Synthesis and solution properties of novel nonionic functional polyurethane surfactants

Abstract

A series of novel nonionic functional polyurethane surfactants were synthesized by the polycondensation of 2,4-toluene diisocyanate with poly(propylene oxide) (weight-average molecular weight ϭ 400, 1000, or 2000) and monoallyl-end-capped poly(ethylene oxide). The chemical structure of the polyurethane surfactants was determined by Fourier transform infrared and 1 H-NMR, and the effects of the concentration, salt, rest time, and temperature on the surface tension were investigated. These polymeric surfactants exhibited excellent surface activity. Sample III, which was synthesized with monoallyl-end-capped poly-(ethylene oxide) (number-average molecular weight ϭ 1000), poly(propylene oxide) (number-average molecular weight ϭ 2000), and tolylene diisocyanate, could reduce the surface tension to 37.6 mN/m at a concentration of 0.06 mol/L at 25°C. All polyurethane surfactants synthesized in this study had low critical micelle concentrations (ca. 10 Ϫ4 to 10 Ϫ5 mol/L) and could reduce the surface tension even at very low concentration levels. Moreover, the surface tension decreased with an increase in the temperature or the concentration of the polyurethane surfactants. The addition of salt resulted in a decrease in the surface tension, and it took some time for the polyurethane surfactants to reach a constant surface tension value. UV spectra were found to be very useful for determining the critical micelle concentration.

Polyurethane-based nanoparticles as stabilizers for oil-in-water or water-in-oil Pickering emulsions

“…9 The surface tension under acidic conditions (pH 3.0) is higher than that in alkaline medium (pH 11.0), probably because the PU-g-PDEM nanoparticles have positively charged and stretched PDEM chains at acidic conditions, the adsorbed nanoparticles cannot arrange themselves well compared with that in alkaline medium due to the steric hindrance. 33 The most effective interfacial tension lowering was at pH 8, which decreased the air-water interfacial tension from the clean interface value of $73 mN m À1 to just 42 mN m À1 at a concentration of 2 wt%. This was a slightly lower interfacial tension than the values achieved by the nanoparticles at pH 3 and 11.…”

“…As discussed above, at pH 8.0, the deprotonation of PDEM chains allows more spare space for nanoparticles to accommodate on the air-water interface, leading to a slightly lower interfacial tension. 33,34 Anyhow, the decrease of surface tension for PU-g-PDEM nanoparticles in aqueous solution reveals their surfactant character.…”

Retracted: Synthesis, Characterization, and Surface Activities of Polymeric Cationic Thiol Surfactants in Aqueous Medium

“…The residues obtained by using conventional small molecular weight surface-active agents constantly have a negative impact on the superiority and quality of the polymeric films formed, and also these residues have antienvironmental influence as a result of their difficult biodegradation tendency and reusing ability (Howard, 2002;Tadros, 2005). Consequently, novel categories of surface-active agents were tailored to increase the emulsification performance of drugs and medicines and to reduce the environmental pollution impacts (Dong et al, 2006;Guo et al, 2009;Holmberg et al, 2003).…”

Synthesis of a novel silicone based copolymeric surfactant and application in emulsion polymerization

“…It has been found that time is needed for copolymeric surfactants to reach a constant surface tension and that the time needed to obtain a constant value of the surface tension varies as the concentration of the copolymeric surfactant changes [32]. According to the experimental results, we conclude that it must take some time for macromolecules of the surfactants to migrate to the surface.…”