Milk Proteins As Ecofriendly Flame Retardants

Many of the compounds used as flame retardants in upholstered furniture and plastics have come under scrutiny for their potentially harmful effects on the environment and human health. Now, researchers have demonstrated that caseins—proteins found in milk—could be a nontoxic alternative (Ind. Eng. Chem. Res. 2014, DOI: 10.1021/ie404089t). Caseins are readily available from the whey by-product of cheese production, says Jenny Alongi of Polytechnic University of Turin, in Italy. She and her colleagues decided to investigate the proteins as flame retardants because of their high phosphorus content. When they burn, a polymer layer of phosphoric acid forms and creates a char that blocks heat transfer to unburned areas of the material, slowing the spread of the fire. The team coated fabric samples with caseins and then tested their flammability. The results were encouraging: In cotton- and polyester-only fabrics, flames quickly extinguished, leaving 86% of the cotton and 77% of the polyester unburned. A 65% cotton-35% polyester blend burned completely but took 60% more time to do so than did untreated material.