Types of plastics: identification, uses, and recycling challenges

Types of plastics: identification, uses, and recycling challenges

Each year, 400 million tons of plastic are produced, generating a significant amount of waste that is difficult to manage. During its manufacture, pollution is emitted, and the products take up a lot of space in containers and landfills. Additionally, many plastics, once recycled, cannot be used for packaging human consumption products, and when different types are mixed, the resulting product is of low quality. Despite these drawbacks, plastic continues to be widely used due to its numerous benefits: it is lightweight, easily moldable, insulating, resistant to corrosion and chemical agents, and above all, economical. These characteristics have led to the massive use of single-use plastics, such as bags, kitchen utensils, plates, and straws.

However, not all plastics are the same. When we talk about plastic, we tend to generalize, and it is important to understand the differences between the various types. In 1988, the Society of the Plastics Industry created the Plastic Identification Code to promote recycling. Today, this system is used internationally in the industrial sector to distinguish the composition of resins in containers and other plastic products.

The different types of plastic are identified with a number from 1 to 7, located inside the classic recycling symbol.

  1. PET (Polyethylene Terephthalate) This plastic is one of the easiest to recycle. It has many properties, such as high transparency and the ability to accept colorants. It is quite resistant, lightweight, and recyclable. It is mainly found in water or beverage bottles. Once recycled, it can be turned into new bottles, synthetic fibers used for textiles, and even cosmetic containers.

  2. HDPE (High-Density Polyethylene) Also known as PEAD, this plastic is also easy to recycle. It has high resistance to impacts, chemicals, and temperatures. It is flexible but has some rigidity. It is lightweight and water-resistant. It can be found in many containers such as milk bottles or motor oil containers. After being recycled, it is often used to make new containers, boxes, toys, detergents, pots, and even some furniture.

  3. PVC (Polyvinyl Chloride) This type of plastic is a bit more complicated to recycle, but it is possible. It can be rigid or flexible, depending on the production process. It has high resistance and low density. It is tough and ductile. It is present in credit cards, pipes, cable insulation, synthetic leathers, or some door and window frames. Once recycled, it can be used as drainage and irrigation pipes.

  4. LDPE (Low-Density Polyethylene) The recycling of low-density polyethylene is possible. It has high resistance, both to impacts and chemicals, similar to HDPE. It is quite flexible, and its transparency depends on its thickness. It is found in cling film, bubble wrap, insulation, and shopping bags, which can be recycled into new bags.

  5. PP (Polypropylene) The recycling of this type of plastic is also possible. It is very resistant and easy to mold. It can be found in bottle caps, straws, tupperware, fibers of some fabrics, and diapers. Normally, once recycled, it can be used as beams or car battery cases.

  6. PS (Polystyrene) This type of plastic has somewhat complicated recycling, but it is possible. It is found in thermal materials, egg cartons, packaging fillers, hangers, and insulation.

  7. Other (Plastic Mixture) The other types of plastics are somewhat more complicated to recycle. When we find the number 7 on a container, it is because it is a mixture of several plastics. Even so, all these types of plastics have a second life in nylon fibers, compact discs, or car parts. The main reason they are difficult to recycle is that the types of resins they contain cannot be accurately determined, as they are made up of various plastics.