Sustainable utilization of betalains rich Rivina humilis L. berries as natural mordant for dyeing silk and wool with eco-friendly natural dye
D. Thangamani, O.M. Mohamed Nawas* and S. Lalitha
Forest Genetic Resource Management Division, Institute of Forest Genetics and Tree Breeding, Coimbatore-641002 (India) thangamanid@ icfre.org
ABSTRACT
Natural dyes are sustainable those cover the area of green chemistry. Natural dyes never pollute like synthetic dyes as they are obtained from the renewable resources. The use of non-toxic and ecofriendly natural dyes on textiles has become significant importance due to the increased environmental awareness associated with synthetic dyes. The synthetic dyes are toxic, mutagenic and carcinogenic agents persist as environmental pollutants. Natural dyes are ecofriendly and do not damage human health. Sustainable utilization of natural resources is the proper management of natural resources for the benefit of the entire human community. Eucalyptus is considered one of the most important sources of natural dyes which have ample natural tannins and polyphenols, with the major colouring component. Rivina humilis L. (Phytolaccaceae) or blood berry has betalains content in its berries which can be used as sustainable resource of natural mordant for dyeing textile filaments. This species prefers damp, shady sites and is a weed of closed forests, forest margins, disturbed sites, waste areas and urban bushland. This study investigated that Rivina berries extract was used as sustainable resource of natural mordant in dyeing eucalyptus leaves on silk and wool fabrics. The dyeing was carried out with and without mordants by Pre, Post and Simultaneous mordanting method. The variations in the colour strength and coordinates with respect to dyed without and with mordant showed a significant difference in colour obtained. The colour fastness to washing, rubbing (dry and wet), light and perspiration of dyed fabrics were tested according to ISO standards. The results showed that silk and wool dyed fabrics without mordant showed a shade of light brown, while Rivina berries mordants exhibited dark reddish brown shades in simultaneous mordanting method. The pre and post mordanted fabrics showed pale brownish shades compared to unmordanted fabrics. The colour fastness to washing, perspiration, rubbing and light were good except unmordanted fabric in simultaneous mordanting whereas pre and post mordanted with Rivina berries showed moderate to good fastness compared to unmordanted farbrics. Hence, Rivina humilis L. berries which occupy wastelands, bushland can be used as sustainable resource of natural mordant instead of synthetic metallic mordants which harm environment.