scholarly journals Two Spectroscopies as Main Source for Investigation of Polymer-Clay Materials

2021 ◽  
Author(s):  
Gustavo Morari do Nascimento
Keyword(s):  
Molecular Structure ◽  
Clay Nanocomposites ◽  
Spectroscopic Techniques ◽  
New Materials ◽  
Smectite Clays ◽  
Lamellar Materials ◽  
X Ray Absorption ◽  
Clay Materials

In the recent years the synthesis and characterization of nanomaterials has been one of the most efficacious way to produce new materials with improved or completely new properties. The polymer-clay nanocomposites are one of the most interesting nanomaterials with the possibility to create a myriad of new materials with many applications. Lamellar materials are classified as two-dimensional (2D), because there are formed by platelets piled up in one crystallographic direction, as the graphite and clays. The synthesis of controlled dimensional nanostructures as well as the characterization of the intrinsic and potentially peculiar properties of these nanostructures are central themes in nanoscience. The study of different nanostructures has great potential to test and understand fundamental concepts about the role of particle dimensionality on their physicochemical properties. Among the various materials studied in the literature, undoubtedly, polymer-clay materials, especially conducting polymers with smectite clays, such as montmorillonites (MMT) are of particular note. Our group have paid many efforts in the characterization of nanomaterials by using powerful spectroscopic techniques to study both the guest and host in case of inclusion compounds, nanofibers, carbon allotropes or many phases present in polymer-clay nanocomposites. There are two central questions that it was possible to address in this study: (i) the molecular structure of the polymer is drastically changed inside the interlayer cavity of clay and (ii) by using the appropriate synthetic or heating route is possible to change the molecular structure of the confined polymer. In the follow lines, it is briefly told the main aspects of resonance Raman and X-ray absorption spectroscopies in the study of polymer-clay nanocomposites.

Characterization of Process Induced Contamination and Residues on Semiconductor Components Via FTIR and Raman Microanalysis

2001 ◽  
Vol 7 (S2) ◽  
pp. 152-153
Author(s):  
H. Gotts
Keyword(s):  
Molecular Structure ◽  
Yield Enhancement ◽  
Spectroscopic Techniques ◽  
Bulk Materials ◽  
Scanning Calorimetry ◽  
Vis Spectroscopy ◽  
Classical Technique ◽  
Raman Microprobe ◽  
Scanning Electron

FTIR and Raman microanalysis may be used as a powerful combination to determine the identity, and hence infer the source, of contaminant particles which diminish yields of semiconductor components and devices. The complimentarity of these techniques arises from the underlying spectroscopic selection rules.Vibrational spectroscopic techniques are commonly used to characterize the molecular structure of bulk organic materials. These bulk materials typically represent purified fractions of components which may be further investigated with various classical instrumental techniques such as Differential Scanning Calorimetry (DSC), Nuclear Magnetic Resonance (NMR) spectroscopy, UV-Vis spectroscopy. However, these classical technique may have limited value for the interrogation of small impure particles or materials of limited quantity(ng.).Elemental techniques such as Scanning Electron Microscopy coupled to Energy Dispersive Spectroscopy are enhanced by the specificity of FTIR Microprobe Spectroscopy and Raman Microprobe Spectroscopy which are now used in process laboratories to characterize and identify particulate and thin film residues with the intent of device yield enhancement.

scholarly journals Thermodynamic and Structural Characterization of the Copper(II) Complexes of Peptides Containing Both Histidyl and Aspartyl Residues

2007 ◽  
Vol 2007 ◽  
pp. 1-9 ◽  
Author(s):  
Csilla Kállay ◽  
Zoltán Nagy ◽  
Katalin Várnagy ◽  
Gerasimos Malandrinos ◽  
Nick Hadjiliadis ◽  
...  
Keyword(s):  
Metal Binding ◽  
Significant Contribution ◽  
Binding Mode ◽  
Side Chain ◽  
Spectroscopic Techniques ◽  
Metal Binding Site ◽  
Carboxylate Groups ◽  
Protected Peptides

