The polyurea samples were respectively immersed in 30% phosphoric acid, 30% nitric acid, 30% sulfuric acid, 10% sulfuric acid, and 10% sodium hydroxide solution, and the tensile strength and tear strength of the samples were periodically tested.
Polyurea coating acid and alkali resistance can be understood as the stability of polyurea material to water and acid-base solution. It includes both the expansion process of polyurea material and its chemical reaction with acid-base solution, leading to aging of coating. the process of.
It can be seen from the experimental results that the mechanical properties of the coatings decreased after the polyurea coating was soaked in different concentrations of acid and alkali solution, and the tensile strength of the coating was significantly higher than the tear strength. The weak acid and weak base have lower influence on the performance of polyurea coating, and the tear strength is not significantly reduced. The polyurea coating can maintain good mechanical properties in weak acid and weak alkali solution.
The mechanical properties of the polyurea coating immersed in 10% NaOH solution are higher than the mechanical properties of the coating after immersion in 10% H2SO4 solution. It can be proved that the polyurea material has better alkali resistance than acid resistance. The 30% nitric acid with strong oxidizing property is more obvious to the coating. After 20 days of immersion, the mechanical properties of the coating are obviously reduced.
