PET (polyethylene terephthalate) is actually polyester. When PET is used in bottles, containers and other applications, it is called PET or PET resin. When PET is used as a fiber, it is often referred to as polyester. The PET bottle was invented by Nathaniel C. Wyeth, a DuPont engineer and brother of American painter Andrew Wyeth. The patent was granted to Wyeth in 1973 and assigned to DuPont. According to the EPA, recycling one pound of PET bottles (that’s about 10 two-liter soda bottles) saves about 26,000 BTUs of energy. PET bottles and the sun are helping millions of people in developing countries gain access to drinking water. Using a system called SODIS (solar water disinfection), residents leave water-filled PET bottles in the sun for hours or days – depending on the amount of sunlight available – as a simple but effective way to destroy disease-causing bacteria and get safe drinking water. More than 1.5 billion pounds of used PET bottles and containers are collected for recycling each year in the U.S. PET is the most recycled plastic in the U.S. and the world. Disposable PET bottles (0.5 liters) are strong enough to hold up to 50 times their weight in water. Chemists are always looking for new ways to make PET lighter without losing any of its strength. 2 liter PET bottles that weighed 68 grams in 1980 now weigh only 42 grams. The average weight of a single 0.5-liter PET water bottle is now 9.9 grams, almost half of what it weighed in 2000. Because of PET’s biostability and durability, woven, knitted and braided PET fibers are sometimes used by surgeons to implant sutures, cardiovascular patches and wound repair nets. More than 150 U.S. colleges and universities, including the University of Pennsylvania, Yale University, Michigan State University and Wake Forest University, are using graduation caps and gowns made from 100 percent recycled PET. Americans recycle more than 1 million single-use PET water bottles every hour.