RESEARCH STARTER

Polyethylene terephthalate

Polyethylene terephthalate (PET) is a thermoplastic polymer resin created by combining ethylene glycol and purified terephthalic acid. Recognized for its versatility, PET is predominantly used in packaging for beverages and food, identifiable by the recycling code number 1. Its properties include being nearly 100% recyclable, lightweight, shatter-resistant, and safe for food and medical storage, as it does not leach harmful chemicals. Beyond packaging, PET fibers are utilized in a variety of products, including clothing, carpets, and sleeping bags, contributing significantly to the textile industry.

Initially discovered during the quest for synthetic fibers, PET gained popularity in the 1950s and has since become a staple in both consumer goods and the clothing industry due to its affordability and durability. However, the widespread use of PET has raised concerns about plastic pollution and health risks linked to its production and disposal. Although PET products are pervasive, only a portion is recycled, leading to environmental challenges. Efforts are underway both in recycling and research to find sustainable alternatives, reflecting the growing awareness of the impact of plastics on society and the environment.

Full Article

Polyethylene terephthalate, or PET, is a thermoplastic polymer resin. PET is created by combining chemicals ethylene glycol and purified terephthalic acid. PET is a remarkably versatile product. It is one of the most commonly used plastics in beverage and food packaging. It is identifiable by the number 1 code appearing at or near the bottom of the container. PET packaging is widely recyclable. It has the strength and safety of glass and the durability of metal. Health-safety agencies approve PET for food, beverage, and pharmaceutical packaging when it meets food-contact requirements. European Union rules adopted in 2022 set requirements for recycled plastics used in food-contact materials, and 2024 guidance from the European Food Safety Authority gives criteria for evaluating recycled PET processes. It is transparent, so consumers can see what is inside the containers and the condition of the products. PET is lightweight, yet strong enough to stack products one atop the other; it can be resealed and is shatter-resistant. Strength and durability make PET fibers ideal in making clothes, carpets, sleeping bags, winter coats, auto parts, and dog beds. Polyester clothing can also shed tiny plastic fibers during washing, adding to microfiber pollution.

Background

Scientist W.H. Carothers was searching for synthetic polyester fibers to use in making textile products. Instead, Carothers discovered nylon, distracting him from the search for polyester fibers. British scientists John Rex Whinfield and James Tennant Dickson later followed up Carothers’s research. Their work led to discovering polyester fibers for making fabrics, plastic sheets, and films. DuPont later commercialized PET film under the trademark Mylar. PET began appearing under other brand names over the years, including Dacron and Terylene for polyester fibers in textiles. Later in the 1950s, researchers developed methods for stretching PET into thin sheets like a film. PET’s properties were found to be ideal in making video, photo, and X-ray film; magnetic recording tape; and packaging films of varying thickness.

A PET bottle patent was published in 1973; PET bottles were transparent, lightweight, held their shape, and were shatterproof. By 1977, local governments, overwhelmed with the plethora of plastic bottles littering and in dumpsters, worked with retailers to begin recycling PET bottles. Containers made from PET resins are widely used for soft drinks and water. European Union rules set recycled-content requirements for PET beverage bottles.

The discoveries birthed the polyester and textile industries that grew rapidly. Polyester fibers were inexpensive to produce and tough. Polyester fibers were an ideal alternative to expensive, handmade cotton (harvest, spin, and weave), wool, and silk materials and processes for making clothes. The inventions eventually led to the mass-market, affordable clothing industry that became a staple of big-box discount stores. Polyester developed into luxury microfibers and blends (“pressing” polyester fibers with rayon, wool, or cotton) that became the basis for wrinkle-resistant, wash-and-wear, no-iron clothes. By the 1980s, polyester and natural fiber clothes made from cotton, wool, and silk were sold in many similar styles.

Monsanto and two MIT architects built a plastic house in 1957 at Disneyland’s “Tomorrowland,” which showcased products for the future. Everything inside and out was made from plastic including walls, floors, doors, handles and knobs, dishes, drapes, bathtubs, and much more.

Polyethylene Terephthalate Today

All the clothes in the closets of the Monsanto plastic house were made from synthetic fibers. What polyester did for textiles, plastic did for raw materials, including wood, metals, ivory, rubber, and shellac. Plastic is inexpensive and molded easily to manufacturers’ needs. What Monsanto envisioned in 1957 became reality in many societies. The ubiquitous PET products invigorated the garbage and recycling industries but weakened companies cleaning and refilling glass bottles; laundering baby diapers disappeared with the advent of disposable diapers; the list of societal changes and industry restructuring was staggering.

