DEPTH PROFILES OF PHOTODEGRADATION IN FIL MS OF ALIPHATIC AND AROMATIC POLYESTERS

Depth profiles of photodegradation in the films of poly(butylene succi nate) (PBSU) and poly(ethylene terephthalate) (PET) irradiated with ul traviolet (UV) light of wavelength 312 nm were investigated. FT-IR-ATR spectra were measured at 10, 25, 50, and 80 mu m in depth from the ir radiated surface. In the case of PBSU, the IR bands were changed durin g irradiation, even at 80 mu m in the depth. On the other hand, in the case of PET, the IR spectra for the portion deeper than 10 mu m were nearly the same as that of the unirradiated film. The different depth profiles in photodegradation between PBSU and PET seem to be mainly ca used by the different photodegradation mechanisms: the Norrish II type for PBSU and photo-Fries rearrangement-photooxidation reaction type f or PET.