Supercritical CO2 as an efficient medium for layered silicate organomodification: Preparation of thermally stable organoclays and dispersion in polyamide 6

Influence of physical state of intercalating agents on intercalation process of high speed airflow pretreated montmorillonite in supercritical carbon dioxide

“…The phenomenon demonstrated that the physical state (solid or liquid) of the surfactants played an important role on the intercalation process of PMMT. Intercalation with high degrees of exchange was obtained when the surfactants were in the liquid state at the reaction temperature and no intercalation of solid surfactants was observed, which was consistent with previous research regarding the intercalation of pristine MMT [13,14], indicating high speed airflow processing had little effect on the intercalation process.…”

“…The TG results verified that some MTAB had intercalated into the interlayer of PMMT after washing, which was consistent with the XRD results. Judging from the onset temperature, which was derived from DTG curves at the point where the derivative weight loss increased to 0.01%/°C [13], the quaternary phosphonium salt-modified PMMT had a better thermal stability than ammonium salt-modified PMMT. The onset temperature for TDTHP-PMMT was close to 300°C, significantly higher than the values for the MTAB-PMMT (204°C) ( Table 2).…”

“…To date, the application of the CO 2 -processing technique can be broken down into three categories: (1) dispersion of commercial clays that has been intercalated by different intercalating agents [11]; (2) direct preparation of polymer/MMT nanocomposites with the aid of supercritical CO 2 [12]; (3) intercalating the structure of natural clay with intercalating agents using supercritical CO 2 as the processing medium [13,14]. Generally, the CO 2 -processing involves immersing the layered clays or their mixtures with intercalating agents/polymers in supercritical CO 2 for a certain time period at a preset temperature and pressure followed by rapid depressurization.…”

Supercritical CO2–ionic liquid mixtures for modification of organoclays

“…The same signature on TGA curve is clear evidence that the cationic exchange of montmorillonite with imidazolium ionic liquid is possible using only supercritical carbon dioxide as a solvent. Up to now, only phosphonium ionic liquids with much shorter alkyl were considered in ScCO 2 to modify MMT but working at very high pressures while using a small amount of co-solvent [22]. The influence of a co-solvent on the modification of lamellar silicates in supercritical carbon dioxide was also considered.…”

Interfacial enhancement of fibrillar silicates (FSs)/EPDM nanocomposites by surface modification of FS in supercritical CO2

“…[12][13][14]. In recent years, it finds application in surface modification of nanoparticles [15], because it can carry the modification agent into the gap between the agglomerated particles by osmosis, which lead to the full contact of the modification agent with the nanoparticle surface. Thus, a high efficient reaction of the modification agent with the functional groups of the nanoparticles could be successfully achieved [16].…”