Plastic is an essential material in our daily lives. From packaging to construction, from electronics to medical devices, plastic is ubiquitous. While there are many types of plastics, they all share a common feature: they are made from molecules known as polymers. These polymers are produced from smaller molecules called monomers, which are chemically bonded together in a process called polymerization. In this post, we will explore the top 25 molecules used in plastic production, what they are used for, and their properties.
| Molecule | Usage | Properties |
|---|---|---|
| Ethylene | Polyethylene | Lightweight, strong, flexible, and easy to mold |
| Propylene | Polypropylene | Lightweight, strong, and resistant to heat and chemicals |
| Vinyl chloride | Polyvinyl chloride (PVC) | Tough, durable, and resistant to chemicals and weathering |
| Styrene | Polystyrene | Lightweight, rigid, and good insulator |
| Acrylonitrile | Acrylonitrile-butadiene-styrene (ABS) | Strong, tough, and heat-resistant |
| Polyethylene terephthalate (PET) | PET bottles and food containers | Lightweight, tough, and resistant to impact |
| Polycarbonate (PC) | Electronic components and safety glasses | Strong, tough, and heat-resistant |
| Polyurethane | Foam insulation and furniture cushions | Soft, flexible, and durable |
| Polyvinylidene fluoride (PVDF) | Chemical storage tanks and pipes | Resistant to chemicals and UV radiation |
| Polyethylene oxide (PEO) | Water-soluble packaging | Water-soluble and biodegradable |
| Polyamide (PA) | Nylon stockings and carpet fibers | Strong, durable, and resistant to abrasion |
| Polybutylene terephthalate (PBT) | Automotive parts and electrical connectors | Strong, heat-resistant, and resistant to chemicals |
| Polymethyl methacrylate (PMMA) | Acrylic sheets and lighting fixtures | Clear, strong, and scratch-resistant |
| Polyphenylene oxide (PPO) | Electrical components and appliance parts | Tough, heat-resistant, and resistant to chemicals |
| Polyoxymethylene (POM) | Gears and bearings | Strong, durable, and self-lubricating |
| Epoxy resin | Adhesives and coatings | Strong, durable, and resistant to chemicals |
| Cellulose acetate | Film and fibers | Clear, strong, and heat-resistant |
| Polypropylene oxide (PPO) | Foams and adhesives | Tough, flexible, and resistant to chemicals |
| Polysulfone (PSU) | Medical devices and aircraft components | Strong, heat-resistant, and resistant to chemicals |
| Polyetherimide (PEI) | Aerospace and electrical components | Strong, tough, and heat-resistant |
| Polycarbonate/ABS blend | Automotive parts and electronic housings | Tough, strong, and heat-resistant |
| Polyphenylene sulfide (PPS) | Electrical connectors and automotive parts | Strong, heat-resistant, and resistant to chemicals |
| Thermoplastic elastomers (TPE) | Seals and gaskets | Flexible, durable, and resistant to weathering |
| Fluoropolymers | Chemical-resistant coatings and linings | Resistant to chemicals, UV radiation, and weathering |
| Thermoplastic olefin (TPO) | Automotive exterior parts | Durable, weather-resistant, and lightweight |
Who produces them
There are numerous companies that produce these chemicals, as they are commonly used in plastic production. Some of the major producers include:
- LyondellBasell Industries
- Dow Chemical Company
- ExxonMobil Chemical
- BASF SE
- SABIC
- DuPont de Nemours, Inc.
- INEOS Group AG
- Solvay SA
- Mitsubishi Chemical Corporation
- LG Chem Ltd.
These companies produce a range of other chemicals as well, and some of them may also produce plastic products.
Recycling
The percentage of each of these chemicals that are recycled can vary depending on the specific type of plastic and the recycling program in place. In general, some plastics are more commonly recycled than others, with polyethylene terephthalate (PET) and high-density polyethylene (HDPE) being two of the most commonly recycled plastics.
According to the American Chemistry Council, the recycling rates for some of the most common types of plastic in the US in 2018 were:
- PET bottles and jars: 29.1%
- HDPE natural bottles: 29.3%
- HDPE colored bottles: 9.4%
- PVC bottles: 0.1%
- LDPE film: 16.2%
- PP containers: 1.3%
- PS containers: 0.2%
These numbers suggest that while some types of plastics have relatively high recycling rates, others are much lower. It’s also worth noting that these rates can vary widely depending on the location and the recycling program in place. Some countries have much higher recycling rates than others, and some recycling programs are more effective at collecting and processing certain types of plastics than others.
Ultimately, increasing the recycling rates for all types of plastics will require a combination of better consumer education, more effective recycling programs, and increased demand for recycled plastics from manufacturers.
Quantity Produced
The annual production volume of each of the top 25 molecules used in plastic production varies widely depending on the specific chemical. The following figures are based on global production estimates for the year 2019 from the Chemical Data Reporting database of the US Environmental Protection Agency:
- Ethylene: 174.7 million metric tons
- Propylene: 115.4 million metric tons
- Vinyl chloride: 22.2 million metric tons
- Styrene: 35.6 million metric tons
- Acrylonitrile: 8.4 million metric tons
- Polyethylene terephthalate (PET): 30.4 million metric tons
- Polycarbonate (PC): 4.6 million metric tons
- Polyurethane: 24.3 million metric tons
- Polyvinylidene fluoride (PVDF): 6,500 metric tons
- Polyethylene oxide (PEO): 400,000 metric tons
- Polyamide (PA): 7.5 million metric tons
- Polybutylene terephthalate (PBT): 1 million metric tons
- Polymethyl methacrylate (PMMA): 3.3 million metric tons
- Polyphenylene oxide (PPO): 3,100 metric tons
- Polyvinyl chloride (PVC): 42.1 million metric tons
- Polyethylene (LDPE): 20.7 million metric tons
- Polyethylene (LLDPE): 28.8 million metric tons
- Polyethylene (HDPE): 53.8 million metric tons
- Polypropylene (PP): 65.8 million metric tons
- Polystyrene (PS): 10.9 million metric tons
- Acetal (POM): 1.9 million metric tons
- Acrylic (PA): 1.2 million metric tons
- Epoxy: 2.2 million metric tons
- Melamine: 1.1 million metric tons
- Polycarbonate/Acrylonitrile-butadiene-styrene (PC/ABS): 3.3 million metric tons
These figures highlight the enormous scale of plastic production, with billions of metric tons of plastic being produced each year globally. While plastic has many valuable properties, the environmental impact of this scale of production is a growing concern, with plastic waste polluting our oceans and landfills, and microplastics being found in our food and water. It is essential that we work to reduce our reliance on single-use plastics and develop more sustainable ways of producing and using plastic in the future.