What makes plastic last long?

For the past years, plastic products have been a part of living. From clothing to plastic wraps on food, plastic has become a staple in every household. Living in a plastic era, it is essential to gain a deeper understanding of the world of plastics. 

When you drop a container of mustard on the floor, you will be thankful for polyethylene terephthalate, or PET because it’s what keeps it from breaking. But when you drop the same bottle into a landfill, you might have second thoughts. Why?

Landfill environments have been the standard solution for solid waste disposal for the past many years. However, people overload the landfills with plastic products, which can take hundreds of years or more to biodegrade. 

The problem lies with the plastic’s composition. Petroleum-based plastics like PET are not organic. This means that decomposing them will take forever. Natural materials like wood, grass, and leftover foods undergo biodegradation. Bacteria in the soil transform these materials into useful compounds. But when you load up an entire plate of plastics and bottles into the ground, the one-celled gluttons are sure to turn up their noses at the sight of them. These bacteria do not have the mechanisms needed to break the plastic down for energy or nutrients. 

The Relationship between Plastic and Bacteria

Plastics came from crude oil and other fossil products. Manufacturers heat these products to high temperatures to form stable polymers from the fossil product’s monomers. Based on a study, you cannot find these polymers too often in nature since their carbon-to-carbon bonds are firm and require a lot of energy to make. Thus, it was only in the last few decades that plastics started to gain popularity, making them a foreign object to many microorganisms. 

Since these microorganisms are not familiar with the new product, they have no idea how to break it down into its elemental components or how to recycle it back to the environment. For instance, not many microorganisms break down metals. However, they can recycle it back to the environment through oxidation or rust. This is where plastics beat Mother Nature.

The molecules that make plastics are resistant to oxidation and other chemical reactions. It is due to the strength between the monomers’ bonds in the plastic polymers. Therefore, it is difficult for plastics to biodegrade at all. When people throw out plastic, it maintains its structure and ends up damaging the ecosystem in more ways than one.  

How Plastics Break without Bacteria

Since bacteria doesn’t break plastic down, how does it degrade over time? The answer is photodegradation. This is a mechanism that breaks down the bond of molecules in plastics through UV rays from the sunlight. However, this process is slower than having some bacteria to break down the plastic. It also requires sunlight, so plastic buried deep down the soil can potentially stay there for a long time. Photodegradation can break down plastics floating in oceans a lot faster. But remember not to throw plastics in any bodies of water. 

Ocean plastics are a massive problem for marine animals. They mistake it as food and end up eating loads of it. Also, some plastic sinks to the bottom of the ocean, where there is not enough sunlight to break it down. As a result, it can stay at the bottom for a long time!

The Lifespan of Plastic Products  

Using plastics is not ideal. Its life cycle length spells big problems for both human and animal health. 

  • Plastic bags – 20 years

These plastic products pose one of the most significant impacts on ocean wildlife. Despite making up a small percentage of waste, plastic bags can fragment into microplastics, seep into the food chain, and end up in people’s bodies.

  • Plastic straws – 200 years

Based on 2018 data, plastic straws are the 11th most found ocean trash. It can take 200 years for a single plastic straw to decompose. What’s worse is that they do not biodegrade and never fully degrade. 

  • Disposable diapers – 500 years

Disposable diapers will decompose when exposed to oxygen and sunlight. When in a landfill, they can contaminate groundwater and pose severe threats to the environment. 

  • Plastic bottles– 450 years

The energy used to produce plastic water bottles can fuel approximately one million cars every year. However, you can only recycle a few water bottles—the others end up on roadsides and in landfills, oceans and waterways. 

Common questions about why plastic lasts so long

Can plastic be recycled?

You cannot recycle all plastic. For instance, plastic bags and plastic straws are not recyclable. For a coffee cup, you need a specialized machine to recycle it. The vast majority of plastics end up in landfills, scattered on the roadside or floating in bodies of water. 

How are plastics made?

Step 1: Extraction: Obtaining of fossil fuels

The first step of plastic production is the extraction of crude oil and natural gas from the ground. 

Step 2: Refinement: Converting into products

These fossil fuels are a mixture of thousands of compounds, so they need to undergo processing in a refinery before being used. Both raw materials are converted into several products: ethane from crude oil and propane from natural gas. 

Step 3: Cracking: Breaking down 

The ethane and propane are sent into a cracker plant and broken down into smaller molecules. Ethane produces ethylene, while propane turns into propylene. 

Step 4: Polymerization: Adding a catalyst

In this step, a catalyst, which links the molecules together, is added to form polymers or resins. It allows plastics to be easily molded into different types, given the pressure and heat. 

Polymerization is a process that converts ethylene into the resin polyethylene and propylene into polypropylene. These resins are melted, cooled down and cut down into pre-production pellets called nurdles. 

These nurdles are transported to manufacturers who use heat to mold the nurdles into different types of plastic products (PET, HDPE, PVC, LDPE, PP, PD, and other plastics). 

Where do plastics go?

Less than 50% of plastics are collected for recycling, while others end up in landfills. In some countries, plastics are incinerated, and others export their wastes to other countries. You can also find plastics in fish and other sea animals, and even in humans.

Plastic lasts so long because of the tight molecular bond that results from the complex process it took to make it. Because it is made to last so long, it takes too much effort to recycle it, making it almost impossible to lessen your carbon footprint while still using a lot of plastic.

What makes plastic last long?