A new polyamide, nylon 4 14, was synthesized and characterized in this paper. The polymer was prepared by melt polycondensation, which yielded materials of molecular weight about 15,000 g/mol. The product was characterized by means of elementary analysis, intrinsic viscosity, infrared spectrometry, H-1 and C-13 nuclear, magnetic resonance, differential scanning calorimetry, and thermogravimetric analysis. In addition, the crystalline transition behavior of nylon 4 14 was carefully investigated by variable-temperature X-ray diffraction (XRD). It was found that well-melt-crystallized nylon 4 14 undergoes Brill transition at 170 degreesC on heating. When it crystallized at high temperature from the melt, nylon 4 14 crystallized directly into a kind of alpha phase with two peaks in its XRD patterns, which is very different from nylon 6 6 and nylon 10 12 and similar to nylon 10 10. Upon further cooling to room temperature, nylon 4 14 preserved the triclinic structure (a phase). (C) 2001 Elsevier Science Ltd. All rights reserved.