Guthrie-Strachan, Jeffry James (2006) The investigation, development and characterisation of novel zirconium-based tanning agents. PhD thesis, Rhodes University.
Various oxygen- and nitrogen-donor ligands were investigated as potential zirconium masking agents in zirconium tanning. [alpha]-Hydroxycarboxylic acid ligands were identified as effective zirconium(IV) chelators in acidic aqueous solution. Glycolic acid, lactic acid, mandelic acid, 4-hydroxymandelic acid, 4-chloromandelic acid and 4-bromomandelic acid complexes were synthesised, isolated and characterised using a range of analytical techniques. Linear Free Energy Relationships were examined to optimise the stability of the zirconium complexes. Hammett [sigma] plots and Yukawa-Tsuno modified [sigma] plots of the mandelate ligand and zirconium complex series indicated that inductive effects dominate within the benzene ring, however, mesomeric effects are significant outside the ring. Zirconium 4-hydroxymandelate complex solutions were identified as the most effective tanning agents and achieved shrinkage temperatures of 80 and 97ºC for hide powder and goatskin, respectively. The zirconium and 4-hydroxymandelic acid interact synergistically to yield leather equivalent to combination tanned leather in one step. Tanning was performed similarly to vegetable tanning processes with a pickle pH of approximately 5 and fixation was achieved upon acidification. Pilot-scale tanning of goatskin produced white tanned leathers and crust leathers which were physically and aesthetically comparable to matched chromium tanned material.
|Item Type:||Thesis (PhD)|
|Additional Information:||Ph.D. (Chemistry)|
|Uncontrolled Keywords:||Zirconium, tanning agents, leather technology|
|Subjects:||Y Unknown > Subjects to be assigned|
|Divisions:||Faculty > Faculty of Science > Chemistry|
|Supervisors:||Watkins, G.M. (Dr.)|
|Deposited By:||Rhodes Library Archive Administrator|
|Deposited On:||14 Jul 2006|
|Last Modified:||06 Jan 2012 16:17|
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