Layer Spacing of Montmorillonites Modified with Rigid Rods

2007 ◽  
Vol 7 (12) ◽  
pp. 4546-4551
Author(s):  
Lorena Solar ◽  
Rodrigo Navarro ◽  
Clara Gómez ◽  
Helmut Reinecke
Keyword(s):  
Interlayer Distance ◽  
X Ray Diffraction ◽  
Layer Spacing ◽  
X Ray ◽  
Modified Montmorillonite ◽  
Rigid Rods ◽  
Montmorillonite Clays ◽  
Rigid Rod ◽  
Clay Layers ◽  
Oriented Parallel

The dependence of the interlayer distance in modified montmorillonite clays on the length of rigid rod molecules used for clay organophilization is studied. Therefore, a series of fully aromatic compounds of different length functionalized with a terminal amine group has been synthesized and transformed into the corresponding ammonium salts. The interlayer distance is determined by X-ray diffraction, the quantity of the modifier incorporated in the clay is obtained by thermogravimetric analysis. It is shown that the distance between layers in the modified clay does not depend on the length of the modifier used. This fact leads to the conclusion that rigid rods must be oriented parallel to the clay layers. On the other hand, the molar percentage of modifier molecules incorporated in the clay structure depends on the length of the rigid rods in the sense that shorter molecules are considerably easier to incorporate than longer ones.

Batch-foamed biodegradable polylactide acid/organic modified montmorillonite clays and polylactide/sericite powder nanocomposites

2012 ◽  
Vol 32 (2) ◽  
Author(s):  
Jin-Wei Chen ◽  
Jian-ling Liu
Keyword(s):  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Cross Sectional ◽  
X Ray ◽  
Mineral Particles ◽  
Foaming Process ◽  
Modified Montmorillonite ◽  
Transmission Electron ◽  
Montmorillonite Clays ◽  
Polylactide Acid

Abstract The properties of microcellular polylactic acid (PLA)/organic modified montmorillonite (OMMT) clays and PLA/sericite powder (SP) nanocomposites were investigated and compared in terms of thermal property, rheological property, particles dispersability, and cell microstructure. The batch-foaming process uses carbon dioxide as the physical blowing agent. According to the transmission electron microscopy and X-ray diffraction characterization, fillers (i.e., OMMT and SP) have good dispersions in PLA matrices. The thermal and rheological properties of solid PLA composites are demonstrated by differential scanning calorimetry and capillary rheometer, respectively. The microcellular morphology of fractured cross-sectional surfaces is characterized by scanning electron microscope. The batch-foamed PLA composites have more uniform cells in comparison with foamed pure PLA parts due to the mineral particles.

scholarly journals Simultaneous Multi-Bragg Peak Coherent X-ray Diffraction Imaging

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 312
Author(s):  
Florian Lauraux ◽  
Stéphane Labat ◽  
Sarah Yehya ◽  
Marie-Ingrid Richard ◽  
Steven J. Leake ◽  
...  
Keyword(s):  
Bragg Reflection ◽  
Volume Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Crystal Substrate ◽  
In Series ◽  
Diffraction Imaging ◽  
Diffraction Patterns ◽  
Lattice Planes ◽  
Oriented Parallel

The simultaneous measurement of two Bragg reflections by Bragg coherent X-ray diffraction is demonstrated on a twinned Au crystal, which was prepared by the solid-state dewetting of a 30 nm thin gold film on a sapphire substrate. The crystal was oriented on a goniometer so that two lattice planes fulfill the Bragg condition at the same time. The Au 111 and Au 200 Bragg peaks were measured simultaneously by scanning the energy of the incident X-ray beam and recording the diffraction patterns with two two-dimensional detectors. While the former Bragg reflection is not sensitive to the twin boundary, which is oriented parallel to the crystal–substrate interface, the latter reflection is only sensitive to one part of the crystal. The volume ratio between the two parts of the twinned crystal is about 1:9, which is also confirmed by Laue microdiffraction of the same crystal. The parallel measurement of multiple Bragg reflections is essential for future in situ and operando studies, which are so far limited to either a single Bragg reflection or several in series, to facilitate the precise monitoring of both the strain field and defects during the application of external stimuli.

