Enhancing corrosion and abrasion resistances simultaneously of epoxy resin coatings by novel hyperbranched amino-polysiloxanes

Hyperbranched and linear amino-polysiloxanes with different functional groups were synthesized from trifunctional, difunctional and amino siloxanes and characterized. The amino-polysiloxanes as curing agents were used for hydrogenated diglycidyl ether of bisphenol A coatings. The effects of amino-polysiloxanes with different functional groups and different branching degrees on the surface properties, mechanical properties, corrosion resistance and thermal properties of the epoxy resin coatings were investigated. The epoxy coatings with hyperbranched amino-polysiloxanes exhibit better reactivity, higher hardness, better wear and corrosion resistance, and higher thermal properties as compared to that with the linear amino-polysiloxane. The coatings with the hyperbranching polysiloxanes can maintain lowest-frequency impedance (|Z|f=0.01Hz) above 108 Ω·cm2 after 30 days of the corrosion test, while coating with the linear polysiloxane only 107 Ω·cm2. Moreover, due to the introduction of trifluoropropyl, the fluorinated hyperbranched polysiloxane/epoxy resin coating (HBPSi-2Ph2F/EP coating) has the highest |Z|f=0.01Hz, up to 4.26 × 109 Ω·cm2. The hyperbranched amino-polysiloxanes as curing agents for epoxy resins would be expected to find wide applications in high performance coatings.