Quantitative Fourier Self-Deconvolution and Fourier Transform Infrared Analysis of Bisphenol-A-Polycarbonate/Poly(Dimethylsiloxane) Random Block Copolymers

Abstract

Fourier self-deconvolution (FSD) is used to enhance the spectral resolution of Fourier transform infrared results obtained from thick solution-cast films of bisphenol-A-polycarbonate-poly(dimethylsiloxane) blends and random block copolymers. Despite the severity of band overlap in the region from 1300 to 1200 cm−1, accurate determinations of bulk composition are made from the deconvolved absorbance (transmission mode) spectra of eleven blends and three random block copolymers. With compositions expressed in terms of each component's relative concentration, these results are used to develop a multicomponent Beer's law relationship that is verified through the determination of appropriate homopolymer absorptivities. Fourier transform infrared attenuated total reflectance results are compared to the multicomponent Beer's law relationship in an effort to quantitate the surface excess of siloxane 0.004–1.6 µm from the air/solid interface.