What Are Permeable Plastics?
Plastics are made up of very large molecules called polymers. Some polymers allow one or more types of gases to pass through them. These polymers, and the plastics they create, are called gas permeable. When used in extended wear contact lenses, gas permeable plastics provide increased durability over soft lenses as well as decreased health risks and easier maintenance. Permeable plastics are ideal for the manufacture of extended wear contact lenses because they allow more oxygen to reach the cornea, which is essential to prevent swelling of the eye. Why Fly GPPM Aboard The Space Shuttle? Gravity may affect many properties of a polymer as it is formed. The GPPM experiment, which flew aboard STS-57 in 1993 and on STS-63 in 1995, showed that plastics made in the microgravity environment of the space shuttle are more uniform and permeable than those made on Earth. Making polymers in microgravity has also helped scientists better understand how polymers are formed. What Are Some Applicatio
