Polyphosphazene Elastomers Containing Interdigitated Oligo-p-phenyleneoxy Side Groups: Synthesis, Mechanical Properties, and X-ray Scattering Studies

2015 ◽  
Vol 48 (14) ◽  
pp. 4882-4890 ◽  
Author(s):  
Tomasz Modzelewski ◽  
Nichole M. Wonderling ◽  
Harry R. Allcock
Keyword(s):  
Mechanical Properties ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Structure Evolution of Thermotropic Polymers by Thermal Annealing. A Light and X-Ray Scattering Study

2015 ◽  
Vol 1765 ◽  
pp. 65-70
Author(s):  
Adriana Reyes-Mayer ◽  
Angel Romo-Uribe ◽  
Michael Jaffe
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Thermal Treatment ◽  
Structure Evolution ◽  
Wide Angle ◽  
Extrusion Axis ◽  
X Ray ◽  
X Ray Scattering ◽  
Extruded Films ◽  
Ray Scattering

ABSTRACTSmall-angle light scattering (SALS) and wide-angle X-ray scattering (WAXS) were used to study the influence of heat treatment on the texture and microstructure of extruded films of high-performance thermotropic liquid crystal polymers (LCPs). The microstructure was correlated with tensile mechanical properties. LCPs based on random units of hydroxybenzoic acid (B), hydroxynaphthoic acid (N), terephthalic acid (TA) and biphenol (BP) were supplied by the former Hoechst Celanese Corp. as 50 μm thick extruded films. The LCPs, denoted B-N, COTBP and RD1000, have B and N as common co-monomers and vary the other co-monomers. Thus, this study also enabled the investigation of the influence of monomer composition on microstructure and mechanical properties. Heat treatments were carried out at temperatures close to the solid-to-nematic transition (Ts→n) for periods up to 5 h, under dry air conditions. The thermal treatment produced either two endotherms or a small increase of Ts→n (B-N and RD1000), or Ts→n increased significantly (COTBP). Moreover, when heat treatment was carried out approximately 40°C below the respective Ts→n, the mechanical Young’s modulus, E, along the extrusion axis increased for all LCPs. Strikingly, for COTBP, E increased over 100% relative to the as-extruded film. The results also showed that the optimum treatment time for improving the Young modulus was between 3 and 4 h. Wide-angle X-ray scattering showed a significant sharpening of crystalline reflections and concentration of the 002 meridional reflection as a result of thermal treatment, suggesting the elimination of defects and a better alignment of the molecular chains along the extrusion axis. This would explain the increase in tensile modulus.

scholarly journals Probing the complex thermo-mechanical properties of a 3D-printed polylactide-hydroxyapatite composite using in situ synchrotron X-ray scattering

2019 ◽  
Vol 16 ◽  
pp. 113-122 ◽  
Author(s):  
Tan Sui ◽  
Enrico Salvati ◽  
Hongjia Zhang ◽  
Kirill Nyaza ◽  
Fedor S. Senatov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
X Ray ◽  
X Ray Scattering ◽  
Hydroxyapatite Composite ◽  
3D Printed ◽  
Ray Scattering

Morphology of Ethylene−Propylene Copolymer Based Ionomers as Studied by Solid State NMR and Small Angle X-ray Scattering in Relation to Some Mechanical Properties

2003 ◽  
Vol 36 (4) ◽  
pp. 1147-1156 ◽  
Author(s):  
M. E. L. Wouters ◽  
V. M. Litvinov ◽  
F. L. Binsbergen ◽  
J. G. P. Goossens ◽  
M. van Duin ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Solid State ◽  
Small Angle ◽  
Solid State Nmr ◽  
Ethylene Propylene ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals Study on Crystallization Behaviors and Properties of F-III Fibers during Hot Drawing in Supercritical Carbon Dioxide

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 856 ◽  
Author(s):  
Xiaoma Ding ◽  
Haijuan Kong ◽  
Mengmeng Qiao ◽  
Zhifeng Hu ◽  
Muhuo Yu
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Treatment Time ◽  
Orientation Factor ◽  
X Ray ◽  
X Ray Scattering ◽  
Hot Drawing ◽  
Supercritical Carbon ◽  
Ray Scattering

