Influence of prepolymer reaction time in the fabrication of palm kernel oil polyol based shape memory polyurethane

Abstract

AbstractVegetable oil‐based shape memory polyurethane (SMPU) has been rapidly developed in the field of advanced polymeric materials due to its unique responsive characteristic. This research aimed to investigate the effect of prepolymer reaction time on the microphase separation, soft segment crystallinity, shape memory, and tensile properties of palm kernel oil polyol (PKO‐p)‐based SMPU. The SMPU samples were prepared via two‐step bulk polymerization process utilizing 4,4‐methylenebis (cyclohexyl isocyanate) (HMDI), polycaprolactone diol (PCL) and 1,4‐butanediol (BD). The reaction time after the addition of PKO‐p varied from 0.5 to 2.5 h in prepolymer synthesis. This reaction time resulted in excellent microphase separation and improve shape memory properties. The Fourier transform infra‐red analysis revealed that the degree of microphase separation of the polyurethane elastomer (PUE) increased with increasing prepolymer reaction time. In consequence, the shape fixity behavior of the PUE samples improved. The tensile strength and strain at break of PUE increased with increasing reaction time up to 2.0 h. However, when the reaction time was prolonged to 2.5 h, both values decreased. Thus, the results showed the advantages of using PKO‐p, which can minimize the usage of petroleum‐based polyol and improve the tensile and shape memory behavior of the PKO‐p‐based SMPU.