Abstract:Smectites are a group of 2:1-layer phyllosilicate minerals that have been extensively studied by small-angle x-ray scattering (SAXS) because of their industrial and environmental significance. In previous studies, a Guinier plot has been used to obtain the radius of gyration of the clay particles, from which geometric information of the particle structure is derived. Using an indirect Fourier transform to treat SAXS data from a dilute montmorillonite suspension, a negative electron contrast at the clay-water i… Show more
“…3e shows experimental SAXS spectra of a PBI/SAMH nanocomposite film (S1) along with a pure PBI (PBI2). Powerlaw q dependence of the S1 (∼q −2.1 ) observed in the low-q region is quite close to the theoretical value from the form factor of disk-like particles (q −2 ) [29][30][31]. Consistent with TEM results, a q −2.1 dependence in the SAXS spectra suggests that the SAMH materials in the nanocomposites are present in the form of thin platelets [7].…”
Section: Performance Of the Pbi/pamh And The Pbi/samh Membranessupporting
“…3e shows experimental SAXS spectra of a PBI/SAMH nanocomposite film (S1) along with a pure PBI (PBI2). Powerlaw q dependence of the S1 (∼q −2.1 ) observed in the low-q region is quite close to the theoretical value from the form factor of disk-like particles (q −2 ) [29][30][31]. Consistent with TEM results, a q −2.1 dependence in the SAXS spectra suggests that the SAMH materials in the nanocomposites are present in the form of thin platelets [7].…”
Section: Performance Of the Pbi/pamh And The Pbi/samh Membranessupporting
“…The scattering intensity of PEG + C12P(17.5) was determined to be the same as that of pristine PEG. By paying attention to the value of R , the height ( H ) of the clay, as a cylindrical model, in the composite material can be calculated using the following equation: 35 …”
Section: Resultsmentioning
confidence: 99%
“… * a Clay additive condition is similar at 5 wt%; * b Interlayer distance of modified clays obtained by PXRD; * c Δ d 001 = ( d 001 of modified clay) − ( d 001 of pristine clay); * d Guinier radii and H values were calculated according to a previous report 35 . …”
Clays are multi-layered inorganic materials that can be used to prepare nanocomposite fillers. Because the multi-layered structure is thermodynamically stable, it is difficult to change a multi-layered material into single layers to improve its dispersity. Previously, clays were modified with dodecylammonium cations to promote complexation with nylon 6, nylon 66, polypropylene, polyethylene, polystyrene, and polycaprolactone to increase the mechanical strength (and/or thermal stability) of the composite material; however, complete exfoliation could not be achieved in these composites. In this study, pillar[5]arenes are synthesized and functionalized with ten cationic substituents as novel intercalants for modifying bentonite clay, which is a multi-layered metal-cation-containing silicate. The pillar[5]arenes exfoliate the clay by forming polyrotaxanes with poly(ethylene glycol) through host–guest interactions.
“…In the low- Q region (<0.01 nm -1 ), the nanocomposite sample displays somewhat weaker power-law Q dependence (as compared to the composite sample) but is still consistent with a nanostructure of isolated few-layer particles separated by ∼10−100 nm. No evidence for the exfoliation of single layers was observed since single exfoliated layers will show a much weaker dependence, ∼ Q -2 , and no Bragg peak. − 5 SANS spectra of (a) pure polyimide, (b) a polyimide/10 wt % as-synthesized AlPO composite, and (c) a 10 wt % PSF nanocomposite (neutron wavelength 6 Å).…”
Here, we report for the first time the fabrication of polymer/selective-flake nanocomposite membranes which can, in principle, be scaled down to submicrometer structures. A layered aluminophosphate with a porous net layer is used as a selective phase and a polyimide as a continuous phase. The microstructures of the nanocomposite membranes are investigated using various characterization techniques including X-ray diffraction, NMR, transmission electron microscopy, small-angle neutron scattering, and dynamic mechanical thermal analysis. Nanocomposite membranes with 10 wt % layered aluminophosphate show substantial enhancement in performance with oxygen selectivity over nitrogen as high as 8.9 (as compared to 3.6 for pure polymer) and carbon dioxide selectivity over methane as high as 40.9 (as compared to 13.4 for pure polymer) in room-temperature permeation measurements. This improved performance, along with permeability estimation through the aluminophosphate layers with a semiempirical model, suggests that the layered aluminophosphate plays a role as a molecular sieve favoring smaller molecules.
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