Cellulosics can absorb high levels of plasticizers.
Every nylon varies but the most common nylons can absorb up to about 9% water and typically absorb about 3% in an average environment. I have never seen phthalates used to plasticize nylon.
Caprolactum can be used to used to plasticizers nylon 6. I think from memory it is used up to about 10%. It sends to migrate to the surface and leave a white scum mark.
Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &
Pat's on the money as usual. Cellulosics like CAP do come with large amounts of plasticizer. There's no reason other plastics couldn't accept large amounts too if there was a need.
The reason nylon and for that matter PE, PP and other semi-crystalline polymers can't adsorb much is that they are around 40-60% crystalline and the crystals are impermeable and don't take up plasticizer so the amounts are lower for that type of plastic.