Spectroscopic and Morphological Study of Irradiated PVC Films Doped with Polyphosphates Containing 4,4'-Methylenedianiline

Polyphosphates containing 4,4'-methylenedianiline moiety were synthesized and their use as polyvinyl chloride (PVC) additives to enhance PVC photostability was investigated. Polyphosphates (0.5 wt %) were mixed with PVC and thin films (50 μm thickness) were prepared. The films were subjected to long-term exposure to ultraviolet light at room temperature to investigate the photostabilizing effects of the polyphosphates. Following irradiation, the intensities of the peaks corresponding to several functional groups in the PVC blends were analyzed using infrared spectroscopy. Additionally, changes in the mass and molecular weight as well as the appearance of defects (e.g., cracks, roughness, and irregularities) in the irradiated PVC blends were evaluated. It was found that polyphosphates inhibited photodecomposition of PVC. It was determined that polyphosphates exhibiting ortho-geometry were particularly effective in stabilizing the PVC blends. Notably, polyphosphates acted as ultraviolet light absorbents, radical scavengers, and peroxide decomposers. The synthesized polyphosphates are highly stable and provided PVC film protection comparable with those previously reported for related polyphosphates, Schiff bases and organometallics.