Polymer Degradation

Polymer degradation is one of the most important areas of polymer chemistry being a major factor restraining application of these outstanding and versatile materials. The idiom "polymer degradation" takes account of different processes, induced by one or more environmental factors such as heat, light, microorganisms, or chemicals that deteriorate polymers producing alterations in their properties. The degradation is the result of irreversible changes that are usually undesirable or, in some cases, required, as in biodegradation or recycling, or else induced to support structure determination. Degradation plays an important role in every life phase of a polymer, i.e., during its synthesis, processing, use and even after it has accomplished its planned purpose. As a result, stabilization is required to extend the life time of most polymers. Compounding with stabilizers is the preferred and well-established method for improving stability. However, monitoring and controlling degradation requires the understanding of many different phenomena, including the diverse chemical mechanisms underlying structural changes in macromolecules, the complex reaction pathways of additives, the interactions of fillers, as well as impurities, and the complicated relationship between molecular-level changes and macroscopic properties. Various schemes to classify polymer degradation exist. Because of its complexity, with regard to both the causes and the response of the polymer, classification is usually performed on the basis of the dominating features. We will refer to the classification based on the main factors responsible for degradation: thermal, thermo-oxidative, photo, photo-oxidative, hydrolytical, chemical, biological degradation, etc. Modern mass spectrometry (MS) methods for their high sensitivity, selectivity, and speediness offer the opportunity to explore the finest structural details in polymer degradation. In fact, whatever the cause, the deterioration mainly yields degradation products frequently bearing characteristic end groups, which can be revealed and differentiated by MS, being indicative of specific degradation pathways