The objective of this study is to demonstrate proof of concept for the development of the next generation of fluorine-free firefighting foam formulations as a replacement for existing aqueous film forming foam (AFFF). The novel foam systems produced in this research are derived from chitosan salts and surfactants that are sustainable, non-toxic, water-soluble (or water-dispersible) and will be applied using existing military firefighting equipment.
These foam systems will meet or exceed both environmental regulations and firefighting performance defined in military specification (MIL-SPEC) MIL-F-24385F Military Specification: Fire Extinguishing Agent, Aqueous Film Forming Foam (AFFF) Liquid Concentrate, For Fresh and Seawater (1994).
The two routes for the non-fluorinated AFFF foams that will be explored are: (1) low molecular weight chitosan salts and (2) hydrophobic modified chitosans as polymeric surfactants. Highly efficient synthetic methods will be used in order to produce large quantities of materials for formulating and testing of these agents. Both routes will be explored concurrently as a risk mitigation strategy to maximize resources and ensure success for this project at the same time.
Both the chitosan salts and the polymeric surfactants will be formulated with other hydrocarbon surfactants and other additives commonly used in manufacturing concentrated foam solutions. The key physical properties of the resulting foam candidates will be measured for their surface tensions in water and hydrocarbons, spreading coefficients (aqueous film formation), expansion ratio (fire extinguishment and burn-back), and drain time (ability to cover fuel surfaces) as part of the optimization of foam formation research. Each of the chemicals used and materials synthesized will be evaluated for their human health effects and environmental impact. Foam candidates will further be evaluated for their optimized concentrations. If the major objectives have been met, a small-scale fire extinguishment and burn-back will be carried out.
The benefits to the Department of Defense are multi-fold and include: (a) elimination of the use of fluorosurfactants and related compounds in current AFFF foam formulations, (b) elimination of legacy issues relating to environmental toxicity, persistence and bioaccumulation, (c) a significant reduction on the potential of ground water contamination and (d) the development of alternative AFFF formulation technology that enables long term sustained manufacturing using cost effective renewable resources. All of this will be achieved while ensuring mission readiness and firefighter safety.