Novel clay-based coating may point the way to new generation of green flame retardants

In searching for better flame retardants for home furnishings—a large source of fuel in house fires—National Institute of Standards and Technology (NIST) researchers defied the conventional wisdom and literally hit a wall, one made of clay.

It wasn’t a dead end, but rather a surprising result that may lead to a new generation of nonhalogenated, sustainable flame retardant technology for polyurethane foam. The thick, fast-forming coating that the NIST team created has a uniformly high concentration of flame-inhibiting clay particles, and it adheres strongly to the Swiss cheese-like surface of polyurethane foam, which is used in furniture cushions, carpet padding, children’s car seats, and other items.

“In effect, we can build the equivalent of a flame-retarding clay wall on the foam in a way that has no adverse impact on the foam manufacturing process,” explains NIST fire researcher Rick Davis. “Our clay-based coatings perform at least as well as commercial retardant approaches, and we think there’s room for improvement. We hope this new approach provides industry with practical alternative flame retardants.”

Davis and his NIST colleagues describe the new coating and the process they used to make it in the journal ACS Macro Letters.*

To date, researchers have built up coatings by stacking thin layers in pairs that are held together by basic electrical attraction. With no clay present, just a pure polymer, a thick coating is formed rapidly, but it isn’t a fire retardant. With clay in every other layer, either the coating is too thin or the clay content is too low to be an effective fire retardant.

The NIST team tried something you would expect not to work: trilayers consisting of a positively charged bottom topped by two negatively charged layers. Under most circumstances, the two negative layers would repulse each other, but it turns out that hydrogen bonds formed between the two negative layers and overcame this repulsive force.

The resulting trilayer yields a unique result: a thick, fast-forming, and high concentration clay coating on polyurethane foam. This nanocomposite coating is 10 times thicker, contains 6 times more clay, and achieves this using at least 5 times fewer total layers than the traditional bilayer coatings.

“The eight trilayer system thoroughly coated all internal and external surfaces of the porous polyurethane foam, creating a clay brick wall barrier that reduced foam flammability by as much as 17 percent of the peak heat release rate,” the team reported. Only a few hundred nanometers thick, the final coating is transparent and the foam still has the same softness, support and feel.

Compared with amounts of current flame retardant applied to polyurethane foam, only half as much of the new clay-based coating was required to achieve comparable levels of performance.

Citation for the research paper: Y.S. Kim, R. Harris and R. Davis. “Innovative approach to rapid growth of highly clay-filled coatings on porous polyurethane foam.” ACS Macro Letters, 2012, 1, 820-824. DOI: 10.1021/mz300102h

New EPA Air Quality Planning Resources for State, Tribal and Local Air Agencies

EPA has released a new Roadmap to help state, tribal, and local air agencies include emission reductions from energy efficiency and renewable energy in State and Tribal Implementation Plans (SIPs/TIPs) to improve air quality. The Roadmap focuses on emissions benefits from energy efficiency/renewable energy policies and programs in the electric power sector. It reflects input received from a number of stakeholders, including state and local energy and air quality agencies.

Now is a great time to include energy efficiency/renewable energy strategies in SIPs and TIPs. First, many states have substantially increased their commitment to energy efficiency/renewable energy policies and programs over the last 10 years. The emissions impacts from these policies and programs are already happening: this manual outlines the latest tools, information, and approaches to quantifying those impacts. Second, emissions reductions from energy efficiency/renewable energy policies and programs can help states and tribes comply with National Ambient Air Quality Standards (NAAQS) at a lower cost than traditional control measures. Third, this information could be very helpful for areas participating in the Ozone Advance Program. Finally, these resources can help state, tribal, and local agencies estimate potential emissions reductions and determine whether they want to reflect those reductions in their SIPs/TIPs.

To accompany the Roadmap, EPA is providing:

  • A webinar on the Roadmap.
  • Draft tool for quantifying the emissions impacts of state, tribal, and local energy efficiency/renewable energy policies and programs.
  • Online training for air quality planners on the electric energy sector.
  • Data on the projected energy impacts of existing state energy efficiency/renewable energy policies to help states and tribes account for policies not reflected in Energy Information Administration’s Annual Energy Outlook 2010.
For more information, please visit the Roadmap website.