Terminally protected pentapeptides with 2 histidines (Ac-HHVGD-NH2and Ac-HVGDH-NH2) and the terminally free peptides containing both internal aspartyl and C-terminal histidyl residues (FDAH and VIDAH) have been synthesized, and copper(II) complexes studied by potentiometric, UV-Vis, CD, and EPR spectroscopic techniques in solution. Both thermodynamic and spectroscopic data reveal that side chain donor atoms of aspartyl and histidyl residues have a significant contribution to the metal binding affinity of peptide molecules. In the case of terminally protected peptides, the role of the imidazole-N donor functions is reflected in the enhanced stability of the 3N and 4N coordinated copper(II) complexes. The amino andβ-carboxylate groups of FDAH and VIDAH create a very effective metal binding site with the (NH2,N−,β-COO−) and (NH2,N−,N−,β-COO−) coordination modes including the N-termini, while the histidine sites are available for the formation of the (Nim,N−,N−) binding mode resulting in the preference of dinuclear complex formation.

On the Role of Characterization in the Design of Interfaces in Nanoscale Materials Technology

2004 ◽  
Vol 10 (3) ◽  
pp. 324-335 ◽  
Author(s):  
S.P. Ringer ◽  
K.R. Ratinac
Keyword(s):  
Three Dimensional ◽  
Atom Probe ◽  
Turbine Rotor ◽  
Clay Nanocomposites ◽  
Multimodal Approach ◽  
Transmission Electron ◽  
Different Types ◽  
And Control

This work reviews recent research on the design and control of interfaces in engineering nanomaterials. Four case studies are presented that demonstrate the power of a multimodal approach to the characterization of different types of interfaces. We have used a combination of conventional, high resolution, and analytical transmission electron microscopy, microbeam electron diffraction, and three-dimensional atom probe to study polymer–clay nanocomposites, turbine rotor steels used for power generation, multicomponent aluminum alloys, and nanocrystalline magnetic materials.

Assessing nickel oxide electrocatalysts incorporating diamines and having improved oxygen evolution activity using operando UV/visible and X-ray absorption spectroscopy

2021 ◽  
Author(s):  
Takafumi Miura ◽  
Shun Tsunekawa ◽  
Sho Onishi ◽  
Toshiaki Ina ◽  
Kehsuan Wang ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Water Splitting ◽  
Oxygen Evolution ◽  
Absorption Spectroscopy ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Uv Visible ◽  
X Ray Absorption

The role of diamines incorporated in a nickel oxide electrocatalyst for water splitting was examined using operando UV/XAFS spectroscopic techniques.

Spectroscopic Characterization of the Nitridation Process of Polymeric Precursors to SI-M-N-O Systems (M=Ti, Zr, Al)

1992 ◽  
Vol 287 ◽  
Author(s):  
F. Babonneau ◽  
G. D. Soraru
Keyword(s):  
Spectroscopic Characterization ◽  
Ceramic Materials ◽  
Spectroscopic Techniques ◽  
X Ray ◽  
Nitridation Process ◽  
Local Environments ◽  
Ceramic Precursors ◽  
Mixed Ceramic ◽  
X Ray Absorption

ABSTRACTA commercial polycarbosilane was modified with various metallic alkoxides to get mixed ceramic precursors in the Si-M-C-O systems (M=Ti, Zr Al). Pyrolysis under ammonia leads to the formation of various ceramic materials depending on the nature of M : Si3N4/TiN, Si3N4/ZrO2 or β′-SiAlON phases.The polymer-to-ceramics conversion have been studied by MAS-NMR (29 Si, 27Al) and X-ray absorption (Ti K-edge). This paper will show how these two complementary spectroscopic techniques can be used to follow the nitridation process by probing local environments of different elements. In addition, it will be pointed out how X-ray absorption can be a powerful tool for the detection of the crystallization of nitride cubic phases.

