Combined effect of hindered amine light stabilizer and antioxidants on photodegradation of poly (vinyl chloride)

Abstract

Casted PVC films with hindered amine light stabilizer (HALS) and antioxidants are photo-irradiated for 400 h and the process of photodegradation is characterized by color differences, ultraviolet-visible (UV-vis) spectroscopy, Fourier transformation infrared (FT-IR) spectroscopy and viscosity-average molecular weight ( Mη). When added to PVC separately, hindered amine derivate (T770) and phenol antioxidant (1076) both have little effect on the dehydrochlorination and oxidation of PVC films. In PVC films with T770/1076, the extension of shorter polyenes is retarded during photo-irradiation of 400 h. The extension of longer polyenes is well retarded from 0 h to 200 h. T770/1076 has only a little effect on the anti-oxidation of PVC films from 0 h to 400 h. The p-phenylenediamine antioxidant (4010NA) and 2-Mercapto benzimidazole (MB) both accelerate the photodegradation and crosslinking of PVC films. However, there is no crosslinking in PVC with T770/4010NA and PVC with T770/MB and the degradation of PVC films is weakened. This phenomenon means the light stabilizer T770 protects antioxidants (4010NA and MB) from photo-irradiation and antioxidants can play a positive role in the antioxidative effect.