Micellization and Adsorption of a Series of Succinimide Dispersants

Abstract

The efficiency of a series of nonionic dispersants at stabilizing carbon-rich particles in oil was evaluated. The dispersants were synthesized by coupling a polyamine to two polyisobutylenes terminated at one end with a succinic anhydride (PIBSA). Their chemical composition was characterized by FTIR absorption. The associative strength of the dispersants was determined from their ability to self-associate in solution into reverse micelles. Their critical micelle concentration (CMC) and aggregation number (Nagg) were determined by fluorescence in an apolar solvent, namely hexane. The associative strength of the dispersants was found to increase with increasing number of secondary amines in the polyamine core. The adsorption isotherms describing the adsorption of the dispersants onto carbon black particles were determined and showed the existence of two binding regimes for the dispersants having more amines in their polar core. Much stronger binding occurred at dispersant concentration lower than the CMC. The weaker binding observed at dispersant concentrations larger than the CMC is believed to result from the dispersants having to compete between micellization and adsorption at concentrations above the CMC.

Highly Concentrated Emulsions: Role of Droplet Size

“…Therefore the increase in surfactant concentration led to the increase of reverse micelles in the continuous phase. However, it is worth mentioning that PIBSA-based reverse micelles in the oily phase of explosive emulsions contain ammonium nitrate in their core (Reynolds et al, 2000(Reynolds et al, , 2001 and that the associative strength (aptitude to induce self-assembly of surfactant molecules) originates from hydrogen-bonding between the surfactant head group and the ammonium nitrate solution (Ganguly et al, 1992;Shen and Duhamel, 2008). In previous studies utilising other succinimide dispersants, it was observed that PIBSA-based surfactants aggregate at low concentration (Viper et al, 1968;Shen and Duhamel, 2008).…”

“…Thus, the effect of surfactant concentration can be understood from the fact that lower CMC is a reflection of both a high associative strength and a strong anchor of the polar head group onto the interface (Shen and Duhamel, 2008), and the effect of surfactant type from the ammonium nitrated-surfactant interaction.…”

IR Studies of Interfacial Interaction of the Succinic Surfactants with Different Head Groups in Highly Concentrated W/O Emulsions

“…The effect of secondary amines on micelles formation was observed earlier for other succinimide surfactants. [8] …”

“…[6,7] The bulk properties of succinic surfactants were investigated. [8] One of the most promising ways to examine the interface structure and interfacial interactions is to perform the IR spectroscopic study, particularly by using the FTIR analysis method. The IR-spectroscopy has been widely used to study the interactions between ions in solution, [9] polymer and surfactant interactions, [10] and interactions between electrolyte and surfactant in emulsions.…”

Micellization and Adsorption to Carbon Black of Polyisobutylene‐Based Ionic Liquids

“…Due to their immense importance to lubricating automotive oils, the structure, mode of dispersion, dispersion efficacy, and self‐assembly (i.e., reverse micellization) of PIB‐based dispersants in nonpolar media has been extensively studied, with the primary focus directed to PIBSI‐type dispersants . For example, using a ruthenium‐based probe and steady‐state fluorescence, Duhamel and Shen demonstrated that PIBSI dispersants self‐associate into reverse micelles within a nonpolar solvent, with the polyamine moieties shielded by a corona of PIB tails.…”