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.

Influence of Recycled Polyurethane Polyol on the Properties of Flexible Polyurethane Foams

“…This confirmed the present of secondary amine groups in PU foam. At wave number of 2,972 and 2,871 cm-1 were attributed to C-H stretching vibration of CH2 group in aliphatic chain which agreed well with Hideyuki Oka and coworker [7]. The absorption peak at wave number 1,727 cm-1 is corresponding to stretching vibration of urethane C=O bond.…”

Advances in stir bar sorptive extraction coating: A review

“…Polyurethane foams (PUFs) are polymers with a wide variety of applications [28][29][30], which have been described to have a high capacity to retain organic vapors in their open cell structure [31][32][33]. These polymers are produced by the reaction of polyisocyanate with polyoils and water in the presence of specific catalyst [29].…”

Water‐blown soy polyol based polyurethane foams modified by cellulosic materials obtained from different sources

“…Soy polyurethane (SPU) foams are gradually gaining industrial importance for both economic and environmental reasons 1–8. As documented in earlier communications,3–6, 8 soy‐bean‐oil‐based polyurethane (PU) foams are produced via the reaction of soy polyol with an isocyanate (NCO).…”

“…Soy polyurethane (SPU) foams are gradually gaining industrial importance for both economic and environmental reasons 1–8. As documented in earlier communications,3–6, 8 soy‐bean‐oil‐based polyurethane (PU) foams are produced via the reaction of soy polyol with an isocyanate (NCO). For water‐blown PUs, foaming basically involves two basic reactions, where the NCO reacts with (1) polyol to generate the urethane linkage that leads to curing and (2) water to form urea and carbon dioxide, of which the latter expands the matrix polymer, that is …”