Molecular engineering and properties of chitin based shape memory polyurethanes

Shape memory polyurethanes (SMPUs) are playing a prominent role in biomedical, self repairing, aerospace and smart materials. Shape memory polyurethanes (SMPUs) were prepared from polycaprolactone diol 4000 (PCL4000), 1-4-butanediol (BDO), chitin, dimethylol propionic acid (DMPA), triethylamine (TEA), and 4, 4′-diphenylmethane diisocyanate (MDI). Trifunctional characteristics of chitin enhanced the thermal and mechanical properties of SMPUs. DMPA was used to obtain higher recovery and lower residual strain. The morphology, microstructure, mechanical, thermo-mechanical, and shape memory properties of synthesized SMPUs were investigated using Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC), dynamic mechanical thermal analyzer (DMTA) and tensile testing techniques. The results showed that crosslinked SMPUs have better thermal and thermo-mechanical properties, and a good shape memory effect.