Vaporization heat of bound water in wood chemically modified via grafting and crosslinking patterns by DSC and NMR analysis

Holzforschung ◽  
2018 ◽  
Vol 72 (12) ◽  
pp. 1043-1049 ◽  
Author(s):  
Yingjie Guo ◽  
Minghui Zhang ◽  
Zefang Xiao ◽  
Haiou Chen ◽  
Yanjun Xie
Keyword(s):  
Cell Walls ◽  
Bound Water ◽  
Weight Percent ◽  
Radiata Pine ◽  
Nmr Analysis ◽  
Scanning Calorimetry ◽  
Chemically Modified ◽  
Low Field ◽  
Vaporization Heat ◽  
Condensed Water

AbstractRadiata pine wood (W) was modified with acetic anhydride and glutaraldehyde (GA) resulting in WAcand WGAto various weight percent gains (WPGs), whereas in WActhe effect is due to grafting and in WGA, crosslinking. The heat of vaporization of bound water (BW) of the modified woods was studied by differential scanning calorimetry (DSC) and the mass loss (due to water loss) of the samples by thermogravimetry (TG). The temperature program was in both cases from 25 to 40°C with 10°C min−1. The adsorbed or condensed water in wood were observed via low-field nuclear magnetic resonance (LFNMR). At a comparable WPG level, the LFNMR analysis showed that the interaction of water with WGAwas stronger than that with WAc. In both modified woods, a considerable reduction in the vaporization heat of BW was visible due to cell wall hydrophobization and bulking. The reduction of condensed water in micropores was lower for WGAthan WAc, probably because BW needs more energy to evaporate from the crosslinked stiff WGAcell walls.

UV-microscopic analysis of acetylated spruce and birch cell walls

Holzforschung ◽  
2004 ◽  
Vol 58 (5) ◽  
pp. 483-488 ◽  
Author(s):  
Christian Hansmann ◽  
Manfred Schwanninger ◽  
Barbara Stefke ◽  
Barbara Hinterstoisser ◽  
Wolfgang Gindl
Keyword(s):  
Cell Walls ◽  
Middle Lamella ◽  
Microscopic Analysis ◽  
Weight Percent ◽  
Cellular Level ◽  
Uv Spectrum ◽  
Spectral Shifts ◽  
Microscopy Analysis ◽  
Absorbance Peak ◽  
Absorbance Spectra

Abstract Spruce and birch earlywood was acetylated to different weight percent gains using three different acetylation procedures. The absorbance spectra of secondary cell wall and compound cell corner middle lamella were determined by means of UV microscopy. Analysis of the spectra showed that the characteristic lignin absorbance peak in the UV spectrum of wood around 280 nm shifted to shorter wavelengths in acetylated samples. A distinct relationship between achieved weight percent gains after acetylation and observed spectral shifts could be established revealing a certain potential to measure acetylation on a cellular level by means of UV microscopy.

Studies on Bound Water of Cellulose by Differential Scanning Calorimetry

1981 ◽  
Vol 51 (9) ◽  
pp. 607-613 ◽  
Author(s):  
Kunio Nakamura ◽  
Tatsuko Hatakeyama ◽  
Hyoe Hatakeyama
Keyword(s):  
Differential Scanning Calorimetry ◽  
Bound Water ◽  
Scanning Calorimetry

scholarly journals Relationship of Moisture Status and Quality Characteristics of Fresh Wet Noodles Prepared from Different Grade Wheat Flours from Flour Milling Streams

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Li Li ◽  
Na Wang ◽  
Sen Ma ◽  
Songzhu Yang ◽  
Xuehua Chen ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Frozen Storage ◽  
Bound Water ◽  
Intermediate Water ◽  
Proton Mobility ◽  
Flour Milling ◽  
Low Field ◽  
Relationship Of ◽  
Wheat Flours

This study was performed to investigate the quality of fresh wet noodles made from flour milling streams. The basic composition, texture properties, cooking characteristics, and moisture status were measured to evaluate the qualities of noodles. The results indicated that as storage time increased, the springiness of fresh wet noodles gradually decreased, but the hardness increased. Additionally, the cooking loss rate was increased obviously, and the water absorption rate generally decreased. The relaxation times T21 and T22, analyzed by low-field nuclear magnetic resonance, showed a downward trend that proton mobility became poor and bound water changed into intermediate water. Noodles made from reduction flour exhibited better quality. Compared to that with ambient temperature storage, the wet noodles under frozen storage showed better quality. The relaxation time T21, and T22 showed a positive correlation with noodle quality.

