UV STABILIZATION OF PET FIBERS - MICROSCOPY STUDY

Ultraviolet microspectrophotometry is used to monitor the radial diffu sion of three vv stabilizers in high molecular weight PET fibers. Unde r identical application conditions, the benzotriazole and benzotriazin e derivative stabilizers show peripheral penetration only, whereas the benzophenone derivative stabilizer diffuses throughout the fiber cros s section. Peripheral penetration of the benzotriazole and benzotriazi ne derivatives does not prevent polymer photodegradation in the unprot ected interior, whereas all regions of the fiber are protected by the more uniformly distributed benzophenone stabilizer. Heavy peripheral d eposition of the benzotriazole stabilizer prevents these highly protec ted regions from polymer photodegradation.