Hydrophobic fluorinated polyurethanes (FPU) with no hydrophilic CH2OH groups were prepared

by using the method of introducing fluorine with perfluoroalkyl ethanol (TEOH-10) for modification of diphenylmethane diisocyanate (MDI) and controlling the MDI adding dosage and time. Water resistance experiments indicated that the FPU showed strong hydrophobic properties

owing to the low surface energy of fluorocarbon chains (CF2CF3) migrated to the surface of the material and formed the organic fluorine membrane which was equivalent to the lotus leaf hydrophobic effect. Especially when the molar ratio of TEOH-10 was 0.3~0.5 to the theoretical quantity of MDI

the water absorption of FPU was only between 0.0182% and 0.0146%

and the high bonding force of FPU was maintained at 10.31~10.79 MPa after soaking in water for 3200 h. The erosion wear experiments showed that the anti-erosion performance of FPU was continuously improved with the increase of fluoride content

however

the cohesive force of FPU was continuously reduced because of the increasing fluoride content. When the mole ratio of TEOH-10/MDI was 0.5

the cavitation erosion amount of FPU reduced from 2.375610-3 kg to 0.933410-3 kg

and the cohesive force of FPU stayed above 10 MPa. These hydrophobic fluorinated polyurethanes are promising to be used as a protective coating of under-water flow parts.