Changes in the properties of Lexan polycarbonate by UV irradiation

Abstract

The changes in the microstructural parameters of Lexan polycarbonate films irradiated with UV radiation at a wavelength of ? = 250 nm were investigated using wide-angle X-ray scattering measurements. The crystal imperfection parameters, such as the crystallite size, lattice strain, and enthalpy, were determined by line profile analysis using the Fourier method of Warren. An exponential function for the column length distribution was used to determine these parameters. UV-Visible spectroscopy study revealed the formation of photo-stabilizers after irradiation. Thermogravimetric analysis revealed that the thermal decomposition temperature increased after the films were irradiated. In the photoluminescence spectrum, the intensities of the peaks at 426 nm in the emission spectra and at 375 nm in the excitation spectra were observed to decrease with an increase in the exposure time. Raman spectra exhibit only minor shifts in some of the bands after the films were irradiated. Atomic force microscopic measurements revealed that the average roughness of the film increased after irradiation. Infrared spectroscopic study revealed that the carbonate linkage was the radiation-sensitive linkage and that the benzene ring does not undergo any changes after being irradiated. © 2012 Elsevier B.V. All rights reserved.