Thermal degradation clay reinforcement

To clarify the mechanisms of the clay-reinforced carbonaceous char formation, which may be responsible for the reduced mass loss rates, and hence the lower flammability of the polymer matrices, a number of thermo-physical characteristics of the PE/MMT nanocomposites have been measured in comparison with those of the pristine PE (which, by itself is not a char former) in both inert and oxidizing atmospheres. The evolution of the thermal and thermal-oxidative degradation processes in these systems was followed dynamically with the aid of TGA and FTIR methods. Proper attention was paid also to the effect of oxygen on the thermal-oxidative stability of PE nanocomposites in their solid state, in both the absence as well as in the presence of an antioxidant. Several sets of experimentally acquired TGA data have provided a basis for accomplishing thorough model-based kinetic analyses of thermal and thermal-oxidative degradation of both pristine PE and PE/MMT nanocomposites prepared in this work. 

In some polymer nanocomposites the initial thermal decomposition will be accelerated due to the presence of alkyl ammonium surfactant on the surface of the clay. For instance in PVC the quaternary ammonium salts may accelerate the degradation of PVC.However, this problem does not exist in clay reinforced natural rubber nanocomposites. 

Botana A, Mollo M, Eisenberg P, Torres Sanchez RM (2010) Effect of modified montmorillonite on biodegradable PHB nanocomposites. Appl Clay Sci 47(3 ) 263-270 Bruzaud S, Bourmaud A (2007) Thermal degradation and (nano)mechanical behavior of layered silicate reinforced poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nanocomposites. Polym Test 26(5) 652-659... 

Clay minerals, in NR, have a remarkable effect on (i) rheological properties, (ii) vulcanization efficiency, (hi) barrier properties, (iv) mechanical reinforcement, (iv) thermal properties, (v) degradation properties, (vi) flame resistance. 

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