Effect of cross-linking density on coating properties of a polyurea coating system

Polyamides were prepared from a dimer fatty acid, triethylene tetramine and diethylene triamine, and cross-linked using e-caprolactam-blocked isophorone diisocyanate. These thermoset coatings were then evaluated for various mechanical, chemical and electrical properties. The effect of the cross-linking density on the coating properties was studied. It was observed that with the increase of the cross-linking density, the general toughness of the coatings increased along with chemical resistances, except for acid resistance and the breakdown voltage. However, it was observed that the flexibility and resistance to rapid deformation of the coatings (ie the rigidity of the coatings) decreased with an increase in the cross-linking density of the coating.