Can nanoparticles really enhance thermal stability of polymers? Part II: An overview on thermal decomposition of polycondensation polymers

With the rapid development of nanotechnologies and nanomaterials since 1990s, the studies on polymer-based nanocomposites have been extensively focused on their properties enhancement. Among these, it is well known that nanoparticles can also enhance thermal degradation of nanocomposites. This review is focused on highlighting the effect of different nanoparticles, their dispersion and the used modifiers, on polymer thermal stability. The whole range of polycondensation polymer matrices is covered. Most of these polymers have reactive end groups which can interact with inorganic nanoparticles surface. Hydrogen or covalent bonds can be formed, which can increase the adhesion of nanoparticles with the polymer matrix, resulting in higher dispersion degrees. This, in most cases, leads to substantial enhancement of thermal decomposition properties. Only in nanocomposites containing montmorillonite there are conflicting results and accelerating degradation was also reported. Organoclays also have similar effects on polymers thermal stability and in this case the achieved clay dispersion (intercalated-exfoliated), as well as the used modifier, can alter the thermal decomposition of polymers. The used amount of nanoparticles plays an important role on the thermal stability of nanocomposites. In most cases thermal stability enhancement takes place at low loading (4-5 wt%) of nanoparticles, while at higher contents thermal stabilization becomes progressively smaller. (C) 2011 Elsevier B.V. All rights reserved.