Hygroscopic Plastics By Jim Hingst Outgassing: Problems Arising Out Of Thin Air Some plastics can absorb moisture from the air. These materials fall into the category called “hygroscopic plastics”. The best known product in this group is polycarbonate . It’s not, however, the only hygroscopic plastic. Nylon and polyester can also absorb water vapor. Water vapor isn’t the only substance that polycarbonate sheet can absorb. Researchers have discovered that polycarbonate can also become saturated with oxygen. While absorption of moisture and oxygen isn’t always a problem, it can be, especially when you are decorating the sheet with vinyl graphics. As the plastic outgases, bubbles can form under the applied vinyl graphics. Polycarbonate can absorb moisture and oxygen from the air. As the plastic outgases, bubbles can form under the applied graphics. Moisture in polycarbonate sheet is also an issue for sign makers, who are th...
