Overview

Degradation of polymers includes all the changes in the chemical structure and physical properties of the polymers due to external chemical or physical stresses caused by chemical reactions, involving bond scissions in the backbone of the macromolecules that lead to materials with characteristics different from (usually worse than) those of the starting material [a.1, a.2] {503329}. Polymer degradation in broader terms includes biodegradation, pyrolysis, oxidation, and mechanical, photo- and catalytic degradation. According to their chemical structure, polymers are vulnerable to harmful effects from the environment. This includes attack by chemical deteriogens oxygen, its active forms, humidity, harmful anthropogenic emissions and atmospheric pollutants such as nitrogen oxides, sulfur dioxide and ozone and physical stresses such as heat, mechanical forces, radiation and ablation. While trying to elucidate the general features of polymer degradation, including the mechanism of elementary reactions, it is important to consider the effects of various physical factors on the reactions. The degradation of materials could either worsen the properties and therefore be undesired, or lead to a useful phenomenon in terms of compatibilisation and stabilisation of the polymer via degradation-induced cross-reactions or recycling of polymer waste through thermal degradation {886353}.

The thermal degradation of polymers refers to the case where polymers at elevated temperatures start to undergo chemical changes without the simultaneous involvement of another compound [a.2]. Thermal degradation of polymers is of paramount importance in developing a rational technology for polymer processing, in using polymers at higher temperature, and in understanding thermal decomposition mechanisms...