Extrem asymmetrisch gebundene Wassermoleküle-Kristallstrukturen von Sr(OH)Cl · 4 H2O, Sr(OH)Br · 4 H2O und Ba(OH)I·4 H2O / Extremely Asymmetrically Bound Water Molecules-Crystal Structures of Sr(OH)Cl · 4 H2O, Sr(OH)Br · 4 H2O, and Ba(OH)I·4 H2O

1991 ◽  
Vol 46 (10) ◽  
pp. 1279-1286 ◽  
Author(s):  
Thomas Kellersohn ◽  
Konrad Beckenkamp ◽  
Heinz Dieter Lutz
Keyword(s):  
Crystal Structures ◽  
Bound Water ◽  
Structure Type ◽  
Water Molecules ◽  
Halide Ions ◽  
Weak Hydrogen Bond ◽  
Scanning Calorimetry ◽  
Unknown Structure ◽  
Stretching Vibrations ◽  
Strong Distortion

The crystal structures of isotypic Sr(OH)Cl ·4 H2O, Sr(OH)Br·4 H2O, and Ba(OH)I·4 H2O are reported. The title compounds crystallize in a hitherto unknown structure type, space group PĪ, Z = 2. The final R values obtained are 0.0261, 0.069, and 0.062, respectively. The coordination of the metal ions is monocapped square antiprismatic with 7 H2O, 1 OH- and 1 halide ion. The halide ions separate metal/water/hydroxide layers. Each of the four crystallographically different water molecules serves as donor for one very strong and one very weak hydrogen bond and, hence, is extremely asymmetrically bound. Owing to this strong distortion, the largest one known so far, the OH stretching vibrations of the H2O molecules are intramolecularly decoupled as shown from vibrational spectra. The enthalpies of dehydration obtained from differential scanning calorimetry are reported.

scholarly journals Studies on the Maximum Bound Water Content by the Differential Scanning Calorimetry on Lipstick

2012 ◽  
Vol 38 (3) ◽  
pp. 197-200
Author(s):  
Khee-Hwan Choi ◽  
Myung-Jin Ann ◽  
Hong-Ha Son ◽  
Kyong-Seub Kim ◽  
Sang-Min Lee ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Water Content ◽  
Bound Water ◽  
Scanning Calorimetry ◽  
Bound Water Content

Determination of T2 cut-off for shale reservoirs: a case study from the Carynginia formation, Perth Basin, Western Australia

2017 ◽  
Vol 57 (2) ◽  
pp. 664 ◽  
Author(s):  
M. Nadia Testamanti ◽  
Reza Rezaee ◽  
Yujie Yuan ◽  
Dawei Pan
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Petroleum Industry ◽  
Bound Water ◽  
Invasive Technique ◽  
Sources Of Information ◽  
Vacuum Oven ◽  
Low Field ◽  
Wide Range

Over recent decades, the low-field Nuclear Magnetic Resonance (NMR) method has been consistently used in the petroleum industry for the petrophysical characterisation of conventional reservoirs. Through this non-invasive technique, the porosity, pore size distribution and fluid properties can be determined from the signal emitted by fluids present in the porous media. Transverse relaxation (T2) data, in particular, are one of the most valuable sources of information in an NMR measurement, as the resulting signal decay can be inverted to obtain the T2 distribution of the rock, which can in turn be correlated with porosity and pore size distribution. The complex pore network of shales, which can have a large portion of pore sizes in the nanopore and mesopore range, restricts the techniques that can be used to investigate their pore structure and porosity. The ability of the NMR technique to detect signals from a wide range of pores has therefore prompted the quest for more standardised interpretation methods suitable for shales. Using low-field NMR, T2 experiments were performed on shale samples from the Carynginia formation, Perth Basin, at different saturation levels. The shale samples were initially saturated with brine and the T2 spectrum for each sample was obtained. Then, they were placed in a vacuum oven and their weight monitored until a constant value was reached. T2 curves were subsequently obtained for each of the oven-dried samples and a cut-off value for clay-bound water was calculated.

scholarly journals Flame-Retardant Mechanism of Layered Double Hydroxides in Asphalt Binder

Materials ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 801 ◽  
Author(s):  
Kai Zhu ◽  
Yunhe Wang ◽  
Daquan Tang ◽  
Qiang Wang ◽  
Haihang Li ◽  
...  
Keyword(s):  
Flame Retardant ◽  
Layered Double Hydroxides ◽  
Photoelectron Spectroscopy ◽  
Cone Calorimeter ◽  
Asphalt Binder ◽  
Bound Water ◽  
Asphalt Binders ◽  
Scanning Calorimetry ◽  
Limiting Oxygen Index ◽  
Double Hydroxides

