According to a report by the Physicist Organization Network on January 16, scientists at the National Institute of Standards and Technology (NIST) have developed a multi-walled carbon nanotube material by using a unique sandwich structure at the nanoscale. Reduce the flammability of foam products. Researchers say the new technology is expected to reduce fires caused by soft decoration by a third. Related papers were published in the professional journal Solid Film.
The new technology, invented by the National Institute of Standards and Technology, combines multi-walled carbon nanotubes with two polymer materials like a sandwich, and superimposes the three layers of material in four layers. This kind of nanomaterial that sounds quite "thick", in fact, even if it is described as "thin as a flap" is not too much - its overall thickness is less than one percent of the diameter of human hair.
At the beginning of the study, materials scientists Jin Yanxi and Rick Davis set three key objectives for the new material: full coverage of the porous surface of the foam, uniform distribution of nanotubes, and easy to promote manufacturing methods.
To this end, they tested a variety of materials, hoping to improve fire resistance and delay flame spread, but the performance is not ideal. In the final test, they chose carbon nanotubes, but this material composed of carbon atoms, like a cylindrical wire mesh, could not be firmly attached to the surface of the foam. To solve this problem, they chose medical carbon nanotubes, which are often used to increase the viscosity of DNA molecules in cell culture. It is characterized by an outer layer of an amino group containing nitrogen molecules. This choice has finally proved to be correct, and the medical carbon nanotubes are evenly distributed among the flame retardant materials and firmly "catch" the surface of the material in contact with them. In addition, this material also makes full use of the rapid heat dissipation of carbon nanotubes. In addition, even in the case of extreme high temperatures, the carbon nanotubes in the coating are completely charred. This scorch layer has a stable flame-retardant structure and can form a carbon protective layer to prevent the flame from continuing to spread.
Davis said that the new technology has a better flame retardant effect than the brominated flame retardants currently used in soft decoration. Foamed articles covering this carbon nanotube flame retardant material have a flammability reduction of 35% compared to untreated. If it can be widely promoted, new technologies are expected to reduce fires caused by soft decoration by one-third.
Whether in public places such as offices and hotels, or in our homes, the use of foam-like decorations is becoming more frequent, and in many cases it is the culprit in the spread of fire. Statistics show that the annual fire caused by soft decoration in the United States reached 6,700 and caused 480 deaths. In fact, people's current biggest remedy for brominated flame retardants is not the flame retardant effect, but its toxicity. The new study pointed out that it was the winner in flame retardancy, but did not explain the toxicity problem. If it is also leading in this respect, it will undoubtedly become a fire protection "protective umbrella" for many beautiful buildings in the future. Of course, the application of flame retardants is far more than construction, defense military, aerospace... its stage is everywhere