What are Plastic Bags Made Of?
Plastic take aeons to decompose. But this much you know – the question you have today is – what are plastic bags made of that they take so long to decompose? Well, they are made from a polymer called polyethene.
The material starts as ethylene (a natural gas extract). It undergoes through processing and treatment to convert it to a polymer which is long chains of hydrogen and carbon atoms. The chains formed vary depending on the kind of polyethene used. Also, because of the difference in material, there are different types of plastics as well.
The general plastics
We’ve mentioned that plastic bags are made from polymers. Now polymers are large and easy to create because they are made from molecular patterns created by monomers. In the case of plastic bags, the repeating patterns are ethylene.
Ethylene undergoes a chemical transformation through a series of treatments and becomes polyethene which is the basic building block of plastic bags. Polyethene has long winding chains of carbon that are bonded and interlaced with hydrogen atoms. Because of this repeating structure, plastic is easy to manipulate into different densities and structures.
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The source of the polyethene varies greatly. However, the most common source is a fossil fuel. Because of this, natural gas and petroleum are the most common sources and ingredients of plastic bags. When the two are properly refined, they make ethylene which is later turned into polyethene.
With that said, we should point out that most manufacturers love using natural gas to petroleum.
HPDE is an acronym for high-density polyethene. It is the most common polyethene and is used in making shopping bags. The plastic created from straight molecule chains that have very little branches and stay linear from start to finish. This linear structure is the source of the strength of the plastic. This is the reason a regular plastic bag is light but can carry several times its weight without tearing.
Unlike HPDE, this type of plastic is made from low-density branching polymer chains. The polyethene chains, instead of being linear spread out numerous times and form a lot of different lines. This makes them super light and feels like a thin film of plastic used to make the tear away bags that the dry cleaners usually use to wrap the clothes they clean.
This is linearly low-density polyethene. The plastic does not branch. It also does not have the same strength as other HDPE plastic versions. Because of this, al plastic bags that are made from LLDPE need to be heavier and thicker than normal grocery bags. An example of these plastic bags is the shiny bags that are found in clothing stores.
What else do you need to know?
Now, while plastic is convenient and readily available, it takes ages to decompose. But on the bright side, you can recycle plastic to reduce pollution and help save the environment. As for manufacturers, instead of them recycling the plastic bags into new plastic bags, they use old plastic bags to make composite lumber and other useful synthetic material.
Speaking of pollution, though plastic takes ages to decompose, its manufacturing process uses 70% less energy and releases less gas, unlike regular paper bag production.