The wondrous uses of PET-based products inspired research and development of other plastic products like PVC used for plumbing in home construction. None of this progress has been without health concerns. Xylene, vinyl chloride, and benzene are cancer-causing chemicals commonly used in the manufacture of plastics. Health concerns about PVC focus mainly on vinyl chloride, a carcinogenic chemical used to make PVC. Trace amounts of acetaldehyde can migrate from PET bottles for water and sodas, while other plastics are used for milk bottles, yogurt cups, and plastic bags. The numbering system mentioned earlier extends from one to seven and identifies different resin types.

In addition to recycling, scientists experiment with enzymes that can break PET into chemical building blocks for reuse. PET is a workhorse material of the modern economy. In addition to health concerns, plastic pollution is a concern; a third of PET products are never recycled but are dumped—harming the oceans and land use and clogging urban infrastructures.

Greenhouse gas emissions from the production of plastics are an environmental concern. An international movement to deal with the problems, called The New Plastics Economy, detailed in a report by the World Economic Forum, demonstrated global concerns about PET and six other types of plastics; in 2022, the United Nations Environment Assembly adopted a resolution to develop a legally binding agreement on plastic pollution, including marine pollution.

Polyethylene terephthalate is the most widely used for water, soda, cooking oil, peanut butter, and other containers; it is not recommended for reuse or refilling. High Density Polyethylene (HDPE) is used for milk containers, detergents, yogurt, bottle caps, hard hats, and other types of containers. It is a nontranslucent plastic that is more resistant to damage in dishwashers but discolors. Polyvinyl chloride (PVC) is used to make plastic pipes, Saran wrap, furniture, flooring, and other plastic products. Vinyl chloride, a chemical used to make PVC, is a human carcinogen, and acute exposure can cause illness. Low-density polyethylene (LDPE) makes plastic film, grocery bags, and trashcan liners. LDPE does not break down easily in the environment. Polypropylene (PP) is used in straws and food containers because of its durability. Packaging pellets, Styrofoam peanuts, and plastic spoons and forks are made from Polystyrene (PS). It causes a significant litter problem, marine debris, and harms wildlife, among other environmental damage. A newer plastic, Eastman Tritan copolyester, is resistant to chemicals and does not degrade as other plastic materials do. It has the look of glass, but is lightweight and shatterproof. Plastics research addresses the demand for sustainability.


Bibliography

“About PET.” PET Resin Association, petresin.org/about-pet/. Accessed 28 May 2026.

“Intergovernmental Negotiating Committee on Plastic Pollution.” United Nations Environment Programme, www.unep.org/inc-plastic-pollution. Accessed 28 May 2026.

Ioakeimidis, C., et al. “The Degradation Potential of PET Bottles in the Marine Environment: An ATR-FTIR Based Approach.” Scientific Reports, vol. 6, 2016, article no. 23501, doi:10.1038/srep23501. Accessed 28 May 2026.

Mathiesen, Karl. “Could a New Plastic-Eating Bacteria Help Combat This Pollution Scourge?” The Guardian, 10 Mar. 2016, www.theguardian.com/environment/2016/mar/10/could-a-new-plastic-eating-bacteria-help-combat-this-pollution-scourge. Accessed 28 May 2026.

“The New Plastics Economy: Rethinking the Future of Plastics.” World Economic Forum, 19 Jan. 2016, www.weforum.org/reports/the-new-plastics-economy-rethinking-the-future-of-plastics/. Accessed 28 May 2026.

Pellis, Alessandro, et al. “Renewable Building Blocks for Sustainable Polyesters: New Biotechnological Routes for Greener Plastics.” Polymer International, 4 Feb. 2016, doi:10.1002/pi.5087. Accessed 28 May 2026.

“Plastic Recycling.” European Commission, food.ec.europa.eu/food-safety/chemical-safety/food-contact-materials/plastic-recycling_en. Accessed 28 May 2026.

Rogers, Heather. “A Brief History of Plastic.” The Brooklyn Rail, May 2005, brooklynrail.org/2005/05/express/a-brief-history-of-plastic/. Accessed 28 May 2026.

“Scientific Guidance on the Criteria for the Evaluation and on the Preparation of Applications for the Safety Assessment of Post-Consumer Mechanical PET Recycling Processes Intended to Be Used for Manufacture of Materials and Articles in Contact with Food.” EFSA Journal, vol. 22, no. 7, 2024, article e8879, doi:10.2903/j.efsa.2024.8879. Accessed 28 May 2026.

“Single-Use Plastics.” European Commission, environment.ec.europa.eu/topics/plastics/single-use-plastics_en. Accessed 28 May 2026.

Tournier, V., et al. “An Engineered PET Depolymerase to Break Down and Recycle Plastic Bottles.” Nature, vol. 580, 2020, pp. 216–19, doi:10.1038/s41586-020-2149-4. Accessed 28 May 2026.

