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Polymer degradation is the reduction in the physical properties of a polymer, such as strength, caused by changes in its chemical composition.Polymers and particularly plastics are subject to degradation at all stages of their product life cycle, including during their initial processing, use, disposal into the environment and recycling. [1]
BPA is a main component of several high-performance plastics, the production of these is low compared to other plastics but still equals several thousand tons a year. Comparatively minor amounts of BPA are also used as additives or modifiers in some commodity plastics. These materials are much more common but their BPA content will be low.
The development of plastics has evolved from the use of naturally plastic materials (e.g., gums and shellac) to the use of the chemical modification of those materials (e.g., natural rubber, cellulose, collagen, and milk proteins), and finally to completely synthetic plastics (e.g., bakelite, epoxy, and PVC).
Plastics are viscoelastic materials meaning that under applied stress, their deformation increases with time (creep). The elastic properties of plastics are therefore distinguished according to the time scale of the testing to short-time behavior (such as tensile test which lasts minutes), shock loading, the behavior under long-term and static ...
Oxo-degradation refers to the breakdown mechanism caused by heat, light or oxygen on plastics that contain additives that accelerate the process of breaking them into smaller fragments called microplastics. [1] These plastics contrast biodegradable or compostable plastics, which decompose at the molecular or polymer level. [2]
Typically, polymeric materials are characterized as elastomers, plastics, or rigid polymers depending on their mechanical properties. [ 5 ] The tensile strength , yield strength , and Young's modulus are measures of strength and elasticity, and are of particular interest for describing the stress-strain properties of polymeric materials.
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An object in the plastic deformation range, however, will first have undergone elastic deformation, which is undone simply be removing the applied force, so the object will return part way to its original shape. Soft thermoplastics have a rather large plastic deformation range as do ductile metals such as copper, silver, and gold.