Sound proofing floor

I appreciate your concern Pedrillo & I think it's wise to considerate those eventualities.
I did mention we want the vinyl to be 1 solid piece and also to seal it to the walls(PL 400 will work permanently). I believe the vinyl will slow any outgassing significantly enough that normal routine ventilation will be adaquate. Let's face it most homes are carpeted and the outgassing will move through carpet much easier (faster) than thru vinyl. In addition you will want your plywood floor to be airtight as well-providing a second barrier. So, I think it should be okay. I was not aware of the cotton batting option but I imagine it would be pretty good.

Thank you Psacanli, you know you make a good point the vinyl should do a good job of slowing down the outgassing! I was also concerned about the vinyl itself, I remember in my research of outgassing that foam was one of the greater culprits and that plastics too, the softer the plastic the greater the outgassing. I don't expect the plywood to slow gassing too much but if vinyl proves to be not so harmful then I will go with your suggestion! Thanks!

Pedrillo,
I am in the middle of a sound proofing project and have found the Green Glue web site to be an excellent practical and no nonsense source of information and test results. I would encourage you to read everything on this site before going too far. They discuss a variety of common approaches and solutions and counter some things that seem intuitively correct. Whether you choose to use their products or not, it is very helpful.

Here is the link.
Green Glue

Green glue appears to be the most commonly used adhesive in soundproofing projects. A friend has a Rives-designed dedicated room which used a lot of that stuff.