Cavitation Behavior Of Polyurethane Coatings In Seawater

This essay expatiates on the ship propeller wreck problem in the ocean, espe-cially cavitation damage, studying the cavitation behavior of the waterborne polyure-thane coating in seawater, providing the scientific basis for the development of wa-ter-based polyurethane protective coatings, for improving the cavitation to resistance of ship propeller has a positive significance.In this paper, water based polyurethane emulsion and coating were prepared by the method of designing the hard segment content of the aqueous polyurethane coat-ing, the cross-linking of the soft segment and the adding amount of the powder. The coating mechanical properties (shore hardness, tensile properties and abrasion re-sistance) and the structure (infrared spectroscopy, differential thermal analysis, con-tact angle, water absorption and dissolution rate) are studied,especially on the coating in seawater of cavitation erosion resistance, by cavitation temperature, coating thick-ness, hard segment content, crosslinking, powder content variables studied coating in seawater of anti-cavitation ability, through time, cavitation, mass loss and surface morphology characterized the ability level. The research shows that the higher hard segment content, the poorer anti-cavitation performance, the shorter time; cavitation temperature is higher, coating resistant to cavitation ability is poorer; coating thick-ness is higher, the anti-cavitation damage capability is strong; n220/n330 is lower, coating resistant to cavitation ability is poorer; powder content increase, increasing the strength of the coating, cavitation to resistance is reduced; substrate of cavitation time is only 3 hours, plus coating door greatly slowed the cavitation effect.According to the result shows that, hard segment content is 30% or n220/n330 ratio is 13, the coating has good emulsion stability, tensile strength is 10.77MPa and fracture extension rate is 1090%, also has good elastic recovery rate (99.16%), when do not add powder, coating with more excellent resistance to cavitation erosion re-sistance and abrasion resistance ability.