Surface Modification of Sepiolite in Aqueous Gels by Using Methoxysilanes and Its Impact on the Nanofiber Dispersion Ability

Abstract

Surface modification reactions on needle-like sepiolite using alkyl and functional silanes have been carried out in the form of aqueous gels. In contrast with modifications in organic solvents, reactions in water make it possible to modify the surface of almost-individual sepiolite fibers and produce either a continuous coating or a nanotexturization of the sepiolite fiber surface, depending on the reaction conditions. This clean procedure substitutes advantageously organic solvent surface modifications and allows the tuning of surface properties such as specific surface area, wetting behavior, and chemical functionalization. A consequence of such tuning is, for example, the excellent dispersion of modified sepiolite nanofibers in a great variety of polymers by routine compounding and processing techniques.

Nanohybrid materials from amine functionalization of sepiolite: Preparation, characterization and application as electrode modifiers for the electroanalytical detection of heavy metal ions

“…At the opposite, the implication of fibrous clay minerals for electroanalytical purposes is scarce, although many works in literature have been devoted to their chemical modification [24][25][26][27][28]. Depending on the nature of the clay mineral, the preparation of organic-inorganic clay-based composite materials, exploited as electrode material proceeds mainly by two processes: (1) the intercalation of organic molecules within layered clay minerals such as kaolinite [29][30][31][32] and montmorillonite [1,[33][34][35][36], and (2) the grafting of functionalized organic molecules onto the surface of clay minerals [6,[37][38][39][40]. This last approach is convenient for all types of clay minerals bearing hydroxyl groups (aluminol or silanol) in their structure since it leads to the irreversible binding of the organic molecule on the clay surface.…”

Magneto-optical Faraday activity in transparent FeCo-sepiolite/polystyrene nanocomposites

“…Further organic modification of sepiolite with MTMS nanotexturises the surface as shown in figure 1b). The nanotexturization consists on evenly dispersed spheres arising from the MTMS self-condensation onto the sepiolite surface (Tiemblo et al, 2011). This nanotexturization of the sepiolite surface enables a fine dispersion of the particles into the polymer matrix by one-step conventional melt extrusion processing.…”

“…Subsequently, sepiolite bearing FeCo (SepFeCo) nanoparticles were organically modified with methyl trimethoxysilane (MTMS) following a previously reported procedure (García et al 2011). Basically, 3 g of FeCo sepiolite were dispersed in a solution of 16 mmol of MTMS in 72 mL of water by means of a lab dissolver (Dispermat® LC2) operating at 12000 rpm during 20 min.…”

PMMA-sepiolite nanocomposites as new promising materials for the production of nanocellular polymers

“…The first one has been modified with a quaternary ammonium salt (S-QAS) and the second one with a silane (S-S). The process to obtain and modify these particles can be found elsewhere [29,35,40].…”

“…Sepiolites have been shown to be appropriate inorganic nanofillers for polymers because of their diameter dimensions at the nanoscale and the high aspect ratio of this fibrous clay. With the appropriate surface treatment these particles can be well dispersed in different types of polymers, including PMMA [28,29]. It has been reported that the addition of sepiolites can improve some properties of the polymeric matrix.…”