Re: A PVA SOURCE and some infor Was A PVA for printing

From: davidhatton@totalise.co.uk
Date: 03/31/06-10:03:38 AM Z
Message-id: <E1FPM66-000Aak-RW@webm9.global.net.uk>

('binary' encoding is not supported, stored as-is) Hi Folks

Take a look at

http://www.dcchem.co.kr/english/product/p_petr/p_petr8.htm

and

http://www.avocadochem.com/onlinecatalogue/suchergebnis.asp

Hope it helps

Regards

David H

On Fri, 31 Mar 2006 07:41 , Katharine Thayer <kthayer@pacifier.com> sent:

>
>On Mar 29, 2006, at 6:02 PM, Katharine Thayer wrote:
>
>>
>> Why the people who want to reproduce gloy want to do that, they'll
>> have to answer themselves. But it's probably worth emphasizing,
>> since the things seem to have gotten confused, that however gloy is
>> made or approximated, PVA all by itself works fine for a
>> dichromated colloid process, as Mike's student demonstrated and as
>> holographers and researchers have been proving for quite a while,
>> and that's why it makes some sense to use dichromated PVA as a
>> standin for dichromated gum in trying to understand the
>> crosslinking mechanism, especially since most researchers believe
>> that the crosslinking mechanism is probably the same for both PVA
>> and gum (although maybe not the same for gelatin).
>
>I can't find Ryuji's post that asks me this question, but looking at
>the Bolte et al paper I was reminded that Ryuji asked me the other
>day to explain my rationale for this last statement. I'm not sure if
>he meant the first part (that the crosslinking mechanism for PVA and
>gum are probably the same) or the last (that gelatin may be
>different.) I'll assume the latter, since the fact that when I asked
>a question about gum crosslinking, Ryuji cited a paper about PVA
>crosslinking, suggests that he's probably in agreement with the
>former. As to the latter, I'll quote the Bolte paper again (the
>introduction): "For a long time chromium (III) the final chromium
>species was thought to be responsible for the crosslinking process in
>dichromated systems. This assumption is quite logical with
>dichromated gelatin, chromium (III) being the only chromium species
>remaining after development. On the contrary, it is more surprising
>when dealing with dichromated PVA, a material in which chromium (V)
>has been proved to be stable..." I suppose it's statements like that
>which make me wonder if maybe the mechanism for gelatin might be
>different than that for PVA/gum.
>Katharine
>

---- Message sent via Totalise Webmail - http://www.totalise.co.uk Up to 2Mb Broadband now from just £11.99 a month
Received on Fri Mar 31 10:04:41 2006