With the advancement of the times, biodegradable plastics are becoming more and more common. When you finish drinking a bottle of Coke or other plastic bottles with satisfaction, when you throw the plastic bottle into the trash can, will you have a question that comes to mind, why do we bother trying to recycle these bottles, can't these bottles be biodegradable?
It's a pity that not all plastics are biodegradable, because humans make large variety of plastics, some of which are specifically designed to be biodegradable, and most of the plastics developed and manufactured in the early days are not biodegradable degradable design.
Let's start with how plastics are created and how biodegradation functions in order to comprehend why plastics don't decompose.
Petroleum, usually referred to as oil, is a fossil fuel. This indicates that it is composed of the remains of extinct living things, including plants, bacteria, and algae. For millions of years, these species were imprisoned deep beneath. They were transformed into fossil fuels there by heat and pressure.
Propylene is a substance found in large quantities in petroleum. In order to speed up chemical reactions, refiners combine heated propylene with a catalyst to create plastic. Propylene molecules start to cluster together like beads on a thread as a result.
A polymer, which is a long molecule consisting of numerous smaller ones connected together, is what the chain is formed of. Literally translated as "many propylenes," its name is polypropylene. And these molecules' bonds with one another are very strong.
The polymers in biodegradable objects, including cardboard boxes, breakdown and are digested by natural microbes when they decompose. They accomplish this utilizing enzymes, proteins that hasten the breakdown of substances like lignin, a naturally occurring polymer present in plant tissues.
The polymers will entirely biodegrade if oxygen is present, which typically means that the microorganisms and the object being broken down are exposed to air. In the end, just carbon dioxide, water, and other living materials will remain.
Because it prolongs the life of the bacteria that break down the substance, oxygen is crucial. When there are enough microorganisms in hot, humid settings like damp leaves on the ground in a warm tropical forest, biodegradation typically occurs most quickly.
However, natural resources for polymers like polypropylene are scarce. The polymer linkages are not recognized by the enzymes in microorganisms that destroy biodegradable materials.
The polymers in discarded plastic may eventually degrade, possibly after hundreds of thousands of years. However, when anything takes so long, the ecosystem has already been harmed. Plastic waste can emit toxic compounds into the air, water, and soil, or it can shatter into tiny pieces that fish, birds, and animals consume it.
Organic materials need air, water, light, or a combination of these things for microorganisms to function in order to breakdown them. By eliminating some or all of these components, biodegradation can be significantly slowed. Because of this, the National Archives' display of our Declaration of Independence, which was printed on parchment (thin animal skin), is kept under tight surveillance. It would biodegrade in the presence of air, water, and light.
Another illustration is the Dead Sea Scrolls. The scrolls were preserved in caves for two millennia and were made of biodegradable materials like papyrus and parchment. They rapidly started to decay after they were taken out of the caves.
What is this related to plastics? Can plastics biodegrade when exposed to air, water, and light? Are plastics biodegradable, in other words?
Regardless of the environment, certain plastics do not biodegrade in any appreciable way, while others do so very slowly if exposed to air, water, and light. Both types of plastic are best recycled or used for their stored energy.
The key point is that some plastics have been designed to biodegrade pretty quickly in a sizable composting facility that purposefully speeds up biodegradation in a tightly regulated environment with lots of air, water, and light. If left in the environment, these plastics will likewise eventually degrade but considerably more slowly because the environment does not "actively speed" biodegradation. But much like other biodegradable materials, they probably won't decompose in contemporary landfills, which essentially serve as garbage storage facilities and are built to slow down biodegradation.
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