The Lateral Cross‐Linking of Polyurethane Using Grafted Epichlorohydrin and the Impact on the Tensile and Thermal Properties

ABSTRACT Epichlorohydrin (ECH) was used as a cross‐linking agent for a series of polyurethanes (PU series). The spectroscopic, thermal, tensile, shape memory, low‐temperature flexibility, and water vapor permeability properties of these PUs were compared with those of a control polyurethane series (CPU series) without ECH cross‐linking. In the thermal test, the soft segment crystallization of the PU series disappeared as the ECH cross‐linking increased. The glass transition temperature (Tg) of the PU and CPU series slightly increased with the increase in ECH content. The tensile strength of the PU series sharply increased at a critical ECH content, whereas that of the CPU series did not. The breaking strain of the PU and CPU series remained the same with the increase in ECH content. The shape recovery of the PU series remained above 90% at 45°C but increased moderately with the increase in ECH content at 0°C. Finally, the PU series with ECH cross‐linking demonstrated better low‐temperature flexibility and lower water vapor permeability than the unmodified PU.