Easy synthesis of self-healing thermoplastic elastomer (TPE) via functionalization of styrene block copolymer (SEBS) with a cyclic amine compound in melt state and rheological assessment of non-covalent dynamic interactions

In this study, an amine functionalized thermoplastic elastomer was easily synthesized by a semi-batch reactive melt compounding method in an internal mixer at 165 °C using maleic anhydride grafted styrene-block-ethylene/butylene-block-styrene copolymer (SEBS-g-MAh) as elastomer phase and 3-amino-1,2,4-triazole (TA) as cyclic amine compound. Then a metal salt, zinc nitrate (Zn(NO₃)₂), was introduced into the melt mixer to form metal-ligand interactions between amine functionalized TPE. Structural, mechanical, rheological, and viscoelastic properties of functional TPE were characterized by various analytical methods such as FTIR, DMA, rotational rheometer, and tensile test. FTIR analysis confirmed that the primary amine groups of cyclic amine compound reacted with maleic anhydride of SEBS-g-MAh to form maleimid groups. Formation of metal-ligand interactions in the modified TPE structure was also shown with various rheological measurements such as strain-dependent, frequency-dependent, and time-dependent test procedures and different mathematical models. It was shown that the strong metal-ligand interactions provided the modified TPE, temperature-induced self-healing property.