Ionic Crosslinking of Polyurethane Copolymers by the Grafted Pendant Groups

摘要

Polyurethane (PU) has undergone an extensive study and can be functionalized by the grafted pendant groups. Actually, poly(ethylene glycol) (PEG) has been grafted to polyurethane to improve the biocompatibility in biomedical applications, and low temperature shape recovery was improved by the grafted pendant group. The tensile strength and the shape recovery were raised by the terminal and the lateral crosslinking. The carbamate unit in PU was frequently employed as the grafting point due to advantages such as ample linking sites, high reactivity, and mild coupling conditions. Shape memory PU with propionic acid side group was already reported for the control of mechanical strength. Meanwhile, the neutralization pairing between dimethylamino and carboxyl head groups was applied for the vesicle formation from single chain surfactants. In this investigation, the PUs grafted with a dimethylamino or a carboxyl pendant group were ionically crosslinked by neutralization to increase their molecular interaction and the impact on tensile strength and shape memory is examined.