Study on Organic Montmorillonite Modified Recycled Optical-Grade Polycarbonate Nanocomposite

2012 ◽  
Vol 214 ◽  
pp. 31-34
Author(s):  
Fu Quan Guo ◽  
Ying Ying Li ◽  
Bin Guo ◽  
Hao Liang
Keyword(s):  
Electron Microscopy ◽  
Great Increase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Organic Montmorillonite ◽  
Modified Montmorillonite ◽  
Mechanical Measurements ◽  
Transmission Electron ◽  
Izod Impact ◽  
Optical Disks

Optical–grade polycarbonate (PC) was separated from optical disks by a chemical approach and used to prepare nanocomposite to make full use of the wasted polymers. A quaternary ammonium-modified montmorillonite (organic montmorillonite, OMMT) was chosen as a modifier and an auxiliary functional resin (CBT160) was utilized to exfoliate the layers of montmorillonite. The characterization results of X-ray diffraction (XRD) and transmission electron microscopy (TEM) for PC/ OMMT (5wt %) revealed that an exfoliation structure of the nanocomposite was obtained. The mechanical measurements show a great increase in tensile strength and Izod impact strength of PC/ OMMT nanocomposite compared with the recycled optical–grade PC.

Water Diffusion Mechanisms in New Bio-Nanocomposites Based on Polyhydroxyalkanoates/Nanoclays

2013 ◽  
Vol 747 ◽  
pp. 682-685
Author(s):  
Raphaël Cretois ◽  
Nadège Follain ◽  
Jérémie Soulestin ◽  
Eric Dargent ◽  
Laurent Lebrun ◽  
...  
Keyword(s):  
Barrier Properties ◽  
Melt Processing ◽  
X Ray Diffraction ◽  
Electronic Microscopy ◽  
X Ray ◽  
Modified Montmorillonite ◽  
Diffusion Mechanisms ◽  
Nanoclay Content ◽  
Water Transport Properties ◽  
Montmorillonite Nanoclay

Nanocomposites based on bacterial semi-crystalline polyhydroxyalkanoates, poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) or poly (3-hydroxybutyrate-co-4-hydroxybutyrate) (P(3HB-co-4HB)), and organo-modified montmorillonite nanoclay are prepared by melt processing. All nanocomposites are characterized by X-Ray Diffraction (XRD) and Transmission Electronic Microscopy (TEM) and exhibit a mainly intercalated structure. Concerning water transport properties, a decrease of barrier properties for PHBV/nanoclay films is measured due to the affinity of nanoclay to water; whereas for P(3HB-co-4HB)/nanoclay nanocomposites, a decrease of the water permeability is observed relative to the tortuosity effect. Eventually, as a function of nanoclay content, a competition is evidenced between the tortuosity effect and the water sorption induced by nanoclay.

The Effect of Polyethylene-Octene Elastomer on the Morphological and Mechanical Properties of Polyamide 6/Polypropylene Nanocomposites

2005 ◽  
Vol 13 (8) ◽  
pp. 795-805 ◽  
Author(s):  
M.U. Wahit ◽  
A. Hassan ◽  
Z.A. Mohd Ishak ◽  
A. Abu Bakar
Keyword(s):  
Mechanical Properties ◽  
Polyamide 6 ◽  
X Ray Diffraction ◽  
X Ray ◽  
Melt Compounding ◽  
Modified Montmorillonite ◽  
Polypropylene Nanocomposites ◽  
Rubber Toughened ◽  
Izod Impact ◽  
Pp Blends

