lysstabile

Lystabile is a term used in materials science to describe substances that retain their color, strength, and functionality when exposed to light, particularly ultraviolet radiation. The English equivalent is photostable. Lystabile materials are sought for outdoor applications where sunlight can cause rapid degradation of appearance and performance, such as pigments, dyes, polymers, coatings, and electronics.

Photostability results from a combination of chemical resistance to photooxidation, resistance to bond cleavage, and sometimes the presence of stabilizing additives. Common strategies include using intrinsically stable chemical structures, incorporating light absorbers to shield sensitive parts of a molecule, and adding stabilizers that scavenge reactive radicals. Widely used stabilizers include hindered amine light stabilizers (HALS), and UV absorbers such as benzotriazoles and benzophenones. In plastics and paints, these additives help minimize fading, yellowing, embrittlement, and loss of mechanical properties under prolonged light exposure.

Testing for lystabilitet typically involves accelerated weathering or light-exposure tests that simulate years of sunlight in a shorter timeframe. Standards and methods, such as ISO and ASTM procedures for testing color change, gloss, and mechanical integrity under light, provide quantitative measures like delta E for color and retention of tensile strength or hardness.

Applications span outdoor coatings, automotive parts, construction materials, textiles, and solar-energy components. While no material is perfectly lystable in all environments, designers balance optical performance, cost, and environmental considerations to maximize stability under expected service conditions.

See also: photostability, photodegradation, UV stabilizers, HALS, UV absorbers.