At 11:27 AM 8/21/97 +1200, you wrote:
>Can anyone give me some expedient advice on the breakdown of
>synthetic rubber?

Roxanne Fea:  in Book 3 of the series Science for Conservators titled
"Adhesives and Coatings"  I find the following:

A useful illustration of the embrittlement produced by oxidation is
provided by natural rubber and its synthetic counterparts (these usually
called elastomers).  Oxygen atoms, like sulphur atoms, can form two
covalent bonds, and can therefore provide similar corss-links to those made
by sulphur in the vulcanisation of rubber.  This is what happens as the
ageing process in the rubber used in, for example, car tyres.
Progressively, oxygen atoms form more cross-links, and...the greater number
of cross links the harder and more rigid is the material. In effect, the
rubber becomes more like a thermosetting plastice and, in a car tyre, the
rubber is unable to undergo the large elastic deformation required every
time the wheel revolves (p. 101)."

I don't know exactly what is in your rubber, but maybe you will find the
above useful.  If you send me your Fax number I will send you the excerpt
plus, and a copy of the cover pages - the citation is elusive!

Good luck!  Karen





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Karen E.K. Brown
Field Service Representative
Northeast Document Conservation Center
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Tel.(508) 470-1010
Fax (508) 475-6021
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