Applications of hydrophobic α,ω-bis(amino)-terminated polydimethylsiloxane-graphene oxide in enhancement of anti-corrosion ability of waterborne polyurethane

Hydrophobic polydimethylsiloxane-functionalized graphene oxide (NH 2 -PDMS-GO), α, ω-bis(amino)-terminated polydimethylsiloxane (NH 2 -PDMS-NH 2 ) and graphene oxide (GO) are grafted into waterborne polyurethane (WPU) to enhance wettability , water resistance permeation and corrosion resistance properties. The result displays that the NH 2 -PDMS-GO and NH 2 -PDMS-NH 2 apparently improve the water contact angle of WPU. The value of water contact angle of WPU/NH 2 -PDMS-GO is 117°, and that of WPU/NH 2 -PDMS-NH 2 is 107.8°. They are higher than that of WPU (76.25°). The water absorption value of WPU is 8.34 wt.%. The values of WPU/NH 2 -PDMS-GO and WPU/NH 2 -PDMS-NH 2 are lower than that of WPU, which are 4.03 wt.% and 5.05 wt.%. For anti-corrosion performance, the WPU/NH 2 -PDMS-GO exhibits the best corrosion resistance ability, which displays the more positive corrosion potential (-0.08 V) and lower corrosion current density (3.636 × 10 −9 A cm -2 ) than others after 21 days immersion in 3.5 wt.% NaCl solution. The EIS results also show that the WPU/NH 2 -PDMS-GO reveals a well long-term corrosion resistance ability, and the impedance modulus Z 0.01Hz is still at 3.47 × 10 7  Ω cm 2 after 80 days immersion in 3.5 wt.% NaCl solution. The |Z| 0.01Hz of WPU decreases to 4.14 × 10 6 Ω cm 2 after 36 days. So, the NH 2 -PDMS-GO could effectively enhance the corrosion resistance of WPU.