Taking the “Hard” Out of Choosing the Right Polyurethane Hardness for the Job: A Study on the Impact of Polyurethane Elastomer Durometer on Mechanical/Wear Properties in Internal Coatings for Slurry Pipes

Abstract Polyurethane (PU) elastomer has a demonstrated record of providing high wear performance in Alberta oil sands mining when it comes being used as an internal coating for slurry pipes. However, choosing the optimal PU elastomer for a given application can be challenging. One method often used for categorizing PU elastomer is hardness, which is measured via durometer in the Shore A scale. Therefore, understanding how durometer values impact the wear properties of PU elastomer is of critical importance. In this study, a PU elastomer samples with durometer values ranging from 65-95 Shore A were prepared via hot casting and immersed in air, water, and bitumen at 85°C for up to 12 months. After immersion, the mechanical/wear properties were tested and compared. Results indicated that in milder mediums (i.e., air and water), mechanical/wear properties improved with decreasing durometer values, which was attributed to higher soft-segment content. In harsher mediums (i.e., bitumen) however, PU with higher durometer values showed greater stability in wear properties over time, despite poorer initial performance. This was attributed to the higher hard segment content of harder PU elastomer, as hard segments boast superior thermal and chemical stability.