The flame retardancy of asphalt binders with layered double hydroxides (LDHs) was investigated using limiting oxygen index (LOI) and cone calorimeter tests. The flame-retardant mechanism of the LDHs was also studied with thermogravimetry and differential scanning calorimetry (TG–DSC), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The cone calorimeter testing results indicated that 2 wt.% of the LDHs can decease the peak heat and smoke release rate of asphalt binders. Because a low dose of LDHs can be well dispersed in asphalt binder and favor the formation of polyaromatic structures during combustion, the thermal oxidation resistance and compactness of the char layer can be improved. The LOI of asphalt binder can be increased and the heat and smoke release during combustion can be decreased with 25 wt.% LDHs. The decomposition of LDHs can absorb the heat release of the initial two stages of asphalt combustion and reduce the burning rate of asphalt. Due to the loss of loosely bound water in the LDHs during the blending process and the decrease of dispersibility at a high LDH dose, the improvement of thermal stability is limited.

scholarly journals Investigation of the effect of aging on wood hygroscopicity by 2D 1H NMR relaxometry

Holzforschung ◽  
2020 ◽  
Vol 74 (4) ◽  
pp. 400-411 ◽  
Author(s):  
Leila Rostom ◽  
Denis Courtier-Murias ◽  
Stéphane Rodts ◽  
Sabine Care
Keyword(s):  
Cell Walls ◽  
Molecular Level ◽  
Bound Water ◽  
Proton Nuclear Magnetic Resonance ◽  
Wood Material ◽  
H Nmr ◽  
Nmr Relaxometry ◽  
Wood Chemical Composition ◽  
S2 Layer ◽  
1H Nmr Relaxometry

AbstractTwo-dimensional proton nuclear magnetic resonance (2D 1H NMR) relaxometry is increasingly used in the field of wood sciences due to its great potential in detecting and quantifying water states at the level of wood constituents. More precisely, in this study, this technique is used to investigate the changes induced by “natural” and “artificial” aging methods on modern and historical oak woods. Two bound water components are detected and present differences in terms of association to the different wood polymers in cell walls: one is more strongly associated with wood polymers than the other. The evolution of the two bound water types is discussed in regard to aging methods and is related to the structure of the cell wall, especially with the S2 layer and the evolution of wood chemical composition (cellulose, hemicelluloses and lignin). The evolution of hydric strains is also discussed taking into account the effect of aging methods on the two bound water components. The obtained results confirm the ability of 2D 1H NMR relaxometry to evaluate the effect of aging at the molecular level and on hydric deformation. Furthermore, this method shows that it is possible to determine the moisture content of wood without the necessity to oven-dry the wood material.

scholarly journals SYNTHESIS AND CHARACTERIZATION OF HYDROXYPROPYL CELLULOSE-CYSTEAMINE CONJUGATE AS A NOVEL CATIONIC THIOMER WITH LIPOPHILIC PROPERTIES

2019 ◽  
Vol 11 (1) ◽  
pp. 222 ◽  
Author(s):  
Deni Rahmat ◽  
Fikry A. R. Rahman ◽  
Liliek Nurhidayati ◽  
Dian Ratih Laksmitawati
Keyword(s):  
Reductive Amination ◽  
Ph Value ◽  
Thiol Group ◽  
Hydroxypropyl Cellulose ◽  
Scanning Calorimetry ◽  
Swelling Behaviour ◽  
Chemically Modified ◽  
Time Period ◽  
Free Thiol Group

Objective: Thiomers have been known as polymer with mucoadhesive properties. The aim of this study was to synthesize the mucoadhesive potential of hydroxypropyl cellulose-cysteamine conjugate (HPC-cysteamine).Methods: The parent polymer HPC was chemically modified by introducing sulphydryl bearing compound using reductive amination. HPC-cysteamine conjugates were prepared at reaction pH value of 5. The reaction was stabilized by the addition of cyanoborohydride. Afterwards, the conjugate was evaluated for optimum free thiol group, swelling behavior, viscosity and mucoadhesive properties.Results: The conjugates showed maximum thiol incorporation on HPC of 1063.03±64.27 µmol/g. The disulphide groups content was 278.71±32.14 μmol/g. Mucoadhesion studies revealed that mucoadhesion of HPC-cysteamine demonstrated 26 h. The swelling behaviour of HPC-cysteamine tablets increased within the time period of study. The viscosity of HPC-cysteamine was higher than that of unmodified HPC. The thermal profile of HPC-cysteamine and unmodified HPC analyzed by differential scanning calorimetry (DSC) displayed a different enthalpy (ΔH) value.Conclusion: HPC-cysteamine conjugate renders better properties which might be more beneficial for drug delivery system compared to unmodified HPC. 

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