Degradation of sulfur-containing aromatic polymers: Photodegradation of polyethersulfone and polysulfone

Abstract Photodegradation of polyethersulfone (PESF) and polysulfone (PSF) was investigated by measurements of the molecular weights and molecular weight distributions of the polymers using GPC. Main chain scission and crosslinking occurs simultaneously in the photodegradation of PESF below the glass transition temperature ( T g ) of the polymer, while crosslinking predominates above T g . On the other hand, main chain scission of PSF was observed even above T g , indicating that the aliphatic side-chain group of PSF promotes chain scission as a hydrogen donor. Quantum yields for the photocrosslinking and chain scission of PSF were of the order of 10 −4 and 10 −3 , respectively. A break in the Arrhenius plots of the quantum yields for crosslinking and chain scission of PESF was observed corresponding to the change in molecular mobility around the T g , while those for PSF showed a minimum. These plots for PSF suggest a deactivation process due to the change in the physical properties of the polymer.