What is Plastic?

Plastic! What is it? Where does it come from? What is it actually made of? Let's find out!

The actual stuff of plastic comes from the oil and gas industry. In fact, your plastic grocery bag is made from byproducts of oil and natural gas refineries around the world. But wait for a second... how do oily gassy byproducts become the average plastic grocery bag? Well, to answer that, we're gonna have to go molecular.

The fossil fuels that are refined in oil and gas factories are made of carbon and hydrogen (hydrocarbon).

They're natural and found in every organism on the planet. When we take these hydrocarbons, subject them to some crazy heat, add chemicals, and do some tweaks here and there, funky stuff starts to happen to the carbon bonds. Meet ethylene.

Ethylene gas is a very stable hydrocarbon, but crank the heat way up, add a pinch of initiator and a dash of catalyst, and presto; you have broken apart the sturdy bond between the carbons and created a much more sociable ethylene that can hang out with each other in long chains.

And the chain goes on and on and on and on and on, creating polyethylene (which is just a fancy way of saying a chain of ethylene molecules).

As cool as the plastic is, we made this endless daisy chain of hydrogen and carbon in totally unnatural conditions and nature doesn't know what to do with it. That's why polyethylene in the ocean takes hundreds of years to break down and can cause a lot of damage if not disposed of or recycled properly.

So let's help the ocean out. Instead of using low-density polyethylene to carry your groceries, maybe try using a paper or cloth bag instead. Now you know!

So all plastics are the same? Wrong.

The 7 Plastic Types

Polyethylene terephthalate (or PET)

What is Polyethylene terephthalate (or PET)? Of the seven different plastic types, polypropylene is marked with a 5. PP stands for polypropylene and is also sometimes called polypro for short. Polypropylene has the highest hot fill point of the first six plastic types.

Polypropylene is often used for food packing because it will not melt in dishwashers or during industrial hot filling processes. It is also used for a wide variety of applications including containers, lids, ropes, thermal underwear, carpets, lab equipment, food packaging, speakers, auto parts, Rubik's cube stickers, and even money.

Polypropylene is also highly resistant to fatigue. It's not as tough as HDPE, but it is less brittle. That’s why most caps and closures are made of polypropylene, particularly those with moving parts.

High-density polyethylene (or HDPE)

What is High-density polyethylene (or HDPE)? HDPE can be pigmented or unpigmented. That means it comes in different colours. Uncolored HDPE is translucent, or “natural”, and is well suited for products with a short shelf life. Like milk. All-natural milk in all-natural HDPE.

HDPE has excellent resistance to most solvents, which makes it the go-to plastic type for detergents, cleaners, industrial chemicals, antifreeze and bleach. It’s also used extensively for less harsh products like shampoo, conditioner, motor oil and soaps.

HDPE is used in a lot of different products. Your breakfast of champions comes in a cereal box with an HDPE liner. You push your groceries around in an HDPE shopping cart. A lot of the items on the shelves come in HDPE. You may bring your groceries home in an HDPE grocery bag.

HDPE makes grocery shopping possible. Recycled HDPE is used to make pipe, buckets (hint, hint), flowerpots, plastic lumber for your deck, and recycling bins. Cool, huh? You can put the recyclable containers you want to recycle in a recycled recycling bin.

Polyvinyl chloride (or PVC)?

What is Polyvinyl chloride (or PVC)? Of the seven different plastic types, PVC is marked with a 3. PVC stands for polyvinyl chloride. Over the past couple of years, PVC has gotten a bad rap.

PVC comes in two forms: rigid and flexible. PVC is made flexible by additives called phthalates.

PVC is the third most commonly used plastic in the world. It's found in raincoats, shoes, credit cards, and laundry detergent containers.

Low-density polyethylene (or LDPE)?

What is Low-density polyethylene (or LDPE)? Of the seven different plastic types, LDPE is marked with a 4. LDPE is short for low-density polyethylene. Guess what HDPE and MDPE stand for? Yep. High and medium.

HDPE is not very squeezable. MDPE is medium squeezy. And LDPE is the squeeziest of all

LDPE is squeezy, but also incredibly flexible and tough almost to the point of being unbreakable. LDPE holds its own shape, that’s why it’s ideal for products that need a good squeeze.

You can use LDPE containers for sauces, lotions, creams, spreads, honey, eye drops, contact lens solution, shampoos and conditioners. It can also be translucent (or natural as we call it in the biz), coloured and opaque.

LDPE is used in a lot of different kinds of common household products. Bags for bread, dry cleaning, fresh produce, and trash cans are made of LDPE. It can also be used as a coating for paper milk cartons and some hot/cold beverage cups. Shipping envelopes and outdoor lumber are also made of LDPE.

LDPE, MDPE and HDPE are all polyethylene which is the most widely used plastic. Low, medium and high-density polyethylene are commonly recycled in most communities.

Polypropylene (or PP)?

What is Polypropylene (or PP)? Of the seven different plastic types, polypropylene is marked with a 5. PP stands for polypropylene and is also sometimes called polypro for short.

Polypropylene is also highly resistant to fatigue. It's not as tough as HDPE, but it is less brittle. That’s why most caps and closures, particularly those with moving parts, are made of polypropylene. I opened and closed this lid exactly 4,668 times before the hinge broke. Now that's tough.

Polystyrene (or PS)?

What is Polystyrene (or PS)? Polystyrene is also one of the clearest plastics on the market. Plus, it can withstand excruciating temperatures up to 200 degrees Fahrenheit. And that food you didn't finish at the restaurant? That's right, it's packaged in a polystyrene to-go container.

Although not as brittle as peanut brittle, and not as flexible as LDPE, polystyrene still shattered during our cinder block drop test. Due to their delicate nature, polystyrene containers may be scratched and scuffed during shipment.

You can find polystyrene in everyday items such as drinking straws, egg cartons, foam plates and cups, cutlery, CD cases and more. In its expanded foam form, polystyrene is used as styrofoam to protect products during transport.

OTHER Plastic?

What is OTHER? Of the seven different plastic types, OTHER is marked with a 7.

Some current plastics that are included in the OTHER category are: phenolic, acrylic, polylactide, polycarbonate, fiberglass, thermoplastic elastomers, styrene maleic anhydride, styrene-acrylonitrile, polyvinylidene fluoride, plus plenty more.