Colloдиon, fleксиble, химические свойства, назначение, производство
Химические свойства
Nitrocellulose is a pulpy, cotton-like solid, or
a colorless liquid solution.
Использование
Nitrocellulose is used as a propellant in artillery ammunition, in small-arms ammunition, in chemical explosives, and in smokeless powder. It is made by reacting cotton with nitric acid.
Подготовка
Cellulose nitrate is prepared according to the following reaction:
C6H10O5+HNO3-->[-C6H7O2(OH)(ONO2)2-]n
The nitrogen content for plastics is usually about 11%, for lacquers and cement base it is 12%, and for explosives it is 13%. The standard plasticizer added is camphor.
Key properties of cellulose nitrate are good dimensional stability, low water absorption, and toughness. Its disadvantages are its flammability and lack of stability to heat and sunlight.
Определение
cellulose nitrate: A highly flammablematerial made by treating cellulose(wood pulp) with concentratednitric acid. Despite the alternativename nitrocellulose, the compound isin fact an ester (containing CONO2groups), not a nitro compound(which would contain C–NO2). It isused in explosives (as guncotton) andcelluloid.
Общее описание
Pale yellow syrupy liquid with an ether-like odor. Floats on water. Produces an irritating vapor. Immiscible with water. Boiling point is around 94°F.
Реакции воздуха и воды
Highly flammable. Insoluble in water.
Профиль реактивности
Nitrocellulose is a solution of pyroxylin in ether and alcohol with a flash point of approximately 0°F.
Опасность
Flammable, dangerous fire and explosion
risk. Somewhat less flammable when wet.
Угроза здоровью
High concentration of ether fumes may cause narcosis, loss of consciousness and respiratory paralysis if inhaled. Contact with eyes causes irritation.
Пожароопасность
Nitrocellulose is a white fibrous solid or amorphous powder. It is wetted with water, alcohol, or other solvent for handling and storage. It may be made to various forms, gel, flake, granular, or powder. Dry material is a low explosive and often used in combination with another explosive, such as nitroglycerine, to obtain more brisance for the composition. Dry nitrocellulose does not detonate but deflagrates. When wetted with water or alcohol, its sensitivity is considerably reduced.
Nitrocellulose presents three types of hazards. As mentioned earlier, it is an explosive compound. It explodes upon burning or friction. It is a flammable solid having a flash point of 13°C (55 °F). It can therefore ignite at ambient temperatures, thus presenting a severe fire and explosion hazard. It burns at a very rapid rate. The combustion products consist of extremely toxic gases: notably, hydrogen cyanide, carbon monoxide, and oxides of nitrogen.
Fires involving nitrocellulose should be fought with extreme caution. Unmanned fixed turrets and hose nozzles should be used. Since nitrocellulose produces oxygen on decomposition, a large volume of water should be applied through spray nozzles to cool the material and wet the entire surface. Self-contained breathing apparatus must be worn by firefighters for protection against highly toxic gases.
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Сельскохозяйственное использование
Cellulose nitrate is a highly flammable material made by
treating cellulose (wood pulp) with a mixture of
concentrated nitric acid and concentrated sulphuric acid.
Despite the alternative name, nitrocellulose, cellulose
nitrate is an ester of cellulose containing -ONO2 groups
and is not a nitro compound. It is used in explosives and
celluloid.
Промышленное использование
Cellulose nitrates are materials made by treatingcellulose with a mixture of nitric and sulfuricacids, washing free of acid, bleaching,stabilizing, and dehydrating. For sheets, rods, and tubes it is mixed with plasticizers and pigmentsand rolled or drawn to the shape desired.The lower nitrates are very inflammable, butthey do not explode like the high nitrates, andthey are the ones used for plastics, rayons, andlacquers, although their use for clothing fabricsis restricted by law. The names cellulose nitrateand pyroxylin are used for the compounds oflower nitration, and the term nitrocellulose isused for the explosives.The outstanding toughness properties ofcellulose nitrate lead to its continuing use insuch applications as optical frames, shoe eyelets,ping pong balls, and pen barrels.
Профиль безопасности
Very low oral toxicity.
Flammable solid. Highly dangerous fire
hazard in the dry state when exposed to
heat, flame, or powerful oxidizers. When
wet with 35% of denatured ethanol it is
about as hazardous as ethanol alone or
gasoline. Dry cellulose tetranitrate burns
rapidly with intense heat and ignites easily.
Moderately dangerous explosion hazard. To
fight fire, use copious volumes of water;
alcohol foam. CO2 is effective in
extinguishing fires of nitrocellulose solvents.
See also EXPLOSIVES, HIGH.
Возможный контакт
It is used in making explosives, rocket
propellants and celluloid.
Экологическая судьба
The physicochemical properties of nitrocellulose limit dispersion
throughout the environment. In addition to those noted
earlier, the melting point of the solid is relatively high (between
169 and 170℃), the flash point is 12.8 ℃, and nitrocellulose
is nonvolatile. Nitrocellulose is insoluble in water, and thus is
not detected in high concentrations in water, and tends to stay
on sediments. Direct decomposition of nitrocellulose is
unlikely, as the degradation process needs a severe chemical
reaction like alkaline hydrolysis to break its beta 1 → 4-
glucoside units bond linkages.
Because of its particulate character, specific gravity, and
low solubility, nitrocellulose particles tend to accumulate in
sediments in aqueous systems. The settled particles are very
stable and resistant to degradation for long periods of time.
They appear to remain unchanged in the environment. Their
biodecomposition by microorganisms is also not likely. No
studies are available on their long-range transport.
хранилище
Nitrocellulose should be stored as a wetted substance and never allowed to go dry. Storage should be in a cool, well-entilated location isolated from all heat sources. Shipping should be in steel drums or barrels wet with 25-35% alcohol, water, or other solvent.
Перевозки
UN2555, UN2556 and UN2557 requires a shipping
label of “FLAMMABLE SOLID.” They fall in DOT
Hazard Class 4.1. UN0342 and UN0343 requires a shipping
label of “EXPLOSIVE.” They fall in DOT Hazard Class
1.3C.
Несовместимости
Dust and powder form explosive mixture
with air. Keep wet; do not allow to become dry. Dry material
is a shock-sensitive explosive. Desensitize using water
or alcohol. Incompatible with oxidizers (chlorates, nitrates,
peroxides, permanganates, perchlorates, chlorine, bromine,
fluorine, etc.); contact may cause fires or explosions. Keep
away from alkaline materials, strong bases, strong acids,
oxoacids, epoxides.
Colloдиon, fleксиble, препаратная продукция и сырье
сырьё
препарат