Combustion of Nitrocellulose: Combustion of Nitrocellulose A modified form of cotton burns quickly
leaving little residue
Purpose: Purpose To observe a rapid combustion reaction
To compare the combustion of untreated cotton with treated cotton
Demonstration: Demonstration The combustion reaction was extremely rapid, leaving little residue
Concepts: Concepts 1. Polymers
2. Polymer Modification
3. Nitration
4. Flash Point
1. Polymers: 1. Polymers Polymers are huge molecules
molecular weights in 10,000X
composed of monomer units
many are found naturally
cotton
wool
DNA
many are synthetically produced
plastics
nylon
In this demonstration the polymer used is cotton
2. Polymer Modification: 2. Polymer Modification Cotton is a polymer made of hundreds of glucose units attached sequentially to each other
For this demonstration cotton was nitrated using a mixture of sulfuric and nitric acid to give the nitrocellulose Glu -Glu -Glu -Glu -Glu -Glu -Glu -Glu -etc -Glu
3. Nitration Reactions: 3. Nitration Reactions Nitration is a common reaction for organic (carbon) compounds
A nitro group is added to a molecule simply by treating it with sulfuric and nitric acid
molecule
In this demonstration cotton was nitrated to give nitrocellulose
4. Flash Point: 4. Flash Point Flash Point is the temperature to which a compound must be heated before it will ignite by a flame in the presence of air
flash point of gasoline is -45 degrees Celsius
flash point of motor oil is 232 degrees Celsius
flash point of nitrocellulose is 4 degrees Celsius
Conclusions: Conclusions Cotton had been treated in order to nitrate it
The modified cotton burned extremely fast
Comments: Comments Guncotton has applications in
explosives and propellants
Guncotton is soluble in alcohol and ether and may be used to cast films and coatings