Mechanical Characterization of Nanoclay Reinforced Polypropylene Composites at High Temperature Subjected to Tensile Loads

2012 ◽  
Vol 488-489 ◽  
pp. 567-571 ◽  
Author(s):  
Reza Eslami Farsani ◽  
Ziba Hedayat Nasab ◽  
S. Mohammad Reza Khalili ◽  
Neda Soleimani
Keyword(s):  
High Temperature ◽  
Tensile Modulus ◽  
Clay Nanocomposites ◽  
Melt Mixing ◽  
Polypropylene Composites ◽  
Twin Screw ◽  
First Time ◽  
Compatibilizing Agent

In this paper, Polypropylene (PP) nanocomposites are prepared by melt mixing in a twin-screw extruder by injection molding. The role of compatibilizing agent is performed by maleic anhydride grafted polypropylene (PP-g-MA) between nanoclay and PP. The effect of nanoclay particles (1, 3, 5 wt %) on the PP composites is investigated for tensile test at high temperature for the first time. Mechanical behaviors of PP/clay nanocomposites at both room temperature (RT) and high temperature (HT) are investigated in terms of tensile properties. Addition of nanoclay showed a significant enhancement in stiffness of PP/clay nanocomposites. Nearly 36% and 157% increase in the tensile modulus at both RT and HT are observed, respectively. But, the increase in tensile strength is almost negligible.

Spectroscopic Characterization of a Pre-Ceramic Polymer For Sic/Tic System.

1990 ◽  
Vol 180 ◽  
Author(s):  
Florence Babonneau ◽  
Patrice Barre ◽  
Jacques Livage ◽  
Michel Verdaguer
Keyword(s):  
Spectroscopic Characterization ◽  
Argon Atmosphere ◽  
Mas Nmr ◽  
Spectroscopic Techniques ◽  
Excess Carbon ◽  
X Ray ◽  
Local Environments ◽  
X Ray Absorption ◽  
Cp Mas Nmr

ABSTRACTPolytitanocarbosilane precursor for SiC/TiC ceramics was characterized by various spectroscopic techniques (29Si and 13C CP MAS NMR, Ti K-edge XANES and EXAFS) in order to follow how titanium ions are incorporated into the polycarbosilane-based polymer. This polymer has been fired in argon atmosphere, and the evolution of the local environments of Si and Ti atoms, during the pyrolysis process, have been followed using 29Si MAS-NMR and Ti K-edge X-ray absorption: this study reveals the formation of Si-O bonds above 500°C, while Ti-C bonds clearly appear around 800°C. Above 1000°C, Si-O bonds are consumed by reaction with excess carbon and the system finally crystallizes into SiC/TiC mixture above 1200°C.

Synthesis and Characterization of Comb-Like Polycarboxylate Superplasticizer

2012 ◽  
Vol 204-208 ◽  
pp. 3881-3885
Author(s):  
Yun Hui Fang ◽  
Zhuo Jun Jiang ◽  
Yu Liang Ke ◽  
Xiao Lu Chen ◽  
Fei Long Zheng ◽  
...  
Keyword(s):  
Molecular Structure ◽  
High Performance ◽  
Graft Copolymerization ◽  
High Performance Concrete ◽  
Synthesis And Characterization ◽  
New Materials ◽  
Polycarboxylate Superplasticizer ◽  
Control Factors ◽  
Expected Performance

Polycarboxylate superplasticizers have become the superstar for high-performance concrete. Because their molecular structure can be easily manipulated by impart new materials to acquire new performance. In this paper, the synthetic parameters adjusting experiment is utilized to get the optimal synthetic formulations. The reaction control factors and polymerization mechanism are also discussed. After characterization, we concluded that the expected performance of polycarboxylate superplasticizer could fabricate through radical graft copolymerization reaction by molecular designing.

scholarly journals Synthesis and Characterization of Lateral Fluoro-substituents Liquid Crystals

2021 ◽  
Vol 11 (5) ◽  
pp. 12495-12505
Keyword(s):  
Molecular Structure ◽  
Differential Scanning Calorimetry ◽  
Liquid Crystal ◽  
Linkage Group ◽  
Optical Microscope ◽  
Synthesis And Characterization ◽  
Spectroscopic Techniques ◽  
Dielectric Measurements ◽  
Scanning Calorimetry

Lateral difluoro substituent liquid crystal based on a three-aromatic core has been synthesized. It has been designed to correlate the molecular structure and mesomorphism with reference to the difluoro substituent and -COO- linkage group. This compound was characterized by elementary analyses and spectroscopic techniques such as FTIR and 1H-NMR. The synthesis compound's mesomorphic behavior was studied by polarizing optical microscope, differential scanning calorimetry, and dielectric measurements. The recent investigation reveals only SmB phase.

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