Study On The Preparation And Anticorrosion Of The EP/PU-SiO₂ Hybrid Material

Epoxy resins (EP) are the most important class of thermosetting matrices used in engineering because of their outstanding adhesion to most surfaces, high mechanical strength,and chemical resistance. They have been used as adhesives, coatings and resin matrices for advanced composites. However, their brittle behavior with low elongation and impact strength restrict the utility for high performance applications. The major concern of this paper is to study the preparation of the EP/PU-SiO₂ nanocomposites by incorporation TEOS via the sol-gel process and synergistic effects of SiO₂ and EP/PU IPNs on improving mechanical and thermal properties of pure EP were investigated by mechanical test, SEM, TEM,DSC, TGA. We investigate the Tafel polarization plots and electrochemical impedance spectrum of the corrosion-resisting coating.The results can be concluded that the incorporation of PU in epoxy improves its toughness, but reduces its strength.15% PU is compatible with EP,it could optimize the mechanics capability. But the strength decreases at the time of toughness' increase. Whereas, the incorporation of SiO2 in EP/PU IPNs improves its strength and toughness at the same time.TG-DSC showed the thermostability of hybrid materials were greatly improved, because the strong Si-O-Si network restricted the epoxy polymer chains and the bond energy of Si-O was bigger than that of C-C.Tafel polarization plots of hybrid coatings on carbon steel in 3.5wt% sodium chloride solution were obtained. The results show that zero current potential (E_corr) of the hybrid coatings increased and the corrosion current (I_corr) decreased. The results from electrochemical impedance spectrum (EIS) indicated that EP/PU-SiO₂ hybrid coating was a coating with big coating resistance and small capacitance. The corrosion resistance was found to increase by 63% after EP/PU-SiO₂ hybrid coating was doped 7wt% SiO₂ inhibitor.