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> > Does this help?
> >
formatting link
> Note they have not shown polymer chain and there is an extra free =
oxygen
> atom.
> > You can assume Vespel polyimide is made from an aromatic diphthalic = type
> > acid and an aromatic diamine.
> > Frank (too)
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> not too much i'm afraid. as i said, i'm a physicist and my knowledge
> of chemistry is somewhat limited, but this link of yours gives me a
> third formula for polyimide:
> c14h9no2 (or o3 - whatever that extra oxygen means...). sort of adds
> to the confusion...
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> Nonetheless i found a structural formula giving the polymer chain in > the link below
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>
formatting link
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> which gives the c22h10n2o5 version on the first page, so that's
> probably what i'm looking for - but still some confusion remains... >=20
The chemistry is good but structure may not be exactally that of Vespel. It is an all aromatic polyimide but the acid and amine moieties may be different. There is/was a grade of Vespel that is/was an aromide. What ever, DuPont does not disclose the actual chemistry. Frank Sr.