Vibrational spectroscopic encoding of polystyrene resin bead: a combined FT-IR and computational study

A novel strategy is described for the vibrational spectroscopic encoding of polystyrene resin bead by combining FT-IR measurements and quantum-chemical computations. The FT-IR spectra of styrene monomer and a polystyrene resin bead were recorded and vibrational frequency computations for styrene monomer were performed using the DFT B3LYP/6-31G* method. A detailed analysis of the vibrational characteristics of styrene monomer and polystyrene resin bead is presented based on combining the FT-IR measurements and the quantumchemical computations. Results indicate that several absorption peaks in the FT-IR spectrum of styrene monomer may come from unpredictable impurity molecules inside the styrene sample and/or from the measurement apparatus itself, which may disturb the analysis of the vibrational spectrum of polystyrene resin bead. The vibrational spectroscopic barcodes for the polystyrene resin bead were obtained by comparing the FT-IR spectra of styrene monomer and the polystyrene resin bead. q 2004 Elsevier B.V. All rights reserved.