Experimental observation of the onset of finite domain boundaries in a simple two-phase system by small-angle x-ray scattering

1983 ◽  
Vol 16 (12) ◽  
pp. 1943-1944 ◽  
Author(s):  
N. Sanjeeva Murthy ◽  
Shaul M. Aharoni
Keyword(s):  
Experimental Observation ◽  
Small Angle ◽  
Finite Domain ◽  
Phase System ◽  
Two Phase ◽  
X Ray ◽  
X Ray Scattering ◽  
Domain Boundaries ◽  
Ray Scattering

Structural evolution during the graphitization of polyacrylonitrile-based carbon fiber as revealed by small-angle X-ray scattering

2014 ◽  
Vol 47 (6) ◽  
pp. 1809-1818 ◽  
Author(s):  
Denghua Li ◽  
Chunxiang Lu ◽  
Gangping Wu ◽  
Junjie Hao ◽  
Yu Yang ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Small Angle ◽  
Local Density ◽  
Treatment Temperature ◽  
Systematic Change ◽  
Phase System ◽  
Two Phase ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

On the basis of a Debye–Bueche correlation length analysis, the small-angle X-ray scattering (SAXS) intensity components due to different scatterers within polyacrylonitrile-based carbon fiber were determined and analyzed separately. According to Guinier's law and other related methods, an intensity component indicating a relatively large scatterer was ascribed to the amorphous structure within the boundaries of fibrils. Results indicated that the amorphous regions decreased in dimension and finally transformed completely into voids as the heat treatment temperature rose to 2773 K. The general trend for microvoids was a systematic change from many small voids to a few large voids, while the local density fluctuation within the samples weakened and finally faded away. In conclusion, the graphitization process of carbon fibers as revealed by SAXS is a systematic evolution from a quasi-two-phase system (fibril, amorphous region and microvoid within the fibril) of high-strength carbon fiber to the true two-phase structure (crystallite and microvoid) of high-modulus graphite fiber.

Small angle X-ray scattering study of porosity variation in a styrene-divinylbenzene copolymer

1981 ◽  
Vol 46 (7) ◽  
pp. 1675-1681 ◽  
Author(s):  
Josef Baldrian ◽  
Božena N. Kolarz ◽  
Henrik Galina
Keyword(s):  
Small Angle ◽  
Structural Parameters ◽  
Two Phase ◽  
X Ray ◽  
Porosity Variation ◽  
Swelling Agent ◽  
X Ray Scattering ◽  
Styrene Divinylbenzene ◽  
Ray Scattering

Porosity variations induced by swelling agent exchange were studied in a styrene-divinylbenzene copolymer. Standard methods were used in the characterization of copolymer porosity in the dry state and the results were compared with related structural parameters derived from small angle X-ray scattering (SAXS) measurements as developed for the characterization of two-phase systems. The SAXS method was also used for porosity determination in swollen samples. The differences in the porosity of dry samples were found to be an effect of the drying process, while in the swollen state the sample swells and deswells isotropically.

Small-angle X-ray scattering of two-phase systems: significance of polydispersity

2010 ◽  
Vol 43 (5) ◽  
pp. 998-1004 ◽  
Author(s):  
Wilhelm Ruland
Keyword(s):  
Size Distribution ◽  
Small Angle ◽  
Two Phase ◽  
X Ray ◽  
X Ray Scattering ◽  
Phase Systems ◽  
Two Phases ◽  
The Relationship ◽  
Ray Scattering

Evaluation of the small-angle X-ray scattering of two-phase systems leads to the determination of the Porod lengthlpand the correlation lengthlc. In dilute systems, the parameter κl=lc/lp− 1 is a measure of the polydispersity of the chord lengthslwithin the dilute phase, which depends on the size distribution and the shape of the particles forming this phase. As an example, the change of κlwith the size distribution is calculated for spheres and spheroids. For dense two-phase systems, κldepends not only on the polydispersities of the chord lengthsl1andl2of the two phases but also on the spatial order in the system. This is demonstrated by examples related to microemulsions. The appendix contains a short discussion on the relationship between chord-length distributions and Bertrand's paradox.

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