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Author: Subject: Melt-blown PP membrane from face mask
Heptylene
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[*] posted on 30-9-2020 at 02:38
Melt-blown PP membrane from face mask


Face masks, which are suddenly available due to (thanks to?) the coronavirus pandemic contain a polypropylene (PP) filter which is very porous and has a high surface area. Does anyone have an idea what these could be used for in the lab? (apart from wearing them)

PP is very chemically resistant, so I'm thinking they could work well to separate electrode compartments in an electrolytic cell, or as "anode bags" in electroplating.

Perhaps as filtration medium too?

Looks like a nice material and I'm sure there is a way to use them for something.
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macckone
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[*] posted on 30-9-2020 at 07:29


Heptylene,
I have made reference to using vacuum cleaner bags as filters and electrolytic diaphragms.
HEPA vacuum bags have a 5um pore size which is perfect for filtering.
The smaller pore size on n95 masks (good luck actually getting them in the US) would work better for a diaphragm.
The masks that are commonly available are not all PP, some are other materials (including some kind of cellulose or viscose/rayon).
And the pore size is not very consistent on the cheap face masks.

[Edited on 30-9-2020 by macckone]
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Herr Haber
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[*] posted on 30-9-2020 at 08:46


Sounds worth investigating

Sreetips uses vacuum filters for his anode bags. It seems to work perfectly fine for him.
I have purchased but never actually used very dense cotton fabric to use as anode bag. The idea was to eventually add them to the cellulose filters from other steps to incinerate them knowing the only entrant would be carbon.
(Though I guess hitting PP in a crucible with a blowtorch gets the same result)




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draculic acid69
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[*] posted on 8-10-2020 at 15:20


Quote: Originally posted by Heptylene  
Face masks, which are suddenly available due to (thanks to?) the coronavirus pandemic contain a polypropylene (PP) filter which is very porous and has a high surface area. Does anyone have an idea what these could be used for in the lab? (apart from wearing them)

PP is very chemically resistant, so I'm thinking they could work well to separate electrode compartments in an electrolytic cell, or as "anode bags" in electroplating.

Perhaps as filtration medium too?

Looks like a nice material and I'm sure there is a way to use them for something.


I was wondering the same thing but if 5um is the pore size I'm not sure if it's helpful for what I have to filter.celite is the only thing that cleans the superfine sediment out of my solution but it takes around 6hrs a litre to filter. Its too long.maybe I'll run it through 3 vac filter papers before I do the celite not sure if the mask pp filters are better than the filter paper

[Edited on 8-10-2020 by draculic acid69]
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macckone
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[*] posted on 8-10-2020 at 17:38


draculic acid69,
The cheap face masks are have pore sizes up to 500um according to this study:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6599448/
But this study says 0.5 to 10um for quality surgical masks:
https://www.ohsu.edu/sites/default/files/2020-03/Proposed%20...

The good n95 masks are unobtainium at the moment.
They should have a 0.5 um pore size to block 95% of 0.3um particles.
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zed
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[*] posted on 17-10-2020 at 01:02


Umm. We were discussing this dillemma about 6 months ago. Some folks had concluded that Harbor Freight Blue PPE shop towels were pretty good mask material. Naturally, Harbor Freight was permanently "Out" of stock. Last I checked, they did have masks, but not necessarily masks I would trust.

I was able to obtain those fancy blue PPE towels from another source. Blain's in the Mid-West beat Harbor Freight's retail price, and shipped them too. Now, I don't know, if the manufacturing method is the same as it was. But, if they prove less than great when tested, they do make good durable shop-towels. I bought two containers, had 'em shipped. Totalled about 35 bucks. Only slightly more than Harbor Freight's retail in store price.

https://www.farmandfleet.com/products/756345-sellars-200-cou...

Now, for my personal breathing, I prefer real protection.
An old school Willson respirator is the minimum. Gas/Vapor cartridge, with Heavy Fiberglass/Fiber prefilter.

Better is a full-face MSA respirator, with a 40mm NATO cartridge. The Optimair Ultravue is OK. The MSA Ultra-Elite, is probably better and certainly more comfortable.

These are great masks, and not terribly expensive, on Ebay. If you attach filtered positive pressure air, you become pretty much bullet-proof as far as Covid is concerned.

