In situ Raman Spectroscopic Observation of Polymer Chains in Semi-Crystalline Polyethylene Solids

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Yusuke Hiejima ◽  
Takumitsu Kida ◽  
Koh-hei Nitta
Keyword(s):  
Conformational Changes ◽  
Tensile Elongation ◽  
Spectroscopic Observation ◽  
Polymer Chains ◽  
Trans Conformation ◽  
Raman Spectroscopic ◽  
Higher Temperature ◽  
Microscopic Origin ◽  
Crystalline Polyethylene

AbstractIn situ Raman spectroscopy is applied for polyethylene solid under various environments to elucidate the morphological and conformational changes. The trans conformation retains up to higher temperature for high-density polyethylene, reflecting higher stability of the orthorhombic crystals composed of stacked trans chains. It is suggested that the conversion of the non-crystalline trans chains to the crystalline phase is the microscopic origin of thermal history in the crystallinity, whereas the transformation between the trans and gauche conformers is practically in thermal equilibrium. Microscopic and dynamic mechanism of deformation during uniaxial stretching is investigated for the molecular orientation and the microscopic load sharing on the crystalline and amorphous chains. Lower crystallinity results in smoother and higher orientation toward the stretching direction, as well as higher load on the amorphous chains, during tensile elongation.

In situ Raman spectroscopic observation of the temperature-dependent partition of CH4 and CO2 during the growth of double hydrate from aqueous solution

2015 ◽  
Vol 93 (9) ◽  
pp. 970-975 ◽  
Author(s):  
Feifei Wang ◽  
Changling Liu ◽  
Wanjun Lu ◽  
Jiasheng Wang ◽  
Yuguang Ye
Keyword(s):  
Aqueous Solution ◽  
Spectroscopic Observation ◽  
Dissolved Gas ◽  
Temperature Dependent ◽  
Optical Cell ◽  
Raman Spectroscopic ◽  
Oceanic Sediments ◽  
Equilibrium Concentrations ◽  
Lower Temperature

Sequestration of CO2 in hydrate form within deep oceanic sediments, to simultaneously replace methane trapped in submarine hydrate, has been considered as an efficient method for CO2 reduction. Consequently, research efforts are underway to deeply understand the properties of CH4 and CO2 hydrates. In this work, CH4 + CO2 double hydrate crystals were grown from aqueous solution in a capillary high-pressure optical cell. The quantitative relationships between Raman intensity and dissolved gas (i.e., CH4 and CO2) concentration in water and in hydrate were established. The partition coefficients of CH4 and CO2 between the hydrate and aqueous phases were measured at 5 constant temperatures from 275.15 to 293.15 K. The equilibrium concentrations of dissolved CH4 and CO2 decrease with decreasing temperatures, indicating more dissolved CH4 and CO2 will be transferred from the aqueous to the hydrate phase at lower temperature. With decreasing temperature, the molality of CO2 in hydrate increases and the molality of CH4 in 51262 cavities decreases, while the sum of the molality of CH4 in 51262 cavities and molality of CO2 in hydrate keeps constant, indicating that CO2 molecules can replace more methane molecules under lower temperature only by occupying the 51262 cavities.

In Situ Raman Spectroscopic Observation of Corrosion Reaction of Fe with Na2O2 up to 833 K

2005 ◽  
Vol 73 (8) ◽  
pp. 675-679 ◽  
Author(s):  
Norikazu OHTORI ◽  
Tomohiro FURUKAWA ◽  
Fumiyoshi UENO
Keyword(s):  
Spectroscopic Observation ◽  
Raman Spectroscopic ◽  
Corrosion Reaction

Application of In Situ X-ray Absorption Spectroscopy to Study Dilute Chromium Ions in a Molten Chloride Salt

2019 ◽  
Author(s):  
Jisue Moon ◽  
Carter Abney ◽  
Dmitriy Dolzhnikov ◽  
James M. Kurley ◽  
Kevin A. Beyer ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Local Structure ◽  
Chloride Salt ◽  
X Ray ◽  
Molten Chloride ◽  
Stable Species ◽  
Higher Temperature ◽  
Cr Concentration ◽  
X Ray Absorption

