Nitrocellulose, also known as cellulose nitrate, is a cellulose nitrate ester derived from natural cotton cellulose through nitration. It boasts advantages such as abundant raw materials, high combustion heat value, and a high volume of combustion products, which are smokeless, non-toxic, odorless, and residue-free.
Cellulose nitrate, also known as nitrocellulose, is a cellulose derivative obtained by esterification of some hydroxyl groups in cellulose with nitric acid. What is the raw material of nitrocellulose? Nitrocellulose, a derivative of cellulose formed by esterification of some hydroxyl groups in cellulose with nitric acid, has several names including nitrocellulose, cellulose nitrate, and common names such as gun cotton, flash cotton, and nitrocellulose fiber, although these are considered incorrect. Cellulose nitrate plastics are created by adding about 20% camphor as a plasticizer to nitrocellulose, resulting in a plastic material commonly known as celluloid.
Nitrocellulose esters were invented in 1833, and a stable form was developed in 1846. Its application in coatings began in 1880 and became commercially viable by 1920. Due to its fast-drying properties, nitrocellulose quickly replaced slower-drying varnishes. Although nitrocellulose alone can form a coating, it tends to become brittle and yellow over time, reducing its usability. Modifications using alkyds, polyesters, natural resins, or plasticizers have improved the toughness and other properties of the coating film, minimizing yellowing and expanding nitrocellulose coatings into a significant category of coatings.
Can nitrocellulose be used as gunpowder? In the military sector, nitrocellulose is frequently used in the firing and propulsion of weapons systems such as guns, cannons, rockets, and missiles, as well as in ignition charges during weapon launches. In the fireworks' industry, black powder, a basic explosive charge, accounts for over 30% of the total charge, and sometimes more than 50%. However, black powder generates substantial particulate matter during combustion, mainly potassium sulfide, potassium sulfate, potassium carbonate, and potassium hydroxide, which can create aerosols in humid conditions and contribute to thick smoke, adversely affecting the visual appeal of fireworks and causing environmental pollution. Industrial nitrocellulose, with its clean combustion products, high energy, and low sensitivity, offers a promising alternative to black powder in fireworks. It is more cost-effective and easier to transport compared to military-grade nitrocellulose.
What is nitrocellulose used as in gunpowder? Nitrocellulose began to be used in gunpowder production in the 1860s. Early use was marked by several catastrophic explosions due to inadequate understanding of nitrocellulose's stability and the potential for self-catalytic decomposition. Nitrocellulose detonation velocity between 6000 and 8000 meters per second (m/s), with research indicating that nitrocellulose and nitroglycerin-based explosive compositions can reach explosion velocities up to 17,000 feet per second. In 1868, Sir Frederick Augustus Abel highlighted that incomplete washing after nitration could cause instability due to residual acid. By the 1880s, French engineer Paul Vieille developed the first reliable propellant, smokeless powder, by adding special stabilizers to nitrocellulose, neutralizing catalytic decomposition products and marking a significant advancement in explosive technology.
In industrial applications, nitrocellulose is used in spray paints, inks, artificial leather, photographic film, cosmetics, and as a smokeless propellant in fireworks. Nail polish contains nitrocellulose due to its low cost, fast-drying properties, and ability to form a hard film that does not harm the skin.
In the mid-19th century, British photographer Frederick Scott Archer invented the wet plate collodion process, which laid the groundwork for photographic technology. This process involved applying a nitrocellulose solution to glass plates to form a light-sensitive layer. After exposure, chemicals like silver nitrate were used for development and fixation, producing images. Pyrogallic acid was later added and replaced by potassium cyanide.
In flexographic printing, nitrocellulose is commonly used as a base for inks. When mixed with solvents such as n-propanol and propyl acetate, it forms a viscous ink that adheres strongly to various printing surfaces. Nitrocellulose inks are valued for their fast drying, strong adhesion, and vivid colors, making them widely used in packaging and label printing.
Celluloid, the first synthetic plastic material, originated in the 1860s and 1870s by mixing nitrocellulose with camphor to create a uniform colloidal dispersion. As a strong, flexible, and highly plastic material, celluloid exhibits excellent waterproof, oil-resistant, and dilute acid-resistant properties, allowing for the production of various colors at low cost. It was widely used in personal care items, crafts, photographic film, and other mass-produced products. By the mid-20th century, the use of celluloid declined with the advent of new synthetic polymers.
Routes of Exposure: Inhalation.
Health Hazards: Nitrocellulose itself is generally harmless to health.
Dangerous Characteristics: The substance is prone to spontaneous combustion in air and can easily ignite and explode upon contact with flames or high temperatures. It may react violently with oxidizers and most organic amines, leading to combustion or explosions. Typically, ethanol, acetone, or water is used as a wetting agent, but once the wetting agent evaporates, it can lead to fire hazards.
Combustion (Decomposition) Products: Carbon monoxide, carbon dioxide, nitrogen oxides.
Engineering Controls: Enclosed operations, local ventilation.
Respiratory Protection: Wear dust masks in high concentrations.
Eye Protection: Wear safety goggles.
Protective Clothing: Wear work clothes.
Hand Protection: Wear protective gloves if necessary.
Other: Prohibit smoking, eating, and drinking in the work area. Shower and change clothes after work. Maintain personal cleanliness.
Skin Contact: Rinse with flowing water.
Eye Contact: Rinse with flowing water.
Inhalation: Remove from the site.
Firefighting Methods: Use misted water, carbon dioxide, foam, or sand.
Use glass bottles, metal barrels, or cans, lined with plastic bags for packaging. Packaging materials should contain at least 25% wetting agents (e.g., water, ethanol, isopropanol, butanol) to enhance stability. Labels should clearly indicate flammable solid (ammonium content below 12.5%) or explosive (nitrogen content above 12.5%). Containers with nitrocellulose must be tightly sealed to prevent evaporation of alcohols and direct sunlight, which could cause nitrocellulose to dry out. Handle carefully to avoid damage to packaging. Storage conditions should be in a cool, well-ventilated warehouse with temperatures below 30°C, away from flames and heat sources. Additionally, store and transport separately from organic amines and oxidizers.
[1]Liu Guojie, Fan Sen. Analysis on the application status and development trend of nitrocellulose in coatings industry[J]. China Coatings, 2014, 29(2): 7-12. DOI:10.3969/j.issn.1006-2556.2014.02.004.
[2]https://zh.wikipedia.org/wiki/%E7%A1%9D%E9%85%B8%E7%BA%A4%E7%BB%B4%E7%B4%A0
[3]https://baike.baidu.com/item/%E7%A1%9D%E5%8C%96%E7%BA%A4%E7%BB%B4%E7%B4%A0
[4]https://www.britannica.com/technology/celluloid
[5]https://patents.google.com/patent/US3668027A/en
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