Synthesis and Characterization of Bis(2-hydroxypropyl)amide-Based Hyperbranched Polyesteramides

Abstract

Polycondensation of 1,2-cyclohexane dicarboxylic anhydride with a calculated molar excess of di-2-propanolamine led to bis(2-hydroxyalkyl)amide based hydroxy-functional hyperbranched polyesteramides in a straightforward manner. Modification reactions of these polymers with lauric esters was conducted in different synthetic approaches. The obtained polymers were characterized by mass spectrometry, using electrospray ionization (ESI) and matrix assisted laser desorption ionization/time-of-flight (MALDI−TOF) techniques, and by size exclusion chromatography in combination with on-line viscosimetry detection (SEC−DV). Comparison of the experimental results with theoretical calculations showed a satisfactory match on molecular weights and polydispersities with fully modified polyesteramides. These values were found to deviate with unmodified and, to a smaller extent, with partially modified polyesteramides. This phenomenon could be attributed to side reactions of the 2-hydroxypropylamide end groups. The lauric ester modified polyesteramides obtained from either consecutive or simultaneous polycondensation and lauric acid esterification were found to be quite similar in structure and molecular weight distribution. This observation underlined the influence of transesterification reactions under the applied conditions.