Photostability of plasticized polyvinyl chloride membranes: A theoretical study

Abstract

The calculation of spectral shifts in the UV-visible region, and the photostability of polyvinyl chloride membranes plasticized with 1-bromonaphthalene, dibutyl phthalate, dioctyl phthalate, o-nitrophenyl octyl ether and tricresyl phosphate, have been systematically investigated using the ZINDO/S method combined with stochastic molecular dynamics with the MMFF94 force field. A Langevin temperature bath was used for the thermostat and the simulation temperature was 298 K during the entire time of the simulation, which was set to 0.6 ns. These methods were employed to predict the molecular structure of the membranes. The absorption wavelengths and the HOMO and LUMO energies of membrane components are reported. In addition, the photostability of the membranes is discussed in the light of the absorption wavelength. Membranes plasticized with tricresyl phosphate and o-nitrophenyl octyl ether show less stability under the action of UV irradiation, as they absorb light with higher energy. Membranes plasticized with butyl and octyl esters of phthalic acid are more stable and show very similar behaviour. A membrane plasticized with 1-bromonaphthalene is likely to be the least sensitive to UV irradiation