Synthesis and characterization of novel odd-even nylons based on eicosanedioic acid

A series of novel odd-even nylons based on eicosanedioic acid, including nylons 11/20, 9/20, 7/20, 5/20, and 3/20, were prepared through step-heating melting polycondensation with various diamines, and the products were comprehensively characterized. The results of FTIR, Raman spectra, NMR, and elemental analysis confirmed that the synthesized polyamides had the expected chemical structures. The viscosity-average molecular weights of the obtained polyamides were in the range of 6.0 X 10(3)-1.4 X 10(4). The melting points of the nylons, determined by differential scanning calorimetry, changed from 167 to 194degreesC. Thermogravimetric analysis gave the decomposition temperatures of the obtained nylons at about 460degreesC, except for nylon 3/20. Furthermore, dynamic mechanical analysis (DMA) was applied to nylons 11/20, 9/20, 7/20, and 5/20. The glass-transition temperatures, measured by DMA, ranged from 29 to 52degreesC. (C) 2004 Wiley Periodicals, Inc.