Vibration and Acoustic Damping of Flexible Polyurethane Foams Modified with a Hyperbranched Polymer

Abstract

The dynamic mechanical properties and acoustic damping of polyurethane (PU) foams loaded with a hyperbranched polymer (HBP) have been studied. The results show a significant modulus enhancement parallel to an increased vibration damping in the low frequency range of ~1 Hz with increased amount of HBP. Furthermore, an increased acoustic damping in the frequency interval of 500—1600 Hz is observed with increasing amount of HBP. The origin of these property enhancements are sought in the morphology and the chemical composition of the PU foam. It has been found that no visible differences in cell sizes and strut thicknesses exist among the foams. However, FTIR reveals significant differences in chemical composition between the foams of different HBP content, indicating increased crosslinking.