Nitrocellulose

Nitrocellulose, also known as cellulose nitrate, is a nitrate ester derivative of cellulose. It is a polymer formed when a fraction of the hydroxyl groups in the glucose units of cellulose are replaced by nitro groups. The resulting material has varying nitrogen content and solubility depending on the degree of substitution. A common representation is (C6H7O2(ONO2))n, with typical nitrogen contents in the 11–13% range for many applications.

Production involves nitrating purified cellulose with a mixture of concentrated sulfuric and nitric acids under controlled temperature and time. The reaction mixture is then quenched in water to stop further reaction, thoroughly washed to remove acids, and dried. The product can be processed into soluble grades for coatings and lacquers or dried to form insoluble, flexible films. Plasticizers are often added to tailor properties such as hardness and elasticity.

Uses are diverse. Nitrocellulose has long been used as a propellant and in smokeless powder due to its energetic nitro groups. It has also served as a fundamental component in early collodions for photography, in nitrocellulose lacquers and varnishes, and in some nail polishes and printing inks. In film history, nitrocellulose film (nitrate film) was widely used before being largely replaced by safer cellulose esters.

Properties and forms vary with nitration level. Soluble nitrocellulose yields viscous solutions for coatings and adhesives, while higher-nitrogen grades form hard or flexible films when plasticized. The material is highly flammable and can be sensitive to heat, friction, and impact, requiring careful handling and storage.

Safety and regulation reflect its explosive potential. It is typically stored in cool, dry, ventilated areas away from oxidizers and ignition sources, with strict controls on aging, disposal, and use.