The act of reducing something or someone to a less regarded state is known as degradation. Degradation is a complex process in polymer science that occurs when a polymeric material is exposed to the environment and stress and loses its initial qualities. Degradation is almost always a negative experience. Polymer degradation is a change in a polymers or a polymer-based product's qualities, such as tensile strength, colour, form, and molecular weight, caused by one or more external elements, such as heat, light, chemicals, or any other applied force. Degradation is frequently caused by a change in the chemical and/or physical structure of the polymer chain, which results in a reduction in the polymer's molecular weight. These changes can be undesirable, such as during use, or beneficial, such as biodegradation or intentionally lowering a polymer's molecular weight. Controlled polymer degradation, on the other hand, is advantageous in some situations.
Polymer stabilisers are chemical additives that can be added to polymeric materials like plastics and rubbers to prevent or delay breakdown. Oxidation, UV-damage, thermal degradation, ozonolysis, and mixtures of these processes such as photo-oxidation, as well as interactions with catalyst residues, dyes, or contaminants, are all common polymer degradation processes. All of these damages the polymer chemically, through chain scission, uncontrolled recombination, and cross-linking, affecting many important qualities like strength, malleability, appearance, and colour.