SIMS and XPS studies of polyurethane surfaces. 1. Preliminary studies

Effects of crosslinking on adhesion behavior of waterborne polyurethane ink binder

“…Moreover, the decrease of the surface free energy is mainly the decrease in p . Some experimental studies have showed that soft segments migrate near the air surface, while the hard segments migrate toward the bulk and aggregate closer to the interface at the substrate surface [28][29][30]. Crosslinking decreases the segmental mobility of PU molecular chains and therefore the enrichment of polar ester groups of soft segment PCL on the surface of WPU film decreases, which produces a decrease in the surface energy of WPU film.…”

Adhesion mechanisms of polyurethanes to glass surfaces. Part II. Phase separation in polyurethanes and its effects on adhesion to glass

“…Numerous experimental techniques including Fourier transform infrared (FTIR) spectroscopy [5,6], near-infrared (NIR) spectroscopy [7,8], differential scanning calorimetry (DSC) [5,[9][10][11], dynamic mechanical analysis (DMA) [12,13], transmission electron microscopy (TEM) [14,15], X-ray photoelectron spectroscopy (XPS) [5,[16][17][18], and many others have been used to analyze phase separation in polyurethanes.…”

“…The hard and soft segments have generally been found to phase separate into discrete phases with a domain size of 10-20 nm [16]. Interfacial studies have shown that the surfaces of polyether-based polyurethanes are enriched with the polyether compared with the bulk [5,16].…”

Preparation and XPS surface chemical analysis of PS/PU nanocomposites

“…At the same time, the enrichment of hard segments on the surface of PU and PS/PU nanocomposites was very obvious, which was contrary to the conclusion of other researchers. [5][6][7][8][9][10] Because of the existence of PS, the amount of the hard segments on the surface of nanocomposites increased, and the increasing extent of that of crosslinking PS/PU nanocomposites was higher than those of uncrosslinking. This was because the formation of anionic PU ionomers in water made hard segments with COO Ϫshift to the surface of particles.…”

“…3,4 It has also been reported that not only does the segregation take place in the bulk, but on the basis of the studies using surface analysis techniques such as X-ray photoelectron spectroscopy (XPS), the surface of these PU is enriched in the soft segments with respect to the bulk composition of the polymers. [5][6][7][8][9][10] According to the conclusion suggested by Lorenz,11,12 anionic PU ionomers in water are stabilized because of electric double layer and solvent effect. Because the soft segment of anionic PU is hydrophobic and hard segment with COO Ϫis hydrophilic, the molecule chains of anionic PU can self-organize to micelles when it is dispersed in water.…”