Oxidative metamorphosis of poly(styrenedisulfide) backbone

Abstract

This is the first report on the oxidation of a disulfide polymer, viz., poly(styrenedisulfide) (PSD). Oxidation was performed using KMnO₄ and KHSO₄, which are strong and mild oxidizing agents, respectively. Fourier transform-infrared spectroscopy (FT-IR) and intrinsic viscosity ([η]) measurements revealed that degradation of PSD occurs to some extent during oxidation when KMnO₄ was used. Further, FT-IR and [η] results indicated that the oxidation of PSD using KMnO₄ is better in heterogeneous conditions than under phase-transfer medium because the degradation was curtailed in the former case. Direct pyrolysis-mass spectrometry (DP-MS), Fast atom bombardment mass spectrometry (FABMS) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) analyses of the oxidized PSD was carried out and the obtained results corroborate well with the FT-IR and [η] studies. Increased rigidity of the oxidized polymers which is reflected in their T_g and [η] values, compared to PSD, was further confirmed by the radius of gyration (R_g) and trans percentage data calculated from the molecular dynamics simulations studies.