Oriented clay nanopaper from biobased components--mechanisms for superior fire protection properties.
The toxicity of the most efficient fire retardant additives is a major problem for polymeric materials. Cellulose nanofiber (CNF)/clay nanocomposites, with unique brick-and-mortar structure and prepared by simple filtration, are characterized from the morphological point of view by scanning electron microscopy and X-ray diffraction. These nanocomposites have superior fire protection properties to other clay nanocomposites and fiber composites. The corresponding mechanisms are evaluated in terms of flammability (reaction to a flame) and cone calorimetry (exposure to heat flux). These two tests provide a wide spectrum characterization of fire protection properties in CNF/montmorrilonite (MTM) materials. The morphology of the collected residues after flammability testing is investigated. In addition, thermal and thermo-oxidative stability are evaluated by thermogravimetric analyses performed in inert (nitrogen) and oxidative (air) atmospheres. Physical and chemical mechanisms are identified and related to the unique nanostructure and its low thermal conductivity, high gas barrier properties and CNF/MTM interactions for char formation.
†Department of Fiber and Polymer Technology, Wallenberg Wood Science Center, Royal Institute of Technology, SE-10044 Stockholm, Sweden.|‡Politecnico di Torino, Alessandria Site, Viale Teresa Michel 5, 15121 Alessandria, Italy.
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Carosio
†Department of Fiber and Polymer Technology, Wallenberg Wood Science Center, Royal Institute of Technology, SE-10044 Stockholm, Sweden.
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Kochumalayil
‡Politecnico di Torino, Alessandria Site, Viale Teresa Michel 5, 15121 Alessandria, Italy.
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Cuttica
‡Politecnico di Torino, Alessandria Site, Viale Teresa Michel 5, 15121 Alessandria, Italy.
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Camino
†Department of Fiber and Polymer Technology, Wallenberg Wood Science Center, Royal Institute of Technology, SE-10044 Stockholm, Sweden.
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Berglund
D000538:Aluminum Silicates / Q000737:chemistry*; D016880:Anisotropy; D001688:Biological Products / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D000077215:Clay; D005390:Fires / Q000517:prevention & control; D005411:Flame Retardants / Q000138:chemical synthesis*; D006358:Hot Temperature; D008422:Materials Testing; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D010209:Paper; D010316:Particle Size; D013814:Thermal Conductivity
D000538:Aluminum Silicates; D001688:Biological Products; D005411:Flame Retardants; D002482:Cellulose; D000077215:Clay
biocomposite; brick and mortar; fire protection; layered silicate; nanocellulose; nanocomposite; thermal stability