The effect of polyol types and molecular weight on the shape memory properties of palm kernel oil - Based polyurethane

The main objective of this study was to investigate the effect of different types and molecular weight (MW) of polyol on the shape memory properties of palm kernel oil-based shape memory polyurethane (SMPU) prepared by two step bulk polymerization procedure. Poly(ethylene glycol) (PEG) and poly(?-caprolactone) (PCL) with MW 2000 and MW 4000 were used as the main material for soft segment. The addition of palm kernel oil polyol (PKO-p) in the SMPU system is due to the concern of the renewable resources. Shape fixity and shape recovery properties were investigated using bending test to evaluate the shape memory effect. The results indicate that the shape fixity of SMPU depends primarily on the types of polyol whereas MW had a slight effect towards the shape fixity. SMPU synthesized from PEG with MW 2000 performed a good shape fixity, about 96% compared to that of PCL with MW 2000, about 29%. In the case of PCL - based SMPU, the increase of shape fixity is proportional to the increase of MW. All samples, except the one based on PEG4000, exhibited excellent shape recovery (100%). � 2019 Elsevier Ltd. All rights reserved.