How is Plastic Made?

If there is one thing without which the modern world would be unimaginable, it is plastic. Present in everything from food packaging to automobile parts to cell phones, plastic has revolutionized how products are made. While plastic is cause for much environmental concern these days, its ubiquity is a testament to its versatility.

So what is plastic, and how is it made?

Broadly speaking, “plastic” is something of an umbrella term. There are forty-five unique types of plastic, and there are hundreds more variations of these, but whether it’s a plastic shopping bag or a the hard casing of a truck bed, all plastic comes from polymers made from carbon and hydrogen that are ultimately derived from natural gas, oil, coal, minerals, and plants.

The process for producing plastics, therefore, begins in refineries, where the vital ingredient in all plastics, naphtha, is separated out from crude oil.

The boiling point of naphtha is then exploited to produce the raw material for plastics: ethylene and propylene, which will be further processed to create high-molecular compounds, a process called “polymerization” which results in the creation of polyethylene and polypropylene.

The creation of polymers is a complex process, and one that relies on sophisticated heat exchanger technology to heat and cool polyethylene and polypropylene powders and pellets to the right temperature. You can click here if you want to see what heat exchanger technology can do to reduce emissions in the plastic making process.

These pellets and powders are the raw material for most of the plastics you will interact with in your day-to-day life, and their stability and highly portable form make them the ideal raw material. 

Both polyethylene and polypropylene are known as thermoplastics, or plastics that will revert to a liquid state if heated. There is another class of plastics, thermoset plastics, which does not — these plastics include common artistic materials like epoxy.

Once in thermoplastic form, polypropylene and polyethylene are then mixed with a variety of different chemical agents to create specific types of plastics like Polyethylene terephthalate or PET, the kind of plastic commonly found in water bottles and food storage containers. They can also be turned into Styrofoam or polyvinyl chloride, the compound used to create the durable PVC piping used by plumbers.  

One of the reasons thermoplastics are such a common feature of modern life is that, with modification from other chemicals and compounds, they can take on just about any form. And unlike other building materials like wood and stone, it is relatively easy and cheap to produce. .

While plastics are rightly viewed as the source for a large amount of environmental pollution, the truth is that modern life would be inconceivable without plastic, and the same scientific ingenuity that gave birth to plastic in the first place is now being used to develop biodegradable plastics and other, safer alternatives.

Love it or hate it, plastic is here to stay. Environmental efforts should focus on improving recycling programs, reducing waste, and making greener forms of plastic that can help us build a better world for tomorrow.