Copolymer coating with outstanding corrosion inhibition properties
A novel class of copolymers containing polyimide and polyurea blocks with unique physical properties and capable of providing effective corrosion protection to aluminum alloy has been prepared.
The structure and properties of polyurea-b-polyimide (PUI) copolymers were controlled by varying the co-monomer concentration. The PUI block copolymer can reorganise into a supra-molecular structure by forming intra- and inter-hydrogen bonding interactions between adjacent copolymer chains, resulting in a dense and compact structure capable of protecting the imide ring from hydrolysis when exposed to a corrosive environment.
Remarkable decrease in surface energy
Apart from minimised surface hydrolysis, the establishment of compacted morphology also leads to a drastically improved barrier property and reduced diffusivity. Increasing polyurea concentration resulted in a remarkable decrease in diffussivity and surface energy, consistent with the measured increase in the coatings durability and corrosion performance. Corrosion inhibition tests were carried out for more than 30 weeks in a saturated NaCl solution containing 3.5 wt% of salt.
The study is published in: Applied Polymer Science, Volume 135, Issue 9, March 5, 2018.
