Investigation of mordanting activity of the flower of Nyctanthes arbor tristis L.(Sepalika) on natural dyed fabrics

Abstract

The fossil fuel era led to the development of the use of textiles based on petrochemicals.  This in turn required different synthetic chemicals as dyeing and fixing agents to enhance consumer appeal of these textiles.  Today this is a global industry of significance.  However, from a national perspective becoming greener by using biopolymers and natural dyes may at this stage of transition prove to be quite beneficial.  This study explores such an opportunity.

Sepalika flowers (Nyctanthes arbor-tristis) (Harshingar, Parijat) belongs to the family Oleaceae. The flower has white petals with an orange calyx. Nyctanthes stems have been found to be a rich source of antioxidant. The aqueous extracts of the flower, calyx and petals were evaluated for cotton dyeing and found to be excellent fixing properties of dyes on fabric. This signifies that the main colour yielding part is in the orange colored calyx of the flower. In this research, attempts have been made to carry out an innovative study with the Nyctanthes flower as a part of an exploration for a cheap natural dye mordanting source. The natural dyed fabrics with Rambutan Fruit skin (Nephelium Lappacium), turmeric (Curcuma Domestica Valet), tea waste (Camelia sinensis), big onion (Alium cepa) and jak (Artocarpus heterophylus) were investigated for their fastness properties. These fastness properties showed excellent to moderate results. In this study, Sepalika (Nyctanthes arbor-tristis) flower extract was used to improve these fastness properties to an acceptable level and to obtain different colour shades. These dyed fabrics were investigated with pre-mordanting, simultaneous mordanting and post mordanting conditions at optimum dyeing parameters.

The fastness properties of naturally dyed cotton fabrics under conventional conditions with sepalika as natural mordanting agents were found under three different mordanting conditions, namely pre mordanting, simultaneous mordanting and post mordanting. Fastness values in the range of 2-4 for samples without mordanting agent were improved to be 4 with the mordanting agent.

The results of this research showed that the naturally dyed cotton fabrics treated under conventional conditions without mordanting showed very poor wash fastness, perspiration fastness, Rub fastness and Light fastness properties. But the treatment with aqueous extracts of fresh and old Sepalika flowers  enhance the fastness properties of naturally dyed fabrics in three different mordanting conditions with the conventional optimum dyeing parameters. Thus, it can be concluded that the extract of (Nyctanthes arbor-tristis) flowers are well suited as bio mordants for naturally dyed cotton textile substrates to enhance the fastness properties of dyed fabrics. These excellent fastness properties revealed that how natural fibres or polymers (cellulose) are bound together with natural mordants (Nyctanthes arbor-tristis) to enhance fastness properties of dyed which reflect the high quality of dyed textile fabrics.