THE 7 TYPES OF PLASTICS, CHARACTERISTICS AND USES - ENVIRONMENT - 2025

The main types of plastics can be classified into 6 different categories plus an additional one that includes plastics with more diverse characteristics. Figures for the end of 2018 indicate that at that time only 19% of the plastic produced was being recycled.

Although it can be considered a small number, it is worth noting that just 30 years ago no plastic consumed by human beings was recycled; Based on this context, it can be said that there has been some progress.

There are six defined types of plastics and a seventh category that includes plastics with peculiar characteristics. Source: pixabay.com

Among the plastic products that are recycled the most are beverage bottles such as soft drinks or juices. However, other types of plastics such as those found in detergent bottles or cables are much more difficult to recycle given their complex composition.

To fulfill the responsibility that inhabiting planet Earth means, it is necessary to know what the different types of plastic are, where they are found and what level of danger their use implies. With this information, it will be possible to make the necessary decisions to favor the conservation of the environment.

Types of plastics according to their characteristics

Each plastic product that we consume has a symbol that allows us to know what type of plastic it is. This symbol is called the Möbius circle and was created by the Society of Plastic Industry in 1988.

Thanks to the small variations of this symbol, we can determine what type of plastic the products we consume daily are made of.

6 specific types have been determined that categorize plastics according to their characteristics, and there is a seventh category that includes other plastics for which there is no complete information on their composition, or whose constituent elements are so particular that they do not fall into other classifications; These plastics cannot be recycled.

Below we will describe the different types of plastics that exist, as well as their most outstanding characteristics and their uses:

PET (polyethylene terephthalate)

characteristics

It is a plastic with a high level of transparency; for this reason it is preferred for storing soft drinks and other beverages.

Likewise, this type of plastic prevents the entry of oxygen, so it is able to keep food optimally.

PET plastic is fully recyclable and is also very cheap to manufacture. The recycling processes that it can undergo are capable of generating a plastic equal to or even better quality than recycled.

The impermeability is another peculiar characteristic of this type of plastic, as well as how light it is. It has a barrier for gases and its color can vary depending on the condensation process it is subjected to.

Applications

As we discussed in previous lines, PET plastic is usually found especially in soft drink bottles and food containers; it is also common to find it in some shampoo containers.

The recycled products of PET plastics are used in the textile sector; They can be found in carpets, pillows or even in sleeping bag fillings.

HDPE or HDPE (high density polyethylene)

characteristics

High-density polyethylene is one of the most used in everyday life. It is characterized by having a certain hardness and by being a bit opaque. HDPE plastic is capable of withstanding temperatures of up to 120 ° C in short cycles, making it more resistant.

The density of this type of plastic is between 0.93 and 0.97 grams for each cubic centimeter. This, coupled with its low branching, makes HDPE plastic have a higher intermolecular strength and, therefore, have more resistance.

Its transformation process can be carried out through different mechanisms; for example, it can be blown, injected or even molded by means of a rotor. This implies that its end use is quite versatile.

Applications

You can find this type of plastic in milk bottles, juice containers, and cleaning product containers.

Bottles of creams and other cosmetic products can also contain HDPE plastic, as can motor oil containers.

After recycling, this type of plastic is often used in garden furniture, bottles, tubes, garbage containers, flowerpots, storage boxes and food containers, among other elements.

PVC (polyvinyl chloride)

characteristics

This type of plastic is considered very difficult to recycle. Several experts on the subject consider that PVC is the most dangerous of the plastics that exist, and this degree of danger is not only reflected in the final result (when it is discarded), but in the entire manufacturing process.

Polyvinyl chloride is among the first plastics discovered by humans and is also one of the most widely used. The reason for this preference it enjoys is that it is characterized by being light and at the same time very resistant, it is extremely durable, has high resistance to fire, low permeability and high insulating property.

Applications

PVC is found in pipes intended to transport drinking water or waste. It is also possible to find it in cable jackets.

In the construction sector, polyvinyl chloride is widely used in the manufacture of swimming pools, in the manufacture of window frames, in the sheets that are placed on the ceilings and in the coatings that are applied both to the walls and to the soils.

Medical products also often include this type of plastic, especially surgical gloves, blood bags, and tubes used for transfusions. It is also possible to find PVC in the packaging of pharmaceutical products, since its resistance and impermeability guarantee the good storage of the elements.

