How is plastic made?

Seven types of plastic are made using natural materials and different catalysts, and although some can be biodegradable, others are not. We are currently producing more than 300 million tons of plastic every year worldwide, with roughly half of that dedicated to single-use applications.

How is plastic made?

According to the Plastics Industry Association, the process of manufacturing plastic begins with refining raw materials like natural gas, oil or plants into things like ethane and propane. These compounds are subjected to high heat in order to break them into tiny monomers, which can later be linked together to make different types of plastic.

A catalyst then combines with these monomers, typically ethylene and propylene, to manufacturer a polymer powder. This powder goes through an extruder to be melted, formed into a long tube within a pipe, and cooled to later make plastic pellets. These pellets are then shipped to the manufacturers that create plastic packaging, water bottles, durable medical equipment, toys, auto parts, and all the other things that are made from plastic.

Many companies are innovating when it comes to plastic because of the usefulness and demand of the material.

How many types of plastic exist?

Seven main types of plastics are comprised of polyethylene terephthalate (PETE or PET), high-density polyethylene (HDPE), polyvinyl chloride (PVC), low-density polyethylene (LDPE), polypropylene (PP), polystyrene or styrofoam (PS), and other miscellaneous plastics. Here is a primer on each:

1. Polyethylene Terephthalate (PETE or PET)

Polyethylene terephthalate is the most popularly used type of plastic today, making up nearly all the plastic bottles and containers in the country. Unfortunately, only about one-quarter of the material is currently recycled. This type of plastic carries the code 1 and is accepted for recycling in just about all programs to be remade into carpet, clothing, shoes, and many other household items.

2. High-Density Polyethylene (HDPE)

Created in 1953, high-density polyethylene was originally used for storm sewer and drain pipes, before finding its way into many other applications today, including most of the plastic bottles and bags we use on a daily basis. Although it is a commonly recycled plastic, only about 12 percent finds its way into new products, such as lumber, fencing, and crates.

3. Polyvinyl Chloride (PVC)

Perhaps the most widely known application of polyvinyl chloride is the popular PVC pipe, which is used in plumbing and many other applications. It is infrequently recycled, and only a very limited number of recycling companies will accept this number 3 plastic. Unfortunately, this popular material contains many harmful toxins. Besides pipes, PVC is frequently found in tote bags, shoes, and window frames and can be recycled to make flooring.

4. Low-Density Polyethylene (LDPE)

Low-density polyethylene has a lower mass than high-density versions. It is perhaps the most popular plastic in our homes, used to create plastic cling wrap, snack bags, squeezable bottles, flexible food packaging, and grocery bags. This packaging makes up more than half of all the plastic that is thrown away. Coded with the number 4, this type of plastic is growing in popularity for recycling companies, which can repurpose LDPE into garbage cans and lumber.

5. Polypropylene (PP)

Polypropylene is also found in our homes as it is used for diapers, kitchen items, bottles, take-out containers, and disposable plates and cups. This plastic, coded number 5, is often collected but rarely completes the recycling process to become items like ice scrapers and battery cables. Alternatives to items such as PP straws are being developed.

6. Polystyrene or Styrofoam (PS)

When you hear about plastics causing problems in the environment and within our oceans, polystyrene is usually the culprit. It is a light plastic that’s easily made into items such as packaging peanuts and disposable cups and plates. It breaks into small, non-biodegradable pieces and can be harmful to animals and sea creatures. This material makes up about one-third of all landfill contents in the United States. Infrequently recycled, PS can be remade into insulation.

7. Miscellaneous Plastics

Other plastics may include polycarbonate, nylon, polylactide, acrylic, styrene, and fiberglass. BPA products are made of miscellaneous plastics as well. Because these plastics do not break down easily, they are difficult and rarely recycled into items such as plastic decking material.

Is plastic biodegradable?

Plastic waste has become a major issue in our world, with many stories about the amount of plastic that has been produced and littered throughout the environment. In response, many companies have introduced the concept of biodegradable plastic. However, many studies show that these materials are not necessarily the solution.

Three common versions of plastic materials are degradable, biodegradable, and compostable. All plastic is degradable because that only means it will eventually become small particles; however, it does not mean the materials will become a natural substance again. Biodegradable plastic, on the other hand, should return to water, carbon dioxide, and compost eventually. In comparison, compostable plastic should break down in a traditional compost site through the work of microorganisms with no toxic byproducts.

However, researchers from the University of Plymouth’s International Marine Litter Research Unit conducted a study that showed that a “biodegradable” bag buried in the soil and the sea for three years was still strong enough to carry items without breaking. A compostable bag was still identifiable in the soil more than two years later, but tore when weight was placed inside it, which signaled some degrading.