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Nitrocellulose is the same chemical ping pong balls, fingernail polish, guitar picks, and fine wood varnish is made of. It is also the primary chemical in smokeless gunpowder. The raw cotton form, known as flash cotton or gun cotton, is used for magic tricks and small special effects. It also has a number of uses in the production of fireworks.
As you will see in the following video, nitrocellulose has a fairly unusual property to be able to ignite on an open hand without passing enough heat to the skin to leave a burn. This can only be done if the nitrocellulose has been very well made or it will burn too slowly and the heat will be in contact with the skin long enough to cause damage. Needless to say, I do not recommend trying this for yourself:
As you will see in the following video, nitrocellulose has a fairly unusual property to be able to ignite on an open hand without passing enough heat to the skin to leave a burn. This can only be done if the nitrocellulose has been very well made or it will burn too slowly and the heat will be in contact with the skin long enough to cause damage. Needless to say, I do not recommend trying this for yourself:
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Nitrocellulose is a nitrated form of cotton made by submersion in nitric acid. Sulfuric acid is typically used to stabilize the reaction and the resulting nitrocellulose. There are several processes to achieve the same end result. The first is to simply form a solution of concentrated nitric and sulfuric acid straight from the bottle to then use as a nitrating bath. A second process, and the one I most often use, is to nitrate the cotton with a solution of potassium or ammonium nitrate and sulfuric acid. The nitrate forms nitric acid when introduced to sulfuric acid, skipping the intermediary step of distilling pure nitric acid. This is the process I will be describing here.
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40 mL sulfuric acid (~95% conc.) is measured into a beaker, and 25 grams of potassium nitrate dissolved into it. The nitrate will be difficult to dissolve, but it can be done with much stirring. At this point the solution will begin to evolve clear acid vapor which should be avoided.
The beaker is then placed into an ice salt bath and let cool down to temperature. The salt will allow the water to cool to a lower temperature than if it were filled with ice alone.
4 cotton balls (~2.5g) are then added to the beaker, and worked into the solution with a stir rod or spoon. This may be difficult because the solution will have turned syrupy from the cold. A step that may be taken which will make the nitrocellulose easier to work with later, is to unroll the cotton balls before adding them to the nitrating bath. When the cotton is well worked in, the reaction is left to sit for a half hour. When that time is up, the beaker is removed from the ice salt bath and left at air temperature.
Another 10-15 mL sulfuric acid is added and the cotton is well worked over again with the stir rod. Any hard knots felt in the cotton must be worked with the rod to allow access to the solution. The beaker is then left to sit for an hour or more.
At this point the cotton is removed and placed in water. It must be washed several times with water to remove most of the acid within them. When washed as well as possible, the cotton is then placed into a sodium bicarbonate (baking soda) solution and worked with the hands until no more bubbles form. It may have to be washed with bicarb several times to fully neutralize. Several more washes with water to remove excess bicarb and the nitrocellulose is complete.
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40 mL sulfuric acid (~95% conc.) is measured into a beaker, and 25 grams of potassium nitrate dissolved into it. The nitrate will be difficult to dissolve, but it can be done with much stirring. At this point the solution will begin to evolve clear acid vapor which should be avoided.
The beaker is then placed into an ice salt bath and let cool down to temperature. The salt will allow the water to cool to a lower temperature than if it were filled with ice alone.
4 cotton balls (~2.5g) are then added to the beaker, and worked into the solution with a stir rod or spoon. This may be difficult because the solution will have turned syrupy from the cold. A step that may be taken which will make the nitrocellulose easier to work with later, is to unroll the cotton balls before adding them to the nitrating bath. When the cotton is well worked in, the reaction is left to sit for a half hour. When that time is up, the beaker is removed from the ice salt bath and left at air temperature.
Another 10-15 mL sulfuric acid is added and the cotton is well worked over again with the stir rod. Any hard knots felt in the cotton must be worked with the rod to allow access to the solution. The beaker is then left to sit for an hour or more.
At this point the cotton is removed and placed in water. It must be washed several times with water to remove most of the acid within them. When washed as well as possible, the cotton is then placed into a sodium bicarbonate (baking soda) solution and worked with the hands until no more bubbles form. It may have to be washed with bicarb several times to fully neutralize. Several more washes with water to remove excess bicarb and the nitrocellulose is complete.
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I am curious if you are familiar with 'the rest of the story' about Nitrocellulose? Why it was first created, by whom, and what can be done with Methyl Ethyl Ketones? I discovered this process when I was in high school (35 years ago) and had several 'colorful' moments in the high school chem lab. Anyway, very interesting history on NC. Great instructible, very good teaching skills.
Chris
check this!