Morphology of Heat Set Segmented Elastomers

1981 ◽  
Vol 54 (5) ◽  
pp. 963-975 ◽  
Author(s):  
J. W. C. Van Bogart ◽  
P. E. Gibson ◽  
S. L. Cooper
Keyword(s):  
Small Angle ◽  
Hard Segment ◽  
Soft Segment ◽  
X Ray ◽  
Domain Shape ◽  
X Ray Scattering ◽  
Ray Scattering

Abstract The technique of small-angle x-ray scattering (SAXS) was used to investigate the morphology of three heat set (200–400% strain at 110–125°C) segmented elastomer samples—two polyester-polyurethanes and one polyether-polyester. The degree of hard-segment ordering in the samples varied from amorphous to slightly crystalline to highly crystalline. The results showed that the hard-segment domains in the semicrystalline materials developed axial ratios of about 2:1 for the axes parallel and perpendicular to the direction of stretch, while the sample with amorphous hard-segment domains showed no similar distortion in hard-segment domain shape and no anisotropy in the thickness of the interface between hard- and soft-segment domains.

scholarly journals Effect of Cobalt Fillers on Polyurethane Segmentations Investigated by Synchrotron Small Angle X-Ray Scattering

2013 ◽  
Vol 2013 ◽  
pp. 1-8
Author(s):  
Krit Koyvanich ◽  
Chitnarong Sirisathitkul ◽  
Supagorn Rugmai
Keyword(s):  
Small Angle ◽  
Hard Segment ◽  
Soft Segment ◽  
Average Diameter ◽  
Theoretical Models ◽  
X Ray ◽  
X Ray Scattering ◽  
Ferromagnetic Cobalt ◽  
Polyether Polyol ◽  
Ray Scattering

The segmentation between rigid and rubbery chains in polyurethanes (PUs) influences polymeric properties and implementations. Several models have successfully been proposed to visualize the configuration between the hard segment (HS) and soft segment (SS). For particulate PU composites, the arrangement of HS and SS is more complicated because the fillers tend to disrupt the chain formation and segmentation. In this work, the effect of ferromagnetic cobalt (Co) powders (average diameter 2 μm) on PU synthesized from a reaction between polyether polyol (soft segment) and diphenylmethane-4,4′-diisocyanate (hard segment) was studied with varying loadings (0, 20, 40, and 60 wt.%). The 300 μm thick PU/Co samples were tape-casted and then received heat treatment at 80°C for 180 min. From synchrotron small angle X-ray scattering (SAXS), the plot of the X-ray scattering intensity (I) against the scattering vector (q) exhibited a typical single peak of PU whose intensity was reduced by the increase in the Co loading. Characteristic SAXS peaks in the case of 0-20 wt.% Co agreed well with the scattering by globular hard segment domains according to Zernike-Prins and Percus-Yevick models. The higher Co loadings led to larger deviations from all theoretical models.

Investigation of microstructural changes in impacted polyurea coatings using small angle X-ray scattering (SAXS)

2011 ◽  
Vol 26 (2) ◽  
pp. 149-154 ◽  
Author(s):  
Edward Balizer ◽  
Jeffry Fedderly ◽  
Gilbert Lee ◽  
Susan Bartyczak ◽  
Willis Mock
Keyword(s):  
Strain Hardening ◽  
Small Angle ◽  
High Speed ◽  
Soft Segment ◽  
National Laboratory ◽  
Argonne National Laboratory ◽  
Steel Cylinder ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Three polyureas with decreasing soft segment molecular weights of 1000, 650, and a 250/1000 blend were molded onto circular steel plates and then impacted with a high speed (275 m/s) conical-shaped steel cylinder. The polyurea layer of the post mortem bilayers was characterized on a molecular level by small angle synchrotron X-ray scattering (SAXS) at the Advanced Photon Source at the Argonne National Laboratory. Analysis revealed that the hard domains of the polyureas with lower molecular weight soft segments reformed and oriented over a greater area of the coating, thus increasing the polymer strain hardening and resulting in visibly less out of plane bilayer deformation. This agrees with the hypothesis that polymer strain hardening is a mechanism that retards necking failure of the metal plate.

A Revised O2 Reduction Model in Li-O2 Batteries as Revealed by in Situ Small Angle X-Ray Scattering

2019 ◽  
Author(s):  
Christian Prehal ◽  
Aleksej Samojlov ◽  
Manfred Nachtnebel ◽  
Manfred Kriechbaum ◽  
Heinz Amenitsch ◽  
...  
Keyword(s):  
Small Angle ◽  
Wide Angle ◽  
Reduction Mechanism ◽  
Reduction Model ◽  
X Ray ◽  
X Ray Scattering ◽  
O2 Reduction ◽  
Ray Scattering

<b>Here we use in situ small and wide angle X-ray scattering to elucidate unexpected mechanistic insights of the O2 reduction mechanism in Li-O2 batteries.<br></b>

In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Matthew Tirrell
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

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.

Mirror to measure small angle x-ray scattering signal in high energy density experiments

2020 ◽  
Vol 91 (12) ◽  
pp. 123501
Author(s):  
M. Šmíd ◽  
C. Baehtz ◽  
A. Pelka ◽  
A. Laso García ◽  
S. Göde ◽  
...  
Keyword(s):  
Energy Density ◽  
Small Angle ◽  
High Energy ◽  
High Energy Density ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Signal ◽  
Ray Scattering
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