Chapter 3 Photodegradation of Polymers

摘要: Publisher Summary Although polymers vary widely in their resistance to photodegradation, almost every polymer deteriorates on continued exposure solar radiation during outdoor weathering. The ultraviolet part of the sunlight that reaches surface Earth is called “solar ultraviolet.” It represents only about 6% total sun but most damaging polymers. Fundamental reactions can take place when are exposed light conveniently divided into two groups according site reaction. Main chain result modification size or shape macromolecular backbone. They responsible for gross effects photodegradation. However, side-group often produce low molecular weight fragments discolouration also contribute reduce usable lifetime With vinyl main initiated by side because these usually chromophores. Both and occur a wide variety mechanisms.