Authors F. Saad, A.L. Mohamed, M. Mosaad, H.A. Othman, A.G. Hassabo,
The technical feasibility of using Aloe Vera Polysaccharide as a thickener for printing on cotton, wool, and polyester fabrics was examined. Alginate, carboxymethyl cellulose, and DELL thickener P were mixed with aloe vera polysaccharide gel to enhance its rheological performance as a thickener in textile printing. The rheological properties of aloe vera polysaccharide gel-based printing pastes with and without different additives were studied. The effect of pH and a reducing agent on the prepared aloe vera polysaccharide gel-based thickeners was examined. The color strength (absorption and dispersion) and fastness of each printing paste were examined on each fabric. The fabrics printed with modified thickeners demonstrated superior rubbing fastness and handle compared with the standard printed samples and the optimal printing properties were achieved with a printing paste containing a 70/30 ratio of aloe vera polysaccharide gel to additive. Printing is a popular method of textile decoration and is defined as the localized application of a dye to specific areas of the substrate. This is usually accomplished by adding printing paste containing dyes or pigments to the fabric’s surface. Printing paste is a viscous liquid that contains dyes and other essential ingredients, and it is applied to the material using a variety of methods such as screen printing and roller printing. Thickeners are important in the formulation of printing paste because they modulate the consistency of the paste to ensure uniform flow during the printing process. The correct color, design definition, evenness, and softness are important factors of successful printing; these factors are affected by the type of thickener used. The use of artificial thickeners in the printing industry has several negative environmental consequences, including undesirable textile behavior, detrimental effects on plumbing systems, and environmental contamination. These negative effects can be reduced by replacing synthetic thickeners with eco-friendly, natural thickeners that are nonallergenic and nontoxic to humans, with few or no waste treatment issues or safety concerns. In addition, thickeners derived from natural plants are nonhazardous, cost-effective, eco-friendly, and do not cause fabric stiffness. Natural thickening agents are extracted from sources such as plants, seeds, algae, and microorganisms. Natural thickeners used in printing are mainly polysaccharides with numerous hydroxyl groups derived from plant exudates, seaweeds, seeds, and roots. Some of them are ideal for printing with a specific color class, but they must frequently be modified to meet printing requirements. Aloe vera gel is 9999.5% water, with the remaining 0.51% solid material containing the polysaccharides and a variety of other compounds such as pectin, cellulose, hemicellulose, galactomannan, acemannan, amino acids, minerals, enzymes, phenolic compounds, and organic acids. Polysaccharides make up most of the dry matter of the aloe vera parenchyma. Recently, extracted aloe vera gel has been used as a thickener in the printing process, the rheological behavior of the aloe gel reportedly offers shear-thinning characteristics, which could be attributed to the gel’s high-water content. Modification might improve the rheological properties of aloe vera gel as a printing paste thickener. Thus far no modification of aloe vera gel has been attempted before using it as a thickener in textile printing. Because aloe vera gel possesses eco-friendly properties, any additives should be also eco-friendly to preserve the main advantage of using aloe vera gel as a thickening agent. Therefore, a new, simple modification process was used in this study. Different biopolymers and a synthetic thickener were added to the aloe vera gel before using it in printing paste. This modification is intended to increase the total solid content of the gel to overcome the rheological disadvantages of its unaltered behavior without reducing the advantages of using aloe vera gel. To determine the desired rheological behavior for a thickening agent in the paste printing process, the rheological properties of unmodified aloe vera gel were compared with two biopolymer-modified gels and one synthetic commercial thickener in this study. The rheological behavior of the modified thickeners was also studied, including the effect of pH and the effect of reducing agents on thickener behavior. The effect of the prepared aloe vera thickeners on the color strength, fastness, mechanical, and physical properties of the various printed fabrics was also assessed. As is standard practice, each fiber type must be printed with the correct printing paste under specific conditions (composition ratio, pH, thickener type, and behavior). Therefore, during this study, the different fabrics (cotton, wool, and polyester) were printed using the appropriate dyes for the fibers (reactive, acidic, or dispersed).
