Nitrocellulose Use Nitrocellulose Production process How to make nitrocellulose
Nitrocellulose: Nitrocellulose is white or slightly yellow cotton, soluble in acetone. Scientific name cellulose nitrate, formerly known as nitrocellulose, nitrocellulose. NC is a polymer. Its molecular weight is very large. Its molecular formula is C6H7O2(ONO2)a(OH)3-an, where a is the degree of esterification and n is the degree of polymerization.
Use of nitrocotton
Embedding agent for microscopy. Biopsies. Used as a binder in the electronics industry.
Nitrocotton is a white or slightly yellow amorphous solid with flock-like appearance, specific gravity 1.6, insoluble in water, easily soluble in alcohol, ether and ester solutions. Nitrocellulose is highly combustible and explosive, and its danger degree depends on the degree of nitrification. Nitrogen content above 12.5% is extremely dangerous, burning in case of fire. The eruption point is 180~185℃. It is safer with 25% water. When the temperature exceeds 40 ° C, it can accelerate its decomposition and spontaneous combustion, the detonation speed is 6300m/s, and the nitrogen content is less than 12.5%, although it is relatively stable, but it is heated or stored for a long time, due to the gradual decomposition and release acid, reduce the ignition point, and it is easy to spontaneously ignite or explode. To prevent decomposition, stabilizers are often added to avoid explosion.
Nitrocotton is a class I flammable goods, explosives, must be stored in a special standard storage room, away from light storage, room temperature shall not exceed 28 ° C, not less than 1 ° C. The quality of nitrocellulose requires strict acidity, acidity (H2SO4) should be less than 0.05%, to prevent spontaneous combustion, in addition, nitrocellulose in the use, crushing, transportation process should pay attention to fire and explosion prevention. Nitrocellulose is mainly used in fireworks for spraying and burning agents.
Nitrocellulose is highly flammable and explosive, and its danger degree depends on the degree of nitrification. Nitrocellulose with nitrogen content above 12.5% is extremely dangerous and will burn in case of fire. When the temperature exceeds 40℃, it can accelerate its decomposition and spontaneous combustion. Nitrocotton with less than 12.5% nitrogen content is relatively stable, but when heated or stored for a long time, it gradually decomposes and releases acid, reduces the ignition point, and has the possibility of spontaneous combustion and explosion. In case of fire, it is strictly prohibited to use sand and other things to cover, so as to avoid explosion.
The production of nitrocotton
1, instruments, drugs: concentrated nitric acid, concentrated sulfuric acid, large grinding reagent bottle and grinding plug, glass rod, large tweezers, steel pot,
Sodium carbonate or bicarbonate, potassium nitrate, diphenylamine, alcohol, high-density polyethylene bottle, black plastic bag.
2, configuration of mixed acid: Add concentrated nitric acid in a large grinding reagent bottle: concentrated sulfuric acid = 1:3 ~4 (V/V), pay attention to the sulfuric acid into nitric acid,
Avoid sputtering. After mixing, stir the bottle gently with a glass rod or shake it slightly. Cover with ground glass stopper and cool to room temperature.
3, nitrification: the absorbent cotton nitrocellulose or paper is immersed in the mixed acid, at the same time, the air bubble is squeezed out with a glass rod, and finally the acid layer is left in the bottle (the nitrated substance is not exposed to the surface of the acid), and the reaction is 20 minutes at room temperature.
4, cleaning: large tweezers take out nitrocellulose, rinse with large water until you can't smell the sour taste.
5. Stability treatment: Put the washed nitrocellulose into dilute sodium carbonate solution for 20 to 30 minutes, and keep the solution alkaline.
Remove and rinse until neutral or slightly alkaline. Let dry and then immerse in 2% potassium nitrate solution, remove and dry, then immerse in 2% diphenylamine alcohol solution, remove and dry.
6, storage: into high-density polyethylene bottle (that is, the 500g capacity bottle that usually holds solid chemicals),
Cover the outside with black plastic bag (nitric acid packaging bottle), dry, cool store, can also put in the refrigerator freezer (do not put in the freezer,
Low temperature will cause fiber breakage, and deflagration will occur when ignited), good quality nitrocellulose can be stored in the refrigerator for several years.
7, burning rate: dry nitrocellulose is the highest, followed by paper, nitrocellulose toilet paper burning rate is slightly higher than black powder, can be used as a fuse.
8, quality identification: ignited, strong cotton will only leave trace residue, no sour taste. Since the nitrocellulose will decompose itself, it is necessary to check the deterioration status regularly when stored for a long time, you can take a small amount of nitrocellulose and smell the acidity of the smoke after combustion. If there is a strong irritating sour taste, the quality is not good, and yellowing is also a sign of deterioration, but slight yellowing does not affect the use and preservation.
9, ignition: the fifth battery and the spring in the ballpoint pen can ignite the nitrocellulose in 5 seconds, the cotton and hemp rope dried after soaking in potassium nitrate solution, incense, lighted sticks, and pay attention not to burn the hand when lit with a lighter or match.
10, use: magic, is an important raw material of firepaper, due to the propulsion force is much greater than black powder, and easy to ignite, can promote 10mm below the metal projectile. Because of the fast burning speed and high pressure, it is not suitable for fireworks. Good quality nitrocellulose burns very fast.
Is nitrocotton dangerous
Dangerous characteristics: spontaneous combustion point 170℃. Flash point 12.78 ° C. Detonation speed: 6300m/s(13% nitrogen). The volume of detonation gas is 841L/kg(13.3% nitrogen). This product will burn and explode when it encounters Mars, high temperatures, oxidants and most organic amines (p-phenyldimethylamine, etc.). If the temperature exceeds 40℃, it can decompose and spontaneously ignite. This product dry long storage deterioration, easy to cause spontaneous combustion, generally add water or ethanol as wetting agent. If the warming agent volatilizes, it is easy to fire. The nitrogen content below 12.5% is a grade I flammable solid.
Fire protection measures: Use water or mist to extinguish the fire. It is strictly forbidden to cover with sand to avoid violent explosion.
First aid: The patient should leave the scene immediately, be placed in a place with fresh air, and wash the injured with water. Severe cases should be sent to the hospital immediately.
Storage and transportation notice: Packaging mark: (nitrogen content less than 12.5%) flammable solid. (more than 12.5% nitrogen content) explosives. Packing method: Glass bottle, external wooden box, padded with non-combustible soft material. Or a metal bucket or can lined with a plastic bag. Storage and transportation conditions: Store in cool, ventilated warehouse, warehouse temperature should not exceed 30℃, away from fire and heat sources. Isolated from organic amines and oxidants. Storage and transportation period must master first-in-first-out, packaging damage to timely repair. The drying condition of the wetting agent should be checked frequently, and the wetting agent should be increased if necessary. In order to evenly distribute moisture, the package can be inverted after a certain period of storage (such as 5 months) (except for reagents), and then adjusted after a period of time. Handle with care to prevent damage to the package.