Nerdy about plastics
300 million tons of new plastic each year😮
Plastic has become an essential material of society. Its ubiquity and low cost has led to a disregard of its finite nature. Plastic shapes the consumer experience. The mold-able, durable, and cheap material enables companies to package and ship products around the world. However, the life of a plastic product is short. The consumer buys the product, uses the product one time, and disposes of it. But plastic does not go away or decompose.
Think of all of the toothbrushes (🪥), plastic bottles, and plastic bags that you have used in your lifetime. Almost every piece of plastic ever created still exists today. These products will represent the fossils of modern humans. When consumers dispose of plastic, it ends up in oceans, waterways, and communities, instead being re-purposed as recycled products. Plastic pollution negatively impacts many ecosystems, the environment, and public health at large. 🤒
What happens to plastic?
Recycling is not what it seems. Plastic, for the most part, can not be recycled, and when it can be recycled, it doesn’t mean it will be. In 2017, the United States Environmental Protection Agency (EPA) reported 8.4% of plastics disposed of were recycled in the U.S. In 2018, it was estimated that plastic recycling rates dropped to 4.4%. This was due to other countries (such as China in 2018) not accepting the US’s export of plastic, mainly because of the high contamination of plastic streams. After this halt on out-of-country exports, many municipalities were forced to divert this waste stream to landfills where it will take plastic over 500 years to decompose. 😞
Once the plastic is disposed of, it might be burned in incinerators (adding to emissions and increasing air pollution), left uncollected, and accumulated in the oceans. The plastic that is recycled doesn’t always end up in new products. When given the choice between new and recycled plastic, it’s cheaper for companies to produce new plastic products, leading to a low market for recycled plastic. ♻️
Plastic Types 101
There are two major categories of plastic: Thermoplastics and Thermoset.
Thermoset
Thermoset plastics contain polymers that cross-link together and create an irreversible bond. This means they can’t be remelted to make new plastic products once they take shape, they are solidified forever.
Thermoplastics
Thermoplastics is a plastic polymer which becomes soft when heated and hard when cooled. This material can be cooled and heated several times.
Thankfully, 80% of plastics in the world are thermoplastics (🎉) meaning they can be recycled and transformed. Thermoplastics are divided into further subcategories depending on their structure and properties. You can find the specific name or number usually printed or embossed somewhere on your plastic products.
Always Remember
Different plastic types should never be mixed together as this will decrease their quality drastically and make it very difficult to recycle them. Moreover, when different types of plastics are melted together they tend to phase-separate, like oil and water, and set in layers resulting in structural weakness and lower quality products.
All plastic types have different melting temperatures, it’s important to know at what temperature each plastic melts, as well as at what temperatures different types can be molded. You can find more about specific melting temperatures here.🌡️