Synthesis of polystyrene-block-poly(styrene-co-acrylonitrile) block copolymers and thermoanalytical studies of nitroxide-terminated poly(styrene-co-acrylonitrile) copolymers
M. Baumann et al., Synthesis of polystyrene-block-poly(styrene-co-acrylonitrile) block copolymers and thermoanalytical studies of nitroxide-terminated poly(styrene-co-acrylonitrile) copolymers, MACRO MAT E, 280(7-8), 2000, pp. 1-6
The synthesis of polystyrene-block-poly(styrene-co-acrylonitrile) block cop
olymers by conversion of polystyrene terminated with 2,2,6,6-tetramethylpip
eridine-N-oxyl (TEMPO) are described. We have found a considerable accelera
tion in polymerization rate and increasing of molecular weights due to the
donor acceptor interaction of styrene and acrylonitrile. Analysis of the bl
ock copolymer composition by means of H-1 NMR spectroscopy allowed to deter
mine the copolymerization parameters. The comparison with the parameters of
the free radical copolymerization shows that there is no influence of TEMP
O on the composition. The polydispersity index of the copolymer subchain in
the block copolymers decreases rapidly with increasing time of polymerizat
ion, depending on the polymerization rate of the copolymerization. The ther
mal stability of nitroxide-terminated poly(styrene-co-acrylonitrile) copoly
mers was investigated by means of thermogravimetry and pyrolysis gas chroma
tography coupled with mass spectrometry. At temperatures above 200 degrees
C the splitting of the nitroxyl polymer bond takes place, indicating a weak
degradation of the polymer. However, there is no effect of the terminator
on the decomposition pattern of the copolymer at 500 degrees C.