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Thermally crosslinked rigid…rod aramids, 1. Synthesis of a new monomer and its polymerization
Author(s) -
Rickert Christoph,
Neuenschwander Peter,
Suter Ulrich W.
Publication year - 1994
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.1994.021950210
Subject(s) - thermogravimetry , monomer , polymer chemistry , diamine , polymerization , chemistry , curing (chemistry) , terephthaloyl chloride , polymer , condensation polymer , electron paramagnetic resonance , nuclear magnetic resonance , organic chemistry , inorganic chemistry , physics
With 2,2,6,6‐tetraoxo‐1,3,5,7‐tetrahydro‐2,6‐dithia‐ s ‐indacene‐4,8‐diamine (DSDA) ( 8 ), a new monomer for the synthesis of thermally crosslinkable rigid‐rod aramids was developed. DSDA was copolymerized with p ‐phenylenediamine and terephthaloyl dichloride by a low‐temperature solution polycondensation to give high‐molecular‐weight aramids (inherent viscosity η inh > 2,2 dL/g). The fraction of DSDA could be varied from 0 to 100 mol‐% of the diamine used in the condensation. All polymers showed a weight loss due to thermal elimination of SO 2 . Thermal crosslinking could be effected by curing the samples at high temperatures (280–320°C). The crosslinking reaction was investigated by means of thermogravimetry (TG), thermogravimetry/mass spectrometry (TG‐MS), Fourier transform infrared (FT‐IR), 13 C cross polarization‐magic angle spinning nuclear magnetic resonance ( 13 C CP‐MAS NMR) and electron paramagnetic resonance (EPR). The activation energy for this reaction was found to be between 150 and 170 kJ/mol. Curing of the polymer samples led to the generation of stable, matrix‐isolated radicals.