Molecular Motion in Surfactant Layers Inside Polymer Composites with Synthetical Magadiite

Abstract

Clays used in polymer‐layered silicate nanocomposites are heterogeneous. To improve insight into structure and dynamics of the interface, the iron‐free and structurally homogeneous layered silicate magadiite was synthesized. Morphology of the magadiite and the extent of intercalation in melt‐prepared composites were characterized by SEM and WAXS. Carbonyl groups in the main chain of the polymer appear to facilitate intercalation. Surfactant motion was studied by 2H NMR and CW EPR. Nanocomposite formation with PCL enhances and microcomposite formation with PS diminishes motion. The activation energies change at the glass transition temperature of PS and the melting temperature of PCL.magnified image

Physical Chemistry of Intercalated System

“…We shall demonstrate this using as an example magadiite modified with long chained phosphorus-containing [39] surfactant (tributylhexadecylphosphonium bromide), which by its intercalation properties is close to organomodified MMT (OMMT) (Fig. 5.2).…”

“…5.6). Molecular mobility of a modifying surfactant (taking for example tributylhexadecyl phosphonium bromide or dodecyl trimethyl ammonium bromide) in layers of synthetic magadiite [39]. In this case tributylhexadecyl phosphonium bromide was bound to imineoxyl radical to obtain spin-labeled surfactants such as which made it possible to use EPR, NMR 31 P, and other techniques.…”

“…ð Þ corresponds to a basal spacing of 1.5 nm) (1); organomodified magadiite (peak at 2θ ¼ 3.0 corresponds to 2.9 nm) (2); organomagadiite after melt annealing at 160 C for 30 min (3); organomagadiite in PS microcomposites (4); and organomagadiite in PCL nanocomposites (peak at 2.58 corresponds to 3.5 nm) (5) [39] perovskites are easily exfoliated into separate single nanosheets. From this point of view exfoliation can be regarded as the ultimate case of intercalation.…”

“…A different ability of silanes to penetrate interlayer space is caused by facilitated diffusion, steric hindrances, which are weaker for TMOS than for Si(OC 2 H 5 ) 4 , etc. General scheme of this combined sol-gel-intercalation process can be briefly described as follows [39,79] (Fig. 5.10).…”

“…Degree of intercalation of a modifier is calculated taking into account interplanar distance D F in a composite, with account for widening of the gallery (from 3.2 to 4 nm), and the magadiite sheet thickness (L ¼ 1 nm) [39].…”