Characterization of Local Structures in Flexible Polyurethane Foams by Solid-state NMR and FTIR Spectroscopy

Abstract

The article examines the characterization of local structures in water-blown flexible polyurethane foams with various amine catalysts. In this study, the authors have applied solid-state nuclear magnetic resonance (NMR) relaxation, nuclear spin diffusion, and Fourier transform infrared (FTIR) microscope analysis on flexible polyurethane foams. Quantitative knowledge of the polymer structure and dynamics by these methods provides a significant insight on understanding the microphase separation and the domain structure of urethane and urea hard segments and polyether soft segments in foam. Furthermore, the authors analyze the influence of hydrothermal degradation on the microphase structure of the foams. A detailed comparison of the fundamental results with conventional foam durability tests (e.g., humid aged compression sets) is described, and the hydrothermal degradation mechanism and the influence of catalysts on the foam stability are discussed.