Polypropylene (PP)

Photograph by Horia Andrei Varlan (2008). Many colored straws thrown on top of each other. Retrieved from https://www.flickr.com/photos/horiavarlan/4273847392/in/photolist-7vEzW1-R7r6Lu-VQCK71-kibyKR-9xHTRD-nuc5Sp-7uovh4-rgam52-2brNJGD-QvLkYZ-VEaj9N-ny8Jq-VEahoo-9xLSZs-MGkDKD-2amBuTE-ochuEh-VHrRvK-SvTgvM-Hf7g21-TVFtXV-2Zs9VR-VUSM3V-9xHTDk-b9iZNB-8ziPUT-d8yjH3-b9iUMV-ekDM3T-be5AAF-23EBfPV-PjktSj-99uVjB-bDKV2J-d5T4Tq-4yjdpB-6kvtdc-JjAMPF-8d1Pdk-9bKNH3-2ddHYg7-b9iYBD-VHrPoP-UFmn1v-2d8nWpm-maQJt-d5T46o-f6YXP-be5AAD-UCoTEG

Link to the licence: https://creativecommons.org/licenses/by/2.0/

Your mom drives you to the doctors, for your flu shot and on your way back home, decides to stop at a restaurant for lunch. You get the left-over spaghetti to-go and finish the rest of your drink, before leaving. For dinner, you decide to finish up the rest of the spaghetti, so you transfer it from the to-go container, into a plastic bowl which you place in the microwave and hit start.  What if I told you there was one chemical which constantly accompanied you all day, until you fell asleep? 

This chemical is called polypropylene, or PP for short. It’s made from multiple units (poly) of propylene, and has the formula (C₃H₆)_n, where n refers to the number of times propylene molecule is repeated. It is resistant to heat, abrasion, bacteria and fungi; however, it can be broken down by UV radiation (sunlight) ¹. 

Polypropylene is found in textile fibers like carpet, rope, blanket, twine, fishing nets, as well as in plastics. Companies like Rubbermaid and Sterilite use PP in their plastic containers; most kitchen ware (i.e: dishes and bowls) has polypropylene in it. Because it is cheap, and it can be sterilized, hospitals use it in medical tubing (i.e: IV tubes and plastic syringes); it’s also found in plastic straws and the battery cases for cars ². 

You might be thinking if Polypropylene is used in such a wide variety of materials, that means it’s 100% safe for human use. The truth is, there is no evidence suggesting it’s harmful to humans, or animals. This basically means, we don’t know whether PP is harmful to humans; maybe it is harmful and maybe it’s the safest material out there ³. 

Polypropylene is used in multiple industries because it’s cheap and it has a great combination of properties that make it extremely useful. More research is needed to determine how safe it is, but until there is a connection between negative health effects and polypropylene, it will continue to be a common part of our lives, one way or another.

 ¹"Polypropylene." In Chemical Compounds, edited by Neil Schlager, Jayne Weisblatt, and David E. Newton, 587-590. Vol. 2. Detroit, MI: UXL, 2006. Gale Virtual Reference Library.

²Narasimhan Calamur and Martin Carrera, “Propylene”,  in Kirk‐Othmer Encyclopedia of Chemical Technology20. 5th ed. (2005)

³"Hazardous Substances Data Bank (HSDB)." U.S. National Library of Medicine. March 5, 2003. Accessed January 28, 2019. https://toxnet.nlm.nih.gov/cgi-bin/sis/search2/r?dbs hsdb:@term @DOCNO 1069.