Biobased Multifunctional Macroglycol Containing Smart Thermoplastic Hyperbranched Polyurethane Elastomer with Intrinsic Self-Healing Attribute

Abstract

Smart biobased self-healable polymers are advanced sustainable materials. Thus, a thermoplastic hyperbranched polyurethane (HBPUR) elastomer was synthesized by using a biobased multifunctional macroglycol along with other required components, for the first time. This biobased macroglycol was obtained by stoichiometric controlled esterification reaction of dimer acid with glycerol. Fourier transform infrared, nuclear magnetic resonance spectroscopic, gel permeation chromatography, and X-ray diffraction studies confirmed the physicochemical structure of the synthesized macroglycol and HBPURs. The degree of branching value (0.78–0.91) of HBPURs varies with this macroglycol content. These thermoplastic PUR elastomers exhibited outstanding toughness (205 MJ.m–³), unprecedented high elongation at break (2810–3160%), good tensile strength (8.2–9.5 MPa), impact resistance (>17.3 kJ/m), scratch resistance (4.0–4.5 kg), durometer hardness (52–60 Shore A), adhesive strength (3.3–6.7 kPa), thermostability (241–249 °C), and chemical and UV-resistance. Notably, HBPURs also showed excellent repeatable intrinsic self-healing efficiency (100%) under exposure of microwave (450 W). Moreover, HBPURs exhibited outstanding thermoresponsive shape recovery (100%) within 50–56 s at 60 °C. In addition, HBPURs showed acceptable biodegradation under the exposure of Pseudomonus aeruginosa and Bacillus subtilus bacterial strains. Again, HBPUR demonstrated superior performance over linear analogous PUR. Thus, HBPUR has great potential as a smart sustainable self-healing thermoplastic elastomer for different applications.