Posted by alexandra_k on April 7, 2020, at 22:10:34
In reply to Re: UVC, posted by beckett2 on April 7, 2020, at 19:33:49
I don't know what the 'electrostatic charge' is about.
I thought it was to do with adsorption.
So, water clings together. Forms a drop. From electrostatic charge.
Then the drop clings to the fabric by adsorption. It adheres.
If it adheres by adsorption then it would dry off.
Once it was dry then it could adsorb water again.
If it became covered in the water it adsorbed then no new water could adsorb to it. They do say something about replacing it with a new once once it has become wet.
Maybe because once it has become wet the water starts to absorb into the fabric. Squash it's way through it. That could draw virus particles through the fabric with it. Which would mean it wouldn't be protecting against 95 per cent of airborne particles anymore.
I think that's the idea...
I read something about the technology that was going into making the fabric. Basically. Nozzles squirting plastic into very very fine fibers that are laid down in a haphazard kind of a way. They wre experimenting with using electrical fields as part of the manufacturing. I don't understand what that means, or how. I think plastics are hydrocarbens which wouldn't align with electrostatic charge so I don't follow...
But they said that by using an electrostatic force or field they were getting finer strands of it which was resulting in higher or increased amounts of particles able to be filtered out when air passed through the material.
I don't understand this.
But it seemed the finer fibers had better filtration properties. But teh finer fibers were fragile and readily broken down. So if you then scrub at the mask with detergent you will likely disrupt the protective surface.
Even UVC treatments seemed to degrade the filtering properties.
I don't know how much gently air-drying them in the ordinary sun-shine until they are dry would disrupt the electrostatic properties... I can only think the electrostatic properties have to do with adsorption of water molecules.
So you would want to dry the masks thoroughly before re-use.
So maybe have a few and give them a few days to dry out or something. To make sure they are properly dry.
I honestly don't know.
Unless people do well-controlled experiments on great numbers of them then we don't really know.
It is important work to be done. Because while these masks do seem to be very very very effective -- they will likely accumulate in biohazard piles to the sky if we don't figure how to more responsibly produce / re-use / conserve them.
poster:alexandra_k
thread:1109408
URL: http://www.dr-bob.org/babble/poli/20191212/msgs/1109461.html