Synthesis of Self-Healing Supramolecular Rubbers from Fatty Acid Derivatives, Diethylene Triamine, and Urea DAMIEN MONTARNAL, PHILIPPE CORDIER, CORINNE SOULIE ´ -ZIAKOVIC, FRANC ¸ OIS TOURNILHAC, LUDWIK LEIBLER Matie `re Molle et Chimie, ESPCI-CNRS (UMR7167) 10 rue Vauquelin, Paris 75005, France Received 25 July 2008; accepted 22 September 2008 DOI: 10.1002/pola.23094 Published online in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: We describe the synthesis of supramolecular self-healing elastomers from vegetable oil fatty acid derivatives, diethylene triamine, and urea. Our strategy to obtain materials that are self-healing but do not flow relies on the use of a wide mo- lecular distribution of randomly branched oligomers equipped with self-complemen- tary and complementary hydrogen bonding groups. We prepared such oligomers with a two steps procedure. In the first step, diethylene triamine was condensed with dimer acids. In the second step, the oligomers obtained were allowed to react with urea. The molecules were characterized by NMR and IR spectroscopies and Monte-Carlo simulations were used to analyze the molecular size distribution. The sensitivity to small variations of the experimental conditions has been examined and the robustness of the synthetic procedure optimized. V V C 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7925–7936, 2008 Keywords: branched; elastomers; molecular weight distribution/molecular mass distribution; Monte Carlo simulation; supramolecular structures; synthesis INTRODUCTION Most thermoplastic elastomers are made of poly- mers connected into a network by physical associ- ations such as small glassy or crystalline domains. 1–3 At room temperature, these materials behave like covalently crosslinked rubbers: they show enormous extensibility and withstand large deformations without flow. They recover their original shapes and dimensions when stresses are released. However, in contrast to chemically cross- linked networks, at high temperatures when glassy or crystalline domains melt, these materi- als can be processed like conventional thermo- plastics. Using polymers or small molecules hav- ing low glass transition temperatures with func- tional groups able to form self-complementary multiple hydrogen-bonds that lead to the forma- tion of supramolecular networks could provide an interesting alternative route towards the develop- ment of thermoplastic elastomers that are easier to process and repair or reuse. The concept of thermoplastic elastomers made of chains associating by directional hydrogen bonds was introduced and demonstrated by Sta- dler and coworkers who synthesized polybuta- dienes functionalized with phenyl-urazole deriva- tives. 4–7 The pairwise associations of urazole groups modify the viscoelastic properties of poly- butadiene chains by considerably increasing the characteristic stress relaxation time. Indeed, stress relaxation, thus, creep and flow are con- trolled by association-dissociation times of func- tional groups and not solely by monomer friction coefficients and the presence of entanglements. Journal of Polymer Science: Part A: Polymer Chemistry, Vol. 46, 7925–7936 (2008) V V C 2008 Wiley Periodicals, Inc. Correspondence to: F. Tournilhac (E-mail: francois.tournilhac@ espci.fr) or L. Leibler (E-mail: ludwik.leibler@espci.fr) 7925