From: Katharine Thayer <kthayer@pacifier.com>
Subject: Understanding Gum chemistry (Was: Re: Sausage and dichromate
Date: Sun, 19 Mar 2006 12:52:31 -0800
> In the meantime, misconceptions and outdated ideas about the
> mechanism of the process continue to be repeated here, which I don't
> think serves our community well. For one example, it is often stated
> here that the crosslinked matrix involves Cr(III), but there is
> little actual research evidence to support this widely-held belief,
> and a recent body of research suggests strongly that for dichromated
> PVA, (the research literature on dichromated PVA is the closest
> approach we have to understanding the mechanism of dichromated gum),
> the chromium involved is Cr(V). (See for example Bolte et al, 2005.
> "Hologram formation reconsidered in dichromated PVA: polymer
> crosslinking around chromium (V). In Practical Holographyy XIX:
> Materials and Applications, Proc of SPIE vol 5742, p. 195-204.)
What did Bolte et al do differently from a large body of previous
studies, including ones done by her group, the difference to which you
give such credibility to supersede the others?
Received on Sun Mar 19 17:20:13 2006
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