55th Inaugural Lecture - 2007 by Prof. O. Akaranta - University of ...

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satisfied International Standards Organization (ISO)requirements for exterior grade adhesives.Antioxidants and InhibitorsFlavonoids of red onion and peanut skin extracts have beenevaluated as antioxidants for vegetable oils and as inhibitorsfor unwanted polymerisation of some vinyl monomers. Theextracts were effective as antioxidants in vegetable oils but atslightly higher concentrations when compared withcommercial phenolic antioxidants (Akaranta and Odozi, 1986;Akaranta, 1994). Similar trends have been reported with theextracts when evaluated as inhibitors for the polymerisation ofvinyl monomers (Akaranta, 1999).Dyes and PigmentsIt has been reported that red onion skin extract containspolyphenols of the flavonoid type (Odozi et al, 1984) whichare capable of directing nucleophilic reactions to the ortho andpara positions (Akaranta and Odozi, 1985). The extract hasbeen coupled with diazonium salts to give azo dyes of variouscolours (Akaranta and Efanga, 1997).10
Figure 1: Reaction of Red Onion Skin Extract with aDiazonium SaltThe azo dyes were formed in-situ in cotton fabrics asazoic dyes and applied to polyester fabrics as disperse dyes.They were found to produce not very bright colours onpolyester fabrics but brilliant colours on cotton fabrics. Thewashfastness tests of the azo dyes on both cotton and polyesterfabrics were satisfactory. The azo dyes with suitable chelatinggroups have been used to produce azo-metal complexessuitable for the pigmentation of alkyd resins in paintformulation. (Akaranta, 1996).11
Page 1 and 2: UNIVERSITY OF PORT HARCOURTAGRO WAS
Page 3 and 4: The Vice - Chancellor, Sir,Members
Page 6 and 7: Table 1: Residues from the Processi
Page 8 and 9: usually used in the production of s
Page 10 and 11: Orange Seed and Peel OilsAll seeds
Page 14 and 15: Figure 2:A Red Onion Skin Extract A
Page 16 and 17: of lignocellulosic materials for ch
Page 18 and 19: Pentosan an aldopentose furfural(in
Page 20 and 21: HOHOOH + ClCH 2COONaalkalinesolutio
Page 22 and 23: peel has been reported as a good po
Page 24 and 25: with superphosphates and used as co
Page 26 and 27: (Azbar et al 2004). The methods inc
Page 28 and 29: polymerized onion skin is highly ef
Page 30 and 31: substrate is in the following decre
Page 32 and 33: Figure 3: A Schematic Representatio
Page 34 and 35: alternatives to the non-renewable r
Page 36 and 37: into our environment. The guideline
Page 38 and 39: CONCLUDING REMARKSMr. Vice - Chance
Page 40 and 41: REFERENCESAdebowale, E.A (1985), No
Page 42 and 43: Akaranta, O. and Anusiem, A.C. I. (
Page 44 and 45: Halliday, D. (1975), Animal Blood a
Page 46 and 47: Thickeners in Latex Paints, Carbohy
Page 48 and 49: Critical Review on Current Treatmen

55th Inaugural Lecture - 2007 by Prof. O. Akaranta - University of ...

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