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 ****************************** Karen E.K. Brown Field Service Representative Northeast Document Conservation Center 100 Brickstone Square Andover, MA 01810-1494 [log in to unmask] Tel.(508) 470-1010 Fax (508) 475-6021 http://www.nedcc.org