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.

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.

A New Insight into Growth Mechanism and Kinetics of Mesoporous Silica Nanoparticles by in Situ Small Angle X-ray Scattering

Langmuir ◽  
2015 ◽  
Vol 31 (30) ◽  
pp. 8478-8487 ◽  
Author(s):  
Zhifeng Yi ◽  
Ludovic F. Dumée ◽  
Christopher J. Garvey ◽  
Chunfang Feng ◽  
Fenghua She ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Growth Mechanism ◽  
Small Angle ◽  
Mesoporous Silica Nanoparticles ◽  
X Ray ◽  
X Ray Scattering ◽  
Mechanism And Kinetics ◽  
Kinetics Of ◽  
Insight Into

scholarly journals Thermoresponsive polymer assemblies via variable temperature liquid-phase transmission electron microscopy and small angle X-ray scattering

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Joanna Korpanty ◽  
Lucas R. Parent ◽  
Nicholas Hampu ◽  
Steven Weigand ◽  
Nathan C. Gianneschi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Small Angle ◽  
Variable Temperature ◽  
X Ray ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Temperature Liquid ◽  
Insight Into ◽  
Ray Scattering

AbstractHerein, phase transitions of a class of thermally-responsive polymers, namely a homopolymer, diblock, and triblock copolymer, were studied to gain mechanistic insight into nanoscale assembly dynamics via variable temperature liquid-cell transmission electron microscopy (VT-LCTEM) correlated with variable temperature small angle X-ray scattering (VT-SAXS). We study thermoresponsive poly(diethylene glycol methyl ether methacrylate) (PDEGMA)-based block copolymers and mitigate sample damage by screening electron flux and solvent conditions during LCTEM and by evaluating polymer survival via post-mortem matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS). Our multimodal approach, utilizing VT-LCTEM with MS validation and VT-SAXS, is generalizable across polymeric systems and can be used to directly image solvated nanoscale structures and thermally-induced transitions. Our strategy of correlating VT-SAXS with VT-LCTEM provided direct insight into transient nanoscale intermediates formed during the thermally-triggered morphological transformation of a PDEGMA-based triblock. Notably, we observed the temperature-triggered formation and slow relaxation of core-shell particles with complex microphase separation in the core by both VT-SAXS and VT-LCTEM.

scholarly journals Measuring the specific surface area of mesoporous silica using x-ray scattering

2014 ◽  
Vol 70 (a1) ◽  
pp. C599-C599
Author(s):  
Julien Cambedouzou ◽  
Olivier Diat
Keyword(s):  
Experimental Data ◽  
Specific Surface ◽  
Surface Area ◽  
Mesoporous Materials ◽  
Specific Surface Area ◽  
Small Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Mcm 41 ◽  
Ray Scattering

The development of porous silica or carbon material with high specific surface area raises a high interest in the field of materials science given their potential interest in a wide range of applications including catalysis, water treatment or drug delivery. Among these mesoporous structures, those consisting of one-dimensional pores aligned along a compact hexagonal packing are of prime importance and can be referred to as "hexagonal mesoporous materials" (HMPM). The most famous silica structures of this kind are MCM-41 and SBA-15. The same symmetry can be found in carbon mesoporous materials, for example in FDU-15 structures. The precise characterization of HMPM is necessary for most of the applications envisioned for these materials (pore size, pore density, specific surface and sometimes thickness of the functionalization layer). Small angle X-ray scattering techniques offer the opportunity to determine the mean structural parameters of HMPM. Although different approaches can be found in the literature in order to numerically reproduce the experimental data obtained on HMPM or hexagonal liquid crystals, when the sample is a powder, fitting the experimental data in absolute scale with numerical models becomes necessary. However, with a large scattering contribution of grain at low q vector as well as short range correlation contribution at large q, the analysis is not so simple. In this paper, we propose a comprehensive study [1] devoted to the quantitative interpretation of small-angle scattering patterns of HMPM in terms of structure and specific surface estimation based on the formalism proposed by Spalla et al. [2]. In the case of two real samples, namely a SBA-15 and a MCM-41 powder, the specific surface area of the mesopores is estimated and is discussed in the light of gas adsorption measurements.

Structure of Methanol Confined in MCM-41 Investigated by Large-Angle X-ray Scattering Technique

2005 ◽  
Vol 109 (2) ◽  
pp. 892-899 ◽  
Author(s):  
Toshiyuki Takamuku ◽  
Hirokazu Maruyama ◽  
Shigeharu Kittaka ◽  
Shuichi Takahara ◽  
Toshio Yamaguchi
Keyword(s):  
Large Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Scattering Technique ◽  
Mcm 41 ◽  
Ray Scattering

Synthesis of SBA-15/MCM-41 bimodal mesoporous silica

2016 ◽  
Vol 1817 ◽  
Author(s):  
Leyla Y. Jaramillo ◽  
Wilson A. Henao ◽  
Elizabeth Pabón-Gelves
Keyword(s):  
Mesoporous Silica ◽  
Textural Properties ◽  
New Materials ◽  
X Ray Diffraction ◽  
Main Interest ◽  
Structure Directing Agent ◽  
X Ray ◽  
Synthesis Parameters ◽  
Nanostructured Silica ◽  
Mcm 41

ABSTRACTNanostructured silica materials with different morphologies and adjustable pore size have been studied by researches worldwide for several applications such as catalysis, separation, adsorption, and templates for new materials. The main interest in the development of these materials is to obtain a structure with a specific combination of pore sizes for a particular application. The morphology and textural properties of pores can be easily changed with the modification of the synthesis parameters, among these, the choice of surfactant or structure directing agent (SDA).Accordingly, in this work, three types of nanostructured silica with different mesoporosity were synthesized by using of CTAB and Pluronic 123 as structure directing agents: SBA-15 and MCM-41 unimodal mesoporous silica and SBA-15/MCM-41 bimodal mesoporous silica.To evaluate the effect of surfactant on the morphology and textural properties of pores, the materials were characterized by scanning electron microscopy (SEM), X-ray Diffraction (XRD) and nitrogen sorption (BET).

Small angle X-ray scattering from MCM-41 and its synthesis gels: optimisation of the synthesis parameters

1995 ◽  
Vol 102 ◽  
pp. 213-230 ◽  
Author(s):  
K.J. Edler ◽  
J. Dougherty ◽  
R. Durand ◽  
L. Iton ◽  
G. Kirton ◽  
...  
Keyword(s):  
Small Angle ◽  
X Ray ◽  
X Ray Scattering ◽  
Synthesis Parameters ◽  
Mcm 41 ◽  
Ray Scattering
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