United States. Researchers at Texas A&M University are developing a new type of flame retardant coating that uses renewable non-toxic materials that are easily found in nature, which could provide even more effective fire protection for several widely used materials.
Dr. Jaime Grunlan, a professor in the Department of Mechanical Engineering at Texas A&M, led the recently published research featured on the cover of a recent issue of the journal Advanced Materials Interfaces.
Successful development and implementation of the coating could provide better fire protection for materials, including upholstered furniture, textiles, and insulation.
"These coatings offer the opportunity to reduce the flammability of polyurethane foam used in a variety of furniture in most people's homes," Grunlan said.
The project is the result of an ongoing collaboration between Grunlan and a group of researchers at the KTH Royal Institute of Technology in Stockholm, Sweden, led by Lars Wagberg. The group, which specializes in using nanocellulose, provided Grunlan with the ingredients it needed to complement its water-based coating procedure.
In nature, both cellulose, a component of wood and various sea creatures, such as clay, a component of soil and rock formations, act as mechanical reinforcements for the structures in which they are found.
"The uniqueness of this current study lies in the use of two natural nanomaterials, clay nanoplatelets and cellulose nanofibrils," Grunlan said. "As far as we know, these ingredients have never been used to make a heat protection or flame retardant coating like a multi-layer thin film deposited in water."
Benefits gained from using this method include the coating's ability to create an excellent oxygen barrier for plastic films, commonly used for food packaging, and better fire protection at a lower cost than other more toxic ingredients that are traditionally used flame retardant treatments.
To test the coatings, Grunlan and his colleagues applied the flexible polyurethane foam, which is often used in furniture cushions, and exposed it to fire with a butane torch to determine the level of protection the compounds provide.
While the uncoated polyurethane foam melts immediately when exposed to the flame, the foam treated with the researchers' coating prevented the fire from damaging beyond surface level, leaving the foam underneath undamaged.
"The nanobrick wall structure of the coating reduces the temperature experienced by the underlying foam, which delays combustion," Grunlan said. "This coating also serves to promote the formation of insulating carbon and reduces the release of fumes that fuel a fire."
Once the research was completed, Grunlan said the next step for the overall flame retardant project is to transition the methods to industry for implementation and development.
Source: www.sciencedaily.com