Some footwear, tents, and waterproof products like inflatable pools are also made using PVC plastic.

The recycling process of this plastic can only be carried out industrially. Its effects are highly polluting, so many companies that use it are promoting the use of other options; the packaging industry is one of those that is promoting the elimination of PVC from its processes.

LDPE or LDPE (low density polyethylene)

characteristics

The main characteristic of low-density polyethylene is its elasticity and hardness. This type of plastic is capable of withstanding up to 80 ° C continuously, and can withstand 95 ° C for a very short cycle.

It is transparent and the main ingredient through which it is generated is natural gas. Its processing can be through injected, rotor molding or blowing, among other ways; This speaks to the versatility of this type of plastic.

Likewise, its manufacturing process is very economical, which is why products whose raw material contains LDPE are widely used in different fields.

Applications

Plastic grocery bags are made of LDPE plastic. This variety is also found in cable system insulation, in bottles that are flexible (those made of soft plastic, such as those containing soaps or creams), and in plastic wrap.

Bags of frozen food and those destined to dispose of garbage in the industrial field are also made of LDPE plastic. Once recycled, this type of plastic can make new plastic bags.

PP (polypropylene)

characteristics

This type of plastic is the one with the lowest density (between 0.89 and 0.92 grams per cubic centimeter). For this reason it is characterized by being very resistant to heat and repetitive movements, but it is not flexible.

It can also be industrially transformed through mechanisms such as blowing, injecting and forming through the use of heat. Its rigidity is very high and it is feasible to subject it to recycling processes.

Applications

Soft drink container lids are made of PP plastic. Likewise, diapers and straws for drinking liquids contain this type of plastic.

Other food container lids such as spreads are also made from PP plastic. Included in this category are the wrappers for some sweets, certain utensils used in the kitchen, and containers for microwave ovens.

PP plastic can be recycled; After this process, it is usually used for containers, trays, brushes, brooms and containers for car batteries, among other uses.

PS (polystyrene)

characteristics

It has the peculiarity of being a very good insulator and having great resistance to blows. It softens through heat and its base is composed of styrene monomer, which is a petrochemical with a liquid consistency.

Apart from being able to be transformed through heat, it is also possible to alter it through blowing and injection processes.

Applications

Food trays and insulated glasses are made of polystyrene. It is also contained in typical containers for storing fast food and even some appliances.

The versatility of PP plastic means that we can also find it in the construction sector, specifically in accessories used in plumbing, in insulating foams or in showers and other implements used in the bathroom.

Likewise, polystyrene is also present in the medical context in test tubes, in trays used for tissue culture and in other items used in diagnostics.

Other plastics

characteristics

The seventh category is made up of those plastics whose components are not fully known, which is why they cannot yet be recycled.

Within this category are also those whose composition is mixed, which makes them very complex. Some of the plastics that are included within this classification are polycarbonate, polyurethane, polyamide and acrylic, among many others.

Applications

Until now, non-recyclable plastics are used in the manufacture of compact discs, containers for sausages, squeeze containers such as toothpaste or sauces, and dishes made especially for use in the microwave oven, among others.

References

1. "The classification of plastics" in The green blog. Retrieved on March 27, 2019 from El blog verde: elblogverde.com
2. "Plastic can be recycled, right?" in Living without plastic. Retrieved on March 27, 2019 from Living without plastic: vivirsinplastico.com
3. "Types of plastics" in Plastics Europe. Retrieved on March 27, 2019 from Plastics Europe: plasticseurope.org
4. "The seven types of plastic: from most to least recyclable" at Coca-Cola Chile. Retrieved on March 27, 2019 from Coca-Cola Chile: cocacoladechile.cl
5. "Types of plastics" in the Argentine Chamber of the Plastic Industry. Retrieved on March 27, 2019 from the Argentine Chamber of the Plastic Industry: caip.org.ar
6. "Types of plastic according to their ease of recycling" in National Geographic Spain. Retrieved on March 27, 2019 from National Geographic Spain: nationalgepgraphic.com.es
7. Freudenrich, C. "How plastics work" in How stuff works. Retrieved on March 27, 2019 from How stuff works: science.howstuffworks.com