[Mollie Piron]

Hello!

I have a 2-3 year old roll of Tyvek that was stored in a cardboard box. I was going to use it for dust curtains over open steel shelving to protect bronzes in our collections storage, but I used two different pH pens to test the tyvek and both gave me an acidic result. I didn’t realize tyvek could become acidic, and I’m guessing its from being store in the cardboard box. I think the answer is pretty clear, but should I not use this as a dust curtain material now? And if not, what other materials would everyone recommend?

Thanks!

[Maggie Wessling]

Hi Mollie,
Did you try unrolling a few yard of the Tyvek and testing the pH again? If contact with the cardboard caused the Tyvek to become acidic, the inner layers may have been protected…
Best,
Maggie

[Mollie Piron]

I checked it and it’s acidic all the way through. We were going to use it because it was something we had on hand, however, since it is no good and we will have to purchase something, is there a different material you would recommend?

[Douglas Sanders]

I don’t believe you can use an Abbey pH pen (assuming this is what you’ve got) on testing the pH of non-paper-based materials. For the pen to work, you must be able to bring acidic components into solution, for the sensitive colored dye to work. Tyvek is well tested in both real-time and accelerated ageing tests and should not be turning acidic. I don’t think there is acid migration that could be occurring from the cardboard in proximity to it.

[Mollie Piron]

Oh, interesting, I did not know that. Thanks Douglas! So the result from the pH pen (Abbey as you guessed) should be disregarded?

[Douglas Sanders]

It is of course my opinion only, but I suspect that the Abbey pen has a tendency to give false-positive readings on some non-cellulosic materials. I tested it this morning on many accepted archival-quality materials around the lab (Remay, mylar, tyvek, etc) and got results that could be interpreted as slightly acidic. I still have my doubts that your Tyvek could be of ‘fault’. Dow Chemical has an excellent page showing results of testing against many solvents, organic acids, oxidizing and reducing agents, all with excellent long-term stability as a result. If you are still in doubt, there are of course other materials that can be effective dust barriers in curtain form for storage shelving- Visqueen (a polyethylene) comes to mind.

[Mollie Piron]

Thank you so much for the information, it has been very helpful! I think I’m going to go ahead with the Tyvek.

[Susan-1]

If you are only using the Tyvek for curtains and they won’t be touching any objects, then, there should be no problem even if the surface is slightly acidic.

Susan

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