scholarly journals Estimation of the Cellulose Microfibril Angle in Acacia mangium Wood Using Small-Angle X-Ray Scattering

2010 ◽  
Vol 2 (4) ◽  
Author(s):  
Tamer A. Tabet ◽  
Fauziah Haji Abdul Aziz
Keyword(s):  
Small Angle ◽  
Cellulose Microfibril ◽  
Microfibril Angle ◽  
Acacia Mangium ◽  
X Ray ◽  
X Ray Scattering ◽  
Cellulose Microfibril Angle ◽  
Ray Scattering

A Study of the Nanostructure of the Cellulose of Acacia mangium Wood by X-Ray Diffraction and Small-Angle X-Ray Scattering

2011 ◽  
Vol 364 ◽  
pp. 480-484 ◽  
Author(s):  
Tabet A. Tamer ◽  
Fauziah Abdul Aziz ◽  
Radiman Shahidan
Keyword(s):  
Small Angle ◽  
Microfibril Angle ◽  
Acacia Mangium ◽  
Mean Value ◽  
Tree Age ◽  
Crystalline Cellulose ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

The purpose of this study was to develop practical and reliable small-angle x-ray scattering and x-ray diffraction methods to study the nanostructure of the wood cell wall and to use these methods to systematically study the nanostructure of Acacia mangium wood grown in Sabah, Malaysia. Methods to determine the microfibril angle (MFA) distribution, the crystallinity of wood, and the average size of cellulose crystallites were developed and these parameters were determined as a function of the tree age and the distance from pith towards the bark. The mean MFA in Acacia mangium increases rapidly as a function of the number of the year and after the 7th year-old it varies between 6° and 10°. The thickness of cellulose crystallites for Acacia mangium appears to be constant as a function of the tree age after 10-year-old. The obtained mean value is 3.20 nm. The size of the cellulose crystallites was also quite constant after 11 year-old. The maximum value of the width of the crystallites for Acacia mangium was 2.34 nm at the pith region, while the minimum value was 0.290 nm at the bark region. The mass fraction of crystalline cellulose in wood is the crystallinity of wood and the intrinsic crystallinity of cellulose. The crystallinity of wood increases from the 3nd year-old to the 10th year-old from the pith and is constant after the 10th year.

Application of Small-Angle X-Ray Scattering to Predict Microfibril Angle in Acacia mangium Wood

2010 ◽  
Vol 173 ◽  
pp. 72-77
Author(s):  
Tabet A. Tamer ◽  
Aziz Abdul Haji Fauziah ◽  
Radiman Shahidan
Keyword(s):  
Cell Wall ◽  
Standard Deviation ◽  
Intensity Distribution ◽  
Small Angle ◽  
Cell Walls ◽  
Microfibril Angle ◽  
Acacia Mangium ◽  
Cellulose Microfibrils ◽  
X Ray ◽  
X Ray Scattering

Partially crystalline cellulose microfibrils are wound helically around the longitudinal axis of the wood cell. A method is presented for the measurement, using small-angle X-ray scattering (SAXS), of the microfibril angle, (MFA) and the associated standard deviation for the cellulose microfibrils in the S2 layer of the cell walls of Acacia mangium wood. The length and orientation of the microfibrils of the cell walls in the irradiated volume of the thin samples are measured using SAXS and scanning electron microscope, (SEM). The undetermined parameters in the analysis are the MFA, (M) and the standard deviation (σФ) of the intensity distribution arising from the wandering of the fibril orientation about the mean value. Nine separate pairs of values are determined for nine different values of the angle of the incidence of the X-ray beam relative to the normal to the radial direction in the sample. The results show good agreement. The curve distribution of scattered intensity for the real cell wall structure is compared with that calculated with that assembly of rectangular cells with the same ratio of transverse to radial cell wall length. It is demonstrated that for β = 45°, the peaks in the curve intensity distribution for the real and the rectangular cells coincide. If this peak position is Ф45, Then the MFA can be determined from the relation M = tan-1 (tan Ф45 / cos 45°), which is precise for rectangular cells.

X-ray scattering studies of thermally modified Scots pine (Pinus sylvestris L.)

Holzforschung ◽  
2005 ◽  
Vol 59 (4) ◽  
pp. 422-427 ◽  
Author(s):  
Seppo Andersson ◽  
Ritva Serimaa ◽  
Tiina Väänänen ◽  
Timo Paakkari ◽  
Saila Jämsä ◽  
...  
Keyword(s):  
Pinus Sylvestris ◽  
Scots Pine ◽  
Small Angle ◽  
Microfibril Angle ◽  
Thermal Modification ◽  
Crystalline Cellulose ◽  
Angle Distribution ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

AbstractWood is thermally modified by heating and steaming in order to change its properties, e.g., to improve the biological resistance and to increase the hardness of wood. The structure of thermally modified Scots pine (Pinus sylvestris) was studied using wide-angle, small-angle and ultra-small-angle X-ray scattering methods. Modification temperatures varied from 100 to 240°C. No marked changes in the microfibril angle distribution were observed. The mass fraction of crystalline cellulose in wood (the crystallinity of wood) and the size of cellulose crystallites increased above 150°C. After modification at 230°C for 4 h the thickness of the cellulose crystallites increased from 3.1 to 3.4 nm. Thermal modification had no effect on the orientation of the voids, but an increase in the porosity of the cell wall was observed. The distance between cellulose crystallites was approximately 4.7 nm in hydrated wood and a decrease in order between microfibrils was observed at 160–200°C.

scholarly journals Measuring the distribution of cellulose microfibril angles in primary cell walls by small angle X-ray scattering

Plant Methods ◽  
2014 ◽  
Vol 10 (1) ◽  
pp. 25 ◽  
Author(s):  
Friederike Saxe ◽  
Michaela Eder ◽  
Gunthard Benecke ◽  
Barbara Aichmayer ◽  
Peter Fratzl ◽  
...  
Keyword(s):  
Small Angle ◽  
Cell Walls ◽  
Cellulose Microfibril ◽  
Primary Cell ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

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>

In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Matthew Tirrell
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

Small angle X-ray scattering study of porosity variation in a styrene-divinylbenzene copolymer

1981 ◽  
Vol 46 (7) ◽  
pp. 1675-1681 ◽  
Author(s):  
Josef Baldrian ◽  
Božena N. Kolarz ◽  
Henrik Galina
Keyword(s):  
Small Angle ◽  
Structural Parameters ◽  
Two Phase ◽  
X Ray ◽  
Porosity Variation ◽  
Swelling Agent ◽  
X Ray Scattering ◽  
Styrene Divinylbenzene ◽  
Ray Scattering

Porosity variations induced by swelling agent exchange were studied in a styrene-divinylbenzene copolymer. Standard methods were used in the characterization of copolymer porosity in the dry state and the results were compared with related structural parameters derived from small angle X-ray scattering (SAXS) measurements as developed for the characterization of two-phase systems. The SAXS method was also used for porosity determination in swollen samples. The differences in the porosity of dry samples were found to be an effect of the drying process, while in the swollen state the sample swells and deswells isotropically.

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