
Keywords
Related Articles
- EP ID EP73700
- DOI -
- Views 77
- Downloads 0
THE INFLUENCE OF THE TYPE SOLVENT ON THE STRUCTURE OF CHITOSAN BLENDS WITH HYALURONIC ACID
The influence of the type solvent on the structure of chitosan, hyaluronic acid and their blend films was investigated. Aqueous acetic acid, hydrochloric acid, sodium chloride and aqueous acetic acid/NaCl were used as so...
CHITOSAN DICARBOXYLIC ACID SALTS
It is possible to obtain salts with specified properties from adipic, succinic and fumaric acids and chitosans of varying degrees of deacetylation and viscosity-average molecular weight. The temperature of the process, t...
BIOPOLYMER COMPOSITES BASED ON GALACTOGLUCOMANNANS (GGMS) AND MICRYSTALINE CHITOSAN (MCCH)
The article presents a method of extracting galactoglucomannas (GGMs) from softwood (spruce). GGMs were extracted using thermal and enzymatic treatment in an aqueous environment. The extracted GGMs, depending on the extr...
ChITOSAN DICHLOROACETIC ACID SALTS
The salts of dichloroacetic acid were obtained from chitosans of different deacetylation degrees (69÷97%) and viscosity-average molecular weights (61÷327 kDa). The mole ratio of dichloroacetic acid to amine groups was 1....
NEW HOMOGENEOUS BLENDS OF DIBUTYRYLCHITIN AND ALIPHATIC POLYESTERS
The results of physical modification of dibutyrylchitin (DBCH) for the purpose of improvement of its imperfect mechanical properties are presented. Thus, the novel blends of DBCH and biodegradable aliphatic copolymer der...