Thermal Analysis Methods in Characterization of Polymer Additives

Analytical methods based on the use of thermal analysis techniques were and still are very popular and often used in the study of plastics. These techniques enable the determination of thermal properties of polymeric materials, such as the glass transition temperature, melting temperature and heat of fusion, temperature and heat of crystallization, and specific heat. The effect of high temperature on polymers can lead to their depolymerization and degradation related to the release of low-molecular-weight decomposition products. Measurement of the material mass change as a function of temperature allows to determine the thermal stability of plastics. The most commonly used research techniques in this field include thermogravimetric analysis (TGA) and dynamic-mechanical thermal analysis (DMTA), in addition to differential scanning calorimetry (DSC). Particularly, TGA is a very rapid accurate technique which, given that the connection between TGA and long-term life testing can be established, should provide proper kinetic expressions and corresponding apparent activation energy of degradation values that can be used to predict the thermal lifetime of polymeric materials. The polymer industry is in fact split between the need to expand and implement a variety of applications and new materials, as well as to protect and maintain their functional properties, and the need for easy disposal or recycling after use. Therefore, the study on the thermal properties of polymers is crucial to improving their recyclability or providing a viable alternative. In particular, lifetime predictions play a key role in facilitating both the design stage and the final disposition. However, thermal analysis methods are not only used to study polymer materials for their desired thermal parameters, degradation, flammability, or development of more effective recycling methods after use. They are also readily applied for the analysis of raw materials, including auxiliaries and additives necessary and widely used in the production and processing of polymeric materials. The additives most often used in the processing of polymeric materials include stabilizers, flame retardants, (nano)fillers, pigments, and processing aids. The following chapter provides an insight into the role of thermal analysis methods in characterization of some polymer additives, both pristine and used as components of polymer composites.