Grafting of niclosamide and salicylanilide onto hydrophilic polyurethane for the control of fungal and barnacle growth

Grafting of niclosamide or salicylanilide onto polyurethane (PU) was executed to develop antifungal effectiveness and barnacle repelling capability in seawater compared with underivatized PU. The PU surface was simultaneously modified to improve the surface hydrophilicity by inserting dimethylolpropionic acid into PU frame or by grafting recycled polyols onto PU. Surface modifications of PU significantly affected its properties, such as cross-link density, tensile and shape memory properties, and flexibility under freezing conditions relative to the unmodified PU. The modification of PU surface also notably influenced the glass transition and the melting and crystallization related to soft segments. The breaking tensile stress and the shape recovery were enhanced significantly after the grafting of polyol due to chemical cross-linking, whereas the breaking tensile strain was not reduced. Some PU samples demonstrated complete antifungal effectiveness against a mixture of fungi, and barnacle growth on PU films was limited in the specifically modified PUs.