PVOHcoat - thermal treatment

Jan 02, 2006 4 Replies
R

I have spincoated a 800nm PVOH coating on a substrate. Polyvinylalcohol 88% hydrolysis grade. PVOH in a watery solution.



The quality of my coating is not good enough: adhesion-type problems.



When I heat my PVOH coating to 120'C for 15 min in a convection oven, quality is good.



Q: What happens physically - I know it is not the water/solvent from the layer has been tested with vacuum-oven tests.



Q:Why can this effect not be reached at lower temperatures? Or any other way, additives, or even other type of polymer? Suggestions welcome.


All the best, Thanks, Roge.


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C

Is it not possible to include a small amount of plasticizer? This will improve adhesion as well as flexibilising the coating. A small amount of polyethylene glycol or glycerol should do it. Another approach might be to harden the coating with small amounts of acetic acid and boric acid, but note this will gel if not coated quickly. And I'm sorry, but I do not have quantities to hand. Colin Cook

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F

Maybe you should increase solution solids to make more viscous. See if a DuPont tech bulletin will help.

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E

May be related to Tg and crystallinity; see

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Ernie

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R

Thanks to all for the help and suggestions. I'll try and use plasticizers first.

Can you possibly specify "a small amount"

Roge

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