Nanostructure of montmorillonite barrier layers: A new insight into the mechanism of flammability reduction in polymer nanocomposites

Isitman, Nihat Ali
Kaynak, Cevdet
This study describes the mechanism of flammability reduction in flame-retarded polymer matrix organo-montmorillonite reinforced nanocomposites. Morphologies of untested polymer nanocomposites and char residues formed by combustion in the mass loss calorimeter are characterized by XRD and TEM techniques. It is postulated that a combination of well-dispersed montmorillonite platelets and flame retardants in the polymer matrix provides nano-structured char formation. Initial montmorillonite dispersion in flame-retarded nanocomposites is found to be a major controlling factor on formed char nanostructures. An initially intercalated structure is invariantly converted to complete montmorillonite collapse whereas an initially exfoliated structure transforms to nano-structured chars demonstrating retained exfoliation or a new state of intercalation via incomplete collapse of montmorillonite layers. It is proposed that nano-structured char formation is the effective mechanism of flammability reduction, i.e. reduction in rate of heat release during combustion, in flame-retarded polymer nanocomposites.


Nanoclay and carbon nanotubes as potential synergists of an organophosphorus flame-retardant in poly(methyl methacrylate)
Isitman, Nihat Ali; Kaynak, Cevdet (2010-09-01)
This study explores whether nanoparticles incorporated in polymers always act as synergists of conventional flame-retardant additives. For this purpose, two different filler nanoparticles, namely organically modified layered-silicate clay minerals or nanoclays and multi-walled carbon nanotubes, were incorporated in poly(methyl methacrylate) filled with an organophosphorus flame-retardant that acts through intumescence. Effective dispersion techniques specific to each nanoparticle were utilized and prepared ...
Impact modified epoxy/montmorillonite nanocomposites: synthesis and characterization
Isik, I; Yılmazer, Ülkü; Bayram, Göknur (2003-09-01)
Diglycidyl ether of bisphenol A type epoxy resin-polyether polyol-organically treated montmorillonite ternary nanocomposites were synthesized in this study. The effects of addition of polyether polyol as an impact modifier on morphological, thermal and mechanical properties of nanocomposites were investigated by X-ray diffraction, scanning electron microscopy (SENI), differential scanning calorimetry, impact and tensile testing. The results showed that organically treated montmorillonite is intercalated by ...
Electrorheological properties of kaolinite, polyindole, and polyindole/kaolinite composite suspensions
Arslan, Yasin; Unal, Halil Ibrahim; Yilmaz, Hasim; Sari, Bekir (Wiley, 2007-06-05)
In this study, polyindole (PIN) and polyindole/kaolinite (PIN/KAO) composite were synthesized by free radical polymerization using FeCl3 as an initiator. Average particle sizes (d(50)) of PIN and PIN/KAO composite were determined by dynamic light scattering (DLS) as 7.2 and 6.2 mu m, respectively. The samples were characterized by FTIR, elemental analysis, DSC/TGA and SEM measurements. Suspensions of KAO, PIN, and PIN/KAO composite were prepared in silicone oil (SO) and the sedimentation stabilities were de...
Nanoceria supported palladium(0) nanoparticles: Superb catalyst in dehydrogenation of formic acid at room temperature
Akbayrak, Serdar; TONBUL, YALÇIN; Özkar, Saim (Elsevier BV, 2017-06-05)
Highly efficient dehydrogenation of formic acid (FA) at room temperature was achieved using palladium(0) nanoparticles supported on nanoceria (Pd-0/CeO2) as catalysts. Pd-0/CeO2 was prepared by impregnation of palladium(II) ions on the surface of ceria followed by their reduction with sodium borohydride in aqueous solution at room temperature. Pd((0)/CeO2 was isolated from the reaction solution by centrifugation and characterized by a combination of advanced analytical techniques. The catalytic activity of ...
Phase transition of chemically synthesized FePt nanoparticles under high pressure
ŞİMŞEK, TELEM; Karci, Ozgur; ÖZCAN, ŞADAN (The Scientific and Technological Research Council of Turkey, 2018-01-01)
We present the results of a study related to phase transformation of chemically synthesized FePt nanoparticles under high pressure from face-centered cubic into face-centered tetragonal structure. As-synthesized nanoparticles are around 4.5 nm and show superparamagnetic behavior at 300 K. After annealing under 60 bar pressure of hydrogen at 400 degrees C for 2 h, nanoparticles exhibit strong ferromagnetic behavior with 5391 Oe coercivity. Results show that high-pressure annealing lowers the decomposition te...
Citation Formats
N. A. Isitman and C. Kaynak, “Nanostructure of montmorillonite barrier layers: A new insight into the mechanism of flammability reduction in polymer nanocomposites,” POLYMER DEGRADATION AND STABILITY, pp. 2284–2289, 2011, Accessed: 00, 2020. [Online]. Available: