Synthesis, Characterization and Emulsifying Property of the Polyamide Elastomer with Favorable Self-healing Performance

Polyamide based self-healing elastomer was obtained through a one-step reaction of dicarboxylic acid and triethylenetetramine. The polyamide elastomer characterized by thermogravimetric analysis indicated a favorable thermal degradation temperature at around 400°C. Differential scanning calorimetry analysis demonstrated that the glass-rubber-viscous flow transition occurred during the heating process from ‒30 to 200°C. The reversible hydrogen bonding interactions, manifested by the temperature-dependent Fourier transform infrared spectroscopy, contributed to the self-healing characteristics of the polyamide elastomer. Time-dependent as well as temperature-dependent self-healing efficiency was quantitatively characterized by tensile tests respectively. The recovered tensile stress at break of the tested specimen could reach more than 90% at 24 h of contact. In addition, the healing behavior was also promoted by the temperature-driven molecular motions since higher self-healing efficiency was gained during the heating process. The polyamide elastomer was feasible to be emulsified by alkyl amine oxide at proper pH condition. The self-healing property of the prepared emulsion was demonstrated by the spontaneous agglomeration of the treated quartz grains, indicated that the polyamide elastomer could be utilized in the aqueous state rather than be constricted to the bulk phase, which greatly expanded the operating conditions of the self-healing elastomer.