Dynamic characteristics and processing of filler polyurethane elastomers for vibration damping applications

Abstract

Polyurethane elastomers have the potential of being used to reduce vibrational noise in many engineering applications. The performance of the elastomer is directly related to the match between the nature of the mechanical loss characteristics and the frequency and temperature dependence of the source of the vibration. Materials with a broad frequency/temperature response to mechanical loss and a high-mechanical stiffness are desirable for situations where load bearing and isolation becomes an issue. Because automobiles, and other related vehicles operate over a broad temperature range, it is desirable for the damping characteristics of the elastomer to be as independent of temperature and frequency as possible. In practice, this is not easy and the creation of materials with the aforementioned mechanical stiffness and loss properties is highly desirable. In this article, the effects of various fillers on the breadth and temperature dependence of the vibration damping characteristics of a filled and cross-linked polyurethane elastomer are explored. These materials have different shapes, sizes, and surface chemistry and undergo different types of interaction with the matrix. The vibration damping characteristics are further varied by the use of a cross-linking agent. Data presented on the rheological characteristics indicate the strength of the filler–polyol interactions. Dielectric relaxation and dynamic mechanical thermal analysis demonstrate the way in which changes in the type of filler, concentration, and amount of cross-linker lead to changes in the location and breadth of the energy dissipation process in these elastomers. The vibration damping characteristics of a selected material are presented to demonstrate the potential of these materials.