ABSTRACT
Novel thickening agents based on galactomannan gum extracted from carob seeds were prepared and their physicochemical properties were determined. This was done via carbamoylethylation followed by carboxymethylation of the gum to block its free hydroxyl groups. Nitrogen content, D.S. of the obtained derivatives as well as the rheological properties of their pastes were measured. The obtained derivatives could be used successfully in white and colored resist printing of silk fabrics. This could be achieved via using two different reactive dye namely Remazol Brilliant Orange FR based on vinyl suiphone and Drimarine Turquoise K2B based on chloropyrimidine. The former can react with sodium sulphite to obtain white resist printing. While the second cannot react giving colored resist printing
ABSTRACT
The suitability of using 2-hydroxy- 1,4-naphthoquinone [Lawsone,I] and some of its synthesized derivatives [II-VI ] as a pigment for printing natural fibers [cotton, wool and silk] was investigated. The effect of varying the structure of 2-hydroxy-1,4-naphthoquinone on the properties of the printed samples was also studied. No change of color and color strength has been observed by introducing -CH2-N [CH2CH2OH] 2 or CH2-N[Et]2 groups in the 3- position of 2-hydroxy- 1,4-naphthoquinone [I] to give derivatives [II] or [III], respectively. On the other hand, the printed samples with semicarbazone derivative [IV] or oxime derivative [V] of 2-hydroxy-1,4-naphthoquinone resulted in an observed change in color and color strength. Furthermore, derivative VI produced by substitution of methylene link in 3-position of a dimeric Lawsone has no affinity for printing cotton, wool and silk
ABSTRACT
Cellulosic wastes of El-Nasr Co. for Intermediate Chemicals were used as a starting material for the preparation of water-soluble methyl cellulose. The obtained methylcellulose sample was polymerized with acrylic acid monomer under the initiation action of potassium persulphate to obtain a thickening agent, which acquires - COOH groups like sodium alginate. Rheological measurements revealed that the prepared composite is water-soluble and acquires non-Newtonian pseudoplastic behavior and can be diluted with water at any ratio. The prepared methylcellulose/polyacrylic acid composite was evaluated as thickening agent in printing cotton fabrics with four different reactive dyes. The results of the colour strength, overall fastness properties and the handle of the printed goods indicate that methyl cellulose/polyacrylic acid composite could be used successfully, a thickening agent, either alone or in a mixture with either sodium alginate or emulsion [i.e., as semi-emulsion] in printing cotton fabrics with reactive dyes
ABSTRACT
Leucaena gum, which is mainly galactomannan, was isolated from leucaena seeds and subjected to oxidation using sodium chlorite under variable conditions. Variables investigated were the concentration of the oxidizing agent and the pH of the medium. The products were analyzed for acidic and reducing expressed as carboxyl and carbonyl contents, respectively. The rheological properties as well as the utilization of the oxidized products as thickening agents in printing polyester fabric with disperse dye were investigated. The results indicated that both acidic and/or reducing properties increased by increasing the concentration of sodium chlorite. The carboxyl content exhibits the highest value at pH 4. Pastes of the oxidized gum are characterized by a non-Newtonian pseudo plastic behavior and their apparent viscosity depends on the concentration of the oxidizing agent. Oxidized gum prepared using a concentration ranging from 1 to 3 g chlorite/100 g gum either alone or in a mixture with sodium alginate can be used successfully in printing polyester fabrics with disperse dyes