Polyethoxylated sorbitans

Fig. 2.9.38. General structural formula of polyethoxylated sorbitan esters. 

Fig. 2.9.39. (top) APCI-LC-MS(+)RIC of polyethoxylated sorbitan derivative and (inset) averaged mass spectrum under peak 1 (bottom) APCI-LC-MS(—) reconstruction chromatogram as before and (inset) averaged mass spectrum under peak 2. Gradient elution separated on RP-Cig column [24]. 

At a certain volume ratio between the phases, the dispersed phase is converted into the continuous phase and vice versa. In the water/kerosene/polyethoxylated sorbitan monostearate system, when this phenomenon, which is known as phase inversion , occurs identical volumes of both phases are used to obtain o/w emulsions with an US horn at 20 kHz [51]. 

Extra mild surfactants (nonionic) polyethoxylated sorbitan ester Combination with amphoteric or zwitterionic surfactants cocamidopropyl betaine Surfactants/glycol soap agents Cationic surfactants Cationic polymers Silicones and derivatives... 

Figure 8. Inhibition of phenanthrene mineralization in soil-aqueous systems with Tween-type sorbitan polyethoxylate surfactant.

Na lauryl ether diethoxy sulfate polyethoxylated (78EO) glyceryl monoeater of coconut oil fatty acids polyoxyethylene (20EO) sorbitan monooleate A%V-dimethyl-/V-lauryl betaine disodium lauryl diethoxy sulfosuccinate... 

Capek and Chudej [87] studied the emulsion polymerization of styrene stabilized by polyethylene oxide sorbitan monolaurate with an average of 20 monomeric units of ethylene oxide per molecule (Tween 20) and initiated by the redox system of ammonium persulfate and sodium thiosulfite. It is interesting to note that the constant reaction rate period is not present in this polymerization system. The maximal rate of polymerization is proportional to the initiator and surfactant concentrations to the -0.45 and 1.5 powers, respectively. The final number of latex particles per unit volume of water is proportional to the initiator and surfactant concentrations to the 0.32 and 1.3 powers, respectively. In addition, the resultant polymer molecular weight is proportional to the initiator and surfactant concentrations to the 0.62 and -0.97 powers, respectively. Some possible reaction mechanisms may explain the deviation of the polymerization system from the classical Smith-Ewart theory. Lin et al. [88] investigated the emulsion polymerization of styrene stabilized by nonylphenol polyethoxylate with an average of 40 monomeric units of ethylene oxide per molecule (NP-40) and initiated by sodium persulfate. The rate of polymerization versus monomer conversion curves exhibit two nonsta-tionary reaction rate intervals and a vague constant rate period in between. 

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