Shel Ann X. Huang, K. Chuang, Stephen Z. D. Cheng
Jun 1, 2000
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Influential Citations
37
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Polymer
Abstract
Abstract A bis[pyrylium tetrafluoromethanesulfonate (triflate)], i.e. p -bis[4-(2,6-diphenylpyrylium)]benzene ditriflate) ( 3 ), has been prepared and polymerized with a series of aromatic diamines. The polymerizations, which were carried out in a dimethylsulfoxide (DMSO)/toluene mixture at 150°C for 3–4 h, were significantly faster than previous polymerizations of an analogous bis(pyrylium tetrafluoroborate). The poly(pyridinium triflate)s ( 5 ) obtained were soluble in polar aprotic solvents and had inherent viscosities that ranged from 8.3 to 18.7 dl/g (0.1 g/dl in DMSO at 30.0±0.1° C ). The rigid-rod polymers obtained from all- para -catenated diamines had viscosities comparable to those of other rigid-rod polyheterocyclics. All of the polymers could be solution cast into tough thin films that had moduli of 2.3–5.5 GPa. The poly(pyridinium triflate)s ( 5 ) were significantly more thermally and thermooxidatively stable than analogous poly(pyridinium tetrafluoroborate)s. The polymers underwent 5% weight losses near 451°C in nitrogen and near 461°C in air when subjected to thermal gravimetric analysis at a heating rate of 10°C/min. The differences in the poly(pyridinium salt) stabilities were shown to be due to the differences in the stabilities of the counter ions.