ortho - and meta -substituted polystyrene polyperoxides: synthesis,characterization and thermal decomposition studies.

Abstract

The alternating copolymers of vinyl monomers with molecular oxygen (polyperoxides) show numerous novel physicochemical properties such as high exothermic degradation. In the work presented, polyperoxides were prepared by oxidative polymerization of ortho- and meta-substituted styrene monomers in toluene in the presence of 2,2′-azobisisobutyronitrile free radical initiator at 50 °C and 0.69 MPa oxygen pressure. The polymeric peroxides of styrene monomers with substituents in the ortho- and meta-positions thus obtained were characterized using NMR and Fourier transform infrared spectroscopies, elemental analysis and electron impact mass spectrometry to confirm the alternating copolymer structure with peroxy bonds in the backbone. Differential scanning calorimetry and thermogravimetric analysis were used to study the exothermic thermal degradation of these polyperoxides. For these polyperoxides, the measured heats of degradation (urn:x-wiley:09598103:media:pi4583:pi4583-math-0001) were found to lie between −169 and −180 kJ mol−1, which are comparable with the urn:x-wiley:09598103:media:pi4583:pi4583-math-0002 values of other vinyl polyperoxides. The exothermic degradation mechanism is supported by thermochemical calculations. © 2013 Society of Chemical Industry