The Encyclopedia takes a different approach to analyzing the effects of degradants on the degradation of materials, as compared to the classical methods commonly used in weathering studies. Here are the key points:
Limitations of Typical Weathering Studies: Conventional weathering studies often take place in natural outdoor environments where weathering parameters are not controlled. This lack of control makes it difficult to separate and understand the individual effects of different degradants on the material. Moreover, exposure sites may be in locations that do not fully represent real-life performance (e.g., no exposure to certain degradants found in urban environments). The resulting sample condition after exposure depends on the combined effects of multiple degradants, and it is hard to repeat or precisely measure all these effects. Also, in many cases, samples are too contaminated to be studied by instrumental methods.
Challenges in Laboratory Weathering Studies: Weathering studies conducted in laboratory equipment often control specific factors such as UV energy, humidity, artificial rain, and temperature during exposure. However, the studied samples are still exposed to a combination of degradants, making it challenging to isolate the partial effects of individual degradants. The typical approach involves grading damage vs. duration and analyzing composition changes vs. duration of exposure, which does not provide a complete understanding of the mechanisms and interactions among different degradants.
Importance of Understanding Degradation Mechanisms: To effectively use different polymeric materials, it is essential to understand the specific mechanisms caused by different degradants. This understanding permits the selection of the most resistant materials for specific applications and the development of effective stabilization strategies to protect materials against degradation. Degradation and stabilization should be described through chemical equations to identify the specific reactions involved and their sequence.
Encyclopedia's Approach: The book aims to compile research results for the most important and commonly used polymers. The focus is on identifying the unitary degradative chemical reactions, including the fate of products resulting from primary degradation, which can influence further degradation mechanisms and rates. Based on these data, the book proposes potential mechanisms of reactions (chemical descriptions of the sequence of events) for each degradation mode.
Transition to Knowledge-Based Utilization: While complete answers may be difficult to provide, the book recognizes the need to start with available data. By shifting from comparative methods to knowledge-based utilization of existing resources, the book aims to facilitate more effective prevention of waste and environmental pollution caused by material failures.
In summary, the book aims to provide a more comprehensive and mechanistic understanding of material degradation caused by various degradants, helping researchers and professionals select suitable materials and develop effective strategies to prevent degradation and environmental pollution.
