“…PU is a molecular backbone containing urethane ( NHCOO ) repeating unit, the soft and hard controllable, balanced performance of functional polymer materials, with good biocompatibility, no distortion, allergic reactions, toxicity in line with medical conditions, simple processing, and other advantages. [8][9][10][11] In general, PU macromolecules are typically made up of alternating soft and hard segments that are chemically connected to one another along the main chain. 12 The soft segment, also known as the flexible segment, has low polarity and is mainly composed of polyols containing ester or ether groups on the chain.…”