Characterization of Polyurethane Grafted with Bis(2-hydroxyethyl) Terephthalate

ABSTRACT Bis(2-hydroxyethyl) terephthalate (BHETPA) was grafted onto polyurethane (PU) to investigate the effects of BHETPA, which contains a rigid aromatic group and flexible hydroxyethyl groups, on the physical properties of PU. The cross-link density, viscosity, tensile strength, and shape recovery notably increased with an increase of BHETPA due to chemical cross-linking by BHETPA. A PU sample demonstrated excellent low-temperature flexibility compared with plain PU, showing complete recovery at approximately 0°C. Therefore, grafting BHETPA onto PU modified the thermal behavior and greatly improved the tensile stress, shape recovery, and low-temperature flexibility of PU compared to plain PU. GRAPHICAL ABSTRACT