The synthesis of polyisoxazoles incorporating fatty acids

Abstract

Polyisoxazoles derived from thermal and base-mediated nitrile-N-oxide cycloaddition to fatty amide derived alkynes with up to 44% biobased content are described and their structural and thermal properties reported. Glass transition temperatures, T_g, (ranged from −1.1 °C to 62.0 °C), and measured molecular weights were dependent upon the level of unsaturation in the fatty amide feedstock, the regiochemistry of the dinitrile-N-oxide monomer and whether polymerisation was thermally or base-mediated. For base-mediated processes the solvent played a critical role in controlling the molecular weights of the obtained polymers. MALDI-TOF-MS, infrared and ¹H and ¹³C NMR analysis indicated polymerisation proceeds to give mixtures of linear, cyclic, branched or furoxan incorporated materials.