Physical Properties

  • Amorphous Density: 0.85 g/cm3 [1]
    • Crystalline Density: 0.95 g/cm[2]
    • Melting Point of 320°F (160°C)
    • Doesn’t Soak up water (good for uses around moisture)

Chemical Properties

  • Very strong against corrosion; doesn’t react with chemicals like alkaline substances, acids, etc.
  • Low flammability
  • Poor UV resistance

Structural Formula

Functional Groups

  • Polypropylene contains a carbon backbone with only Carbon to Carbon Bonds and Carbon to Hydrogen bonds
  • The bonds look like the following:

C-C                   C-H

  • Contains methyl groups as well (CH3)

Chemical Production Process

  • Tin Chloride (TiCl3) acts as a catalyst and is added to a hydrocarbon solvent
  • Propylene is polymerized. Pressure is 10 kgf/cm and the temperature is between 60°C and 80°C.
  • The catalyst is broken down using methanol and the polymer is washed. Polypropylene is then separated from the solvent


  • food packaging,
  • textiles
  • reusable containers (high m.p. allows them to go in the dishwasher)
  • thermal pants and shirts made for the military
  • laboratory equipment,
  • Loudspeakers
  • automotive components

History of Polypropylene

  • Was discovered by Paul Hogan and Robert L. Banks in 1951
  • In an attempt to make dimers and trimers of ethylene and propylene (with a chromium oxide catalyst) for gasoline use, they accidentally produced some crystalline polypropylene and linear polypropylene
  • Process was patented by Phillips Petroleum at the beginning of 1953

Environmental Implications of Polypropylene

Polypropylene is a polymer that can be both used as a structural fabric and as a fibre. Because polypropylene has the ability to be broken down in the environment easily, scientists have discovered a way to create an environmentally friendly plastic bag. This plastic product is known as a non woven polypropylene. These bags are accepted by recycling plants and centres because they are easily broken down, and are very cheap to manufacture. These bags are being shipped to grocery stores, where most of our plastic bags are found. The physical properties of PP allow it to be strong enough to be used as a daily shopping bag.

This non woven polypropylene is helping to encourage and promote a clean environment for us to live in, and shows that there are multi-purpose alternative to the highly polluting plastic bags we’re all come accustomed to.

Works Cited

DeLaney, D. E., & Reilly, J. E. (1998). A new approach to polymer rheology for process and quality control.: An article from: Plastics Engineering. Texas: Society Of Plastics Engineers, Inc..

Harrison, K. (n.d.). Polypropylene, What is Polypropylene? About its Science, Chemistry and Structure. Chemistry, Structures & 3D Molecules @ – Home. Retrieved April 5, 2010, from

Lim, H. (2009, December 30). Using Non Woven Polypropylene For an Environment Friendly Bag. EzineArticles Submission – Submit Your Best Quality Original Articles For Massive Exposure, Ezine Publishers Get 25 Free Article Reprints. Retrieved April 5, 2010, from

Morris, P. J. (2005). Polymer Pioneers: A Popular History of the Science and Technology of Large Molecules (Center for History of Chemistry, No 5). NA: Chemical Heritage Foundation.

Plastipedia – Polypropylene PP. (n.d.). British Plastics Federation – The UK’s Leading Plastics Trade Association. Retrieved April 5, 2010, from

Polypropylene. (n.d.). Water Treatment and Purification – Lenntech. Retrieved April 5, 2010, from

[1] Amorphous density means to have no defined shape, or an easily altered shape; this means that polypropylene would be a liquid for this density to be measured

[2] Crystalline density occurs when the polymer has a regular, defined pattern, which would occur when polypropylene is

author avatar
William Anderson (Schoolworkhelper Editorial Team)
William completed his Bachelor of Science and Master of Arts in 2013. He current serves as a lecturer, tutor and freelance writer. In his spare time, he enjoys reading, walking his dog and parasailing. Article last reviewed: 2022 | St. Rosemary Institution © 2010-2024 | Creative Commons 4.0


  1. Plastic is made from crude oil, so it can be broken down to liquid hydrocarbons. Which hydrocarbons would be dependence on the plastic type and process used; polypropylene (5) is simply a synthetic polymer..when trying to break it down, you would want to get it down to its smaller unit..a propylene monomer. Then hopefully these liquid hydrocarbon monomers can be recycled and re-used..however polypropylene is often not recycled, due to cost and sorting.

  2. as part of our year 8 exams, We are doing a project about environmentally friendly alternatives.
    I have chosen to do the difference between polypropylene nonwoven shopping bags and paper shopping bags.
    I understand that the polypropylene bags can be recycled but I need to find out what the polypropylene shopping bags break down to. can you help?


Leave a Reply

Your email address will not be published. Required fields are marked *

Post comment