Ultra-Elite SCBA Masks, available as fire department surplus for~$50, can be adapted to utilize standard Gas Mask cartridges. Good stuff.

https://us.msasafety.com/Air-Purifying-Respirators-%28APR%29...


https://www.ebay.com/itm/MSA-Ultra-Elite-Full-Face-Mask-Resp...

The Ultra Elite. This particular model, is set up for SCBA, but if you unscrew a few screws and remove the bottom plate, you can unscrew and remove the SCBA Adapter, exposing the native 40mm NATO connection within. Replace the bottom plate, and you have a standard NATO gas mask. It will fit a PAPR unit As-is. If you wish to attach a 40mm NATO cartridge directly, just trim off the obstructing plastic appendages, on the mask. Just an example. Sometimes, they appear to be new.

SCBA itself is great, but not for the PPE most of us need. SCBA
utilizes a cylinder of compressed air, for about a 30 minute air supply. It's utilized by firefighters, and the mask and tank are accompanied by thousand of dollars worth of sophisticated high tech equipment. Requires a lot of training, just to use the gear.

Oddly enough, Gas Mask prices are rather high right now, and stock is low. A year ago, new surplus, was cheaper than what a beater costs now. Supply and demand!




[Edited on 17-10-2020 by zed]
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[*] posted on 18-10-2020 at 08:13


If looking for membranes for electrolytic cells one can buy anion or cation membranes from Fumasep or Fulecellstore online.
Not all membranes are very expensive, Fumasep has some membranes that is about 25 Euros for a 30x20cm sheet.
https://www.fumatech.com/EN/Onlineshop/index.html
Its not very cheap but it will not ruin you.
Finding alternative cheap membrane materials are quite interesting though.
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DavidJR
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[*] posted on 19-10-2020 at 01:22


Quote: Originally posted by zed  

Oddly enough, Gas Mask prices are rather high right now, and stock is low. A year ago, new surplus, was cheaper than what a beater costs now. Supply and demand!


Yeah, I had to wait ~5 months for some backordered 3M filter cartridges. I couldn't get them at my usual supplier and everywhere else was out of stock, which never happened before covid-19. I wonder if it is caused directly by demand for the cartridges, or possibly by 3M's production capacity being redirected towards covid-19 directed products.
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zed
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[*] posted on 19-10-2020 at 04:49


David, the shortage of 3M stuff, is pretty much world wide. It's decent stuff, but a consumer brand.

Well. it has all been consumed. Full face respirators, were for a long while in very short supply, and very expensive. Full list price, plus! And, 3M's full list price, is pretty exhorbitant. No cartridges. None!

American retailers were completely out, with no prospects of being restocked. Retailers based in China were offering 3M, but I suspected it was counterfeit. I surely wouldn't trust it.

Thus, the reliance upon Nato type gas mask stuff. To start out, it is better stuff. Military spec.. And, the cartridges are universal 40 mm. The cartridges from different manufacturers are interchangable. But, don't believe folks who say their Russians stuff is compatible, it isn't.

As for effectiveness, Nato stuff is better. For Covid protection, even long expired cartridges are fine.

The Nato Cartridge, generally includes a Hepa filter, plus a back-up of Carbon particles. The Carbon elements may become less effective after decades long storage. Hepa filters do not deteriorate or expire.

Where you are, there is an abundance of NATO type stuff available. Moreover, you are close to Israel where every man woman and child, needs to be prepared for gas attacks, at all times. They have lots of inexpensive surplus available, and their Gas Mask Cartridges, are considered some of the finest in the world.

Me? I'm on the other side of the planet. But, for you, Israel is just a hop, skip, and a jump, away.

The Israelis can supply possibly the least expensive PAPR units on the planet. New, surplus units, have been selling for about $50 Dollars in Israel. A much higher degree of Covid protection than any ordinary respirator. Positive pressure!

https://www.ebay.com/itm/ISRAEL-NEW-PROTECTIVE-HOOD-KIT-WITH...

Like all good things, prices are going up. A less expensive supplier. He's new. Doesn't have an established track record yet. Less, of a problem for you. Like I said, I'm on the far side of the planet. Months away, by mail.

https://www.ebay.com/itm/Israeli-Gas-Mask-Hood-Kit-NBC-prote...



[Edited on 19-10-2020 by zed]

[Edited on 19-10-2020 by zed]
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