Rubber-toughened nanocomposites (RTNC) consisting of ternary blends of polyamide 6 (PA6), polypropylene (PP) and polyethylene-octene elastomer (POE) containing 4 wt% of organophilic modified montmorillonite were produced by melt compounding followed by injection moulding. The blend composition was kept constant (PA6/PP=70/30 parts by weight) while the POE content was varied between 5 and 20 wt%. Maleated PP (PP-g-MA) was used as compatibilizer. The morphology of the RTNC was studied by scanning electron microscopy and X-ray diffraction (XRD). The mechanical properties of RTNC were studied through tensile, flexural, Izod impact and fracture toughness properties. While the tensile and flexural properties were found to decrease with the increasing concentration of POE, the toughness was significantly enhanced as compared to the neat PA6/PP blends. In general, the blends containing 10-15 wt% of POE had the best balance of stiffness, strength and toughness. The addition of 30 wt% of PP in the PA6 matrix improved the compatibility between PA6 and the rubber phase. XRD established that the organoclay was well dispersed (exfoliated) and preferentially embedded in the PA6 phase.

Use of an External Electric Field to Convert the Paraelectric Phase to the Ferroelectric Phase in Ultra-thin Copolymer Films of P(VDF-TrFE)

2000 ◽  
Vol 655 ◽  
Author(s):  
Matt Poulsen ◽  
S. Adenwalla ◽  
Stephen Ducharme ◽  
V.M. Fridkin ◽  
S.P. Palto ◽  
...  
Keyword(s):  
Phase Transition ◽  
Electric Field ◽  
External Electric Field ◽  
Ferroelectric Phase ◽  
Paraelectric Phase ◽  
Continuous Process ◽  
Structural Phase ◽  
X Ray Diffraction ◽  
Layer Spacing ◽  
X Ray

AbstractX-ray diffraction was used to probe the structural changes associated with the conversion of the paraelectric phase to the ferroelectric phase that results from the application of a large external electric field. The samples under study are ultrathin (150 to 250 Å) Langmuir-Blodgett films of the copolymer vinylidene fluoride (70%) with trifluoroethylene (30%) deposited on aluminum-coated silicon. Theta-2theta X-ray diffraction was used to measure the change in inter-layer spacing perpendicular to the film surface. Upon heating at zero external electric field, the crystalline films undergo a structural phase transition, at 100± 5°C, from the all-trans ferroelectric phase to the trans-gauche paraelectric phase. [1,2] Above the phase transition temperature, the non-polar paraelectric phase can be converted back to the polar ferroelectric phase, in a smooth continuous process, using a large external electric field (∼1 GV/m). For example, at 100° C the ferroelectric phase first appears above 0.2 GV/m and increases steadily in proportion while the paraelectric phase decreases until complete conversion to the ferroelectric phase is achieved at approximately 0.6 GV/m.

X-ray Diffraction Studies of the Axial Tensile Modulus of Rigid-Rod Polymer Fibers

1988 ◽  
Vol 134 ◽  
Author(s):  
P. Galen Lenhert ◽  
W. Wade Adams
Keyword(s):  
Tensile Modulus ◽  
Polymer Fibers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Axial Tensile ◽  
Heat Treated ◽  
Before And After ◽  
Control Computer ◽  
Rigid Rod ◽  
Fiber Sample

ABSTRACTWe report the design and use of a device to measure the axial tensile modulus of high modulus fibers by following the change in the meridional X-ray spacings as a function of applied tension. The device, which mounts on a Picker 4-circle automated diffractometer, applies tension to the fiber sample by a cantilever arrangement. Tension is measured by a strain gauge bridge on the cantilever arm. The tension is adjusted and read by the control computer, a VAX 11/730. Measurements made on PBZT and PBO fibers before and after heat treatment are reported. For PBZT fibers (as spun, and heat treated at 525° C and 650° C) with tensile moduli of 186, 283 and 290 GPa, the X-ray determined moduli are 348, 385 and 395 GPa. For PBO fibers (as spun and heat treated at 600° C and 665° C) with tensile moduli of 166, 318 and 290 GPa, the X-ray determined moduli are 387, 477 and 433 GPa. These modulus values are to be compared with theoretical values presented by Wierschke in the previous paper and sonic modulus values discussed by Jiang et al in the following paper.

