Plastic Bottles
While plastic bottles are widely used because of their availability and durability, these same reasons are why plastic bottles have wreaked havoc on the environment.
Pictures like the one above have become a symbol for environmentalism in the 21st century. The chemistry of water bottles make them chemically resistant, durable and rigid. While these physical properties make plastics the perfect container, it also makes them an environmental nightmare.
Water bottles were first synthesized using the infamous chemical Bisphenol-A (BPA). BPA was used as a reagent to form plastics, however it was discovered that small amounts of it would dissolve, or leach, into the contents of the plastic container. When BPA is ingested, it mimics hormones within the body and can cause all sorts of health issues including liver failure and cancer. Today, plastic water bottles are synthesized from polyethylene terephthalate (PET). This familiar clear plastic can also take the form of clothing articles and tape. It is the choice plastic for bottles because it is safe, durable and rigid.
To form PET, a polymerization reaction occurs between two monomers: ethylene glycol and terephthalic acid. Each monomer has a set of functional groups on either side of the molecule. The term functional group is a fancy way to describe areas of reactivity on a molecule. The functional groups on ethylene glycol and terephthalic acid like to react with one and another and continue to do so to form a long chain - that chain is PET! As the plastic is created, it is often made into pellets which then are sent to water bottle manufacturers.
The PET pellets are mixed with recycled plastics and melted to enable manufactures to shape the PET into the classic plastic bottle shape. Unfortunately, typically only 50% of the plastic used in a water bottle can be recycled. During the recycling process, which involves harsh cleaning and melting processes, the PET chain is shortened as a result. Since the recycling process compromises the polymeric chain, the rigid and lightweight properties of the PET are also compromised. Virgin PET material is used in combination with recycled PET to maintain its integrity.
Hundreds of billions of water bottles are made each year, and the National Geographic has some truly shocking facts about recycling plastic water bottles I want to share. It takes 450 years for a plastic water bottle to decompose, yet in the US, which uses millions upon millions of plastic water bottles every year, only 30% of plastic water bottles are recycled. As a result, plastics are thrown away into landfills and oceans. Annually, over 1 million tons of plastic items like water bottles end up in the ocean. Think about how large that number is. This has created a floating island of plastic waste three times the size of France! These facts alone highlight the plastic waste crisis our world faces today and the desperate need for a chemical alternative to plastics.
But don’t abandon all hope just yet. Scientists and chemists around the world are racing to come up with ways to curb water bottle use and find more environmentally friendly alternatives. Biodegradable plastics and revamped recycling methods are examples of exciting research chemists are contributing to right now and just another example of how important chemistry is to our everyday lives.
https://www.nationalgeographic.com/environment/2019/08/plastic-bottles/#close
