Article by: Teresa Pinho | 14ºC
The 21st century has a common enemy that has boomed in the last 60 years – Plastic. The truth is that it is a material with numerous benefits. However, and like everything that is too much is an exaggeration, the overproduction of plastic has been having very harmful consequences for the environment. But is plastic itself the culprit? Let's get to know the types of plastics, the advantages and disadvantages and which ones are recyclable and how to use and reuse them more consciously.
What is plastic anyway?
A plastic is any object that is obtained by chemically modifying polymers, mostly derived from petroleum. It can take various forms such as liquid (resins), molded solids (rubbers), fibrous (bottles), spongy (styrofoam), sheets, doughs, among others. It tolerates high temperatures and is resistant to oxidation and adverse weather conditions. The different boiling temperatures of the different plastics allow their separation through distillation/or pyrolysis processes.
The first plastic appeared in the second half of the 19th century.
Plastic is much more present in our daily lives than in single-use plastic bottles, straws, packaging and bags. The plastic that we don't see is present in buildings and plumbing, in vehicles (cars, motorcycles, boats, planes...), power supply cables, mobile phones, computers, small and large appliances, industrial machines, textiles, fitness machines, disposable medical and scientific research equipment, among others.
How many of us imagined carrying water or storing food, without being in a container with some plastic component?
Plastic is the enemy for being extremely comfortable to the egocentric way of living of the human being. Of course it has many advantages..! We start with durability. Plastic lasts an average of 35 years intact and has properties that make it moldable into almost anything, while still being resistant to heat and water. In the vast majority, it is so resistant that it does not break. All this for a significantly small economic value – which has a huge weight in the decision between this and any other material. Its airtight power reduces food waste and prevents contamination of liquids, not only in food, but in the storage and transport of toxic/harmful products.
As for the disadvantages…
The first and most obvious is the fact that they are synthesized from fossil fuels. About 4% of the oil and natural gas extracted goes directly to the plastics industry. This number could reach 20% if the rate of plastic use increases to the level that it has. Durability and strength can also be a disadvantage. For many decades, plastic was placed in landfills and thrown into freshwater courses and the sea, being a huge danger to flora and fauna, both terrestrial and marine. How many have seen plastic pictures around turtles and seals? But the danger goes far beyond that.
Polymers and monomers end up breaking down into microplastics/nanoplastics and being ingested by fish, thus entering the food chain and harming, in addition to death, the ingestion of harmful and carcinogenic substances – eventually reaching humans. To add to the fact that they are not biodegradable, plastics can only be recycled a certain number of times and only if they are not contaminated, for example, with fats.
Plastics are one of the biggest pollutants in the world, and there is a “continent” of plastic floating in the Pacific Ocean with an estimated size of 80,000 tons of plastic and occupying 1.6 million km2.
Many times we want to contribute to a more sustainable environment and we don't know which plastics are less harmful or which can be recycled We help!
Plastics are divided into two categories: thermoplastics and thermosets. The former are composed of polymers that do not undergo a chemical reaction and melt at high temperatures, so they are recyclable. The second are composed of polymers that undergo an irreversible chemical reaction that does not allow them to transform into another object.
Thermoplastics
Polyethylene terephthalate (PET) (1) is the plastic from which bottles, cosmetics, bottles for food or hospital use, textile fibers are made. It can be recycled except when mixed with other materials – for example in clothing fibers that are mixed with cotton.
High density polyethylene (HDPE)(2) is often called the “green” plastic as it can be produced from plant sources other than petroleum. It's recyclable. We find HDPE in detergent and oil packaging, supermarket bags, lids, etc.
Polyvinyl chloride (PVC) (3) is found in water containers, mayonnaise, juices, sewage pipes, hospital supplies such as blood bags, toys, medication packaging. It is very resistant and can be recycled if separated from other plastics. It has a carcinogen called dioxin.
Low density polyethylene (LDPE) (4) is also found in shopping bags, tetrapack film, disposable diapers, garbage bags. Like HDPE, it can be made from other plant sources, so it is also recyclable and “green”.
Polypropylene (PP)(5) is a plastic used in food boxes, industrial packaging, hot water pipes, wires and cables, automobile parts, carpet fibers, syringes, ropes, among others . It is also recyclable. However, there is a variant of PP called BOPP (Bioriented Polypropylene Film), a metallized plastic present in wafer plastics, which is more difficult to recycle.
Polystyrene (PS) (6) is a widely used and recyclable plastic. We find PS in disposable cups, refrigerator doors, yogurt cups, disposable plates and cutlery. It is a thermoplastic resin.
Poly lactic acid (PLA) (7) is the king of green plastics. In addition to being recyclable, it is compostable, biocompatible and bioabsorbable. It can be obtained from beet starch and other vegetables. Disposable plates and cups, pens, plastic bags, packaging and containers are objects where we find it. When mixed with other plastics it becomes difficult to recycle.
Thermoset
Polyurethane (PU) (7) is more common than we think. Ashtrays, industrial parts, shoe soles, foam mattresses and sofas, switches, telephones and cell phones, dish sponges, surfboards, electrical parts, among others, are made of PU. This polymer is not recyclable, or very complicated to recycle.
Ethylene Vinyl Acetate (EVA) (7) is a flexible material and used in slippers, gym equipment, toys, shoe soles. Its recycling is very difficult and uncommon.
Bakelite (7) was the first synthesized plastic. It is a resin that gives rise to the polyphenol polymer. It is resistant and infusible, cheap and used in pot handles, telephone components and lamp sockets. It is little used, it was a very used plastic in the beginning of plastics. Its recycling is difficult and unusual.
Phenolic resin (7) is a plastic used as an electrical and thermal insulator and used in coatings, adhesives, paints and varnishes. This resin is not recyclable.
There is a more recent designation – the oxide-degradable plastic or “oxy-biodegradable”, in which the thermoplastics PP, PE, PS and PET are inserted. These are plastics that can be degraded by oxygen, using additives that facilitate their degradation. The negative component of this process is the creation of micro and nanoplastics.
The most important thing is that we know what we are buying, through the respective symbols….and ...make good use of plastics until they are no longer useful, subsequently separating them correctly in order to reduce our ecological footprint.