(Phys.org) —Natural dyes have been used as the colouring of natural fibres, in cosmetic products, to produce ink, watercolour and artist's paints. Natural dyes produce an extraordinary diversity of rich and complex colour. Besides that, natural dyes are a renewable resource since it is not dependent on petroleum as are many synthetic dyes. The main objective of this research project is to study the effect (dose response) of sunlight exposure on Rhizophora dye solutions by using UV–Vis and FTIR spectrophotometer.
Rhizophora dye is a kind of natural dye which is extracted from Rhizophora Apiculata plant Rhizophora is a genus of tropical mangrove trees. Rhizophora apiculata is widely found along the tropical coastal areas and offshore islands near Peninsula Malaysia. It grows on sandy oil substrate or on along the islands especially in muddy areas. Rhizophora is used primarily as timber, building material, fencing, firewood, medicines as well as dyeing and tannins for staining leather.
The induced colour changes of dyes under the effect of radiation have been sufficiently documented in literature. Most of the reported experimental work was done on aqueous aerated acidic or alkaline organic dye solutions. The decrease in the absorbance of solutions on irradiation was suggested to be used in chemical dosimetry.
The Rhizophora dye solutions were prepared by soaking the Rhizophora bark, flower and leave in distilled water for 7 days. The sunlight exposure is carried out up to 30 days. UV-Visible spectra of the dyes were measured by using UV–Vis spectrophotometer (Palo Alto, CA).
The outcome of the research project was Rhizophora dye solutions could possibly be applied as chemical dosimeters.
There are several experiments recommended for future studies as following:
i. To investigate the dosimetric performance for dye solutions of various natural dye.
ii. To further understand the dosimetric properties of Rhizophora Apiculata dye polymer blends
Explore further: Capturing light in an efficient dye trap