Synthesis and characterization of alternating poly(amide urethane)s from ε-caprolactone, diamines and diphenyl carbonate

The synthesis of alternating poly(amide urethane)s 5a–d was performed in three steps using ε-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 1H 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 ε-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.