Paper Bags or Plastic Bags? Everything You Need to Know


How are plastic bags made?
Unlike paper bags, plastic bags are typically made from oil, a non-renewable resource. Plastics are a by-product of the oil-refining process, accounting for about four percent of oil production around the globe. The biggest energy input is from the plastic bag creation process is electricity, which, in this country, comes from coal-burning power plants at least half of the time; the process requires enough juice to heat the oil up to 750 degrees Fahrenheit, where it can be separated into its various components and molded into polymers. Plastic bags most often come from one of the five types of polymers -- polyethylene -- in its low-density form (LDPE), which is also known as #4 plastic.

How does plastic bag recycling work?
Like paper, plastic can be recycled, but it isn't simple or easy. Recycling involves essentially re-melting the bags and re-casting the plastic, though, according to the U.S. EPA, manufacturing new plastic from recycled plastic requires two-thirds of the energy used in virgin plastic manufacturing. But, as any chef who has ever tried to re-heat a Hollondaise sauce will tell you, the quality isn't quite as good the second time around; the polymer chains often separate break (thanks to reader MaryBeth for noting the difference between "separate" and "break" -- the former implies that the chains can come back together, which they can't), leading to a lower-quality product.

What does that mean to you? Basically, plastic is often downcycled -- that is, the material loses viability and/or value in the process of recycling -- into less functional forms, making it hard to make new plastic bags out of old plastic bags.

Up next: But what about biodegradable plastic bags?

Tags: Biodegradable | Bioplastics | Green Basics | Plastic Bags | Reusability | Shopping