The specialists additionally estimated the base measure of surrounding oxygen expected to keep the sap ablaze.
Flame retardants turn green.
Using compounds of plant origin, researchers are developing a new generation of flame retardants that could one day replace fire-fighting chemicals added by manufacturers of furniture, electronics and other consumer products.
Many traditional synthetic flame retardants end up igniting because they are associated with health problems such as thyroid disorders and cancer (SN: 3/16/19, p. 14). And flame retardants obtained from landfill waste can stay in the environment for a long time (SN: 04/24/10, p. 12).
Scientists have yet to perform toxic tests on new plant innovations. “In general, products that come from plants are less toxic … often doomed,” said Bob Howell, an organic scientist and polymer scientist at Central Michigan University in Mount Pleasant.
Howell’s team presented the work at the American Chemical Society’s national meeting on August 26 in San Diego.
The raw materials for these plant-based retarders are gallic acid – found in nuts and tea leaves – and a substance in buckwheat called 3,5-dihydroxybenzoic acid. Treatment of these compounds with a chemical called phosphoryl chloride turns into chemical flame retardants called phosphoric esters. Because these herbal ingredients are common and the chemical treatment process is straightforward, which makes these retarders easy on a large scale, Howell explains.
Howell and his colleagues tested flame retardants in a resin used to make electronics, automobiles and airplanes. Compared to chips made from pure resin, it takes longer for the resin enriched with the retarder to rise in fire. And “it doesn’t burn for long when you get it,” Howell said. Treated chips are killed in less than 10 seconds, while untreated chips are burnt until no resin remains. In the experiments, flame retardants of plant origin were not compared to conventional uncontrolled substances.
The specialists additionally estimated the base measure of surrounding oxygen expected to keep the sap ablaze. “The higher the number, the better the flame retardant,” Howell said. In gas chambers, untreated resin is burned with only 19% oxygen, while treated resin cannot be burned without at least 33% oxygen.