Designing Greener Chemicals Award | Chemical & Engineering News
Volume 92 Issue 42 | p. 34
Issue Date: October 20, 2014 | Web Date: October 16, 2014

Designing Greener Chemicals Award

Department: Science & Technology | Collection: Green Chemistry, Sustainability
News Channels: Environmental SCENE, Materials SCENE
Keywords: retardant, surfactant, perfluorocarbon, toxicity, bioaccumulation

Solberg Co., Green Bay, Wis., for developing halogen-free firefighting foams made from a blend of biobased surfactants and sugars

Fluorinated surfactants are critical components of firefighting foams. But the surfactants come with significant health and environmental concerns because they are persistent, bioaccumulative, and toxic. Solberg Co., a leading global maker of the foams, addressed the issue head-on with its halogen-free Re-Healing foaming liquid concentrates in which halogenated materials are replaced by an environmentally benign blend of biobased surfactants and complex carbohydrates.

In 2006, with mounting evidence of the potential toxicity of long-chain fluorosurfactants, EPA and the fluorochemicals industry established a voluntary stewardship program to phase out the compounds. Foam formulators began switching from long-chain (C8 and longer) to short-chain (C6 and shorter) fluorosurfactants. The short-chain versions are still persistent, but they are not believed to be bioaccumulative. However, 40% more fluorosurfactant is required in the new formulations to meet firefighting foam performance standards.

Rather than switching to a short-chain fluorosurfactant, Solberg came up with its Re-Healing formulations made from a blend of surfactants such as alkyl polyglycosides and alkyl sulfates, according to Steven Hansen, Solberg’s vice president and general manager. These compounds are derived from plant sugars and oils rather than from petroleum and are already used in household and personal care products such as soaps and toothpaste.

The formulations also include a complex carbohydrate such as cane sugar molasses, a proprietary polysaccharide, glycol ether solvent, and glutaraldehyde as an antibacterial agent, Hansen says. This mix of components helps optimize performance in all kinds of weather. The foams are biodegradable, completely falling apart after six weeks.


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GREENER FOAM Solberg's halogen-free liquid concentrate is formulated to generate foam for preventing and fighting fires at airports and industrial facilities. Credit: Solberg


“For a long time, chemists have been halogenating organic compounds precisely because it helps different molecules survive in a variety of demanding end-use applications,” observes David J. C. Constable, director of the American Chemical Society’s Green Chemistry Institute, which helps administer the awards process with EPA. “However, we now know that persistence is generally not a good thing from an environmental perspective. Our experience with ozone depletion suggests that innovations like Solberg’s are essential. Their work once again proves that a desired chemical function in a commercial product can be delivered in a variety of ways and can be delivered with high performance, low cost, and greater environmental benefit.”

 
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