The Effects of Grafting and Crosslinking Aliphatic Dicarboxylic Acids onto Polyurethane on the Tensile Stress and Shape Recovery

The aliphatic dicarboxylic acid, glutaric acid or dodecanedioic acid, were used for the grafting onto polyurethane (PU) or cross-linking of PUs to gauge its impact on the hydrophilicity, tensile stress, and shape recovery properties of PU. The cross-link density and solution viscosity gradually increased, but the maximum tensile stress and shape recovery sharply increased with the increase of diacid content due to the chemical linking using the grafted diacid. The soft segment melting and glass transition were not substantially affected by the grafting of diacid. The water swelling of the diacid-grafted PUs gradually improved with time. The low temperature flexibility of PU slightly improved by the grafted glutaric acid compared with the control series PU. Therefore, the grafted dicarboxylic acid could enhance the hydrophilicity, maximum tensile stress, shape recovery, and low temperature flexibility of PU.