Influence of molecular structure on the dynamic thermoelasticity of polyphasic polymer systems

1985 ◽  
Vol 63 (1) ◽  
pp. 189-195
Author(s):  
Robert H. Marchessault ◽  
Terry L. Bluhm ◽  
Hrire M. Gharapetian ◽  
Pudupadi R. Sundararajan
Keyword(s):  
Dimethyl Formamide ◽  
Polymer Systems ◽  
X Ray ◽  
X Ray Scattering ◽  
Order Of Magnitude ◽  
Spherical Structures ◽  
Thermoelastic Response ◽  
Heat Pulses ◽  
Molecular Morphology ◽  
The Relationship

The relationship between the dynamic thermoelastic behavior and molecular morphology of polyphasic polymer systems was studied. A sensitive tensometer equipped with a 50 W/I2 V heating lamp provided uniform and controlled heat pulses to one side of the film. For various extension ratios, the stress change (Δσ) as a function of the sample temperature, was recorded, both for increasing and decreasing extension ratios.The amount of increase in stress Δσ with temperature was different for Kraton GX-6500 samples cast from either toluene, cyclohexane, or heptane. The variation of Act with temperature was dependent on the extension ratio and was always greater for increasing extension. The slope of Δσ with temperature decreased at 100–150% elongation in all Kraton GX-6500 samples during increasing extension. However, this slope increased at higher elongations. Small angle X-ray scattering studies on Kraton GX-6500 showed the presence of lamellar, rod shape, and spherical structures in samples cast from toluene, cyclohexane, and heptane solvents, respectively. The extreme dependence of elastomeric behavior on polyphasic morphology caused Kraton samples to show a strong decline in thermoelastic response with cycling.X-ray studies on the films of Spandex, cast from dimethyl formamide, at different extension ratios showed the onset of crystallization at about 150% elongation. The thermoelastic studies performed on Spandex films also showed an increase in slope of Δσ vs. T at 150–170% elongations, which was attributed to the influence of increased crystalline orientation on thermoelastic response. X-ray studies on unstretched and stretched Hytrel films showed the presence of crystallinity. The magnitude of Δσ and variation with temperature for Hytrel films was greater than that of either Spandex, Kraton GX-6500, or cross-linked natural rubber.By comparison with the latter, only Hytrel was superior in the magnitude of Δσ variations with temperature. This was attributed to intrinsic crystallinity and the orientation which developed on stretching. At extension ratios λ = 2, Δσ for Hytrel was an order of magnitude greater than for cross-linked natural rubber.

Fundamentals of Kinematical X-Ray Scattering Theory

2014 ◽  
pp. 1-14
Keyword(s):  
Scattering Theory ◽  
Profile Analysis ◽  
Reciprocal Lattice ◽  
Line Profile Analysis ◽  
X Ray ◽  
X Ray Scattering ◽  
Basic Concepts ◽  
Lattice Planes ◽  
The Relationship ◽  
Ray Scattering

The broadening of X-ray line profiles is usually described by the kinematical scattering theory. In this chapter, the basic concepts and equations of the kinematical X-ray scattering are presented in order to better understand the theory of line profile analysis. The correlation between the crystal structure and the diffracted intensity distribution is shown. The scattering angles of the diffracted peak maxima are given by the Ewald construction in the reciprocal space. The correspondence between the reciprocal lattice vectors and the lattice planes is also presented, and the relationship between the scattering angle and the lattice plane spacing is given by Bragg’s law.

scholarly journals Process Induced Skin-Core Morphology in Injection Molded Polyamide 66

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 894
Author(s):  
Yvonne Spoerer ◽  
René Androsch ◽  
Dieter Jehnichen ◽  
Ines Kuehnert
Keyword(s):  
Polarized Light ◽  
Skin Layer ◽  
Crystalline Morphology ◽  
Polyamide 66 ◽  
Thin Sections ◽  
X Ray ◽  
X Ray Scattering ◽  
Order Of Magnitude ◽  
Injection Molded ◽  
Ray Scattering

Polyamide 66 (PA 66) was injection-molded to obtain samples with a structure gradient between skin and core, as it was revealed by analysis of the semi-crystalline morphology using polarized-light optical microscopy (POM). Wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS) were employed to characterize thin sections with a thickness in the order of magnitude of 50 µm, allowing detection of crystals of different perfection, as a function of the distance from the surface. It was found that the transparent and non-spherulitic skin layer contains rather imperfect α-crystals while the perfection of α-crystals continuously increases with extending distance from the surface. Since variation of the molding conditions allows tailoring the skin-core morphology, the present study was performed to suggest a reliable route to map the presence of specific semi-crystalline morphologies in such samples.

