title: Nanoparticle networks reduce the flammability of polymer nanocomposites.
abstract: Synthetic polymeric materials are rapidly replacing more traditional inorganic materials, such as metals, and natural polymeric materials, such as wood. As these synthetic materials are flammable, they require modifications to decrease their flammability through the addition of flame-retardant compounds. Environmental regulation has restricted the use of some halogenated flame-retardant additives, initiating a search for alternative flame-retardant additives. Nanoparticle fillers are highly attractive for this purpose, because they can simultaneously improve both the physical and flammability properties of the polymer nanocomposite. We show that carbon nanotubes can surpass nanoclays as effective flame-retardant additives if they form a jammed network structure in the polymer matrix, such that the material as a whole behaves rheologically like a gel. We find this kind of network formation for a variety of highly extended carbon-based nanoparticles: single- and multiwalled nanotubes, as well as carbon nanofibres.
authors.affiliation: Fire Research Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8665, USA. takashi.kashiwagi@nist.gov
authors.forename: Takashi
authors.initials: T
authors.lastname: Kashiwagi
authors.forename: Fangming
authors.initials: F
authors.lastname: Du
authors.forename: Jack F
authors.initials: JF
authors.lastname: Douglas
authors.forename: Karen I
authors.initials: KI
authors.lastname: Winey
authors.forename: Richard H
authors.initials: RH
authors.lastname: Harris
authors.forename: John R
authors.initials: JR
authors.lastname: Shields
mesh_terms: D004548:Elasticity; D005411:Flame Retardants / Q000032:analysis*; D005782:Gels; D008420:Manufactured Materials / Q000032:analysis*; D008970:Molecular Weight; D049329:Nanostructures / Q000737:chemistry*; D036103:Nanotechnology; D037742:Nanotubes, Carbon / Q000737:chemistry; D011108:Polymers / Q000737:chemistry*; D012212:Rheology; D014783:Viscosity
chemical_list: D005411:Flame Retardants; D005782:Gels; D037742:Nanotubes, Carbon; D011108:Polymers