“What Is PET?” American Beverage, 9 Feb. 2024, www.americanbeverage.org/education-resources/blog/what-is-pet/. Accessed 28 May 2026.

“What Is PET?” National Association for PET Container Resources, 2015, napcor.com/what-is-pet/. Accessed 28 May 2026.

“What You Should Know About Microfiber Pollution.” U.S. Environmental Protection Agency, 28 July 2020, www.epa.gov/sites/default/files/2020-08/documents/article_2_microfibers_formatted.pdf. Accessed 28 May 2026.

Full Article

Polyethylene terephthalate, or PET, is a thermoplastic polymer resin. PET is created by combining chemicals ethylene glycol and purified terephthalic acid. PET is a remarkably versatile product. It is one of the most commonly used plastics in beverage and food packaging. It is identifiable by the number 1 code appearing at or near the bottom of the container. PET packaging is widely recyclable. It has the strength and safety of glass and the durability of metal. Health-safety agencies approve PET for food, beverage, and pharmaceutical packaging when it meets food-contact requirements. European Union rules adopted in 2022 set requirements for recycled plastics used in food-contact materials, and 2024 guidance from the European Food Safety Authority gives criteria for evaluating recycled PET processes. It is transparent, so consumers can see what is inside the containers and the condition of the products. PET is lightweight, yet strong enough to stack products one atop the other; it can be resealed and is shatter-resistant. Strength and durability make PET fibers ideal in making clothes, carpets, sleeping bags, winter coats, auto parts, and dog beds. Polyester clothing can also shed tiny plastic fibers during washing, adding to microfiber pollution.

Background

Scientist W.H. Carothers was searching for synthetic polyester fibers to use in making textile products. Instead, Carothers discovered nylon, distracting him from the search for polyester fibers. British scientists John Rex Whinfield and James Tennant Dickson later followed up Carothers’s research. Their work led to discovering polyester fibers for making fabrics, plastic sheets, and films. DuPont later commercialized PET film under the trademark Mylar. PET began appearing under other brand names over the years, including Dacron and Terylene for polyester fibers in textiles. Later in the 1950s, researchers developed methods for stretching PET into thin sheets like a film. PET’s properties were found to be ideal in making video, photo, and X-ray film; magnetic recording tape; and packaging films of varying thickness.

A PET bottle patent was published in 1973; PET bottles were transparent, lightweight, held their shape, and were shatterproof. By 1977, local governments, overwhelmed with the plethora of plastic bottles littering and in dumpsters, worked with retailers to begin recycling PET bottles. Containers made from PET resins are widely used for soft drinks and water. European Union rules set recycled-content requirements for PET beverage bottles.

The discoveries birthed the polyester and textile industries that grew rapidly. Polyester fibers were inexpensive to produce and tough. Polyester fibers were an ideal alternative to expensive, handmade cotton (harvest, spin, and weave), wool, and silk materials and processes for making clothes. The inventions eventually led to the mass-market, affordable clothing industry that became a staple of big-box discount stores. Polyester developed into luxury microfibers and blends (“pressing” polyester fibers with rayon, wool, or cotton) that became the basis for wrinkle-resistant, wash-and-wear, no-iron clothes. By the 1980s, polyester and natural fiber clothes made from cotton, wool, and silk were sold in many similar styles.

Monsanto and two MIT architects built a plastic house in 1957 at Disneyland’s “Tomorrowland,” which showcased products for the future. Everything inside and out was made from plastic including walls, floors, doors, handles and knobs, dishes, drapes, bathtubs, and much more.

Polyethylene Terephthalate Today

All the clothes in the closets of the Monsanto plastic house were made from synthetic fibers. What polyester did for textiles, plastic did for raw materials, including wood, metals, ivory, rubber, and shellac. Plastic is inexpensive and molded easily to manufacturers’ needs. What Monsanto envisioned in 1957 became reality in many societies. The ubiquitous PET products invigorated the garbage and recycling industries but weakened companies cleaning and refilling glass bottles; laundering baby diapers disappeared with the advent of disposable diapers; the list of societal changes and industry restructuring was staggering.

The wondrous uses of PET-based products inspired research and development of other plastic products like PVC used for plumbing in home construction. None of this progress has been without health concerns. Xylene, vinyl chloride, and benzene are cancer-causing chemicals commonly used in the manufacture of plastics. Health concerns about PVC focus mainly on vinyl chloride, a carcinogenic chemical used to make PVC. Trace amounts of acetaldehyde can migrate from PET bottles for water and sodas, while other plastics are used for milk bottles, yogurt cups, and plastic bags. The numbering system mentioned earlier extends from one to seven and identifies different resin types.

