The synthesis of alternating poly(amide urethane)s 5a-d was performed in three steps using F-caprolactone, diamines, and diphenyl carbonate as starting materials. The microstructure and nature of the end groups of the poly(amide urethane)s were determined by means of H-1 NMR spectroscopy, which reveals an alternating sequence of amide and urethane linkages in a linear chain with hydroxy and phenyl urethane end groups. The molecular weight and polydispersity of the polymers obtained (5700 < M-n < 7900, 1.25 < M-w/M-n < 1.38) were determined by means of gel permeation chromatography. The thermal properties determined by means of DSC show that the poly(amide urethane)s 5a-d are semicrystalline materials having one or two endothermic transitions similar to the poly(amide urethane)s 10a-d prepared from F-caprolactam, amino alcohols, and diphenyl carbonate. Thermogravimetric analysis of poly(amide urethane)s 5a-b shows a single step decomposition, while poly(amide urethane)s 10a-c decompose in two steps indicating that different degradation mechanisms are operating. (C) 2004 Elsevier Ltd. All rights reserved.