Photostabilizing Efficiency of Ultraviolet Light Stabilizers for Rigid Poly(vinyl chloride) Against Photo-Oxidation

摘要

The photostabilizing efficiency of different light stabilizers in polyvinyl chloride) (PVC) was investigated by discoloration, ultraviolet (UV) reflection experiment, Fourier transform infrared spectrum (FTIR), and scanning electron microscopy (SEM). The results show that the addition of light stabilizers can slow down discoloration of PVC. The UV reflection results verify that this change is due to the distribution of light stabilizers on irradiated surfaces, which can absorb (such as organic stabilizers) or reflect (such as titanium dioxide) UV light differently. The order of stabilizers that can slower the extent of discoloration is titanium dioxide (TiO2) >Tinuvin 234 (U4) >XT 833 (H2), U4 >Tinuvin 531 (U3) >Chimassorb 944 (H1), phenyl salicylate (U1). FTIR results show that the carbonyl group of pure PVC, TiO2, and H1 -doped PVC increases significantly, indicating that the photo-oxidation reactions of these irradiated samples are relatively serious. The SEM results show that the surface damages of PVC doped with U2, U4, and H2 are somehow slighter, with only small holes or cavities on the surface, whereas the surfaces of pure PVC and H1-doped PVC are full of big and deep holes and some holes or cavities of 10 μm are detected.