In addition to recycling, scientists experiment with enzymes that can break PET into chemical building blocks for reuse. PET is a workhorse material of the modern economy. In addition to health concerns, plastic pollution is a concern; a third of PET products are never recycled but are dumped—harming the oceans and land use and clogging urban infrastructures.

Greenhouse gas emissions from the production of plastics are an environmental concern. An international movement to deal with the problems, called The New Plastics Economy, detailed in a report by the World Economic Forum, demonstrated global concerns about PET and six other types of plastics; in 2022, the United Nations Environment Assembly adopted a resolution to develop a legally binding agreement on plastic pollution, including marine pollution.

Polyethylene terephthalate is the most widely used for water, soda, cooking oil, peanut butter, and other containers; it is not recommended for reuse or refilling. High Density Polyethylene (HDPE) is used for milk containers, detergents, yogurt, bottle caps, hard hats, and other types of containers. It is a nontranslucent plastic that is more resistant to damage in dishwashers but discolors. Polyvinyl chloride (PVC) is used to make plastic pipes, Saran wrap, furniture, flooring, and other plastic products. Vinyl chloride, a chemical used to make PVC, is a human carcinogen, and acute exposure can cause illness. Low-density polyethylene (LDPE) makes plastic film, grocery bags, and trashcan liners. LDPE does not break down easily in the environment. Polypropylene (PP) is used in straws and food containers because of its durability. Packaging pellets, Styrofoam peanuts, and plastic spoons and forks are made from Polystyrene (PS). It causes a significant litter problem, marine debris, and harms wildlife, among other environmental damage. A newer plastic, Eastman Tritan copolyester, is resistant to chemicals and does not degrade as other plastic materials do. It has the look of glass, but is lightweight and shatterproof. Plastics research addresses the demand for sustainability.


Bibliography

“About PET.” PET Resin Association, petresin.org/about-pet/. Accessed 28 May 2026.

“Intergovernmental Negotiating Committee on Plastic Pollution.” United Nations Environment Programme, www.unep.org/inc-plastic-pollution. Accessed 28 May 2026.

Ioakeimidis, C., et al. “The Degradation Potential of PET Bottles in the Marine Environment: An ATR-FTIR Based Approach.” Scientific Reports, vol. 6, 2016, article no. 23501, doi:10.1038/srep23501. Accessed 28 May 2026.

Mathiesen, Karl. “Could a New Plastic-Eating Bacteria Help Combat This Pollution Scourge?” The Guardian, 10 Mar. 2016, www.theguardian.com/environment/2016/mar/10/could-a-new-plastic-eating-bacteria-help-combat-this-pollution-scourge. Accessed 28 May 2026.

“The New Plastics Economy: Rethinking the Future of Plastics.” World Economic Forum, 19 Jan. 2016, www.weforum.org/reports/the-new-plastics-economy-rethinking-the-future-of-plastics/. Accessed 28 May 2026.

Pellis, Alessandro, et al. “Renewable Building Blocks for Sustainable Polyesters: New Biotechnological Routes for Greener Plastics.” Polymer International, 4 Feb. 2016, doi:10.1002/pi.5087. Accessed 28 May 2026.

“Plastic Recycling.” European Commission, food.ec.europa.eu/food-safety/chemical-safety/food-contact-materials/plastic-recycling_en. Accessed 28 May 2026.

Rogers, Heather. “A Brief History of Plastic.” The Brooklyn Rail, May 2005, brooklynrail.org/2005/05/express/a-brief-history-of-plastic/. Accessed 28 May 2026.

“Scientific Guidance on the Criteria for the Evaluation and on the Preparation of Applications for the Safety Assessment of Post-Consumer Mechanical PET Recycling Processes Intended to Be Used for Manufacture of Materials and Articles in Contact with Food.” EFSA Journal, vol. 22, no. 7, 2024, article e8879, doi:10.2903/j.efsa.2024.8879. Accessed 28 May 2026.

“Single-Use Plastics.” European Commission, environment.ec.europa.eu/topics/plastics/single-use-plastics_en. Accessed 28 May 2026.

Tournier, V., et al. “An Engineered PET Depolymerase to Break Down and Recycle Plastic Bottles.” Nature, vol. 580, 2020, pp. 216–19, doi:10.1038/s41586-020-2149-4. Accessed 28 May 2026.

“What Is PET?” American Beverage, 9 Feb. 2024, www.americanbeverage.org/education-resources/blog/what-is-pet/. Accessed 28 May 2026.

“What Is PET?” National Association for PET Container Resources, 2015, napcor.com/what-is-pet/. Accessed 28 May 2026.

“What You Should Know About Microfiber Pollution.” U.S. Environmental Protection Agency, 28 July 2020, www.epa.gov/sites/default/files/2020-08/documents/article_2_microfibers_formatted.pdf. Accessed 28 May 2026.

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