Polyurethane coatings modified with ladder‐like polysiloxane

In this work, ladder‐like polyphenylsiloxane containing silanol groups was used for modification of polyurethane (PU) based on MDI and polypropylene oxide polyol. The obtained coatings have excellent mechanical performance and adhesion to steel. This improvement was confirmed through a combination of characterization techniques. The tensile strength and strength adhesion to steel increase by more than one order of magnitude when polysiloxane fraction increased from 10 to 50 wt.%. With an increase loading level, the coating transforms from hydrophilic to hydrophobic. The reinforcement effect was motivated by restriction of molecular mobility in PU matrix as was shown by solid‐state ¹H NMR spectroscopy and formation of chemical bonds between PU and polysiloxane units.