Modification of polyurethane by graft polymerization of poly(acrylic acid) for the control of molecular interaction and water compatibility

Abstract

Polyurethane (PU) was graft polymerized with poly(acrylic acid) (PA) to form a PA-grafted PU (UA) series, and a control PU (C) series containing free PA was also prepared for comparison. The grafted PA could be ionized, and an ionized PA-grafted PU (IUA) series was separately prepared. The spectroscopic, thermal, tensile, shape memory, low-temperature flexibility, and water permeability properties of the polymer series were compared. With an increase in the PA content, the T m did not change, but ΔH m decreased for the UA, IUA, and C series. The T g did not significantly change with the increase in PA content for the UA, IUA, and C series. The tensile strengths of the UA and IUA series sharply increased with the PA content, whereas that of the C series did not. The breaking strain of the UA, IUA, and C series remained the same with the increase in PA content. The shape recovery and shape retention of the PU–PA series remained high after four repeated tests. Finally, the IUA series PU demonstrated better low-temperature flexibility and water compatibility than the unmodified PU.