Synthesis and characterization of caprolactone based polyurethane with degradable and antifouling performance

Abstract In this work, a degradable polyurethane composed of caprolactone (CL) and L-Lactide (LLA) as soft segments, and 4,4'-methylenebis(cyclohexyl isocyanate) (H12MDI) and polytetramethylene ether glycol (PTMEG) as hard segments, was prepared. Hydrolytic degradation experiment revealed that the degradable polyurethane (PU) could be degraded in artificial seawater. It also showed that caprolactone-co-polyurethane (CL-PU) copolymer with higher crystallinity degraded much slower in artificial seawater. However, the introduction of LLA resulted in an increase in the hydrophilicity and reduction in the crystallinity of degradable PU, as demonstrated by the contact angle analysis. The result of the scanning electron microscope showed that the surface of degradable PU renewed under static condition. Moreover, degradable PU was able to be used as a carrier, and it controlled the release rate of 4, 5-dichloro-2-octyl-isothiazolone (DCOIT). The anti-diatom (Navicula incerta) test demonstrated that the (caprolactone-co-L-lactide)-co-polyurethane 4 (CL/LAx-PU4) with DCOIT contents prevented the adhesion of diatom Navicula incerta (88.37 % reduction) due to their self-polishing and the release of antifoulants. Therefore, the degradable PU consisted of CL, LLA, and DCOIT could be a durable resin with good antifouling activity for the application in the marine anti-biofouling field.