Structure, morphology and thermal stability of synthetic fluorine mica and its organic derivatives

The morphology and thermal stability of a completely inorganic synthetic fluoromica (Somasif ME-100) and four organophilic fluoromicas were investigated comparatively by using different techniques as FTIR, XRD, SAXS, GPC, SEM and TGA. These organophilic micas which were intercalated with oligoether-based (Somasif MEE and MPE) and alkyl-based (Somasif MAE and MTE) ammonium salts present, as typical morphology, families of mica domains with lateral dimension up to 4 μm, formed by the association of nanosized mica aggregates having different distances between platelets. Somasif micas containing alkyl-based ammonium salt presented the higher proportion of lamellae not successfully organically modified, whereas the modified fluoromicas containing oligoether-modifiers showed the highest volume fraction of aggregates with higher interlayer distances d (up to 6.1 nm). All organophilic fluoromicas have thermal degradation from 200 to 460 °C and Somasif MPE with PPG moieties has the best thermal stability among the organomicas.

► Somasif micas containing alkyl-based ammonium salt presented the higher proportion of lamellae not successfully organically modified. ► Modified fluoromicas containing oligoether-based ammonium salt as intercalant showed the higher volume fraction of aggregates with higher interlayer distances d (up to 6.1 nm). ► Somasif MPE containing as intercalant an ammonium salt with PPG moieties has the better thermal stability among the organomicas.