Before revision: Urea has been used for stabilizing celluloid in the 19th century (and even in early American military powders), but like other water-soluble bases, it also attacks nitrocellulose, so German chemists substituted hydrogen atoms with nonpolar organic radicals to diminish this URL
After revision: Urea has been used for stabilizing celluloid in the 19th century (and even in early American military powders), but like other water-soluble bases, it also attacks nitrocellulose, so German chemists substituted hydrogen atoms with nonpolar organic radicals to diminish this effect.