Napalm is a highly flammable, gelled incendiary substance developed for use as a weapon. This sticky material is designed to burn intensely and adhere to targets, making it far more effective than liquid fuel alone. The manufacturing process evolved significantly over time, moving from an aluminum soap powder thickener to a synthetic polymer mixture.
The Initial Discovery and Composition (Napalm-A)
The original formula, Napalm-A, was developed in 1942 by a team of chemists at Harvard University led by Louis Fieser. The goal was to create a stable, reliable gelling agent that could be mixed with gasoline, replacing the scarce natural rubber previously used.
The resulting compound was a brownish, dry powder consisting of coprecipitated aluminum salts of fatty acids. The gelling agent was made from aluminum naphthenate and aluminum palmitate, which gave the substance its name (a portmanteau of naphthenic and palmitic acids). This powder was combined with a petroleum product, typically gasoline or kerosene, to create the final incendiary gel. The aluminum soaps acted as a thickening agent, turning the volatile liquid fuel into a viscous, sticky substance that burned slower and for a longer duration.
The Manufacturing Process: Creating the Gel
The manufacturing of Napalm-A involved producing the thickening agent in large batches. This aluminum soap powder was created by reacting a mixture of fatty acids, such as naphthenic and palmitic acids, with an aluminum salt like aluminum sulfate in the presence of caustic soda. This reaction caused the aluminum soap to precipitate out as a solid material, which was then dewatered and dried to isolate the fine powder.
The dried aluminum soap powder was packaged and shipped for final mixing. The finished incendiary gel was typically prepared on-site by mixing the powder with gasoline. This blending process was crucial, as the amount of thickener added determined the final viscosity, which could range from a syrupy liquid for flamethrowers to a thick gel for bombs. A common mixture used approximately 6% napalm powder combined with 94% gasoline.
The resulting mixture had a gelatinous consistency that allowed it to adhere stubbornly to surfaces as it burned. The industrial process had to ensure the gel was homogenous and stable, preventing the thickener from separating from the fuel during storage or deployment.
The Evolution to Napalm-B
A chemically distinct and superior version known as Napalm-B was introduced, primarily for use during the Vietnam War era. This newer formula abandoned the original aluminum soap thickener in favor of a synthetic polymeric mixture. The chemical composition of Napalm-B typically included polystyrene, benzene, and gasoline. A common ratio consisted of approximately 46% polystyrene, 33% gasoline, and 21% benzene.
Polystyrene, a common plastic, acted as the gelling agent, dissolving in the benzene and gasoline to create a stable, sticky gel. This new composition offered several significant improvements over the original aluminum soap mixture. Napalm-B was more stable in storage and less susceptible to environmental factors like moisture, which had degraded the quality of Napalm-A.
Crucially, the change in chemistry extended the burn time of the weapon dramatically. While the original napalm burned for only 15 to 30 seconds, the synthetic Napalm-B could sustain its intense combustion for up to 10 minutes. This increased burn duration and superior adherence made the new formulation significantly more destructive. The manufacturing process shifted from mixing a powder to dissolving the polystyrene polymer into the liquid hydrocarbon solvents, resulting in a more consistent and predictable incendiary gel.