Organomodified montmorillonite OMMT

Talc particles of different lamellarity and specific surface area have been incorporated into polyethylene vinyl acetate (EVA) copolymer/magnesium hydroxide (MH) composite system.63 The fire retardancy of this system has been studied and compared with formulations containing only EVA and MH and formulations containing EVA, MH, and organomodified montmorillonites (oMMT). It was observed that talc with higher lamellar index showed fire behavior similar to that of EVA/MH/ oMMT system with some intumescence. 

The FR properties of polymer-layered silicate nanocomposites have been studied for a wide range of polymers, especially for organomodified montmorillonites (OMMT) in thermoplastics. Depending on the nature of the polymer, the decomposition pathway and decomposition products may change.8 A major consequence of the introduction of modified clays is the formation or the enhancement of charred structure, caused by cross-linking processes possibly catalyzed by the nanoparticles. 

LDH layered double hydroxide, MMT montmorillonite, OLDH organomodified LDH, OMMT organomodified MMT aEach sample contain 4 g MgO, 5 g ZnO, 0.5 g stearic acid and 1 g ethylene thiourea... 

FIGURE 10.14 Compression force versus gap of EVA/PA6/APP-based intumescent formulations measured at400°C without (REF) and with nanoparticles (Si02, silica OMMT, organomodified montmorillonite LDH, lamellar double hydroxide). 

The rich bibliography on polymer-clay nanocomposites shows that the effect of montmorillonite on thermal properties of matrix is complex and many factors contribute to the enhancement of the glass transition, such as the OMMT dispersion, interfacial strength, type of polymer matrix, preparation method, possible catalytic effects induced by organomodifier and/or montmorillonite itself, and so on [10]. Also, in the case of CNTs, many studies report the importance of thermal properties of nanocomposites containing CNTs, particularly with thermogravimet-ric analysis (TGA), since a significant enhancement in thermal stability of the... 

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