ABSTRACT
The degradation of filled polymers is characterized by a number of features that are atypical of normal (unfilled) polymers. The degradation of polymers proceeding at high temperatures in vacuo or in an inert gas atmosphere (helium, argon, etc.) is referred to as thermal degradation, while in ambient air or oxygen, the term is thermal-oxidative degradation. However, these features are normally associated with the prehistory of production of the filled polymer. In particular, the methods available for the introduction of fillers may influence not only the physical and chemical properties of polymers, but also their molecular characteristics. Thus, the mixing of melts or solutions of polymers with disperse fillers causes, in a number of cases, noticeable shifts in their molecular mass distribution. This is mainly associated with the mechanocracking of filled polymers, which is enhanced in the presence of fillers. The fragments of macromolecules produced interact either with each other or with the filler surface to form a grafted layer. These mechanochemical processes leading to variations in the molecular characteristics of polymers also affect thermal and thermal-oxidative stability, normally decreasing it. In addition, the conditions of introduction of fillers into polymers (temperature, concentration, intensity of mixing, environment, presence of adsorbed moisture, oxygen, etc.) also have a substantial effect on the polymer decomposition process. The filler plays a key role in the decomposition processes of polymer fillers, since the latter affect the whole complex of properties and structures of the polymers produced.
