scholarly journals Synchrotron and Raman Study of the Rotator Phases and Polymorphism in Tricosane Paraffin

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1341
Author(s):  
Enrique Blázquez-Blázquez ◽  
Rosa Barranco-García ◽  
María L. Cerrada ◽  
Juan C. Martínez ◽  
Ernesto Pérez
Keyword(s):  
Phase Behavior ◽  
Variable Temperature ◽  
Low Frequency ◽  
Frequency Region ◽  
Time Variable ◽  
Wide Angle ◽  
Multistage Model ◽  
X Ray ◽  
X Ray Scattering ◽  
Raman Study

A detailed study of the phase behavior of n-paraffin C23H48 has been performed by means of real-time variable-temperature experiments with synchrotron radiation. Two detectors were employed for simultaneous analysis of the small-angle (SAXS) and wide-angle X-ray-scattering (WAXS) regions. This paraffin presents a very interesting phase behavior, involving two crystal polymorphs, three rotator phases and the liquid state. The Ostwald rule of stages is invoked to find similarities of the rotator phases with the eventual transient mesomorphic structure in the multistage model of polymer crystallization. That study is complemented by variable-temperature Raman experiments covering frequencies down to 150 cm−1. It was found that the low-frequency region is the most informative regarding the phase transitions, and specifically the intensity of the first overtone. From these analyses, several parameters are evaluated as function of temperature.

scholarly journals Nanocomposites of PCL and SBA-15 Particles Prepared by Extrusion: Structural Characteristics, Confinement of PCL Chains within SBA-15 Nanometric Channels and Mechanical Behavior

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 129
Author(s):  
Tamara M. Díez-Rodríguez ◽  
Enrique Blázquez-Blázquez ◽  
Nadine L. C. Antunes ◽  
Maria Do Rosario Gomes Ribeiro ◽  
Ernesto Pérez ◽  
...  
Keyword(s):  
Mechanical Behavior ◽  
Mechanical Response ◽  
Variable Temperature ◽  
Structural Characteristics ◽  
Structural Features ◽  
Wide Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Polymeric Chains ◽  
Mesoporous Particles

A study of different nanocomposites based on poly(ε-caprolactone) (PCL) and mesoporous SBA-15 silica that were prepared by melt extrusion was carried out by analyzing the possible effect of this filler on the crystalline details of PCL, on its mechanical behavior, and on the eventual observation of the confinement of the polymeric chains within the hollow nanometric silica channels. Thus, simultaneous Small-Angle and Wide-Angle X-ray Scattering (SAXS/WAXS) synchrotron experiments at variable temperature were performed on these PCL nanocomposites with different mesoporous silica contents. The importance of the morphological and structural features was assessed by the changes that were observed during the mechanical response of the final materials, which determined that the presence of mesoporous particles leads to a noticeable reinforcing effect.

scholarly journals Variation of Ultimate Properties in Extruded iPP-Mesoporous Silica Nanocomposites by Effect of iPP Confinement within the Mesostructures

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 70
Author(s):  
Rosa Barranco-García ◽  
José M. Gómez-Elvira ◽  
Jorge A. Ressia ◽  
Lidia Quinzani ◽  
Enrique M. Vallés ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Variable Temperature ◽  
Time Variable ◽  
Degradation Behavior ◽  
Precise Information ◽  
X Ray ◽  
Silica Nanocomposites ◽  
X Ray Scattering ◽  
Ultimate Properties ◽  
Mcm 41

Nanocomposites based on isotactic polypropylene (iPP) and mesoporous silica particles of either MCM-41 or SBA-15 were prepared by melt extrusion. The effect of the silica incorporated into an iPP matrix was firstly detected in the degradation behavior and in the rheological response of the resultant composites. Both were ascribed, in principle, to variations in the inclusion of iPP chains within these two mesostructures, with well different pore size. DSC experiments did not provide information on the existence of confinement in the iPP-MCM-41 materials, whereas a small endotherm, located at about 100 °C and attributed to the melting of confined crystallites, is clearly observed in the iPP-SBA-15 composites. Real-time variable-temperature Small Angle X-ray Scattering (SAXS) experiments with synchrotron radiation turned out to be crucial to finding the presence of iPP within MCM-41 pores. From these measurements, precise information was also deduced on the influence of the MCM-41 on iPP long spacing since overlapping does not occur between most probable iPP long spacing peak with the characteristic diffractions from the MCM-41 hexagonal nanostructure in comparison with existing superposition in SBA-15-based materials.

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>

scholarly journals On the amorphous layer in bone mineral and biomimetic apatite: A combined small- and wide-angle X-ray scattering analysis.

2020 ◽  
Author(s):  
Federica Bertolotti ◽  
Francisco J. Carmona ◽  
Gregorio Dal Sasso ◽  
Gloria B. Ramírez-Rodríguez ◽  
José Manuel Delgado-López ◽  
...  
Keyword(s):  
Bone Mineral ◽  
Amorphous Layer ◽  
Wide Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Biomimetic Apatite ◽  
Ray Scattering

Time-resolved isothermal crystallization of absorbable PGA-co-PLA copolymer by synchrotron small-angle X-ray scattering and wide-angle X-ray diffraction

Polymer ◽  
2001 ◽  
Vol 42 (21) ◽  
pp. 8965-8973 ◽  
Author(s):  
Zhi-Gang Wang ◽  
Xuehui Wang ◽  
Benjamin S. Hsiao ◽  
Saša Andjelić ◽  
Dennis Jamiolkowski ◽  
...  
Keyword(s):  
Small Angle ◽  
Isothermal Crystallization ◽  
Wide Angle ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering
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