Evolution of the structural orientation in polyacrylonitrile precursors during stabilization revealed by in-situ synchrotron wide-angle X-ray diffraction and polarized infrared spectroscopy

2016 ◽  
Vol 29 (10) ◽  
pp. 1158-1164 ◽  
Author(s):  
Yiran Zhou ◽  
Xu Han ◽  
Xiaoyuan Hu ◽  
Lianghua Xu ◽  
Weiyu Cao
Keyword(s):  
Infrared Spectroscopy ◽  
Thermal Relaxation ◽  
Thermal Stabilization ◽  
Orientation Factor ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Polarized Infrared Spectroscopy

Evolution of the orientation structures of polyacrylonitrile (PAN) precursors during thermal stabilization was investigated on the basis of in situ temperature-dependent measurements including synchrotron wide-angle X-ray diffraction and polarized infrared spectroscopy. The results indicated that the Hermans orientation factor of PAN crystallites increased firstly and then decreased in the process of stabilization, while the orientation of molecular chains showed a two-stage decrease. These were mainly attributed to the thermal relaxation of molecular chains and the cyclization reactions, which also resulted in the physical shrinkage as well as the chemical shrinkage apparently observed from the thermal mechanical curves of the precursor.

In situ time resolved wide angle X-ray diffraction study of nanotube carpet growth: Nature of catalyst particles and progressive nanotube alignment

Carbon ◽  
2015 ◽  
Vol 87 ◽  
pp. 246-256 ◽  
Author(s):  
Périne Landois ◽  
Mathieu Pinault ◽  
Stéphan Rouzière ◽  
Dominique Porterat ◽  
Cristian Mocuta ◽  
...  
Keyword(s):  
Diffraction Study ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray

Molecular motions of a tetraphenylethylene-derived AIEgen directly monitored through in situ variable temperature single crystal X-ray diffraction

CrystEngComm ◽  
2021 ◽  
Author(s):  
Wei Meng ◽  
Lin Du ◽  
Lin Sun ◽  
Lian Zhou ◽  
Xiaopeng Xuan ◽  
...  
Keyword(s):  
Single Crystal ◽  
Phenyl Ring ◽  
Functional Group ◽  
Variable Temperature ◽  
Molecular Motions ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Conformation Changes

One organic functional group was introduced to distinguish the four phenyl ring of tetraphenylethylene, and the In situ temperature-dependent crystal structures were determined to exhibit the conformation changes of tert-butyl...

Evolution of Carbon Fiber Microstructure During Carbonization and High-Temperature Graphitization Measured In Situ Using Synchrotron Wide-Angle X-ray Diffraction

2015 ◽  
Vol 1754 ◽  
pp. 13-18 ◽  
Author(s):  
Michael Behr ◽  
James Rix ◽  
Brian Landes ◽  
Bryan Barton ◽  
Eric Hukkanen ◽  
...  
Keyword(s):  
High Temperature ◽  
Carbon Fiber ◽  
Tensile Modulus ◽  
Fiber Bundles ◽  
Wide Angle ◽  
High Modulus ◽  
Structure Property ◽  
X Ray Diffraction ◽  
X Ray

ABSTRACTThis paper will discuss the structure-property model developed that correlates the tensile modulus to the elastic properties and angular distribution of constituent graphitic layers for carbon fiber derived from a polyethylene precursor. In addition, a high-temperature fiber tensile device was built to enable heating of carbon fiber bundles at a variable rate from 25 °C to greater than ∼2300 °C, while simultaneously applying a tensile stress. This capability combined with synchrotron wide-angle x-ray diffraction (WAXD), enabled observation in situ and in real time of the microstructural transformation from different carbon fiber precursors to high-modulus carbon fiber. Experiments conducted using PAN- and PE-derived fiber precursors reveal stark differences in their carbonization and high-temperature graphitization behavior.

Synthesis and Electrorheological Characteristics of Conducting Polymer/Clay Nanocomposites

2007 ◽  
Vol 124-126 ◽  
pp. 1083-1086
Author(s):  
Jun Hee Sung ◽  
Hyoung Jin Choi
Keyword(s):  
Conducting Polymer ◽  
Electrorheological Fluid ◽  
Clay Nanocomposites ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Internal Structures ◽  
In Situ Emulsion Polymerization

Nanocomposites of conducting polymers of polyaniline (PANI), poly(oethoxyaniline) (PEOA) and polypyrrole (PPy) with clay prepared via either in-situ emulsion polymerization or solvent intercalation were investigated especially for electrorheological fluid (ER) application. Internal structures of these nanocomposites were examined via wide angle X-ray diffraction (WAXD), and transmission electron microscope (TEM). The intercalated nanostructures analyzed via WAXD and TEM were correlated with the electrical property change originated from the nanoscale interaction between clay and conducting polymer. Moreover, their ER behaviors were measured via rotational rheometer with external electric field controller.

Synthesis and Characterization of Copper(II) Complexes with Long Chain Dithiocarbamates

2014 ◽  
Vol 976 ◽  
pp. 164-168 ◽  
Author(s):  
Nayely Torres-Gomez ◽  
Alfredo R. Vilchis-Nestor ◽  
Rosa Maria Gomez-Espinosa ◽  
Ivan Garcia-Orozco
Keyword(s):  
Infrared Spectroscopy ◽  
Copper Complexes ◽  
Nanocrystalline Structure ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Long Chain ◽  
Scanning Electron

Copper complexes of dithiocarbamates ligands were obtained from RNH2 (R = C6H13-, C12H25- y C18H37-) and an excess of CS2 in the presence of NaOH. Sodium hexyldithiocarbamate is not possible to isolate from solution but the other two were obtained and characterizedby infrared spectroscopy, UV-vis and powder X-ray diffraction. Copper complexes were obtained in situ from ligand solution as greenish powders. All the complexes were characterized by infrared spectroscopy, UV-vis, powder X-ray diffraction and Scanning Electron Microscopy. The complexes show an amorphous phase in the case of DCu12 and nanocrystalline structure for DCu18, as observed in XRD.

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