The local structure of dilute CrCl<sub>3</sub> in a molten MgCl<sub>2</sub>:KCl salt was investigated by <i>in situ</i> x-ray absorption spectroscopy (XAS) at temperatures from room temperature to 800<sup>o</sup>C. This constitutes the first experiment where dilute Cr speciation is explored in a molten chloride salt, ostensibly due to the compounding challenges arising from a low Cr concentration in a matrix of heavy absorbers at extreme temperatures. CrCl<sub>3</sub> was confirmed to be the stable species between 200 and 500<sup>o</sup>C, while mobility of metal ions at higher temperature (>700<sup>o</sup>C) prevented confirmation of the local structure.

Micro-Raman Spectroscopic Observation of Water Expulsion Induced Destruction of Hydrophobic Clusters in Crystalline Lysozyme

2009 ◽  
Vol 113 (29) ◽  
pp. 9633-9635 ◽  
Author(s):  
Jing-Jing Shou ◽  
Guang Zeng ◽  
Yun-Hong Zhang ◽  
G. Q. (Max) Lu
Keyword(s):  
Spectroscopic Observation ◽  
Raman Spectroscopic

Crystallization of Amorphous Silicon-Aluminum thin Films: IN-SITU Observation and Thermal Analysis.

1991 ◽  
Vol 237 ◽  
Author(s):  
Toyohiko J. Konno ◽  
Robert Sinclair
Keyword(s):  
Activation Energy ◽  
Amorphous Alloys ◽  
Amorphous Matrix ◽  
In Situ Observation ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Higher Temperature ◽  
Sputter Deposited

ABSTRACTThe crystallization of sputter-deposited Si/Al amorphous alloys was examined by transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). In-situ high-resolution TEM reveals the existence of an Al layer between the amorphous matrix and the growing crystalline phase. The activation energy for the growth is about 1.2eV, roughly corresponding to the activation energy of Si diffusion in Al. These two observations support the view that a crystallization mechanism, in which an Al buffer layer provides the shortest reaction path, is responsible for the reaction. The product microstructure exhibits secondary crystallization at a higher temperature.

An in situ Raman spectroscopic method for quantification of polyethylene glycol (PEG) in waterlogged archaeological wood

Holzforschung ◽  
2020 ◽  
Vol 74 (11) ◽  
pp. 1043-1051
Author(s):  
Åke Henrik-Klemens ◽  
Katarina Abrahamsson ◽  
Charlotte Björdal ◽  
Alexandra Walsh
Keyword(s):  
Polyethylene Glycol ◽  
Spectroscopic Method ◽  
Calibration Model ◽  
Efficient Treatment ◽  
Raman Spectroscopic ◽  
Archaeological Wood ◽  
Validation Set ◽  
Impregnation Period ◽  
Polymer Impregnation

AbstractThe weakened microstructure of archaeological wood (AW) objects from waterlogged environments necessitates consolidation to avoid anisotropic shrinkage upon drying. Polymer impregnation through submergence or spraying treatments is commonly applied, and for larger and thicker objects, the impregnation period can stretch over decades. Thus, for efficient treatment, continuous monitoring of the impregnation status is required. Today, such monitoring is often destructive and expensive, requiring segments for extraction and chromatographic quantification. This study proposes an in situ Raman spectroscopic method for quantification of polyethylene glycol (PEG) in waterlogged AW. A calibration model was built on standards of PEG, cellulose powder, and milled wood lignin using orthogonal partial least squares (OPLS). The OPLS model had a strong linear relationship, and the PEG content in wood of varying degrees of degradation could be determined. However, the accuracy of the model was low with a root mean square error of prediction of 11 wt%. The low accuracy was traced to the heterogeneity in the calibration and validation set samples with regard to the small probing volume of the confocal instrumental setup.

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