Dave Williams wrote: > > John Winters wrote: > (SNIP) > I have seen boats from four different major manufacturers that degraded to > the point where the finger test failed. In defence of the manufacturers all > of the boats were built during the days before Vinyl ester resins. So, the > resins used were probably Isophthalics at best or orthophthalics at worst. > > What does "isophthalics" mean? > > What does "orthophthalics" mean? [snip] These are different isomers of phthalic acid -- the benzene-based dicarboxylic acid which forms part of the backbone of a phthalate-ester-based polymer. Isomers are molecules having the same atomic composition but a different arrangement of the atoms. In practical terms, I suspect the phthalate ester-based polymers were more susceptible to early embrittling, and were not as tough as the vinylester-based polymers. Your dictionary may have them listed the way I have spelled them. -- Dave Kruger Astoria, OR chemist *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************Received on Sun Dec 20 1998 - 20:01:01 PST
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