Most polymeric materials

including plastics、rubbers、fibers、coatings and so on

underwent photoaging when used outdoors and their services lifes were thus cut down.In order to protect effectively the polymeric materials from photo-deterioration

the mechanisms of photo-aging and photostabilization of polymers had been studied widespreadly and several types of light stabilizers developed successively.But since the photo-aging of polymers had been being made more and more complicated by the continuously extended ranges of use and deteriorated environment and their photo-protection becoming more and more difficult

the study of the mechanisms of photo-aging and photostabilization of polymers and development of light stabilizers were very active all the way at home and abroad.In the first part of this paper

the mechanisms of photo-aging of polymers were expounded.