Kaolinite Nanocomposite Platelets Synthesized by Intercalation and Imidization of Poly(styrene-co-maleic anhydride)

Abstract

A synthesis route is presented for the subsequent intercalation, exfoliation and surface modification of kaolinite (Kln) by an imidization reaction of high-molecular weight poly(styrene-co-maleic anhydride) or SMA in the presence of ammonium hydroxide. In a first step, the intercalation of ammonolyzed SMA by guest displacement of intercalated dimethylsulfoxide has been proven. In a second step, the imidization of ammonolyzed SMA at 160 °C results in exfoliation of the kaolinite layers and deposition of poly(styrene-co-maleimide) or SMI nanoparticles onto the kaolinite surfaces. Compared with a physical mixture of Kln/SMI, the chemically reacted Kln/SMI provides more efficient exfoliation and hydrogen bonding between the nanoparticles and the kaolinite. The kaolinite nanocomposite particles are synthesized in aqueous dispersion with solid content of 65 wt %. The intercalation and exfoliation are optimized for a concentration ratio of Kln/SMI = 70:30, resulting in maximum intercalation and interlayer distance in combination with highest imide content. After thermal curing at 135 °C, the imidization proceeds towards a maximum conversion of the intermediate amic acid moieties. The changes in O–H stretching and kaolinite lattice vibrations have been illustrated by infrared and FT-Raman spectroscopy, which allow for a good quantification of concentration and imidization effects.

Pressure-induced structural phase transitions in natural kaolinite investigated by Raman spectroscopy and electrical conductivity

“…The Raman peak at 3622.0 cm -1 comes from the stretching vibration of the inner hydroxyl, whereas other three Raman peaks are correspondent to the inner surface hydroxyl stretching vibration. All of these obtained Raman peaks coincide with prior studies (Frost 1995(Frost , 1997Frost et al 1999;Zhang et al 2014;Samyn et al 2015).…”

Fine Migration Control in Sandstones: Surface Force Analysis and Application of DLVO Theory

“…Most of these platelets are in the form of clusters and can move together based on attractive forces between individual plates. Similar kaolinite platelet configurations have also been found in other sources. − …”

Bio-Based Coatings for Paper Applications

“…Kaolinite clay is also frequently used in nanocomposite coatings, but it has a stronger cohesion between the adjacent aluminosilicate layers and intercalation or exfoliation is consequently more difficult. Recently, a new way for modification of kaolinite clay has been presented by the precipitation of hydrophobic organic nanoparticles [97]: the intercalation of kaolinite is done by ammolysed poly(styrene-co-maleic anhydride) or SMA in first instance and followed by further exfoliation in parallel with the surface deposition of poly(styrene-co-maleimide) or SMI nanoparticles ( Figure 6). When applied as a paper coating, the modified kaolinite provides the advantage of better dispersion of the platelets within the coating and a better localization of the hydrophobic moieties at the paper surface.…”