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Embrittlement is a significant decrease of ductility of a material, which makes the material brittle. Embrittlement is used to describe any phenomena where the environment compromises a stressed material's mechanical performance, such as temperature or environmental composition. This is oftentimes undesirable as brittle fracture occurs quicker ...
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 ]
Crazes (surface cracks) produced by ESC in PMMA drinking beaker. Environmental Stress Cracking (ESC) is one of the most common causes of unexpected brittle failure of thermoplastic (especially amorphous) polymers known at present. According to ASTM D883, stress cracking is defined as "an external or internal crack in a plastic caused by tensile ...
Crazing is a yielding mechanism in polymers characterized by the formation of a fine network of microvoids and fibrils. [1][2] These structures (known as crazes) typically appear as linear features and frequently precede brittle fracture. The fundamental difference between crazes and cracks is that crazes contain polymer fibrils (5-30 nm in ...
In polymer chemistry photo-oxidation (sometimes: oxidative photodegradation) is the degradation of a polymer surface due to the combined action of light and oxygen. [1] It is the most significant factor in the weathering of plastics. [2] Photo-oxidation causes the polymer chains to break (chain scission), resulting in the material becoming ...
Brittleness. A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Breaking is often accompanied by a sharp snapping sound.
Polymer fracture is the study of the fracture surface of an already failed material to determine the method of crack formation and extension in polymers both fiber reinforced and otherwise. [1] Failure in polymer components can occur at relatively low stress levels, far below the tensile strength because of four major reasons: long term stress ...
Crystallization of polymers is a process associated with partial alignment of their molecular chains. These chains fold together and form ordered regions called lamellae, which compose larger spheroidal structures named spherulites. [1][2] Polymers can crystallize upon cooling from melting, mechanical stretching or solvent evaporation.