Authors Abdelrehim, M. ; Komber, H. ; Langenwalter, J. ; Voit, B. ; Bruchmann, B.
Title Synthesis and Characterization of Hyperbranched Poly(urea-urethane)s Based on A A* and B2B* Monomers
Date 28.09.2004
Abstract Hyperbranched aromatic and aliphatic poly(urea-urethane)s were prepared by the one-pot method using 2,4-toluylene diisocyanate (TDI), isophorone diisocyanate, and 2(3-isocyanatopropyl)cyclohexyl isocyanate as AA* monomers and diethanol amine and diisopropanol amine as B<SUB>2</SUB>B* monomers. The characteristics of the resulting polymers were very sensitive to slight changes in the reaction conditions, such as temperature, concentration, and type of catalyst used, as can be seen from the results of gel permeation chromatography and differential scanning calorimetry. The structures were analyzed in detail using <SUP>1</SUP>H and <SUP>13</SUP>C NMR spectroscopy. By using model compounds, the different isomeric structures of the TDI polymers were deduced, their percentages of their linear, terminal, and dendritic subunits were calculated, and their degree of branching (DB) was determined. DB values up to 70% were reached depending on the reaction conditions and stoichiometry of the monomers. The number of terminal groups decreased significantly when dibutylamine was used to stop the reaction instead of B<SUB>2</SUB>B*, indicating the presence of a significant number of unreacted isocyanate groups in the hyperbranched product when the polyaddition reaction was stopped. &copy; 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3062-3081, 2004
Journal Journal of Polymer Science: Part A: Polymer Chemistry 42 (2004) 3062-3081

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