Copolymer-layered silicate hybrid surfactants from the intercalation of montmorillonite with amphiphilic copolymers

摘要

A novel class of surfactants was prepared from the ionic exchange reaction of sodium montmorillonite (MMT) and a comb-branch shape of maleated polypropylene (MPP) derived copolymers consisting of pendent quaternary ammonium salts, polyoxyalkylene linkers, and a polypropylene (PP) backbone. The hybrid surfactant is composed of a hydrophilic silicate core and a hydrophobic PP corona. In the silicate core, there are approximately 6-10 silicate layers which are intercalated by multiple ammonium salts of the copolymer at d spacing of 19 Angstrom. Surrounding the core, the flexible PP strains contribute to the hydrophobic property in balancing with the hydrophilic silicates to form a water-in-oil (W/O) type cluster structure. When using 2000 g/mol molecular weight poly(oxyethylene)amine, the copolymer (MPP-POE2000) intercalated MMT hybrid was found to be dispersed well in toluene at an average 570-580 nm particle diameter. The aggregated particles exhibited an ability of lowering the toluene/water interfacial tension until 5.0 mN/m at a critical concentration of 0.01 wt %. The aggregated particle size is indifferent to the temperature change in the range 25-75 degreesC, implying the unusual thermal stability of the MMT-template hybrid surfactants and possibly the presence of a single-molecular surfactant micelle with the MMT primary particle as the central hydrophilic core. [References: 23]