Ecotoxicology of lead shot and benefits of alternatives — a compilation

There has been a lot of recent press coverage about the ecotoxicology of lead shot and the benefits of alternatives. Some recent articles are:

Myra E. Finkelstein, Daniel F. Doak, Daniel George, Joe Burnett, Joseph Brandt, Molly Church, Jesse Grantham, and Donald R. Smith. (2012). “Lead poisoning and the deceptive recovery of the critically endangered California condor”. Proceedings of the National Academy of Sciences Published online before print June 25, 2012, doi: 10.1073/pnas.1203141109
Abstract: Endangered species recovery programs seek to restore populations to self-sustaining levels. Nonetheless, many recovering species require continuing management to compensate for persistent threats in their environment. Judging true recovery in the face of this management is often difficult, impeding thorough analysis of the success of conservation programs. We illustrate these challenges with a multidisciplinary study of one of the world’s rarest birds—the California condor (Gymnogyps californianus). California condors were brought to the brink of extinction, in part, because of lead poisoning, and lead poisoning remains a significant threat today. We evaluated individual lead-related health effects, the efficacy of current efforts to prevent lead-caused deaths, and the consequences of any reduction in currently intensive management actions. Our results show that condors in California remain chronically exposed to harmful levels of lead; 30% of the annual blood samples collected from condors indicate lead exposure (blood lead ≥ 200 ng/mL) that causes significant subclinical health effects, measured as >60% inhibition of the heme biosynthetic enzyme δ-aminolevulinic acid dehydratase. Furthermore, each year, ∼20% of free-flying birds have blood lead levels (≥450 ng/mL) that indicate the need for clinical intervention to avert morbidity and mortality. Lead isotopic analysis shows that lead-based ammunition is the principle source of lead poisoning in condors. Finally, population models based on condor demographic data show that the condor’s apparent recovery is solely because of intensive ongoing management, with the only hope of achieving true recovery dependent on the elimination or substantial reduction of lead poisoning rates.

News stories covering this study

Joel E. Pagel, Peter B. Sharpe, David K. Garcelon, Annie E. Little, Sharon K. Taylor, Kate R. Faulkner, and Carol S. Gorbics. (2012) “Exposure of Bald Eagles to Lead on the Northern Channel Islands, California.” Journal of Raptor Research 46(2):168-176. doi:
Abstract: Bald Eagles (Haliaeetus leucocephalus) were one of the upper-trophic-level avian predators on the Channel Islands, California, prior to their extirpation by 1960 caused in part by large amounts of DDT discharged into the Southern California Bight. From 2002 to 2006, 61 Bald Eagles were reintroduced onto the northern Channel Islands, as part of a 5-yr feasibility study conducted under the auspices of the Montrose Settlement Restoration Program. In December 2005, a yearling Bald Eagle female was found on Santa Rosa Island with a broken wing and elevated lead levels in her blood of 52.2 ug/dl (0.522 ppm). This incident raised concerns that lead poisoning could be a potential threat to the restoration effort and prompted further investigation. Femurs from five female and two male Bald Eagles reintroduced to the northern Channel Islands were collected postmortem for analyses of lead and other metals. Lead levels detected in femurs of these birds ranged from 0.2 to 55.0 ppm (dry weight). Lead levels in liver were also determined for two of the seven Bald Eagles. Analysis of Bald Eagle movement data from satellite telemetry transmitters suggested that eagles that spent the most time on Santa Rosa Island had the highest lead levels. The results of this study suggested that spent ammunition containing lead found in carrion (offal and entire carcasses) from deer and elk hunting on Santa Rosa Island may have been a primary source of contamination. The on-island hunt program converted to nontoxic bullets in 2007 and ended in late 2011.

Copper Opportunities: Copper Ammo Emerging as the “Bullet of Choice” among Minnesota Deer Hunters (Whitetales)
One favorite tradition among deer hunters is sharing the stories of the hunt following each year’s deer season. This year there are some new and compelling stories emerging from hunters who have switched to copper bullets for deer hunting.

Technical Fact Sheets and Emerging Contaminants

The US Environmental Protection Agency (EPA) Federal Facilities Restoration and Reuse Office (FFRRO) published these technical fact sheets, which provide brief summaries of contaminants of concern that present unique issues and challenges to the environmental community in general and to FFRRO in particular.

Each fact sheet provides a brief summary of the contaminant, including physical and chemical properties, environmental and health impacts, existing federal and state guidelines, and detection and treatment methods. Sources of additional information about each contaminant are also included in the fact sheets.

These fact sheets are intended for use by project managers and field personnel in addressing specific contaminants at cleanup sites and are updated annually to ensure they include timely information.

Greener Products Essential to Sustainable Healthcare

Read the full story from 3BL Media.

Recognizing that human health is connected to the health of the planet, healthcare providers and suppliers are making strides to reduce their environmental impact. A major component of this is through greener products and supplies.

Lara Sutherland, an expert in sustainable purchasing, can attest to this. As Director of Business Membership for Practice Greenhealth, the nation’s leading membership organization dedicated to sustainable healthcare, she sees firsthand how suppliers are revamping product formulas, changing manufacturing processes, and introducing reusable components and recyclable materials, among many other initiatives.

She cited the Johnson & Johnson internal Earthwards® process of product lifecycle analysis as an example. “They’re doing some incredible stuff,” Sutherland said. “I haven’t seen anything else like it. Earthwards® is aptly phrased: Toward improvement. They really want to do something that helps the environment.”