In order to obtain F-III fibers with high mechanical properties, pristine F-III fibers were hot drawn at the temperature of 250 °C, pressure of 14 MPa, tension of 6 g·d−1, and different times, which were 15 min, 30 min, 45 min, 60 min, 75 min, 90 min, and 105 min, respectively, in supercritical carbon dioxide (Sc-CO2) in this article. All the samples, including the pristine and treated F-III fibers, were characterized by a mechanical performance tester, wide-angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), and thermogravimetric analysis (TGA). The results showed that the thermal stability of F-III fibers was enhanced to some extent, and the tensile strength and modulus of F-III fibers had great changes as the extension of treatment time during hot drawing in Sc-CO2, although the treatment temperature was lower than the glass transition temperature (Tg) of F-III fibers. Accordingly, the phase fraction, orientation factor fc of the (110) crystal plane, fibril length lf, and misorientation angle Bφ of all the samples were also investigated. Fortunately, the hot drawing in Sc-CO2 was successfully applied to the preparation of F-III fibers with high mechanical properties.

Microtubule nucleation sequence studied by time-resolved x-ray scattering and electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 766-767
Author(s):  
Eva-Maria Mandelkow ◽  
Eckhard Mandelkow ◽  
Joan Bordas
Keyword(s):  
Electron Microscopy ◽  
Dynamic Equilibrium ◽  
Time Resolved ◽  
X Ray ◽  
Additional Information ◽  
X Ray Scattering ◽  
Low Concentrations ◽  
Microtubule Growth ◽  
Ray Patterns ◽  
Ray Scattering

When a solution of microtubule protein is changed from non-polymerising to polymerising conditions (e.g. by temperature jump or mixing with GTP) there is a series of structural transitions preceding microtubule growth. These have been detected by time-resolved X-ray scattering using synchrotron radiation, and they may be classified into pre-nucleation and nucleation events. X-ray patterns are good indicators for the average behavior of the particles in solution, but they are difficult to interpret unless additional information on their structure is available. We therefore studied the assembly process by electron microscopy under conditions approaching those of the X-ray experiment. There are two difficulties in the EM approach: One is that the particles important for assembly are usually small and not very regular and therefore tend to be overlooked. Secondly EM specimens require low concentrations which favor disassembly of the particles one wants to observe since there is a dynamic equilibrium between polymers and subunits.

Time-Resolved Cryo-Electron Microscopy of Oscillating Microtubules

1990 ◽  
Vol 48 (1) ◽  
pp. 502-503
Author(s):  
Eva-Maria Mandelkow ◽  
Ron Milligan
Keyword(s):  
Electron Microscopy ◽  
Dynamic Instability ◽  
Entire Solution ◽  
Reaction Scheme ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
A Chain ◽  
Ray Scattering

Microtubules form part of the cytoskeleton of eukaryotic cells. They are hollow libers of about 25 nm diameter made up of 13 protofilaments, each of which consists of a chain of heterodimers of α-and β-tubulin. Microtubules can be assembled in vitro at 37°C in the presence of GTP which is hydrolyzed during the reaction, and they are disassembled at 4°C. In contrast to most other polymers microtubules show the behavior of “dynamic instability”, i.e. they can switch between phases of growth and phases of shrinkage, even at an overall steady state [1]. In certain conditions an entire solution can be synchronized, leading to autonomous oscillations in the degree of assembly which can be observed by X-ray scattering (Fig. 1), light scattering, or electron microscopy [2-5]. In addition such solutions are capable of generating spontaneous spatial patterns [6].In an earlier study we have analyzed the structure of microtubules and their cold-induced disassembly by cryo-EM [7]. One result was that disassembly takes place by loss of protofilament fragments (tubulin oligomers) which fray apart at the microtubule ends. We also looked at microtubule oscillations by time-resolved X-ray scattering and proposed a reaction scheme [4] which involves a cyclic interconversion of tubulin, microtubules, and oligomers (Fig. 2). The present study was undertaken to answer two questions: (a) What is the nature of the oscillations as seen by time-resolved cryo-EM? (b) Do microtubules disassemble by fraying protofilament fragments during oscillations at 37°C?

X-ray scattering by 1D molecular Guinier-Preston zones in ordered smectic phases

1992 ◽  
Vol 2 (6) ◽  
pp. 899-913 ◽  
Author(s):  
Patrick Davidson ◽  
Elisabeth Dubois-Violette ◽  
Anne-Marie Levelut ◽  
Brigitte Pansu
Keyword(s):  
X Ray ◽  
X Ray Scattering ◽  
Smectic Phases ◽  
Ray Scattering
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