Biodegradable solvent-induced shape-memory hyperbranched polyurethane

Solvent-induced shape-memory polymers are of immense interest in various fields, especially biomedicine, as the high transition temperatures required to induce shape recovery in thermoresponsive shape-memory polymers can have adverse effects. In this work, hyperbranched polyurethane was prepared from poly (epsilon-caprolactone) diol, butanediol, monoglyceride of Mesua ferrea L. seed oil, triethanolamine, and toluene diisocyanate by a pre-polymerization technique. Biodegradation of the polyurethane was assessed by the broth culture technique, and adequate biodegradation was noted in Fourier transform infrared spectroscopy and scanning electron micrography studies, thermogravimetric analysis, and measurements of mechanical properties. The shape recovery of this hyperbranched polyurethane was tested by immersing it in various solvents with differing solubility parameters. The prepared polyurethane showed excellent shape recovery within a short time (10 min) in dimethylformamide. A differential scanning calorimetric study showed decreases in the glass transition temperature and the melting temperature of the sample when it had recovered its shape. The solubility parameter, polarity, and size of the solvent molecules were found to exert the strongest influences on the shape recovery. The studied hyperbranched polyurethane has the potential to be used as an advanced solvent-responsive shape-memory material.