When Styrofoam meets gasoline, a surprising and rapid physical transformation occurs. Styrofoam, widely used for insulation and packaging, immediately shrinks and collapses upon contact with the fuel. The ultimate product is a highly viscous, sticky, and concentrated material. This drastic change occurs because of the fundamental chemical properties of the two materials, creating a substance far more hazardous than its components alone.
The Science of Dissolution
The material commonly called Styrofoam is expanded polystyrene (EPS) foam, which is structurally about 98% trapped air and only 2% polystyrene polymer. Polystyrene is a thermoplastic, a long-chain molecule whose chains are nonpolar.
Gasoline, a complex mixture of hydrocarbon compounds, is also largely nonpolar. This shared characteristic drives the interaction, following the principle “like dissolves like.” Gasoline acts as an effective solvent for the nonpolar polystyrene.
The gasoline molecules penetrate the polystyrene structure, separating the long polymer chains. This process is a physical dissolution, not a chemical reaction, as the polystyrene molecule is not fundamentally altered. As the solid polymer dissolves, the vast amount of trapped air is released, causing the instant collapse of the foam volume.
Properties of the Resulting Polymer Slurry
The substance remaining after the foam collapses is a thick, highly concentrated polymer slurry—a solution of polystyrene dissolved in gasoline. This mixture is a gelatinous material, extremely sticky to the touch. It exhibits a remarkable reduction in volume; a large container of foam collapses down into only a small fraction of its original size.
This concentrated mixture is exceptionally flammable because the volatile gasoline solvent is still present, trapped within the dissolved polymer matrix. This material has been used as a crude adhesive or sealant due to the sticky nature of the dissolved plastic. Once the gasoline fully evaporates, the material hardens into a dense mass of solid polystyrene.
The consistency of the slurry can be controlled by the ratio of foam added to the gasoline, resulting in anything from a thick syrup to a stiff gel. This sticky property has been linked to its comparison with a crude form of napalm, as the gel adheres readily to surfaces. The trapped gasoline means the material burns slower and hotter than plain gasoline, sustaining a fire for a longer duration.
Essential Safety Warnings and Hazards
The combination of gasoline and Styrofoam creates an immediate and severe fire hazard. The resulting slurry is highly flammable and difficult to extinguish once ignited because the thick polymer material traps the burning fuel. The sticky nature of the gel makes it particularly dangerous, as it can adhere to skin or other surfaces while burning.
The process of mixing these materials releases toxic vapors that are harmful to inhale. Gasoline fumes contain various volatile organic compounds, including benzene and toluene. Additionally, the dissolution of polystyrene releases styrene vapors.
Contact with the skin should be strictly avoided, as the mixture can cause irritation or chemical burns. Due to the extreme flammability, the release of toxic fumes, and the difficulty in safely handling or extinguishing the resulting substance, attempting to create this mixture for any purpose is strongly discouraged. This process should not be undertaken in enclosed spaces or without professional safety equipment.