Annealing Effects of Schottky Contacts on the Characteristics of 4H-SiC Schottky Barrier Diodes

1999 ◽  
Vol 572 ◽  
Author(s):  
S. C. Kang ◽  
B. H. Kum ◽  
S. J. Do ◽  
J. H. Je ◽  
M. W. SHIN
Keyword(s):  
Schottky Barrier ◽  
Schottky Barrier Diodes ◽  
X Ray ◽  
Annealing Temperatures ◽  
X Ray Scattering ◽  
Different Temperatures ◽  
Annealing Effects ◽  
Evolution Of Microstructure ◽  
The Relationship ◽  
Ray Scattering

ABSTRACTThis paper reports on the relationship between the microstructure and the device performance of Pt/4H-SiC schottky barrier diodes ( SBDs ). The evolution of microstructure in the metal/SiC interfaces annealed at different temperatures was characterized using X-ray scattering techniques. The reverse characteristics of the devices were degraded with annealing temperatures. The maximum breakdown voltages of as-deposited devices and 850 °C annealed devices are 1300 V and 626 V, respectively. However, the forward characteristics of the devices were found out to improve with annealing temperatures. X-ray scattering analysis showed that Pt-silicides were formed by annealing performed at or higher than 650 °C. The formation of silicides was shown to increase the roughness of the Pt/SiC interface. It is believed that the forward characteristics of the SBDs be strongly dependent on the crystallity of silicides formed in the Pt/SiC interface during the annealing process.

Investigation of the relationship between reflectance difference spectroscopy and surface structure using grazing incidence X-ray scattering

1995 ◽  
Vol 152 (1) ◽  
pp. 9-21 ◽  
Author(s):  
D. W. Kisker ◽  
G. B. Stephenson ◽  
I. Kamiya ◽  
P. H. Fuoss ◽  
D. E. Aspnes ◽  
...  
Keyword(s):  
Surface Structure ◽  
Grazing Incidence ◽  
Difference Spectroscopy ◽  
X Ray ◽  
X Ray Scattering ◽  
Reflectance Difference Spectroscopy ◽  
The Relationship ◽  
Ray Scattering

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.

Conformation study on poly(L-tyrosine) in dimethyl formamide by small-angle X-ray scattering

Biopolymers ◽  
1977 ◽  
Vol 16 (11) ◽  
pp. 2351-2361 ◽  
Author(s):  
Fumiyuki Hamada ◽  
Yoshitaka Ishimuro ◽  
Toshio Hayashi ◽  
Akio Nakajima
Keyword(s):  
Small Angle ◽  
Dimethyl Formamide ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Effect of compatibilizing agents on the physical properties of iPP/HDPE organoclay blends

2013 ◽  
Vol 33 (7) ◽  
pp. 589-598 ◽  
Author(s):  
Samia Boufassa ◽  
R. Doufnoune ◽  
Abdelhak Hellati ◽  
Nacceredine Haddaoui ◽  
M. Esperanza Cagiao
Keyword(s):  
Maleic Anhydride ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering ◽  
The One ◽  
Grafted Epdm ◽  
The Relationship ◽  
Butadiene Styrene

Abstract Blends of isotactic polypropylene (iPP) and high density polyethylene (HDPE), with and without compatibilizers and with different organoclay amounts (1%, 3%, and 5%), were systematically investigated to assess the effect of the additives on the crystallinity of the blends, as well as the correlation between the microhardness, H and the Young’s modulus E. The compatibilizers used were: maleic anhydride grafted styrene ethylene butadiene styrene (SEBS-g-MAH), maleic anhydride grafted polyethylene (PE-g-MAH), maleic anhydride grafted polypropylene (PP-g-MAH), ethylene propylene diene monomer (EPDM), and maleic anhydride grafted EPDM (EPDM-g-MAH). The thermal properties and crystallization behavior were determined by differential scanning calorimetry (DSC) and wide angle X-ray scattering (WAXS). Macro- and micromechanical properties were also investigated. The results obtained showed that the addition of clay slightly increases the crystallinity αWAXS of the blends. However, the hardness H decreases enormously only by adding 1 wt% of clay. With higher clay amounts, H increases again. The relationship between the Young’s modulus E and the hardness H for all the studied blends was found to be somewhat higher than the one obtained for polyethylene (PE) samples with different morphologies.

X-ray scattering from a thickness-modulated phase of lipid membranes

2019 ◽  
Vol 52 (2) ◽  
pp. 440-444
Author(s):  
S. Madhukar ◽  
V. A. Raghunathan
Keyword(s):  
Lipid Membranes ◽  
Structural Parameters ◽  
Membrane Thickness ◽  
X Ray ◽  
X Ray Scattering ◽  
Least Squares Fit ◽  
Order Of Magnitude ◽  
Modulated Phase ◽  
Analytical Expressions ◽  
Ray Scattering

An electron density model for small-angle X-ray scattering from a novel thickness-modulated phase of lipid membranes is presented, and analytical expressions are derived for the intensities of the diffraction peaks. Structural parameters of the membranes in this phase have been determined from a least-squares fit of the calculated intensities to the observed ones. The amplitude of the thickness modulation is found to be about an order of magnitude smaller than the membrane thickness, which accounts for the very small number and very weak intensities of the peaks arising from these modulations.

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