Bio-based elastomeric hyperbranched polyurethanes for shape memory application

The bio-based shape memory hyperbranched polyurethanes (HBPUs) have attracted tremendous attention both from academic and industrial researchers due to their strong potential in biomedical and other advanced applications. In the present investigation HBPUs have been synthesized from poly(??-caprolactone)diol as a macroglycol, butanediol as a chain extender, triethanolamine as a branch generating moiety, monoglyceride of Mesua ferrea L. seed oil as a bio-based chain extender, at different percentages and toluene diisocyanate by a two step one pot A₂?+?B₃ approach. The structure of the synthesized hyperbranched polyurethane was characterized by FTIR, ^IH NMR, XRD and SEM studies. ¹H NMR study indicates the formation of highly branched structure with degree of branching 0.93 for polyurethane with 5?wt% monoglyceride. TGA results indicated the increment of thermal stability from 185 to 240?°C with the increase of monoglyceride content from (0?C15) wt% for the HBPUs. The shape memory effect of the hyperbranched polyurethane increased with the increase of monoglyceride in the polymer. However, mechanical properties like tensile strength and elongation at break decreased from 19.31 to 11.48?MPa and 835 to 497%, respectively, with the increase in amount of bio-based component. Excellent impact strength and very good chemical resistance were also observed for the hyperbranched polymers. The studied bio-based HBPUs exhibit excellent shape fixity (95?C99)% as well as shape recovery 100%. Thus, the studied HBPUs have the potential to be used as advanced shape memory materials.