Browsing by Author "Nnorom, Onyekachi Onyinyechi"

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    Extraction and application of natural dyes from rothmannia whitfieldii (Uri) and baphia nitida (Uhie)
    (Federal University of Technology, Owerri, 2016-12) Nnorom, Onyekachi Onyinyechi
    The renewed interest in natural dyes across the globe is due to some discoveries of environmental hazard and toxic effect of synthetic dyes to humans. Unfortunately, most natural dye yielding plants and their properties are neither known nor documented. In this research work dyes were extracted from locally prepared Baphia nitida plant cakes (uhie) and dry Rothmannia whitfieldii fruit (uri). Extraction methods used are water, alkali, organic acid and organic solvent at room temperature and at 65OC with a material to liquor ratio of 1:50. It was found that only alkali solution extracted dye from both plant sources while organic solvent extracted only from uhie. More dye was extracted at 65OC and the spectrophotometer results of wavelength of maximum absorption of the dye extracted by alkali were 620nm for uhie dye and 670nm for uri dye. Analysis of dye extracts in the area of fabric dyeing using alum (kAl(SO4)2.12H2O) as mordant and sodium dithionite (Na2S2O4) as reducing agent, FTIR spectroscopy and colour fastness to washing and rubbing indicated that both uri and uhie dyes tend to be direct dyes. Both dyes do not necessarily require mordant and reducing agent to dye a cotton fabric at room temperature and at 60OC. Uri dyes better at temperatures above room temperature. From FTIR spectroscopy the possible presence of conjugated double bonds were observed in both dyes and tannins only in uri dye. Uri dye had a better wet and rub fastness than uhie dye but similar wash fastness. Also both dyes did not stain adjacent cotton fabric during washing. However, there is a need to further purify both dyes and study their interactions with other fibres.