Improvement in Adhesion, Abrasion Resistance, and Aging of Polyurethane Coatings Prepared with Polycarbonate Diol for Internal Pipelines

Abstract

The paper deals with the improvement of adhesion, abrasion resistance, and aging of polyurethane coatings made with polycarbonate diol (PCD) intended for internal pipelines. The influence of the polyol nature on the properties and aging resistance of polyurethane coatings synthesized at laboratory scale using polyether glycol and PCD is determined. The use of PCD or mixtures of 50% by weight polyether glycol (PTMEG) and 50% by weight PCD in the synthesis of the polyurethane coatings strongly reduces the amount of material removed by abrasion. On the other hand, the use of 40% by weight PTMEG and 60% by weight PCD increases the mechanical properties of the polyurethanes and their pull-off strength values in joints made with steel substrate. After aging by immersion in water at 70°C for two weeks, the reduction of pull-off strength in the joint made with the polyurethane made with PTMEG and with a PCD and PTMEG mixture is similar but the loci of failure are different. Only the polyurethane coating prepared with 40% by weight PTMEG and 60% by weight PCD mixture shows a cohesive failure in the coating.