This month the Bank of Canada will be issuing the new $20 bill.  Just like the changes we saw earlier in the year with the $50 and $100 bills, this new $20 will be made from plastic. 

In this demonstration, I dip the bill into a solution of rubbing alcohol (70%) and water.  This makes for a great party trick – especially if you do it with larger denominations as people’s perception of the value that could be lost increases!  The cotton fibres absorb the water and stay cool because of the protective layer of water around them and the alcohol burns away.  If you try this, be aware that at a certain point the flames can evaporate the water and begin burning the paper bill.  When the alcohol flames start to die down, that is the moment when you should put out the fire.

This trick will not work with the new polymer notes.  They are made from a plastic polymer known as polypropylene.  Polypropylene is used to manufacture a wide variety of goods, including thermal underwear, ropes, carpets, and reusable containers.  It has a natural tendency to by hydrophobic (repels water) and so is excellent for use in products that need to be waterproof.  It is the water absorbing properties of the cotton fibres in the traditional $20 bill that allow this lighting-money-on-fire trick to work.  If you did this with a polymer note it would definitely damage the bill.

Many other countries have been using polymer notes for years.  Australia has been using polymer bank notes since the early 90s and many other countries have made the switch since then.  The Bank of Canada made the switch from paper to plastic notes to modernize our currency and crack down on counterfeiters.  These bills are laced with a multitude of security features, including two transparent windows with security features embedded into them.  Another advantage of using polymer notes is that they are estimated to last 2.5 times longer than paper, reducing the cost of manufacturing and replacement.  Subsequently, this will reduce the environmental impact of producing our currency.

As with all new products, there is some skepticism as to whether these bills will actually withstand the wear and tear of daily life.  The concern is that these plastic notes will melt if accidentally sent through the dryer or left sitting out on a car dashboard in the direct sunlight.  The Bank of Canada states that they have put these bills to the test, exposing them to extremely hot temperatures (140°C) and extreme cold (-75°C).  Many other countries with hotter climates (Australia, Vietnam, Mexico) have been using polymer notes for years without any melting bills.  The chemistry behind these bills doesn’t lie – polypropylene has a melting point between 130°C and 170°C, temperatures that this money will probably never be exposed to under normal conditions.

For more information on the new $20 bill visit the Bank of Canada’s website:
http://www.bankofcanada.ca/banknotes/bank-note-series/polymer/