The Impact of Microphase Heterogeneity From Segment Distributions on the Damping Performance of Polyurethane

ABSTRACT In this work, polyurethanes (PUT‐X/PUP‐X) with distinct microphase structures were synthesized via a simple two‐step process. While maintaining identical chemical group compositions, the microphase heterogeneity of the polyurethanes was systematically enhanced by regulating the average molecular weight of the polyols. The microstructures of the materials were analyzed and characterized, and their dynamic mechanical properties were investigated, revealing an inverse correlation between the degree of microphase heterogeneity and dynamic mechanical performance. Furthermore, this study supplements the LA/TA (loss area/tan δ area) linear additivity theory in the damping group contribution theory, demonstrating that the damping properties of polyurethane are not solely determined by the type and number of chemical groups but are also significantly influenced by the internal microphase structure‐induced heterogeneity. This research provides a more comprehensive theoretical foundation for the subsequent design and development of high‐damping polyurethane.