There shouldn’t be a problem with polyester teraphthelate (Mylar is no longer made; Melinex is often substituted) creating a micro environment as it is permeable to vapour and gases. I have encapsulated a wet document in order to see if mould would result. It dried quite quickly.
Aside from this, PT provides quicker and easier access to documents compared with those interleaved with a/f tissue, the static charge provides support and eliminates the need for repairs, and the document can be photocopied or scanned without removing it.
