International. They prepared a new class of copolymers containing polyimide and polyurea blocks with unique physical properties and capable of providing effective corrosion protection to the aluminum alloy.
The structure and properties of polyurea-b-polyimide (PUI) copolymers were controlled by varying the comonomer concentration. The PUI block copolymer can be rearranged into a supramolecular structure forming intra- and inter-hydrogen bond interactions between adjacent copolymer chains, resulting in a compact and dense structure capable of protecting the imide ring from hydrolysis when exposed to a corrosive environment.
Noticeable decrease in surface energy
In addition to minimized surface hydrolysis, the establishment of compacted morphology also leads to a drastically improved barrier property and reduced diffusivity. The increase in polyurea concentration resulted in a noticeable decrease in diffusivity and surface energy, consistent with the measured increase in coating durability and corrosion performance.
Corrosion inhibition tests were conducted for more than 30 weeks on a saturated NaCl solution containing 3.5% by weight of salt.
Source: Applied Polymer Science.
