Study On Preparation Of Polyaspartic Polyurea And Its Property Of Anti-Cavitation

Polyurea is a kind of environment-friendly coating which developed from polyurethane. The latest one is polyaspartic polyurea. It has been applied to many engineering projects. Cavitation erosion is one of the main erosion manners on the hydraulic machines and buildings, it made them short-life. It will improve the material property of anti-cavitation for painting elastomer coating on the surface of metal material. In this paper, we will preparating polyaspartic polyurea and chosed 3 from 5 samples, applying them in experiment of anti-cavitation.This paper prepared isocyanate prepolymer in NCO% of 15% from HDI Trimer and PTMG. And prepared polyaspartic from amine terminated polyoxypropylene and dialkyl maleates via Michael Addition Reaction, because of amine terminated react with isocyanate faster than polyaspartic. So we added isocyanate to exhaust amine terminated, and titration the amine value of polyaspartic by HC1. We prepared polyaspartic polyurea from HDI Trimer prepolymer and polyaspartic ester, MOCA as chain extender, changed the contend of MOCA to get a series coatings. After the test of those coatings, the result showed that raise the contend of MOCA can increase tensile strength and adhesion of the coating and decrease elongation at break. All of the 5 samples had pretty dent resistance for their pretty flexility. Polyaspartic polyurea has good property of water-resistant for lot of hydrophobic group on its molecular chains.Paint polyurea coating which prepared above on the initial stage of test sample. After cavitation experiment, the result showed that the coating with contend of MOCA in 0.158 was better than contend of MOCA in 0.250 and 0.210. The result of recorded the progress of the damage of coating under cavitation indicated that the damage of the coating which contend of MOCA in 0.158 was fatigue damage, the frequency impact from high speed water jet which caused by the bubble collapse near the coating made the fatigue damage. All of the 3 samples are better than modified epoxy resin and rigid polyurea. This showed that the polyaspartic polyurea could apply in anti-cavitation.