Free-standing Smectic LC Elastomer Films

2001 ◽  
Vol 709 ◽  
Author(s):  
C. Tolksdorf ◽  
R. Zentel ◽  
R. Köhler ◽  
U. Dietrich ◽  
M. Lösche ◽  
...  
Keyword(s):  
Optical Microscopy ◽  
Liquid Crystalline ◽  
Film Plane ◽  
X Ray Diffraction ◽  
Free Standing ◽  
Layer Spacing ◽  
X Ray ◽  
Precursor Polymer ◽  
Layer Structures ◽  
Freely Suspended

ABSTRACTWe probe the mesophase transitions and layer structures in thin ordered smectic liquid crystalline elastomer films by means of x-ray diffraction and optical microscopy. Oriented elastomer films of submicrometer thickness are produced by crosslinking freely suspended smectic polymer films. After crosslinking, the mesomorphism is similar to that of the precursor polymer. Smectic layers align parallel to the film plane. The layer spacing increases with temperature in the SmC* phase while it decays above the SmC*-SmA transition.

Modification of clays with styrenic ionic liquid by Synthesis of in-situ Polystyrene Nanocomposite

e-Polymers ◽  
2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Mohammad Galehassadi ◽  
Fatemeh Hosseinzadeh ◽  
Mehrdad Mahkam
Keyword(s):  
Electron Microscopy ◽  
Ionic Liquid ◽  
Clay Nanocomposites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Modified Montmorillonite ◽  
Transmission Electron ◽  
Insitu Polymerization ◽  
Thermal Stability Of

Abstract Nanocomposites of polystyrene (PS) was prepared with new styrenic ionic liquid, N-(4-vinyl benzyl)-(N,N-dimethylamino) pyridinium chloride[VBMAP], surfactants used as organic modifications for the clays. Sodium montmorillonite (Na-MMT) was successfully modified by [VBMAP] to become OMMT through cation exchange technique which is shown by the increase of basalspacing of clay by XRD. The composite material based on polystyrene and organo-modified montmorillonite (OMMT) was prepared by insitu polymerization and characterized. The morphology of the polymer/clay hybrids was evaluated by X-ray diffraction (XRD) ,transmission electron microscopy (TEM) and scanning electron microscopy (SEM), showing good overall dispersion of the clay. The thermal stability of the polymer/clay nanocomposites were enhanced, as evaluated by thermogravimetric analysis.

Preparation of Anion Modified Montmorillonite-Polystyrene Nanocomposite by Suspension Polymerization

2009 ◽  
Vol 87-88 ◽  
pp. 499-503
Author(s):  
Yi Wang ◽  
Hui Xia Feng ◽  
Jian Hui Qiu
Keyword(s):  
Thermal Stability ◽  
Anionic Surfactants ◽  
Suspension Polymerization ◽  
Layered Silicate ◽  
High Thermal Stability ◽  
X Ray Diffraction ◽  
X Ray ◽  
Modified Montmorillonite ◽  
Silicate Nanocomposites ◽  
Ft Ir

To ensure good compatibility between polymer and montmorillonite (MMT), three types organophilic-MMT were prepared and the influence of modifying agent style on the modification effect was studied. The results of X-ray diffraction(XRD) show that the modified reagents are all intercalated into the galleries of MMT, which are also proved by patterns of FT-IR and thermogravimetric analysis(TGA), and the spacing of MMT layers increases from 1.23 nm of the pristine MMT to 2.10nm, 3.52nm and 4.14nm for CTAB, SDS and DBS modified MMT respectively. The results also indicate that the d-spacing and exfoliation degree of anionic surfactants inserted MMT is bigger than that of the cationic surfactants treated MMT, which are usually used to preparation polymer layered silicate nanocomposites in literatures. So PS/SDS-MMT and PS/DBS-MMT nanocomposites were prepared by suspension polymerization. The structure of complex were characterized by XRD and no peak can be observed by the spectra, which suggest that the clay platelets have been exfoliated and dispersed in the PS matrix and the both complex are all have exfoliated structure. FT-IR spectrums analysis confirmed the existence of MMT which implied that the layers of silicate was distributing in composites. The results of TGA show that nanocomposites possess exceptionally high thermal stability and the DBS treated composite has higher thermal stability than that of SDS treated.

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