Iron oxide pigments and degradation

I am trying to find literature on the chemical interactions between
pigments/metal ions and artists' paint media insofar as these
influence drying/curing and subsequent deterioration.  At the moment
I am working on iron oxide pigments which, despite a common
conception of being photochemically inactive, can show strong
pro-degradative effects, especially in oil paints.

I have been able to find surprisingly little material in print to
explain this behaviour apart from some limited references to the
effect of iron oxide pigments on the drying of oils.

Ferrous and ferric ions are well known catalysts for oxidation
reactions in biological systems, but the most I have been able to
find about iron oxides in organic polymer media are unreferenced
observations that they "can catalyze transesterification reactions
and can react with carboxylate -containing paint media; they can
also catalyze a variety of radical-mediated reactions."

I was wondering if anyone could point me in the direction of
references or other source material which demonstrates this (or
other) reactivity of iron oxides or other iron compounds in the
degradation of polymers. Thanks in anticipation,

Alan Phenix
FOM Institute for Atomic & Molecular Physics
Postbus 41883
1009 DB Amsterdam
Netherlands

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                  Conservation DistList Instance 11:11
                 Distributed: Wednesday, July 23, 1997
                       Message Id: cdl-11-11-005
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